# 89 Chevy C1500 HELP!!!!



## Jazzy4409 (Apr 11, 2010)

I have an 89 Chevy C1500 with a 350 TBI, This is briefly what it is doing. It will start on the first try but after start it sounds as if it floods out and stalls. I have to feather the gas to keep it going. If I put the pedal to the floor it just stalls. On start-up it seems to be pooring alot of gas. I full cone out of each injector. I thought it wasnt getting enough gas but someone said it is getting to much. I have checked all the fuses, I have changed the fuel pressure regulator diaghram, the ECM and have cleaned everything. I am at a loss. I have no idea what it is. Any help would be great. Thanks


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## octaneman (May 13, 2009)

Hi Jazzy4409


The symptoms you describe could be that your engine has a massive vacuum leak from somewhere. Check all vacuum hoses and the surrounding area of the intake manifold, if your computer has registered any codes please extract them and have them posted. To much fuel can have several possibilities which would include; temperature sensor, TPS, IAC and MAP sensor. Before you go out and start replacing components, each of the sensors have to be tested to make sure they are working properly, if you got access to a DVOM it would help with the diagnosis to isolate the problem. Start off by checking the basics such as; Timing, spark intensity, spark plugs, air filter etc...Once your satisfied everything is OK, then we'll focus ECM controls.


post back your findings.


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## Jazzy4409 (Apr 11, 2010)

Octaneman,

I checked everything like you said. Good news and bad. I used my manual and checked the IAC, TPS and the MAP all checked good. I also checked anything and everything as far as vacuum i could see. Weird thing is while I was doing this I left the vacuum line that goes from the back of the TBI to the MAP off and started it up. Ran great! fired up, idled, and put it to the floor and ran like a champ. While running I put the vacuum line back on the MAP and it instantly died. I figured it had to be the MAP, even though the volts are reading exactly like the manual said. I bought a new one and put it on. Everything is exact. I leave the vacuum hose off and it runs great, put it on and it dies. So? I have it running now which is good, I capped off all vacuum lines 1 in front of the TBI and 1 in the back of TBI. Capped off the MAP but now the truck idles high. Not anything ridiculous but at idle the jets are pushing a nice even spray. probably about 2K RPM is a guesstimate. I dont have a TAC on it so I have to just give you a rough wag at what it is. Any suggestions? Thanks again for your help. wouldnt have gotten anywhere without it.


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## Jazzy4409 (Apr 11, 2010)

Octaneman,

Well disregard everything I said previously. Went out there later this evening and...behold!!!! it is doing it again. Not nearly as bad but it starts and idles but once it is in drive and you let off the brake and get going it starts to sputter, you hit the gas and it floods out. I am totally lost.


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## octaneman (May 13, 2009)

On cold start the temperature sensor to the computer is not sending the signal for the computer to lean out the the fuel ratio. The computer thinks the engine is always at cold start therefore the excess fuel being dumped. Have the temperature sensor tested with DVOM and check it's resistance in relation to antifreeze temperature, your manual should have a chart to compare temperature/resistance values. 


please post back your findings.


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## wolfen1086 (Oct 4, 2007)

jazzy I just read your other thread titled TBI nightmare.

Yes you can change over from TBI to a carb, but its not as easy a fix for your problem as you think, theres a hellofa lot of work, time and parts required to do it.


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