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Showing results for tags 'TBI'.
Found 6 results
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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!
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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?
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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".? -
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
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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! -
This is my 1995 GMC Sierra SLE, running at 142,000 miles. Bought it used at a small business dealership for $6500.
