lean problem with 1994 s10 4.3-help

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08-07-2008 | 07:36 PM

dale7600

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Joined: Aug 2008

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lean problem with 1994 s10 4.3-help

I have a problem with my 1994 s10 blazer with a 4.3 vortec that has thecpi system. It dose not idle but if I spray starter fuel in the intake hole it will run fine at idle. I have already replace the injector system and check the fuel pressure which runs 58-60 psi. I alsocheck the vacum which is at 17lbs, and the EGR vaule is good and clean, replace mass air senor to. all that is left is the computer but it dose not give a bad code saying its bad, it dose give me a masa air senor code still even after replaceing it. at higher speeds there is no problem.
Anyone know what could be the problem?

08-07-2008 | 08:57 PM

swartlkk

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Joined: May 2005

Posts: 41,188

From: Waterloo, NY

RE: lean problem with 1994 s10 4.3-help

94 CPI motor does not have a mass air flow sensor... MAP, manifold absolute pressure, sensor yes.

What is your fuel pressure at idle?

08-08-2008 | 07:51 PM

dale7600

Thread Starter

Joined: Aug 2008

Posts: 2

RE: lean problem with 1994 s10 4.3-help

Sorry you are right its not the mass air flow sensor...but MAP, manifold absolute pressure sensor and the fule psi is 58-60 psi

do you have a idea of what i should look at?

08-08-2008 | 08:27 PM

swartlkk

Administrator

Joined: May 2005

Posts: 41,188

From: Waterloo, NY

RE: lean problem with 1994 s10 4.3-help

Good fuel pressure. Almost sounds like you have a pretty serious vacuum leak causing a lean condition at idle. More fuel corrects the problem. I would start by checking all vacuum lines over for cracks or breaks.