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Found 16 results

  1. Hey everyone, so I'm pretty new to the chevy 350's. I have the 350 small block tbi with an NV3500 transmission. I'm looking to get more power and see what peoples builds are because the 350 is gutless with this transmission. Thank you all in advance!
  2. Greetings all. I have a1992 g3500 5.7. At idle and steady rpm she runs ok but has slight misfires not any one cylinder kinda like popcorn popping . Could it be a dripping injector (tbi)? 61000 miles. Fresh fuel . Good tune up. Whats the best way to see tbi spray pattern?
  3. When traffic light turns green, I kicked the throttle pedal, finally, this time, I got the power that a 454 supposed to give me, I almost cried. ======= 1994 Chevy Suburban Silverado K2500 454 L19 TBI 4L80E 153K miles ======= Months ago, I posted several topic (2 or 3) about it stall and knock sound under the floor, while cruising on highway. Well, the "highway" include GGB (Golden Gate Bridge).? 94' 454 stall while driving and knock sound under the cab 94'454 stall again, after change fuel pump Take note that I am actually completely a newbie, new driver (2 years), new vehicle owner, and new to America. So maybe some thing in my topic is wrong, but I don't tend to misleading. Shattered catalyst After the GGB stall, I found its power is weaker than before, and sounds like the exhaust is blocked, and when drive next to a vehicle or wall, I can hear air bleeding sound. Then got MIL code 32, EGR, however I can't find any problem on EGR system. This 454 engine use Linear EGR system, the valve is controlled by ECM directly, no vacuum pipe. I tried to remove air filter, to make it performs better, then find the blocked-exhaust sound become louder. Then one day the stall happened again, I found the knock sound sounds more like opening a soda can. So I visited a muffler stop, turns out the catalyst is shattered, quite big loss. ? Since I don't have enough money for a catalyst, and it may be shattered again, so I asked them to put a steel pipe instead as a temporary manner. After that, the compressed air sound is disappeared, the blocked-exhaust sound is lighter but still there, and the performance is better but still weak. So shattered catalyst blocked exhaust, caused air bleeding sound. And caused extremely high pressure in EGR system, too much exhaust injected into intake manifold when EGR is open, caused ECM think EGR have problem, light MIL and sending code 32. Fired chip in ICM (ignition control module ) The last time it stalls, at a quiet place, I finally figured it out that it feels and sounds like wrong timing, and when press throttle pedal, it back fires, and the harder press the pedal, the louder the sound is, very loud. And when it back fires, I can feel shock on throttle pedal. I told this to my mechanic, he told me to replace the ICM. He said back to old days, he replaced many of it. He suggested me to purchase new one, because it's cheap, even from ACDelco, and this thing usually break down for years parked vehicles, vehicles in junk yard usually parked for years. I opened the metal cover of old ICM, find one of chips is black, oil or something around it is dark brown, the metal cover supposed to be glued to the plastic shell, but the gap near the black chip is open, so it's clear that the chip was exploded. After I changed the module, 3K+ miles so far, including 2 round trip from San Jose to Yosemite, stall never happened, I think the stall problem is officially solved. So the broken ICM caused wrong timing, and stall. "Knock sound" is actually backfire, the exhaust is under floor, so I felt it's knock sound under floor. Back fire caused huge pressure burst in exhaust, then transferred to intake manifold and throttle body via EGR system, caused shock on throttle pedal. Thank god this didn't ignite the gas-air mixture, or my trouble gonna be bigger.? Wrong base timing That's NOT all folks! I found it still very weak, on I680, the climb at east of Fremont, it even can't maintain 60MPH! WTF?? At this time, what I have done on it: Fueling system: New Delphi fuel pump, capable of over 60PSI; New fuel filter, ACDelco; Fuel injector, tested and cleaned; Fuel pressure regulator, changed new spring, 30PSI; Air intake system: New air filter, ACDelco; Ignition system: Distributor cleaned; New ICM, ACdelco; Full assembly of distributor and ICM from junk yard as spare part. New spark plugs, wires and ignition coil, ACDelco. Cylinder pressure: I forgot reading, but within normal range. I pulled out the distributor for cleaning and ICM change reason, but when I put it back, I tried to find the timing mark. However, only engine block have the mark, the distributor don't have mark from factory, only a mark made by the ex-owner's mechanic, and it turns out it's wrong. So I tried to do base timing. I borrowed ignition timing light from my mechanic. But I can't find the "timing connector". At that time, I thought cold start and idle is running at base timing. So you guess it, runs over 20 degree ******. Then one day, I read my shop manual carefully, find out cold idle is NOT base timing, and only when the "timing connector" disconnected, the engine runs at base timing. However I can't find the connector, then after some dig on internet, I finally find it: inside the cab, passenger side, by the side of the blower motor, a single pin connector, tan with single black stripe lead, that's it. It's a bit far from "adjacent to the distributor".? Then I borrowed the timing light again, do the base timing, hit the road again, the result, on I680, maintain 70MPH easily, like I write at beginning of this topic, I almost cried! Just recently days, it even reached over 90MPH when climbing! Yeah it's speeding too much, but you know the traffic flow on highway is a bit crazy after reopen, probably due to people lock in their home for too many days. ======================================================= So That's all folks, I currently focus on renew my truck camper, including solar panel, painting, bathroom convention, jack system rebuilt, then maintenance on the 1996 Ford F250xl, 350 engine, and convert to dually, create a "FAKE F350". ? Then come back, I found the A/C compressor is dead, my mechanic suggested me to get one from junk yard, because most of them from car part shop are rebuild in China, you know what, even I am Chinese, I always avoid "China".?
  4. I have a 1993 k3500 454 NV4500... The engine is a semi fresh rebuild(50K miles) with a small cam. I have replaced the following some parts multiple times... The truck has a stumbling rough idle. Seems to lack power to me but im not sure. If i take the truck for a short drive when i come back and go to instantly restart it has no fire from injectors....hit it with a little ether and shes up and running again. Im fairly positive i have that narrowed down to a weak oil pressure sensor.(changing it tomorrow). The truck runs pig rich and never seems to go into Open loop.(i think heated 02 will change that). I AM OPEN TO ALL SUGGESTIONS.. out of ideas myself. I have a ALDL cable with WinALDL & Tuner pro rt but quite frankly do not know what i am looking for I have attached a copy of my logs at a idle. https://docs.google.com/spreadsheets/d/1ZuvfldSA_rejBc0FAmCb38zTbHMIlfNR4CoTWgblQSU/edit#gid=361545408 Parts replaced less than 300 miles ago.( All new with AC Delco parts) Completely Rebuilt TBI unit with 2 inch spacer New TPS & IAC i did my best to calibrate them New map sensor Pickup Coil ( Timed at 4 degrees BTDC with connector unplugged) Cap rotor & Plugs & Wires ICM Ignition coil o2 sensor ( Re wired from ecu wire was broke assuming when they reinstalled the engine) *** I plan on switching to a heated o2 due to my long tubes. CTS Knock sensor (Wire was also broken) Newer fuel pump & Filter 15k ago with all new lines Im sure there is plenty others im forgetting. The EGR is deleted as are all other vac lines except MAP,PCV. I am at my wits edge with this truck but i love it very dearly. Hopefully the geniuses on here can help me figure it out. At this point any direction is better than none. Thank you very much you can email me at [email protected] Or text me at 724-570-8672 if that is easier. Lucas Picture of said truck causing me all this heartache
  5. Hey guys, I'm new to this forum and new to owning my first chevy truck (with a small problem - hopefully!) and I wanted to post this here for some help/advice/guidance. I have done some research on this problem and only found one other post on the internet with this problem so it seems like a rare one! Unfortunately, the post I found died once the OP stopped responding. So here is the story and the problem:. As of yesterday, I am the new owner of my first Chevy truck! It's a: 1989 GMC Sierra 2500 with a TBI 350 It's completely stock and runs great! (while the EST Bypass wire is connected) No check engine light Got it for $500 There is a problem... The truck does not pass CA smog testing Smog Visual: Passed Smog Emissions/sniffer: Passed Smog Functional test: Failed The reason it failed (as printed on the smog failure report) is: Ignition timing is not readable. Also vehicle will not run when single wire tan/black connector is disconnected which is procedure for checking timing. This was my first attempt at resolving the problem: Started the engine and warmed it up Disconnected the tan/black EST bypass connector WHILE the engine was running and the engine went from idling smoothly to a idling rough. Using a timing light: I set the timing to 0 degrees. The engine then began to run smoothly! I reconnected the EST bypass connector. (This was done while the engine was still running - The engine continued to run smoothly.) I shut the engine off I started the engine and it ran perfectly fine. (I thought I had resolved the issue!) Just to double check: I shut the engine off then I disconnected the EST bypass connector again. I tried to start the engine Results: Engine cranks over but does not start After realizing the engine was not going to start: I reconnected the EST bypass connector. The engine took quite a bit of cranking before it started. Once started, it ran fine. Basically I am able to replicate the exact same same problem that the smog shop came across. Based on my research, the correct procedure to check the timing is: Warm up engine Shut off engine Disconnect EST bypass wire Start engine (Cannot get past this step...) Set timing to 0 Shut off engine Reconnect EST bypass wire I'm guessing this is the procedure the smog shop is trying to follow so seems I need to get this to work for them so the smog test passes. I hope this is enough details for everyone. Please let me know if you have any ideas guys. Thanks for the help in advance!
  6. This is my 1995 GMC Sierra SLE, running at 142,000 miles. Bought it used at a small business dealership for $6500.
  7. My good friend, who I help keep running, has a 1993 C2500HD- the one w/ the TBI fuel injection on a 5,7L block & the Eight Bolt 2WD hubs/rims. It's been running ok for a long time w/ more than 430K miles, mostly freeway, on the OD. It does though have a few nagging issues, one of which is the tachometer bounces up and down erratically while the motor is running. It's most pronounce when the RPMs are low, like around 1K-2.5K, but never really goes away. The truck also has trouble sometimes pulling up-grade without getting some pinging from the motor. (Usually running 87 roz/ron octane...), I mention it in case the two things are related (Jumpy Tach & slight but persistent 'ping' going up steep grade on the freeway) in case they are related.
  8. Im experiencing what seems to be vapor lock on my 94' yukon 350. It only happens when i try to start it after it has heated up a lot, during which time, it sputters and dies. It runs fine after holding a rev(around 2500 rpm) for 20-30 seconds. This is exactly what a carb filled with boiling gas does, until you burn all the hot fuel. When it does it really bad, i can hear hissing from the gas cap, which is a new gas cap. This is my first fuel injected truck, so im not sure how the fuel system works on this, but i would assume that its a clogged line going to the vapor canister, or possibly a bad fuel pump. Any thoughts or experience on this would be a great help. Thank you.
  9. Hello everyone, new member here from Tucson. I recently purchased a Yukon, and i suspect a bad alternator, but i am new to TBI so this may be normal behavior. When cold, im pulling a solid 14v, as the truck warms up, the voltage drops to 12v. With lights and a/c running its 11v, and it seems to have nothing to do with rpm. The truck has a new 600/750 CCA battery. Is this normal behavior for a 350 TBI? Thank you.
  10. Hi everyone I hope someone from this site will be more helpful than the last site I tried using. Ok here is what I got 1992 k1500 blazer with tbi 350. My question is if this motor can be changed from flat tappet to roller or am I better off to buy a new crate long block L31 vortec 350? (if I can use roller cam I'll put new 906 vortec heads on it) I'd like to run a lt4 cam or something of that range.is like to build it up and get 300rwhp. It has true duals already. I've been thinking of changing the 2 barrel tbi over to the 4 barrel efi unit with self tuning if need be. And I will not do an ls swap I owned two before and don't like them at all that's why I got rid of them for a 350 again and they drank more gas than my blazer does 10mpg and 13mpg is what I got on the ls trucks my blazer get 19mpg any help from you guy would be great And no emissions where I live
  11. 2006 2500hd 6.0 put in new plugs, wires ,crank pos sensor,cleaned throttle body,MAF ...started up running good..went to go for a drive .plugged in scannner to erase cel and it started idleing rough...cleared codes ,engine died instantly..now it wont start...cranks but wont start...please HELP..Where do i even start?
  12. I have a 95 GMC K2500 5 speed with the 350 TBI and manual Tcase which I believe is the NP241 and the 5 speed I know is an NV4500. I don't think it's got the granny gear but I don't know for sure. It also has a 3.73 Posi. Good running truck for me, but you can't get much power out of a tbi. So before I dump money in it, I want others opinions for what's best. I am selling my '91 Corvette and using that money for my truck. I am wondering what you guys think is the best swap out there without having to do too much work, and being able to retain my current trans, tcase etc. I don't have the funds to swap those, so what's the best out there? I was thinking of doing a built 383 tpi build, or a 383 LT1 build just because what I currently have, would bolt to the block of both of those. What I really want to do is a Dmax LBZ swap but money is a playing factor in this. I guess the numbers I want to make are 350 plus HP and around 400 torque. I want to know prices etc. I could really use the help, thhank you.
  13. Truck shuts off as soon as i put it in gear and after initial start-up. I've bought a new IAC and cleaned throttle body and replaced the gasket. Any ideas to what else i can check out to fix this problem?
  14. Hey everyone, I am having issues with my 92 c1500 5.7l. I made this account because I desperately need help from people who know more about these things than I do. So let's start. The first thing you need to know is that I have a weird truck. Someone who had it before me said they had the CTS (cooling temperature sensor) go bad, and the temperature gauge doesn't work. Their fix for it? They hooked a manual toggle switch up to the ECU so that they can flip the switch on when the engine is cold, dumping more fuel, and flip the switch off when the engine warms up, giving it a leaner air/fuel mixture. I believe the issues I have may have something to do with this. Where the problems start: The truck will idle fine if it is COLD with the toggle switch on, and will idle fine when the engine is at normal temp with the switch off. If it's cool but not cold, it will idle rough (rpms almost die and the jump back up to 1500 then down again) with the switch off, and die with the switch on. I figure this is simply because this switch doesn't give it a healthy air/fuel mixture because it's not adjusted gradually by the computer; instead it's simply rich (on) or lean (off). Next, when I back out of the driveway, it does fine (I slightly ride the clutch out and back out) Then I go to first gear, and let off the clutch slowly, and give it a tiny bit of gas, just like any other manual tranny. Now, if I have a perfect or near perfect launch, no problems occur. But, if I am in a rush, or simply not paying enough attention (I'm rather inexperienced) the truck will buck. Normal right? Well this thing doesn't buck once or twice.. As I continue to accelerate through first, it will buck HARD. enough to make the front end dip like 6 inches repeatedly. If I don't let off the gas, I slow down and it continues to buck even when I'm not on the throttle. If I do let off the gas, it will either clear out and stop, or will keep going. If I turn it off and crank it over again and roll into first, the problem totally clears out. Assuming we have the bucking problem out of the way, I will accelerate up through first. Sometimes this is smooth, sometimes there are dead spots, and sometimes there are lots of dead spots. I shift into second. Sometimes the shift is smooth, sometimes it kind of jerks forward, and sometimes it jerks HARD. I accelerate through second, and this is where the worst dead spots are as far as acceleration. It doesn't act like the gears are slipping or something, but rather like it is having trouble firing properly and is losing power. Once I accelerate past 2.5k or 3k, it runs like a dream. Shift into 3rd, and all problems stop almost 100% of the time. Very rarely it will jerk into third or fourth, but usually these shifts are clean. I figure this is because by now the wheels are moving plenty so that they are enough to keep the engine spinning alone. I will almost guarantee this is NOT a transmission issue. My clutch doesn't smell, it disengages and engages properly, and the tranny NEVER grinds except if I don't go into a different gear before reverse, which I'm told is pretty normal. Another clue that this isn't the transmission is that when it bucks, the higher RPMS that it jumps to are the normal ones, and when the rpms drop, it is due to a loss of power. This I have tested by trying to floor it when I'm bucking, and it really doesn't do anything except kill the sometimes engine and I have to restart it. If it were a tranny problem, it would just go out. Can someone please tell me what's going on here? Is the toggle switch the cause of this? Bad TPS? Something else? All three? I'm happy to provide pictures, videos, or further explanation for anyone who wants to take this problem on with me. Thanks so much in advance. Also, I will include a video with this post as soon as it uploads to youtube. EDIT: I should probably include that it NEVER backfires. If I'm in neutral and the truck is warm, the engine sounds VERY strong and does not have any problem picking up RPMs when revving. It sounds like a beast, and when it's warm it rarely misses in idle. Video: Skip to 4:30 to see it buck hard in first gear.
  15. I have a 1994 GMC Yukon 350 TBI 4WD that has a significant lope to the point of stalling, especially when in gear. When in park it will lope between 800 to 1000 rpms and when in gear sitting still will lope between 200 and 700 rpms and every so often, stall out. You can feel an intermittant stumble when actually driving although tach doesn't show it then. The stall will also occur sometimes when coming to a stop. The motor has plenty of power. Changed almost all sensors/components - see below for list of replaced items. I can temporarily fix the issue if I unplug the Coolant Temp Sensor the truck will stumble really hard several times and if it doesn't stall, it will smooth out completely 800 RPM for about 1 minute then starts to stumble again. Putting the vehicle back into park, plugging the CTS back in then putting the vehicle back into gear for about a minute then unplugging the CTS again will once again will repeat the temporary fix most of the time. Plugging the CTS back in once the lope has started has no effect. I have checked the voltage going to the CTS and it remains a steady 5V. I have tried 3 CTS's with the same results. Also about one in every 20 trips the vehicle will show no signs of any lope or stumble or very little. Could this be a PROM issue? Replacements already performed: ECM(computer) - had to use old PROM as new ECM doesn't come with it. Coolant Temp Sensor (x3) EGR and solenoid IAC (x2) Vacuum lines everywhere MAP sensor Fuel Pump Fuel Filter Distributor (whole thing) Plugs/Wires Coil Injectors Fuel Pressure Regulator Intake gaskets Removed and cleaned all grounds Alternator TBI Gasket Thermostat 195 Suggestions from any GM Genius'?
  16. I have a 1989 k2500 5.7 tbi with 171,xxx miles on it. I've had no issues with it until a month ago when the engine is under load it cuts out, as soon as I let off it back fires and everything is normal. I've replaced cap and rotor, plugs and wires, coil, egr valve and solenoid, map sensor, tps and fuel filter trying to track down the culprit. Ran the codes, it came back with code 34 map sensor. Unsure why, cleared the codes and it throws it again. The truck idles just fine just won't drive well. I should probably also include that the truck has no cat anymore and is 3" straight pipped back to a flowmaster. Unsure if that will make any difference with help as it had had this set up for over a year prior to any issues. Please help, I'm not used to these tbi systems but more familiar with old school engines that only need suck, blow, bang to run correct.
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