Need Help In A Bad Way

Tiny
CHEVYMANCALI
  • MEMBER
  • CHEVROLET SILVERADO
Hey all.

i have a 1989 chevy 4x4,2500 6 lug, automatic trans. The truck has a new engine in it with less than 6000 miles on it (goodwrench HO 350) ( dont know the actual milege of the truck itself as I bought it used about a year ago and the odometer doesnt work). One day about 2 weeks ago I was up deer hunting and the check engine light popped on, and the thing started surging real bad, no power, etc, etc. I drove it home ( about 15 miles away) and took it to my neibor and mechanic. Keep in mind that the truck generally runs like it just came off the showroom floor.


now, we checked the trouble code, and it read that it was running real lean ( code "44"). He hooked it up to his diagnostic machine, and it said that it wasnt getting the O2 it should so we replacxed the O2 sensor. No good. So far we have replaced


O2 sensor
temp sensor
MAP module
intake gaskets ( it had a small leak)
computer ( plugged in a new one and tested it, same thing, no change)
fuel filter
throttle body base gasket
fuel pump in the tank ( which we havent checked yet, and it could be causing it I suppose)


i got it back yesterday and it ran like new again. This morning, I took off to go hunting AGAIN and I got about 10 miles from home and the light popped on AGAIN and it started running real crappy and surging AGAIN.

now, like I said, the truck ususally runs like brand new.


all the diagnostic computer stuff says everything fine, exept its running lean and the computers trying to compensate for the problem by spraying more fuel thru the injectors ( throttle body injected of course). Im on social security and cant keep pumping money out just replacing things in the hopes that it will fix it.





any suggestions'?
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Wednesday, September 26th, 2007 AT 10:21 AM

5 Replies

Tiny
FISHERMAN
  • MEMBER
Running lean.
Check the spray pattern on the injectors.
Could be a clogged injector.
Or malfunction injector

let us now if you test them.
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Wednesday, September 26th, 2007 AT 11:54 AM
Tiny
CHEVYMANCALI
  • MEMBER
Injectors were checked ( both good) and replaced (with new ones) just to see if that was the problem-no change.

Im having him pull the fuel tank and replace the fuel pump today just to make sure. That might be it. I may be wrong, but im thinking if the fuel pump isnt workng properly that the computer might seee it as a "lean" situation and attempt to enrichen the system leading to the surging

OH, by the way, the computers trying to enrichen the system, seeing it as lean when it is seemingly pumping the correct amout of fuel its enrichening the system to the point you can smell the gas in the xaust. I had a guy email me and say that it might be the IAC ( ANOTHER new part I forgot to list) OR possibly the fuel pump ( his reasoning was that if the fuel pump is not putting out the factory presure that even though its getting gas that it would possibly see it as a "lean" situation)
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Wednesday, September 26th, 2007 AT 12:33 PM
Tiny
FISHERMAN
  • MEMBER
[quote="ChevyManCali"]

injectors were checked ( both good) and replaced (with new ones) just to see if that was the problem-no change.

Im having him pull the fuel tank and replace the fuel pump today just to make sure. That might be it. I may be wrong, but im thinking if the fuel pump isnt workng properly that the computer might seee it as a "lean" situation and attempt to enrichen the system leading to the surging

OH, by the way, the computers trying to enrichen the system, seeing it as lean when it is seemingly pumping the correct amout of fuel its enrichening the system to the point you can smell the gas in the xaust. I had a guy email me and say that it might be the IAC ( ANOTHER new part I forgot to list) OR possibly the fuel pump ( his reasoning was that if the fuel pump is not putting out the factory presure that even though its getting gas that it would possibly see it as a "lean" situation)[/quote

IAC= Idle Air Control

Well did you check the pressure on the gas line before pull out the pump?

Also: did you check the pressure regulator?

Could be that the pressure its not regulated at the correct PSI.
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Wednesday, September 26th, 2007 AT 2:04 PM
Tiny
CHEVYMANCALI
  • MEMBER
Nope, didnt check it myself, but I called him and told him to check it, and hes supposed to. Ill let you know what he finds
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Wednesday, September 26th, 2007 AT 2:40 PM
Tiny
CHEVYMANCALI
  • MEMBER
We found it was the fuel pump. Thanks for the replies
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Thursday, September 27th, 2007 AT 9:13 PM

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