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will not run when cold

1K views 7 replies 7 participants last post by  pigfat 
#1 ·
We have a 1989 chevy 1/2 ton 4x4 that is stalling when it is cold. When you start it up it will fire up then stalls in about 10-20 seconds. I checked the codes and it came up throttle positioning sensor, knock sensor (it was broke off at the plug), and coolant temp sensor. We replaced them and it is still stalling. If you spay starting fluid or carb cleaner into the throttle body it will stay running. It starts fine as long as it is warm. I did notice that you have to spay towards the passenger side injector to keep it running. If you only spray the drivers side injector it will still stall.


So does anyone have a clue on what is going on and how to fix it?
 
#2 ·
sounds like you need to check fuel pressure. that would be a good place to start if nothings been mucked with. has the fuel filter ever been changed? if not that could be part of the problem to.
 
#6 ·
I was like that until I lost 130 lbs. Now I don't mind running... :teehee:

Sounds like a bad fuel injector or low fuel pressure. Check to see if there is fuel spraying from the passenger side injector. A timing light pointed at the injectors will help you see the fuel spray.

Also unplug the coolant temp sensor, this will richen the fuel mix and may let it run longer.
We tried unplugging the coolant temp sensor and it did not help. I will try the timing light trick. I wanted to check the timing anyways. Thanks for the idea...

That's what I was thinking, I have seen those injectors not work cold and then start after a few mins.
The funny thing is I at first thought it might be an injector or fuel problem. But my father in-law and his friend who owns the truck wanted me to try changing the other stuff first. The owner originally took it to a shop in Grand Haven and the said it was the oxygen sensor. He had them change it but that did not help either.
 
#7 ·
The first thing to check is fuel pressure.You can loan the tool from autozone for a $150 deposite.After you detrermin that you have 10-11 psi check your idle air control valve,and check your egr valve for a chunk of carbon holding it open.If the truck is running,and you unplug the coolent temp sender,the idle should change.there may be two temp senders,one for the dash,one for the computor,make sure you check the correct one.
Im betting on a bad fuel pump.
 
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