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• 350 tbi low idle problems. 5~ PSI. It doesn't always do it right away, unless the AC is on. Dec 11, 2013. Twist and pull the vacuum off of the bottom of the air cleaner and lay the air cleaner aside. You can probe dark blue wire on TP sensor. I have a 1994 GMC Sierra 4x4 with the 5. Here is my problem, at idle the oil pressure drops between 12-17 psi and a rattling noise occurs. Its not to bad when you are just off idle driving around, but when you give it about half throttle it doesn't pull at all. Now go and remove the connector from the IAC. I have replaced the temp sensor, starter after it locked up a week ago, and the alternator the day before yesterday. AUTOMATIC. #1 · Apr 1, 2008. Revving seems normal. Ran better, but still stalled. The computer is commanding the fuel to lean out I assume because it is sensing it is running rich. 1991 Suburban said: My truck is a 1991 V-1500 Sub, 5. 7L 350 TBI (Rear 2WD) is stalling and/or having very rough "chugging" and power surges during very low rpms when I initially start accelerating, in reverse, or coming to a stop. Feb 20, 2012 · Anonymous. Feb 17, 2005 · I have had problems with my headers damaging the wires due to heat. My brother named him The Golem, hence my username. Check Vacuum Lines for Leaks: A vacuum leak in the intake system is one of the most frequent causes of idle surge and stumble. It seems low, like fluctuating between 500-900 rpm. -changed fuel filter. Last GM 350s, Vortec 5. #1 · Dec 31, 2010. Bogie. Black is a ground. This could explain your surging idle. #Lemanster: Our Ultimate Road-trip Cruiser Build! Jan 8, 2021 · This cam is designed specifically for the TBI 350 small-block and specs at 194/214 degrees of duration at 0. It has 200K on it. Dec 10, 2013 · 1990 Chevy 350 TBI wont idle. At the exhaust, the best way I can describe the sound is like "chuff chuff chuff chuff" However, I've pulled the plug wires one by one and it only gets worse, like a true dead cylinder. 60mxer Discussion starter. The engine is a 350 tbi with 700r4 transmission. First, the fuel pumps are extremely picky and prone to fail if run out of fuel. #1 · Jul 16, 2004. hello 3 years ago i started this project. it idles a little rough when cold but not too bad when Mar 12, 2009 · Change to a heavier straight weight oil say 40 or 50, if the pressure comes up everywhere, it's probably a leak that's internal to the pump, a filter failure, the relief valve hung up, or excessive bearing clearance. When it does hold an idle, it stalls right when I put it into gear. When it does stay running, i can disconnect and reconnect the CTS and everything will go back to normal. There should be a grounding lug on the box. • Erratic idle. Feb 5, 2011 · 8697 posts · Joined 2010. Sometimes it is no big thing, sometimes pressure/volume problems arise. When it gets to operating temperature and the idle drops more it is more noticeable. I just replaced the Idle Air Control valve because i was told that could be it. So far it has a new distributor (for an unrelated problem), idle valve, throttle position sensor, knock sensor, temperature sensor, fuel filter, plugs & wires. #1 · Oct 19, 2012. engine should be around 4. CP8071. Here are a few potential answers: 1. Poor idle can be caused by about a hundred different things. 7L tbi 350 Will Not Idle/Stalls. Oct 19, 2009 · Chevy Mechanic: John. I put everything from the old engine on it except I replaced the factory intake manifold with an Edelbrock TBI Performer, replaced the EGR valve, and replaced the radiator and installed electric fans. Runs good but after warmup at idle it surges probably 300-500 rpm. -checked fuel pressure, good (12psi). It seemed to be struggling with idle so I turned the connector for my IAC 180 degrees and tried again. AFter it warms up it starts to backfire (not loud backfire more like small pops) out the exhaust when idleing, It doesnt doesnt backfire when running down the road mainly just at idle. The truck still shifts at the normal rpm and drives at normal rpm. When started cold the engine should start without pushing down on the gas pedal. Voila it ran beautifully! Today I replaced my O2 sensor and both CV axles. After searching, learning, and testing different components this what I got. Apr 3, 2023 · 350 Tbi rough idle overfueling. Stock fuel pressure should be around 9-13 PSI for GM TBI. Nov 8, 2009 · Recently bought a used 92 Sub with 5. The problem I'm having is intermittently, 1-2 days a Jan 4, 2004 · Low oil pressure at idle on rebuilt 350. This usually causes an extremely rich mixture or flooding and no starts. Oct 20, 2012 · 183 posts · Joined 2009. PCV valve seems to be buzzing, not sure if this can cause this problem but just seems odd. If it does not do it in park or neutral, it could be a number of things. Start the engine. I replaced the plugs, wires, cap, rotor, and air filter. I've tried everything that I could think of that could be the issue and I don't know what could be Feb 22, 2016 · The problem that I seem to be having is the truck misfires at idle only. If it doesn't come down, it may be suspect. 25 at idle position and about 4. I have spent countless hours going over the engine looking for vacuum leaks and believe every thing is OK on that front. The engine is revving up and down when I come down to an idle. As you can tell, it doesn't deliver May 20, 2010 · If I remember correctly, when you hook the by-pass wire back up and recheck timing, it should be sitting on about 10 degrees advance. has full power while driving. Apr 14, 2024 · 1. 350 TBI. My 1990 GMC 1500 with an automatic 5. May 5, 2004 · C. 1990. #10. Me and my dad had just gotten done rebuilding my Chevy 350. 8 posts · Joined 2008. Truck Model. With key on, slowly open throttle while observing meter reading. OBS Enthusiast. Any ideas? Dec 28, 2014 · I have a 1987 chevy r10 with a 350. I adjusted the "base idle screw" and it runs a lot better. Just low idle at. After replacing the fuel pump, filter and ignition moduel, I still have a problem with it idling very low rpms and(but runs verry smooth) but becomes rough after a couple of seconds at idle and tries to quit. Dec 31, 2010 · 5568 posts · Joined 2004. At idle in park, the engine revs up Nov 19, 2022 · Engine Size. Voltage should be less than 1. #1 · Apr 4, 2022. Having one cylinder not firing would cause the engine to idle pretty low and then with the extra fuel it would die at idle. Engine Size. 442-inch lift. #1. 1987, 1978, 1976. Sep 8, 2010 · 1990 tbi 350 no power. I've looked in all the forums and I find people with a similar problem to mine and have tried their fixes with no luck. Don't drive it until it's plenty warm. The IAC (and computer) control the idle speed. The truck. #4. Plug the vacuum lines with golf tees or other suitable item. The IAC (Idle Air Control) controls the air passing through a throttle pate bypass passage. Now, when I crank the engine, it struggles to start, and when it fires it immediately goes to redline and stays there. Alright, i had posted before about my surging idle. May 31, 2023 · The timing specs for a chevy 350 tbi are 0 degrees btdc at idle with the electronic spark control unplugged and 10-16 degrees btdc at idle with the electronic spark control connected. Which appears to be normal. That shouldn't cause idle problems. Oct 19, 2017 · 95 GMC TBI 350 accelerating problems. Dragged the CJ-7 up to Northern California and ran the Rubicon last week. 7L tbi and timed it. turn ignition switch to on for 10 seconds , do not start 2. which is bad but thats not the main problem. To do this, find the ground wire (black, about a # 10 wire), remove it from the block, clean and re torque. If it is stuck open, it is a larger than necessary vacuum leak. Aug 18, 2002 · TBI surging at idle, Help! Just finished a 350 TBI / 700R4 / 3. Jul 16, 2017 · A leak there will cause a higher idle than the IAC can compensate for. If voltage is good, check that you have a good ground from the ECM to the block. Feb 3, 2007 · I've spent countless hours trying to troubleshoot my 89 350TBI engine in my 240,000 mile otherwise incredibly dependable Suburban The engine runs like crap, ECM says code 44 - lean condition. So recently my 1995 K1500 pickup 350 auto with 162k miles can't hold an idle and stalls after idling for a short amount of time. Jun 9, 2017 · Do this by slightly by turning the primary idle speed screw out (counter-clockwise) about a half turn. 1. The new motor runs fine, but one thing I now notice is that the idle speed seems slow. I have a 93 k1500 350 TBI and when i got her back on the road a few weeks ago i noticed the engine bogs out at stops and has a slow response time after about 45. RECOMMENDED 350 TBI MODS. I figure this has been discussed before but I haven’t found a definite answer, I’ve got a 1987 Chevrolet V20 with a 350 tbi paired to a sm465, and it idles around 2000 on a cold start and comes down to around 1200-1400, I’ve never got it to get Jun 20, 2006 · Jun 19, 2006. Any ideas on what's wrong? (It's got an SM-465 in it if that helps) movietvet. 2 with the Howell EFI kit which is based off a 4. There are various actions you can take to attempt and fix the problem if your TBI-equipped car exhibits idle surge and stumble. Start cold and let it warm up. All sensors on the throttle body are new, tps, map sensor, iac, new fuel pump, new fuel filter. I have read that steady, low vacuum readings indicate possible vacuum Feb 2, 2024 · Every cold start until the engine warms up it runs not good at all. its a 1990 chevy k1500 with a 350 tbi engine. 7 TBI with 306,000 miles on it. TBI is surging with steady part throttle in open loop when cold. Jan 2, 2004 · If it fails it can cause rough idle due to incorrect fueling from the ECM due to the sensor giving incorrect data. 20,000 MILES. These are attached to the bottom of the air cleaner. I’ve had a previous thread and it went all over the place, I’m here now because my problem is back and I never got a fix. 5L rough idle, sputter, almost stall. May 7, 2020 · I have a 1992 k1500 5. 00 V. So I begin every project with a new upgraded Dec 21, 2017 · It was idling a little slow, but no stumbling or backfiring through the TBI. 2WD. 2. Jul 17, 2012 · 32K views 19 replies 11 participants last post by cobalt327 Jul 22, 2012. Nov 7, 2003 · The 1st problem is the oil pressure reads 15 at an idle, warmed up and up to 35 when running. Mar 24, 2023 · 4. So I'm getting a light "surging" with my engine. The sensor voltage with key on. Has new cap, rotor, temp sensor, plugs, fuel pump. Carb and vacuum leaks are the main cause of this issue most of the time. Problem came back for about 30 seconds then ran smooth. V 2500 Suburbans. It's always when I'm half throttle at cruising speeds it will surge 2-300 rpms and it's annoying as fuck. Bad valve cover gasket. Symptoms: • Seems to run OK when cold but not what it should. Oct 30, 2005 · Sounds like my (departed) 200K mile+ 350 TBI Suburban-I think mine had bad cam bearings. It sounds like an IAC problem to me. When it is warm and you crank it, smetimes it will Nov 24, 2010 · 5. It won't idle on its own, you have to step on the gas to keep it going. Truck Year. It's not throwing any ecm codes. I know it is a tbi motor but it almost acts like it needs a carb float adjustment! You have to pat the accelerator in 2nd gear to keep it from bucking like a wild horse. 7 TBI that's just gone through a frame up restoration, drive train is all brand new, fuel filter, fuel pump, TBI Rebuilt Kit, etc. This was quite bothersome descending hills in low range/first. Only thing that appears to help is manually pinching egr shut and it idles great but hesitates to rev with it pinched May 8, 2010 · Here goes. The injectors are spraying contant at idle. If this truck has the electronic transmission like a 4l60e or 4l80e the faulty coolant or tps reading will definitely affect the transmission. I have an 89 Chevy C15. One being a sticking Torque Converter Clutch solenoid (TCC). Mine will run rough on warm up. It's a 350 TBI. i just rebuilt a 350 chevy its bored 30 over everything is new,oil pressure drops to 0 at idle when warm,any ideas . Check the 3 circuits from the MAP to the ECM. Measure the vacuum level in the intake system with a Feb 11, 2005 · Check your alternator out put for 14. 050-inch tappet lift with 0. I have replaced the Idle Air Control(IAC), Coolant Temp Sensor, Fuel Pump, plugs, distributor cap so far. 9. Canada. it surges at idle and at a steady rpm cant figure it out. Remove and check this valve carefully. V10 Suburban silverado. First off, I have access to a GM Tech 2 with an OBD 1 connector, so I can see what the computer is trying to do to my timing as I drive. It's my first GMC ever . I have a 91 Silverado K1500 4x4, 5. It does have allot of miles on it (275,000) but for the most part it runs like a clock. Feb 18, 2012 · As the truck warms up, the misfiring goes away completely, but the idle is far from smooth. The idle valve and tpi both tested bad, and replacing them helped on general driveability but didn't affect the stalling. I had problems with random (searching) idle speed and stalling when clutching after being at speed (like slowing down on an off-ramp). “Bad men need nothing more to compass their ends, than that good men should look on and do nothing. Jul 15, 2005 · Recently rebuilt the 454 in my 1990 TBI Burb. Nov 6, 2014 · Re: 87 Chevy 350 TBI low Idle issue. Question type: General. Wait for 30 seconds. Runs great and has under 100k kilometres on it, but at idle it bogs down to a near stall before returning to normal idle speed. I am using a Auto Ray EZ scan 5000. I just put new heads on my 5. Location. 1991 CHEVROLET SILVERADO. Apr 11, 2008. 1987. If the pressure stays the same or falls further it's a leak on the pick up side of the pump. Connect a scan tool, verify ALL the sensors and computer outputs like the IAC and timing advance 'n' EGR. Remove the wing nut on top of the air cleaner and lift the air cleaner off the throttle body to access the vacuum lines. Picked up a 1988 K3500 last year with what I believe to be a TBI 350. I have a little update. Greg. 7L 350 TBI Surging/Sputtering/Missing. It is not consistent in that sometimes it is worse than at others. The IAC (and computer) is what gives the engine a “fast idle” speed when started cold. I also have a high volume oil pump. Feb 10, 2009 · The stock chip should work fine with a mild cam. IAC valve is a regulated vacuum leak, controlled by the ECM. I am not getting as good of fuel economy as I think I should. Dec 26, 2007 · 1,430. Jul 24, 2016 · 1995 K1500 5. 8 Atlas II transplant last Sunday. 390. etc. 7. I have to turn it over several times in order to get it to start than I have to feather the gas alot in order to keep it running after a few minutes it idles on its own really low idle. I purchased the vehicle with 184k miles on it and it now has 236k. My 93tbi has an edelbrock cam in it with the stock chip and it runs just fine. 350, 350, 350. The surge is like a whup-whup-whup-whup until I add throttle and rev it out. I have a 94’ Suburban with a 5. If I accelerate really slowly then I can get it up to speed. Two things to check. First I start with a new Fuel pump, STOCK 75lph TBI fuel pump will only support about 230hp before the fuel pressure drops like a rock. When you first start the truck whether it is hot or cold it idles up and down and will clear out instantly without notice. The issue is this: lately, it simply will not start without starting fluid. FYI, New distribtor, Idle Air Control Motor, and EGR. 7L. Aug 11, 2008 · 1 . I have a 92 350 TBI she is hard starting when its cold. If you have a vacuum ga on the unit and rev it and the ga drops but is very slow to recover now you are talking timing issues with the valve train, not the timing with the light. 50 to 5. 5 volts at WOT. Has anybody solved the issue of the 2. ”. Once the engine gets to around 110-120 the rough idle/RPM hunting behavior begins. When I had the old 350 that was running on 7/8 it frequently went into stall condition mode and ran at 1000 rpm instead of 550 when idling. but it runs great when accelerating or about Nov 13, 2006 · Nov 14, 2006. I have a rebuilt 350 with a mild cam, Edelbrock 650 cfm carb, Powerhouse intake and a noisey gear drive. Especially when it's been driven - shut down for an hour - and restarted. Key on to run without starting, under the hood you will hear the Idle Control Valve clicking, ( The clicking is the ICV closing) unplug the ICV connector. I did notice that my truck doesn’t seem to have the high idle that other TBIs have. Dark blue is signal to computer. Check Engine Light comes on Nov 26, 2021 · Jacob. 8. That’s closed loop. Also, if the ECM sees a "Stall condition" it will increase the idle until you start it back up or for a set period of time. Aug 11, 2018 · If the engine speeds up, there is your leak. When I put the motor in about five years ago it ran great, until recently. I ordered a crate motor from Summit. 1990 Suburban manual transmission 5. The gasket is notorious for failing. There is no adjustment on the TBI. Mar 3, 2016 · Truck Year. If the timing is not changing, except for centrifugal at higher RPM's I would suspect the ignition module. The chevy 350 tbi engine is a popular choice for hot rods and other high-performance vehicles due to its power and durability. I replaced the Idle Air Control Valve and the idle seemed to be rather steady in park and gear for the past 4 months. #1 · Jul 17, 2012. May 23, 2016 · Anyway, I've had an erratic idle problem with our '89 K1500 5 speed since it had the bad motor in it. I can feel the injectors clicking. V20, K10, K10. Hi guys, I've been having a problem with my truck for quite some time now. It was working fine before and right after the flip. I recently rebuilt the 350 in my moms 1990 Chevy 1/2 ton 2wd pickup. But still haven't found the cause. The ECM knows what idle RPM is supposed to be, and will always use the IAC to try and maintain that. if i unplug tps is mellows out but still there i have a dynamic efi computer that i use tuner pro to tune it with. I bought it with a blown engine (they let it run out of oil. Jul 29, 2021 · It generally won't fix anything, and will usually cause other problems. Along with what botie said I would check to make sure the injectors were clean. Could even be the base plate carb gasket. It ran ok, but was in need of a tune-up. -changed coolant temperature sensor, and verified proper resistance, good. When the AC is on it's significantly worse. You could have a bad ECM,but the reading with key on. turn ignition switch off for ten seconds 3 . Asked by coyboy350 Jan 05, 2015 at 10:20 PM about the 1994 Chevrolet C/K 1500 Silverado Extended Cab 4WD. May 13, 2023 · Running rich is based off the visual observation of a black tail pipe. You will have to hold the throttle open just enough to keep the truck running while you do this. Once the closed loop temp has been reached, the computer starts to lower the idle speed. V8. The 'Burb has 125000 miles, 350 TBI, 4L60e, and 4wd. The next day it wouldn't even start unless you used starting fluild or poured gas down the throttle body. Jan 18, 2010 · cold start problem. Goldie, silverado002 and Lerch98. First of all, Im a new square body owner, I just picked up a 1987 V10 Suburban Silverado a week ago, and love it! The truck is in great shape for its age, though it does need paint/bodywork and tires. 3 ElCamino has recently had its original motor rebuilt. Feb 9, 2011 · 1987 Suburban, 350, 700r4, stock GM crate motor with about 30k on it. Plug in your jumper wire connecting the A and B terminals. the engine was rebuilt 7 months ago, and idles smooth as silk with great oil pressure when in park Sep 29, 2017 · We have a 1990 2wd 350 tbi with similar issues. Sometimes it clears out immediately or a few seconds later. No power, struggles up hills, runs a little better at higher rpm's, won't climb a hill from a stop hardly at all. I recently finished up a rebuild on my 1989 C2500 TBI 5. I have replaced the engine temp sensor, the connections to the coil, the Dec 17, 2016 · Code 15 means the coolant temp sensor is reporting the temp is stuck at -40*. I've got a Jeep 4. Truck would want to idle @600-650 RPM when warmed up but often while just sitting there already idling at 600-650 it would start to idle up to almost 1,500 rpm at times. 7 liter TBI engine. #13. a little history on the engine i built its a Jan 22, 2017 · The truck will stay in high idle (about 1800 rpm in neutral/park and 1000-1100 in gear) until the truck warms up then idle returns to normal (Usually about 10ish minutes). SOURCE: chevy 350 express van 2000 runs great idles rough. I have an issue with my ole 89 i’ve been struggling to find the answer to for quiet sometime and was wondering if some of you pro’s may can point me in the right direction. My mechanic did the following and the stumble at idle still has not gone away. Aug 9, 2012 · 1994 5. Ever since day one, I noticed that I only get 12” vacuum in idle (park). The engine has a little over 500 miles on it. start engine and verify proper engine speed ( should be about 450-475 for automatic trans slightly higher for manual ) i hope this helps you . Apr 4, 2012 · Timing issue on a 1994 350 TBI. Turn the key to on, but dont start the engine. If the intake gaskets, base plate gaskets, or Dec 23, 2006 · If not hopefully you have digital volt meter. only annoying at this point but am concerned as to where this is going. I had invested the money in buying a comp cams, thumpr cam. There is a large “sucking” sound coming from the throttle body when it is warmed up. Restarting the engine should reveal an increase in the IAC steps to perhaps around 8-10. Mar 19, 2011 · L05 TBI 350 Idle Air Control Valve Problems, Need help calibrating. -Rebuilt TBI with kit. #11 · Feb 6, 2011. I recently did a intake manifold gasket on my truck, and have been trying to get the timing right, but a few things are striking me as odd. Howdy, So I recently bought an 87' GMC SIERRA short box with the 350 TBI and When I start it, it surges bad and trys to die, and then begins to idle better but still not right it sounds like a misfire. Feb 5, 2011 · The engine seemed to run fine while driving. Apr 1, 2008 · 6. Insert a u shaped paper clip into the ALDL connector between the "A" and "B" terminals. So the problem seems to be that something is advancing the timing way out of range on cold start for 30 to 45 seconds, then it comes back to normal and runs fine. 398/0. "Setting minimum air" is a procedure to make sure idle is proper, but is only really needed (sometimes) when components have been changed. Start the engine, adjust the idle, my truck likes about 600-650. Jun 15, 2018 · I recently installed a bored out TBI from CFM Tech, as well as an injector spacer and a 14 psi spring from The Throttle Body Shop on my 1994 Chevy Suburban. 20W50 fixed it right up, and it even started OK down to 0F! Might need something a little thinner in SD winters, though. Likely you need to reset your IAC (Idle Air Control) valve. 7 tbI I have replaced every sensor on. 2 volts at idle. motor had igniton timing redone. I've replaced the fuel pump, fuel pressure regulator in the throttle Jul 16, 2004 · 840 posts · Joined 2004. Apr 18, 2019 · This is a video about rough acceleration rough idle low idle and possible stalling . At a cold start it takes alot of cranking to get the sending unit to move and once the gauge goes over 10 it starts right up, but i mean alot of cranking. -new air filter. New used motor went in and the problem still existed but wasn't as frequent. Apr 4, 2022 · 5 posts · Joined 2022. The truck has the stock L05 350 TBI with 192,*** miles. I went to start it up so I could bleed the power steering (replaced the Jan 8, 2016 · The idle air control valve is programmed to regulate and maintain the engine idle speed at a constant rate. Vacuum on a tight engine is 18-22 inhg. Low voltage to EFI can cause the described problem. and all the parts used were AC Delco. This should slow the engine down. 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. When tearing into the engine I had to have a valve job done on the stock cast iron heads. It could be that it needs a simple tune-up. Then shut the engine off long enough for the TPS to reset. Sputters just off Idle. The symptoms: The truck starts fine when cold or hot. You can hear it in the exhaust and feel the engine shake only when it is idling, put it in drive and it goes away. Like. Aug 26, 2009 · Turns out there are two very common and easily correctable problems with tbi motors. H. It would stall while sitting at idle in park or when in gear at a stop sign. I am having a terrible time with getting it to idle smooth. Make sure you don't have a failing TPS, or leaking vacuum hose to the MAP sensor that's creating idle issues. I put it on a computer account the check engine light was coming on after it warmed Jun 9, 2019 · Truck Year. 94 5. Posted on Jun 30, 2009. The truck will idle all day but when I try to take off it sputters and misfires. Drives great with good power and gets decent gas mileage. #2 · May 5, 2004. I don't see any vaccum lines disconnected. The engine is a tbi from heads up but has an older block. Remove the air cleaner assy, on the back passenger side of the engine there is a vacuum hose from the intake manifold that goes to a black, plastic "Y-type" vacuum check valve behind the distributor. 10. 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. I wouldn't worry too much about the O2 sensor because I have had headers on mine with the single wire O2 just after the collector with no problems for years. "Any time there is a high idle on a TBI or other fuel injection setup, there is too much air getting into the motor. Hey everyone i just recently did a cab swap after a flip out in Jean. 474 posts · Joined 2002. I have about a 1,000 miles on the new engine and I'm having a few issues. I am using Dakota Digital Gauges. While rebuilding it I installed a fuel pressure sensor post fuel filter and at idle its 10. If the IAC is working properly, the idle will come down on it's own after several minutes of high idle. -new gaskets for TBI. My engine stalls or almost stalls when I come down to an Dec 2, 2011 · After that, go after the brain. Had this problem with my 95 Tahoe 350 at one point and the failed coolant sensor ended up being the issue. It does this with both old and new TPS Sep 25, 2019 · I recently put a new long-block 350 in my '87 Chevy Suburban V20. 7 L truck and after an oil pressure problem got Feb 10, 2007 · I have a 1987 Chevy 3/4 ton 4x4 that has been giving me some problems lately. May 8, 2005 · This is related to the 350 TBI in a 93 K1500 Silverado. This is basically stock setup. #1 · Oct 3, 2020. Great fit, easy swap. 5 posts · Joined 2012. It doesn't effect anything other than the idle. It will idle around 550rip'ems but it's pretty rough. Cold start idle to warm is fine and truck idles around 650/700 Oct 3, 2020 · 25 posts · Joined 2020. #1 · Oct 31, 2010. Ive got a 91 silverado 350 with some idle problems. Hope this points you good direction. 7L 350, TBI, Auto, 220Kmiles Its been a great truck, for the most part it runs and drives great! but at low idle or low rpm's it missis,sputters,surges and if im just barely giving it any gas it almost wants to stall out. Check the ignition timing,making sure you have advance at idle. Assure the plug wires are routed correctly--ESPECIALLY 5 and 7. The ECM sets this. 71 Answers. The RPM on my engine does not come down when I come to an idle. It has less power than before I rebuilt it. I don't think that applies to an 89 TBI. The 02 sensor was replaced last fall when this issue started. I notice right from cold start that the rpm’s don’t stay higher and Jan 10, 2021 · CHEVY TBI. This is a 5 volt circuit. Feb 6, 2009 · This 1986 4. 1989 CHEVROLET SILVERADO. Nov 22, 2017 · Once the engine temp gets above ~100F, the computer switches over to the O2 sensor to manage the fuel mix. While cold with the idle still on the high side it seems smooth and normal. hotrodthug Discussion starter. This vacuum leak can be at the IAC valve. 350/ 700R. It goes away after I drive it for a minute or it warms up to closed loop. Sometimes idles perfect, other times it will lope till it dies like a Step 1. It has about 200k. I have a 1993 Chevy Silverado with a 350 v-8 and tbi injector. 88Silverado said: Mine was doing a similar thing. when I put it in gear it bogs down and will sometimes stall then the idle comes up a little bit and Oct 31, 2010 · 12 posts · Joined 2010. I recommend upgrading to the 1996 Vortec 155lph fuel pump which can support up to 450hp and plugs right into a factory TBI sending unit. Two wire sensor right beside your thermostat housing with black and yellow wires. Jan 14, 2010 · Jan 21, 2010. For surging idle on a TBI I would start with a thorough check for vacuum leaks, especially at the throttle shaft and at the base of the throttle body. Coolant temp Jan 6, 2011 · 1994 TBI idle problem New Distributer, rebuilt throttle body, new IAC new injectors, timing setPROPERLY. 5. Idle speed in Neutral is about 725, in gear it is about 500-550. 1987 Chevrolet V20 350 TBI Frankenstein engine and sm465 trans. When you first start it u need to give it throttle for a few seconds to keep er running and when she does stay running she idles really low, then if your not giving her gas and you cut the wheel shell cut out. 400rpm and has a slight stutter. Mar 1, 2017 · Help Boosted 350 tbi surging problem. Henderson, Nevada. Nov 20, 2018 · Warm the truck to operating temperature, turn it off. Easy to replace, any junkyard with chevy/gmc trucks has a dozen of them. Jan 17, 2014 · 2. I've replaced the fuel filter. ) So I knew it needed a new engine when I bought it. 7 hesitation problem. :welcome: Like. Than it smooths out as truck warms up and runs like a Jan 11, 2019 · 89 k1500 idle issues. Gray wire should be 5 volts. Jul 18, 2015 · MEMBER. I did install a new Mellings high pressure high volume oil pump to help out with the cam. Those sensors fail to high resistance, making the engine controller think the coolant iis -40F and really lay on the fuel heavy to choke the engine. May 23, 2016 · Well, it didn't seem to idle rough until a few weeks after we bought it haha. When I crank it up on a cold day, it will start but idle just high enough to stay running (probably around 300 rpm) and will sometimes stall and give a poof of smoke out the top of the throttle body. The o2 sensor is cycling between . 7 TBI. First, replace your coolant temp sensor. If the valve fails or has any issues it can cause the idle speed to be thrown off. It stumbles and has a obvious misfire with a pop from the exhaust. 4 and 800 MV constantly. This may result in an unusually high or low idle speed, or in some cases a surging idle speed that repeatedly climbs and falls. Jan 20, 2018 · I have a very similar problem. 3 system. New PCV , good cap/rotor/wires/plugs, 6500 miles on new engine ( Flat tops eddelbrock 3702 cam, 3 angle valve job, headers hi flow cat glass pack) new oxygen sensor. All went well except I experienced the engine surging at idle. It fires right back up very easily. It idles perfectly in neutral but when in gear (D) it often stalls. It runs great, slight surge sometimes at idle and like I said when cruising. No knocks, no blowby, no rattles, just super low hot oil pressure in idle, sub 10 PSI. engine off is correct. HI, I recently installed a rebuilt 350 into my c1500 and the truck runs but it's exhaust reeks of gas and is smokey. I shut it off, reconnected the EST wire and restarted. 7 TBI motor. ux ke uw vh ww ja pu tg so mx