95 4.3 cpi problems

[Guest 240zxt]

my truck 95 s10 ss stopped running the other day. I sprayed starter fuild in the intake and it ran for a sec. so I figured the fuel pump was bad since I did'nt hear it kick on. well I take off the bed of my truck to get to the fuel pump and replaced it. still would not crank.Checked fuel pressure and it was 60 psi I took the upper intake off and it looked like my cpi unit was leaking so then I order a new cpi complete kit for $500. well after putting it back togather with the new cpi unit it fills my cylinders with gas in just a few seconds when I'm trying to start it. not sure what is causing this? any help or info would be great.

[660Z]

I`m having problems with my 94 ss CPI at the moment also. But I`ve never had the problem like what your describing. Did you buy a new unit or rebuilt. I`m guessing for a $500 kit you bought new. If it`s rebuilt the injector or popets could be stuck open or bad, either case you should have a warranty. From what I understand the rebuilt ones just have the regulator replaced and then blown out the door.

 

Any codes showing? (Like EGR) You might have to erase the codes for the unit to work proberly. If you don`t have a scaner just unplug the weather connection off of the + battery cable for 15-30 seconds and that will clear the codes. Whenever a code pops up, any new comp controlled sensor won`t work right until the code is cleared. Every new part has a signiture prorameter that the computer must comunicate with.

 

On these units the regulator is what usually goes bad, Napa sells a replacement regulator and the nut kit (the hoses that feed the injerctor) rather then buying a whole unit. However you can only get so far with doing that, which I think is the problem in my case. I`m replaceing my CPI injector tomarrow. It started as a stumble accelerating but would clear up if I gave it more gas. I let it go and the problem got worse to the point of not being drivable...but the idle was always fine so I thought it was an electrical problem. The truck has 125 k on it. No codes showing.

 

I thought it was the TPS....nope (I relpaced the MAP,TPS and ignition module earlier this year just because of age they still worked fine, I put them back on to find the problem)

 

Acted like a bad coil....nope

 

Replaced the coil pickup in the distributor...The wires had broken insulation showing bare wire and the cloth covering the coil windings was missing and burned....still not the problem.

 

Pulled on the injector wire and the truck shuts down. Take off the upper plenum and move the wire and the injector clip moves. Go to take it off and it breaks....replace the clip and wires...still not the problem.

 

Now after all this, the driving is fine but it wants to shut down while at idle and stop lights....In other words acting like one of the symtoms of a bad CPI unit.

 

Hope this helps, I feel your pain!

Mark