Roger Feb 12, 2018 · I understand but my truck is 100% factory original with only 20,000 original miles on it. My '88 C1500 with 350 TBI; 700R4 and 2. Dec 10, 2013 · I did install a new Mellings high pressure high volume oil pump to help out with the cam. 50R18- SSBC Slotted Rotors EXHAUST - Custom 5" with 6" Black Aussie Stacks TRANSMISSION-Built by Tim Hecker-GMax 5 Pac -Precision ML Converter -MikeL Pump Rub Wear Plate -Transfer Case Brace PERFORMANCE - 60% Over Injectors- PPE Dual Fueller- AFE Pro Dry S Jul 20, 2023 · I have a 87 Chevy R1500 w/ 350 TBI. After adjusting the idle, turn off the engine a reconnect the AIC harness. org. Someday I’ll do it just to clean it up. -checked Idle Air Controller, good. If your TPS is working properly it will adjust the fuel and the IAC will limit the fuel. Feb 24, 2011 · At idle to 1/4 throttle, the engine runs smooth. It is a 1991 motor using the painless harness. I've changed the Gasket, IAC, TPS, CTS, EGR Valve, Fuel Filter, Ran injector cleaner through it, Tested for Vacuum leaks, Checked Fuel Pressure, reset the air rate screw, and IAC. -checked fuel pressure, good (12psi). You'll hear the IAC screw resetting. Jul 3, 2013 · If the IAC passages are restricted, it can cause it to idle to slow. anything that causes the rpm to increase or decrease, such as a vacuum leak, egr flow, or misfire could result in the PCM changing the IAC pintle position resulting in surging. 1988 was the last year of May 23, 2010 · the idle screw hole has little cover over in the front of the tbi on the side the throttle is on couldnt get picture up sorry. Producing up to 210 hp in factory spec, this engine can also be retrofitted into an older car with a performance carburetor to produce up to 250 hp. Back to the Tech Page Oct 31, 2010 · Alright, i had posted before about my surging idle. These vehicles featured a 350 ci, 5. The three adjustments I made were #1 adjusting initial timing to 12 BTDC, #2 removing the carb, lightly bottoming out the idle mixture screws and then opening them to 1. Any ideas what may be causing this? The plug in Diagnostic reader says all Jan 4, 2004 · most gauges aren`t accurate below 10 psi, some as much as 15. 7 Small Block Chevy with TBI (throttle body injected) EFI system, and swirl port heads. Jul 28, 2010 · I just did the sweep test and the TPS was smooth. Tools required are a multimeter, and a small blade or a knife to slightly nick Jun 13, 2024 · Shut off the engine and reconnect the Idle Control Motor. You need to punch a hole in the plug to pull it out, then you have access to the idle set screw. 6L LBZ Duramax / ZF6 / NP241 with 1 ton solid axle swap) Adjusting the idle Jun 7, 2019 · I recently rebuilt my 1990 k1500 350 tbi and upgraded to vortec heads. For 1986 vehicles, have an assistant place the transmission in Drive and apply the brake pedal, then set the idle speed to 400-450 rpm. It idles perfectly in neutral but when in gear (D) it often stalls. After I adjust my idle, I use a scan tool to insure AIC counts are greater than zero. Under the hood it sounds like its sucking alot of air from the carb but I'm not sure. Adjust the idle speed and Air/fuel slightly to were i'm idling around 850 in park/neutral and idling at 650 in gear. 7, TBI, I replaced my IAC to eliminate the surging I was experiencing when stopped at stop lights whenever the AC kicked on, the new IAC fixed this issue but now Idle RPM are through the roof, I attempted to adjust the torx idle adjustment screw with now luck, turning screw counter clockwise did nothing, turning it clockwise raised RPM even further. You may get some good answers here, for there are a few members who really know factory TBI stuff. Idle surge or idle hunting and high idle. Prior to removal he should have measured it. 1993 Chevy Truck C 1500 Truck 2WD V8-350 5. Jul 11, 2020 · Wait 30 seconds after key on to let IAC close. There is a whole section dedicated to TBI. a carb'd engine? Jan 29, 2012 · I was wanting to know the right way to set the timing on my 87 C10 truck. Start the truck and see if you have the correct idle speed (425 plus or minus 25 RPM in drive and in Open loop. -Rebuilt TBI with kit. Jul 24, 2016 · 1995 K1500 5. IAC valve is used to maintain correct idle speed. After 30 seconds unplug the IAC valve. Its got a 350 TBI and I had replaced the intake on it and now i just need to set timing. If you identified a difference in engine idle RPMs with the Idle control motor connected and disconnected, confirm your hypothesis by reconnecting it and starting the engine again. i have found that the idle when warm and in drive should be about 550 RPM and my truck is sitting at about 250 RPM in those conditions and tends to stall. Its a pain to keep Gm 5. I pull and plug the vac advance line, set the timing to 12 BTDC. so i un screwed the IAC from the throttle body and jumped the pins (i think they were the right ones) and it didnt move at all, but my check engine light kept flashing one pause then twice , over and over so i dont know what this could be a fix for your hard to start flooding condition Oct 13, 2008 · It is a 91 chevy truck with the 350 (5. -changed coolant temperature sensor, and verified proper resistance, good. 85000 miles on the engine, presumably never rebuilt. Turn the screw to adjust the idle speed to 650 RPM +/- 50 RPM. Operation. Start engine. I adjusted the "base idle screw" and it runs a lot better. Ground ALDL terminals A to B KOEO and disconnect the IAC. 7 TBI motor. 12. Turn on the ignition, but don't start the engine. Sep 1, 2014 · The TB is in immaculate shape, and the components are incredibly clean for being almost 20 years old. I have a bone stock 350 out of a 74 nova. Their is a adjustment for the throttle stop but it has a plug in it. I recently took the car to the mechanic to get the throttle body gasket replaced because I didn't feel comfortable taking off the throttle body. Idle speed in Neutral is about 725, in gear it is about 500-550. I have a timing light. Try disconnecting the throttle cable and see if the idle returns to normal. The ECM sends voltage pulses to the IAC motor causing the IAC motor shaft and pintle to move in or out a given distance (number of steps) for each pulse, (called counts). You might need to disconnect your battery for a few minutes to clear the codes and then run the truck again to see what codes come back. It's possible that over time this will burn out the AIC motor. I apologize if I'm thread jacking here, but I could really use some help. Thanks for the tip. Pretty much all issues are going to fall into 4 catagories. There's an adjustment screw concealed in the body of the TBI, which is for the minimum air rate adjustment. Jun 15, 2004 · 1. Amazing how reliable TBI’s are. Nov 26, 2021 · Make certain the thermostat is open when adjusting idle speeds, that cant be overstated. There is no adjustment on the throttle cable - only the minimum air adjustment screw. 7 TBI This is a very easy fix to possibly remedy your idle problem. (ISC actuator must have vacuum applied so that it is not contacting the throttle lever. 032" IIRC) by pushing down on the rocker arm. Checking and adjusting timing specs for your chevy 350 tbi engine may sound daunting, but it’s actually a simple process. May 26, 2014 · Wondering if anybody can help me out. Disconnected spark advance and started up. Jan 12, 2018 · 1990 1500, 350 TBI, I have been tracking down multiple problems on my truck just to get it in decent running shape in preparation for the 5 speed swap I'm doing. The idle should go back to what it was when the idle control motor was last connected. New MAP, EGR, O2, TPS, ESC, distributor and coil. I just rebuilt the TBI and installed all new gaskets. Aug 17, 2002 · Just finished a 350 TBI / 700R4 / 3. Aug 12, 2019 · When I was having problems I bought a TBI rebuild kit but after I found the correct fuel pressure solved my problem I put that on the shelf. Throttle adjust tensionTbi/carb hot-rodding Carburetor and efi conversions1994 c1500 suburban tbi -> carburetor swap finished!. We suggest adjusting the idle to 700 RPM or desired RPM (the throttle adjustment screw is located on the opposite side of the TPS). At 800 rpm, my vacuum fluctuates fairly steadily between 14 and 16. 7L tbi 350 Will Not Idle/Stalls Jump to Latest 11K views 18 replies 8 participants last post by xPosTech Aug 17, 2016 Customer: I have a 1993 chevy silverado. Ran and started fine for a few years. Block the drive wheels, set the emergency brake, and start the engine. hope this helps Feb 17, 2020 · There's an idle adjustment screw on the front driver side of the throttle body housing behind a steel plug. With this at stock location you now can adjust the air screw for best running just like on a carb. This prevents the ECM from adjusting the idle speed while you make your adjustments. Adjust ISC actuated idle speed to 1300 +/- 50 rpm. 11. When I give it the throttle quickly it jumps from 1 to 20. You have to drill out a metal cap which covers the screw (Torx T-15 I think?). 7 TBI conversion 1978 Mustang II King Cobra Road Racer - Holley 650, MSD 6AL, 5 speed, 10 point Roll Cage, 9" posi, fuel cell, custom interior. I've replaced the plugs (ac delco coppers), o2 sensor (ngk), egr valve (delphi - old one was completely shot) and associated hoses/lines. 4 engine. 7L crate engine comes with a 36-month unlimited mileage warranty. Feb 26, 2008 · I bought a 1990 Chevy 1500 pickup several months back. Plenty of power loss. The 059-8758 is an excellent replacement crate engine for 1987-1995 GM trucks, vans, and SUVs. Especially when it's been driven - shut down for an hour - and restarted. Couldn't get the idle to cooperate. Valve Adjustment Procedure for Small and Big Block Chevy After the engine has been thoroughly warmed up the valves may be adjusted with the engine shut off as follows: With engine in position to fire Number 1 cylinder the following valves may be adjusted: Exhaust 1-3-4-8 Intake 1-2-5-7 Nov 8, 2009 · The adventure continues! In all, I have replaced the TPS, IAC, MAP sensor, EGR valve, all vacuum lines, fuel filter, plugs, wires, cap, rotor. i. Please DON’T hit accept until you are completely satisfied with the answer. For 1987-88 vehicles, set the idle screw to obtain 400-450 rpm. It does it sometimes at idle when cold and does it just going down the road at 40-45mph when it gets into overdrive and is running in the 1500RPM range. like a race car or a harley. Everything i have read points to the IAC valve. normal Re: high idle with tbi 350 08-23-06 06:35 PM - Post# 989935 In response to bowtie-badboy well i tryed the reset thing and i dont think it worked cause i herd no sounds . Our Chevy TBI 350 ci 5. in. Yesterday I swapped the entire tbi with a known running truck that did not surge at idle, My truck still surged. All went well except I experienced the engine surging at idle. 1000 RPM is normal on initial startup, but should come down to 700-800 in Park after a minute or so. About your vehicle. Jul 20, 2014 · This is almost identical to the issue I'm having. Save Share In this Hagerty DIY, Kyle Smith walks you through the process of adjusting timing on a Chevy small-block engine. The engine should be at operating temperature for this. You are now going to adjust "minimum air". Nov 20, 2018 · I put a Holley TBI on my '87 with 350. if anyone has experience with this or a link to a helpful video that would be Jun 9, 2022 · You drill sideways towards cap, take a flat chisel after drilling to the cap and use the chisel to knock the cap out sideways. thirdgen. Aug 14, 2004 · If this is the case, you have to set the idle timing to match what the ECU thinks timing is. By continuing to use this site you consent to the use of cookies on your device as described in our cookie policy unless you have disabled them. 4. 1986 Chevy G20 Tow Rig - 5. Jan 8, 2021 · Upgraded Vortec cylinder heads, a more aggressive camshaft, and reprogramming TBI chip to make 300 horsepower or more with a GM Chevy 305, 350, and 454 engine with factory TBI injection. until it smooths out. 6) Turn the ignition off. Insert the clip ends into the ALDL in the 'A' and 'B' pins. It was starting and idling fine, but whenever it was in gear it would start to run rough and eventually die, or if I drove it it would die at stoplights. Recently rebuilt/resealed the TBI, and put in a new distributor and set timing. 4 liter 454 TBI. . The surge is like a whup-whup-whup-whup until I add throttle and rev it out. i have to keep my foot on it for about 5 min. They can be hard to find without a smoke machine. 7 WOT. Reinstall air cleaner and remove the paper clip from the ALDL connector. most likely you have a vac leak or dirty iac . Truck sat for about 7 yrs and am getting it road ready for my nephew. com, Super mechanic here. If you have access to a scan tool use a hook up for a 1990 350 cu. Sep 16, 2023 · What should the timing be on a 1992 gmc Yukon 57 tbi after disconnecting the computer? The timing should be set at 0 degrees. Jun 20, 2006 · TBI is surging with steady part throttle in open loop when cold. to/2Yy2Vacnew IAC valve https://amzn. 7 350 TBI. I just replaced the Idle Air Control valve because i was told that could be it. Jun 27, 2011 · INJECTION (TBI) This bulletin defines the controlled idle speed and minimum idle air rate specifications for 1987 and 1988 model year trucks for all engine applications with TBI. 6. I cleaned the balancer, made a white mark where the timing line is and ensured I had set the timing at, in the end, 5* BTDC. Problem is when I first start the truck in the morning (or after sitting awhile) and go to take off, it will chug, bog out, or barely go for a few seconds, then snap out of it and run fine. It runs fine but I can't get the idle to drop. When in gear it WILL stall without pressure on the pedal and when trying to accelerate it spits and sputters and will not allow take off in any form. The tbi has been cleaned and everything replaced to include the TPS. Be sure and pay attention to the detail about having the truck fully warm and IN GEAR when you set the idle. Start engine, adjust the base idle screw on the throttle plate until about 500 rpms is reached then verify the TPS voltage is at . 8) Jan 2, 2021 · As primitive as these first computers were, the Chevy engineers worked this all out on slide rules and fingers and toes. But the car died once when I was slowing down, so I thought I'd try it out. Things t Sep 22, 2009 · when cold, it will start and idle but pretty rough. 5TD 4l80e with a couple of mods May 10, 2009 · there is no idle position sensor, there is an iac,idle air control stepper motor that is located on the tbi,throttle body injection unit,there is a tps on the tbi as well,throttle positioning sensor, so if you are looking for an idle adjustment it is not possible to just turn a screw, first you should check for vacuum leaks,a vacuum leak will cause the idle to go up,the block learn will also Sep 3, 2007 · Re: 95 Chevy S-10 4. I have a 1995 Chevy G30 with a 350 and TBI. TBI base idle adjustment Chevy 350 Hello and welcome to Just answer. it'll run like that for about 5 min. Dana 60 SAS, stage 1 160cc injectors, T500 High Pressure Oil Pump, TS 6-position chip, full 4" exhaust, intake, 285 Falken Rocky Mountain AT's, boost/EGT/trans temp pillar gauges, etc With no air allowed to enter the IAC's port, a warm engine should idle extremely low. 5) Adjust the idle stop screw so the engine idle speed obtains 550rpm in drive (auto trans) or 650rpm in neutral (manual trans). Apr 4, 2012 · 1986 Chevy G20 Tow Rig - 5. Dec 2, 2011 · 88 chevy k2500, started as reg cab lb, now reg cab shortbox, sas 17'' of lift, 52'' front springs f. The truck has 190K miles on it and runs fine other than a misfire. Reconnect IAC valve. Dec 25, 2005 · 350 TBI acceleration problem Engine & Drivetrain 1995 Chevrolet 2 Door Tahoe (6. it would help to have a scanner that could read the data stream and see where the IAC counts are. here's a link to th Jan 20, 2014 · How to set timing with timing advance connector disconnected chevy K1500 truck. Mileage is decent at 18 plus. I have a tachometer gauge I installed. It should have a cover unless someone has messed with it. I followed the idle adjustment procedure (Jump "A" and "B" on ASDL, turn key on, wait 30 seconds, diconnect the IAC harness, fire motor and adjust throttle plate for minimum idle). THIS I Oct 20, 2015 · I'm back with more problems my 350 tbi will not idle without making a loping noise. Unplug IAC and start engine. 5 turns out. Drives great. If the computer does not see a voltage reading on the TPS (Throttle Position Sensor) that shows it is at idle, the computer will not move the IAC. It goes away after I drive it for a minute or it warms up to closed loop. Throttle Body Injection Fuel Pressure Nov 6, 2014 · The 1947 - Present Chevrolet & GMC Truck Message Board Network > 47 - Current classic GM Trucks > The 1973 - 1987 Chevrolet & GMC Squarebody Pickups Message Board: 87 Chevy 350 TBI low Idle issue Apr 11, 2011 · Re: 87 Silverado 350 tbi idling rough « Reply #9 on: April 14, 2011, 07:52:09 AM » Do you have an idea how long you did not have a check engine light?Some of those codes could be old and are not an issue still. also make sure your running the correct temp t-stat if its to cool your rpms will be higher and your temp sensor could cause high Sep 21, 2006 · I have a 1988 chevy half to with a 350 tbi and it idles low how do i adjust the idle - Answered by a verified Chevy Mechanic We use cookies to give you the best possible experience on our website. Typically 2 problems. -checked distributor bushing play, good. Some people, however, have reported rich idle that they cannot tune out due to the TBI injector firing strategy with high pressure stock injectors or with the 454 injectors. Disconnect power from the ECM for at least 10 seconds to clear codes (in case any are present) and reconnect the IAC electrical connector. I’m trying figure out what changed to make the idle go too high. By running in drive I can bring vacuum up into the low teens but lose a couple MPG. Once you find what it needs to be set at, just set the timing at idle just as you would normally would. 3. Thanks again for all the help y’all! Aug 26, 2009 · The only adjustment for "idle air" is a screw in the front side of the throttle body. My first guess would be the IAC is bad. I was having touble with fast idle and a hesitation with accelerating at low speeds. Jun 22, 2018 · Insert a T-30 size Torx driver into Idle adjustment screw that is located behind the plug removed earlier. It is not intended to adjust idle speed, per-say. It's intent is to set "minimum air". Now Im trying to correctly reset the Idle screw. Every thing is new Ac Delco. 7 TBI conversion 1991 Chevy Suburban 1/2 ton 2WD w/ chevy SBC 350-3/4 ton Customer: 1989 Sliverado Blazer, 5. Jun 4, 2021 · When you changed the Idle timing, did you change the idle RPM? What's your Average cruise RPM? My mild 355 engine (signature specs in the Camaro) is close (9. If the TBI gaskets are more than 3 years old replace. I have a little update. 6 volts WOT. Apr 18, 2022 · resetting the timing on a tbi chevy gmt400 After trying several other fixes I finally diagnosed and repaired the problem part. Turn T20 screw clockwise to raise idle to desired RPM. Setting it + or - wont matter much, as the computer will run what the Chevy boys told it to do way back in the day including adjusting out your silly attempt to fool it. Nov 25, 2014 · Base idle is set by the PCM using input from various sensors. -new gaskets for TBI. At the beginning of this summer, I tried raising the idle a little bit for more AC performance, not realizing that the IAC would just bring the idle back down. I replaced the Idle Air Control Valve and the idle seemed to be rather steady in park and gear for the past 4 months. 5 comp ratio 193 tbi heads Summit 1103 cam Stock bottom end Holley street dominater intake with a summit 650 vac sec carb 06-06-09 01:32 PM - Post# 1712124 Hi, I have an '87 chevy 3/4 ton 4X4 truck with a 5. Tbi to carb swapWork annular carburetors discharge do carb demon boosters tuning flow Carb tbi swapTbi carb swap chevy. Mar 19, 2011 · L05 TBI 350 Idle Air Control Valve Problems, Need help calibrating. We hope to develop and understanding of the location (addresses) and function of all the tables in […] Apr 2, 2023 · modify your Oem fuel pressure regulator on gm and Chevy TBI units. Jul 23, 2008 · I'm seeming to have quite a bit of trouble adjusting my timing/ idle speed. Setting the TBI idle speed: Two settings to double check on the TBI are: 1) the min. Nov 25, 2016 · Between your TBI and distributor you have a vacume line leading to a TVS switch. Unplug the IAC valve located on the passenger side, rear of the throttle body. Apr 15, 2018 · Truck is a 94' Yukon, TBI. The exact setting is on the emissions label on the radiator shroud, but in What people like about TBI is its simplicity with only a few sensors is also one of its biggest downfalls. Had fuel pump and sending unit replaced, fuel filter, map sensor, coolant temp sensor, EGR, IAC motor, TPS. 7L Jan 7, 2015 · Vehicle: 1990 c1500 with a 350 tbi/700r4 Problem: High idle at cold start (around 2000RPM) High idle when warmed up (around 900-1100rpm) Slightly rough idle when warm. 7L 700r4 2008 BMW 335xi coupe, 6 speed twin turbo idle speed” is. 3 Powerstroke diesel. To adjust the TPS, attach a digital volt/ohm meter as shown in Figure 4. 7L 350. Oct 4, 2023 · Order a Chevy TBI 350 ci 5. 7L 350 TBI unplug the computor (tan/blk wire on the passenger side firewall) then run a timing light, set it at 0, and if it falls on its face on a full throttle start, advance the distributor about 5 degrees counter clockwise and test again. 2. It doesn't always do it right away, unless the AC is on. 2 idle 13. I have had this truck for about 3 months and the idle is to high . Jul 9, 2017 · To recap for my Chevy 350 dying at idle. You may very well find an answer there. Vortec heads or other aftermarket Fast Burn heads require less total timing because of the fast burn chambers (makes sense). Idle Air Control Tools needed: Torx bit # T-20 Paper Clip Small Punch Take the paper clip and open it up and form it into a big "U" shape. If the idle speed is out and timing etc are in, then adjust using the idle adjustment screw. I did not change the distributor or ignition module. just stalls. to/2YXCFkRTake out the iac valve, clean the nasty gunk off the part that moves i Apr 22, 2011 · I have a 1992 Chevrolet K2500 350 tbi that idles high about 1200 to 1500 rpm sometime's will idle about 800 rpm. Aug 15, 2022 · About Press Copyright Contact us Creators Advertise Developers Terms Privacy Policy & Safety How YouTube works Test new features NFL Sunday Ticket Press Copyright May 27, 2019 · changing out the seems like forgotten idle air control on a chevy tbi Feb 6, 2009 · Wait until the idle stabilizes, then check and adjust the idle speed as necessary: For 1985 vehicles, set the idle screw to obtain 500-600 rpm. 7 tbi. The stock TBI adjustment screw was blocked off, but you could drill out the plug Aug 16, 2010 · TBI is capable of supporting engines with 360+ hp with FP/tuning/injector upgrades. I have played around with the idle speed and 16 is the most I can get. 7 TBI stalling out when put into drive or reverse gear as well as stalling at idle and or sever hesit Apr 3, 2023 · UPDATE, after rebuilding the TBI unit egr isn't moving at idle must have been a vacuum leak. Additionally, step by step procedures are provided for performing the controlled idle speed check and the minimum idle air rate check. When i first start the truck it slowly rises from 1000 to 1500 rpm then comes down after five minutes to 1000 rpm then when i drive it for a few minutes then it starts idling at 1100 rpm when the truck is in drive. sounds lumpy. Performance otherwise fine, no stumbling off idle or missing under load or revving in neutral. Got timing roughly set around 0. I too agree on the air leaks. 1987-1995 Chevy Idle Air Valve replacement to fix Idle issues on the 5. This is likely ~10, but you will need to know exactly what it is so that the ECU can properly control total timing. We will see how this compares to what the “target idle speed” is set at in the chip. While idling it's not like a heavy misfire just randomly misfiring more like a light stumble and under load it feels under powered and sometime it's like it cuts out completely for a second or 2 then it picks up fine the motor is a brand new crate engine not even 6000 miles 02-23-10 03:57 AM - Post# 1867778 In response to wlfee69 Welcome to the site. Now, go remove the connector from the IAC. 78 volts at closed throttle and went to 4. Jan 11, 2024 · I do not think I had any leaks around the TBI area. Then set your base idle speed. 7) with TBI. 2 with the Howell EFI kit which is based off a 4. 1994 GMC K1500 with a 5. bbc , 79 dana hp 60 chevy outers, 14bolt ff spooled divorced 205 and cut 40'' gumbos 1998 k3500 gmc crew cab dually L65 6. I would suggest a comprehensive compression test with all plugs removed recording all pressures and then repeating the test on each cylinder after adding a Apr 8, 2018 · Best Throttle body cleaner https://amzn. May 31, 2014 · Hello I'm new here and I need some help with my engine at idle it shakes it won't smooth out I don't know what to do Here is the specs of my engine 350 . 1. Before adjusting ISC actuator you must first check the minimum idle speed to be within specifications. The throttle body gasket had broken and was letting in too much air caus Sep 9, 2019 · Removing the hardened, tamper-resistant cap from the TBI base and adjusting base idle to 500 RPM in drive (with the IAC air channel in the TBI base temporarily plugged and ignition timing set to zero with ESC bypassed) will benefit idle quality and off-idle driveability issues and also help with the standing wave in the belt (that I suspect is Jan 20, 2018 · My mechanic did the following and the stumble at idle still has not gone away. This will apply mostly to 1987-1998 vehicles with Throttle Body Inje The ECM controls the idle, NOT the throttle plate position. I had already done a tune up and replaced most all parts recently, so decided to adjust idle. May 31, 2023 · How To Check And Adjust Timing Specs For Your Chevy 350 Tbi Engine. The Holley TBI has an open idle adjustment screw, but just turning it, wouldn't keep the idle steady and wouldn't raise the idle when cold or a/c was on. There is a Torx screw on the Feb 11, 2005 · Checking fuel pressure is definitely a first step in troubleshooting a bad idle, especially with a TBI system. From your info, you have a bad diaphram on the brake booster. THEN see what you controlled timing is. Mine was out of adjustment. Feb 23, 2010 · RIG-2002 CC/SB 2500HD SUSPENSION-Rancho 4 in. Have two new fuel injectors which are not on yet however spray pattern looks decent on current ones and both are working. how to set ignition timing on tbi 350 engines. 7 / 350 tbi throttle body -cleaned & matched injectors Removing idle stop cap from a gm tbi and adjusting the idle Idle speed throttle body screw mixture tbi stop adjustment injection 1989 autozone fig cap minimum awl carefully pierce pry access Ac102 ac1 new idle air control valve for chevrolet blazer tbi gmc Changing IAC Valve on a 1987 R10 to fix a idle issue. Installed stock rebuilt engine a few weeks ago. Another TBI motor found in trucks was the 7. Post: TBI idle adjustment question (Topic#189758) spiderhole Contributor Posts: 292 1988 Chevy K1500 5. When i hook the vac advance back up, idle speed in park shoots to around 1200/1300 rpm. In this video, I will show you how to set the base idle for your Chevy or GM V8 engine. Replaced most of the vacuum lines. Hagerty’s DIY series is your handy-dandy, ea Feb 13, 2021 · Both cold adjust methods are correct but, I agree with Ray, you only go 1/2 turn after zero lash. The ECM sets idle speed by driving the "air idle control" solenoid in and out, as required. idle air setting, and 2) the base commanded idle speed and IAC counts. I read somewhere that if you remove the IAC valve from the throttle body but leave the electrical connector connected and turn on the ignition, the valve should cycle. Current issue, Backfiring at idle and when rev remotely hard it acts like it wants to stall but feather the throttle it will rev but backfires through the intake and stalls out timing is dead zero, acting like its hitting and missing. I have checked all vacum lines and replaced the oxygen sensor on the exaust, also replaced the intake manafold gasket and the Idle air control IAC, I have run OB1 diagnostic and only code 12 present. 58 volts, if not you will need to Jun 20, 2020 · Set your timing to zero degrees with the EST bypass wire disconnected, then reconnect the EST by pass wire. Jumper the A & B connections on the diagnostic link with a paper clip or what not. Jan 6, 2011 · warm up the engine to operating temp. adjusting minimum air should not be required unless someone played with the idle adjustment . 7 cruise and 12. This may be the root of your issue, incorrect adjustment procedure. com/watch?v=MX3vsRDfKJg Programming 101 Bruce Plecan The Programming 101 project analyzes GM OEM fuel and ignition management issues. You can use a late 80’s or early 90’s GM TBI definition. It seems if I could tweak the throttle stop a half a turn it would cure the problem,but the manual says it's not adjustable. it idles around 1500 to 1800 rpm and it is tearing the transmission apart. May 15, 2006 · You will need a timing light with the adjustment knob or a balancer with timing tape to see 40 degrees. Jun 21, 2021 · Base starting point is installing the new idle screw to the same point as the stock set screw was at. 3L TBI - Idle troubles Good Evening dgoad, it is not uncommon when engines have vacuum leaks to find exhaust valves get a little burned, which could well be your problem. Oct 17, 2017 · Checking and adjusting the TPS (throttle position sensor) on the 91 GMC C3500 dually with a 454 big block V8 7. Unplug the idle air control unit (IAC). Insert a T-30 size Torx driver into the Idle adjustment screw that is located behind the plug removed earlier. If this is clogged with oil it will tell the distributor your engine is cold. This is a follow-up video to my question about the GM 5. Fire up the engine and using the idle adjustment screw somewhere on the throttle body, adjust the idle to where you want it. I have spent a month cleaning and overhauling. I run a high volume oil pump in my small block, at idle when it`s hot, the gauge reads zero, but at 650 rpm idle speed, that`s not turning very fast, and the cam is going half the speed of the crank, so that puts it to 325 rpm, so it`s going to be low at idle, as long as there isn`t any death knocks or loud rattles, I don`t worry Mar 6, 2013 · 10. and still have issues while idling. shut it off and jumper A and B terminals in the ALDL (connector under dash) then turn on key and go under hood and unplug the Idle Air control. adjustments require a throttle Dec 20, 2004 · DIsconnect the IAC with Key on, then start vehicle. Username Post: TBI idle adjustment question (Topic#189758); spiderhole Contributor Posts: 292 Loc: Radnor, PA Reg: 09-22-07 10-18-13 11:34 AM - Post# 2392067 In response to someotherguy Thanks for the welcome Richard. Wait 30 seconds. Couldn't find the problem. We have tried adjusting the distributor to set the idle but it seems to have no affect. -changed fuel filter. Idle issues has to be one of the most common issues that I get contacted about. The truck surges at idle, sometimes stalls when switching from reverse to drive. Set the idle speed by adjusting the idle speed screw. Consult a service manual or see below for any check engine light code definitions. how to use a timing light - https://www. When tightening to zero lash spinning the push rod is OK but you're at zero lash when the push rod is against the lifter, you should be able to feel it move up and down a little against the spring inside the tappet (~. Idle tbi adjustment gm. I replaced every sensor and electronic component, rebuilt entire TB including replacing injectors and regulator, checked fuel pressure (was steady at 12 psi). Is their anyway to lower the idle on a throttle body. Sep 22, 2008 · I just fired up the new Chevy 350 TBI in the FJ60. With a carburetor, if you need more idle speed you just turn the curb idle screw clockwise and this opens the throttle blades to allow more air into the engine. Check and clean the air idle valve. 5. The engine idle speed is controlled by the ECM through the Idle Air Control (IAC) valve mounted on the throttle body. Think of it as sort of an idle speed screw, though you can't really treat it that way. May 9, 2009 · Current truck: 1996 Ford 250, 7. You need access to this when you reset the IAC. OBD2 read out will show idle however this idle is based on both new idle screw and air screw settings. I can time the engine to 0 degrees with the ecm wire disconnected and it runs good at idle, however, when i turn the truck off, unplug the battery and connect the ecm wire, the timing just stays at 0 degrees and doesnt advance it like it should. I keep thinking that I should rebuild a 25 year old TBI on principle but it runs so well I hate to mess with it. Idle. 73's has 20 inches of rock steady vacuum at an idle in Park. 13. i have seen where to adjust the idle on the TB but dont know how to get by the cap on it. It basically almost dies out, and then surges back to life (probably a little higher than normal idle), then repeats continuously until you apply some throttle. I know your supposed to disconnect some wire, need to know where the wire is at. Is tnhis normal for TBI vs. Cruising on flat level ground in OD at 55 I only see about 7-10 inches. Lift -Bilstein Shocks -Tie Rod Sleeves -Moto Metal 957 wrapped in Toyo Open Country M/T 35x12. Jun 29, 2007 · Keep in mind, if you adjust the idle too high, the ECM will try to lower it by extending the AIC pintal. Turn the key to the “RUN” position with I thought the idle was low. -new air filter. 90 Chevy K2500 350 motor TBI. then it smooths out and idles at around 1k rpm or slightly higher. Reconnect idle air control unit (IAC). Jul 11, 2024 · This page is dedicated to the owners of these vehicles equipped with GM's dual point fuel injection (model 220 tbi). The linkage is tight, but not high-sprung, and the cruise control cable has a little play so it is not causing the high idle. You’ll need a timing light, a wrench, and a basic understanding of timing marks and procedures. WHILE THE KEY IS STILL ON. The “minimum idle speed” must be less than the “target idle speed”, otherwise, during normal operation, the IAC pintle could bottom out on the air passage seat of the TBI, and damage will occur to the stepper motor of the IAC control. May 10, 2024 · Tbi carb swap How do carburetors work? 350 chevy barrel tbi carb. The truck also has stock pistons, distributor, crank, and tbi. Remove vacuum hose on ISC actuator on warm engine. The cruise cable is the other connector on that lever. Looked everywhere for how to set it. The TBI mechanicals were nice and snug, nothing seemed worn out. May 8, 2005 · Not sure if there are many TBI experts here, but if so can someone pls explain what might be happening? This is related to the 350 TBI in a 93 K1500 Silverado. Turn off engine and disconnect the negative battery terminal from the battery. Jul 22, 2016 · I have a bone stock 1977 Chevy c20 custom deluxe 2 1/8" dual exhaust with old glass packs 5. This is done to control idle speed electronically. This was quite bothersome descending hills in low range/first. It started at . I had problems with random (searching) idle speed and stalling when clutching after being at speed (like slowing down on an off-ramp). I found it in a guys yard where it had been for 2 years. Didnt change a thing. if it's warm, it won't idle on it's own. Start the engine. Refer to SPECIFICATIONS/IDLE SPEED. 7L Chevrolet truck. Plugged the Apr 17, 2016 · What you adjusted was the throttle cable. 7l 350 4 bolt mains with th400 transmission and the original stock 4 barrel quadrajet carburetor. yet i still have an extream high idle problem, any sujestions Jun 9, 2017 · This is a small stepper motor that controls the amount of air that is by-passed around the throttle blades. But you also need to check out www. A rough idle in a 1994 Chevy 1500 350 fixed using basic tools! If the video was helpful to you be sure to like and help out the channel, thanks! Sep 15, 2017 · Hi I have a 1991 chevy Silverado that just started about a week or 2 ago misfiring randomly and cutting out under load. Key off, remove jumper wire, and plug IAC back in, and Mar 5, 2004 · Most but not all were non roller blocks with similar power numbers to the LO3. The TBI motor also came in a 350 version in Chevrolet Caprice Classics. My AFRs are 13. 6 comp, 230/236 cam) to your 383 specs and its a carb. I had not tools or experience to tell me this. Look at the area on the TBI just ahead of the throttle crank arm. 8 Atlas II transplant last Sunday. 3 system. 30 over Flat top pistons 9. Chris for a GM TBI application to read the data, or to check for stored codes. We have had my truck running quite a few times before, but every time it had been unsuccessful in its idle. This video demonstrates how to test a TPS on a 1994 Chevy C1500 with a 350 TBI. youtube. Adjusting the idle correctly takes a long time- it sure as hell aint no 5 minute deal, its gotta run a long time. 7L 700r4 2008 BMW 335xi coupe, 6 speed twin turbo Jun 2, 2008 · My father in law's '91 Chevy was running poorly, so we put new plugs, wires, cap and rotor on it, and it's running better, but it it still surging at idle. Dragged the CJ-7 up to Northern California and ran the Rubicon last week. Nov 22, 2001 · This is a non chevelle question regarding my 87 burban with TBI. 350 5. Jan 12, 2003 · Re: Timing adjustment on \'94 Chevy. Although just a small number of cars were equipped with tbi in 1987, this changed very rapidly in 1988 when it was introduced on the F bodies (Camaro and Firebird) and expanded to include the Chevrolet Caprice, Monte Carlo and the truck lines as well. It May 5, 2004 · I've got a Jeep 4. Several EFI DIY’erst are focused the GM 1227747 ECM, a TBI system, used in 4/6/8 cylinder GM trucks and Vans from 87-91. 7L crate engine online today. This was a big block engine but its throttle body can be implemented onto your small block set-up. My timing is 16* idle, and 36* WOT (36* all in at 2800) cruise is about 26*. Aug 22, 2018 · ive been doing my research lately and i am still left with one question. Dec 11, 2013 · My 95 350 TBI was getting about 30% more fuel than it should at idle (data logs showed this). I have a 1991 K2500 with the 5. All of my reading says do not knock out the idle adjustment cap to ajust the idle. ) See image VIEW A. So, the truck is a 92 k1500, has 20,000 miles on the new GM crate 350, new throttle body, rebuild trans about same time eng was put in. qkzx mwcsfxoz fjgwpip uzp iwkmlhkg ypti vzsiy iqtixb ixr skjle