I have a 94 s-10 blazer 4.3 and cpi unit went out about 4 months ago and ran fine until yesterday and unit went out again.
Besides being a defective part, is there anything that can be causing this to happen? I'm puzzzzzzeled!!!!!! Is this a common problem ?

 

I had one go out too. Ebay usually has them for $250 which is the cheapest I found. Only took me about 1.5 hrs to do the job, so I hope youre doing it yourself. My buddy paid $1200 to get his done.

As far as what causes it, the fuel pressure regulator goes out on the unit, which they sell on ebay for $30, but I am leary of doing that because who knows what damage higher fuel pressure has done to the inside of the unit. I have been told that it is luck of the draw wether you get one that will last, or one that is gonna go out again. If mine goes out again, I am planning to pull the whole CPI unit and all of its wiring off and go either with an aftermarket EFI system, or a TBI setup from a junkyard. I refuse to keep fixing the same problem. Hope this helps.

 

Thanks. A friend of mine has his own shop in town and did not mark up too high for me so all said and done price of part 325, plus labor of 200, which was the first time. this time part had 1 yr warranty so I was safe there, so all I paid was 175 for labor but he greased ,rotated tires,installed lug nut stud and paid half of the intake gasket . I did ok I think!!!!!!!!!!!!! He told me not to let it get too low on fuel (which I have before ) it can pick up garbage and plug things up. I don't have a garage, or the tools, or time, but I do have one hell of a GOOD FRIEND ( that takes the time to figure things out)!!!!!!!!!!!!!!!!!!!!!!

 

Glad to hear it. Other than that, I absolutely love my 94. It has been an awesome truck. Good luck with this injector.

 

I was wondering, when a cpi unit is going out.Will you get fuel in the oil pan? And will it flood easily? Because that's what my 93 S10 Bazer is doing. Plus I have a code that indicates a bad O 2 senser and lean fuel mixture.

 

Yep. That is the first sign of a bad injector. Your O2 sensor is probably bad too though. I would change that asap.

 

Do not think that the only thing wrong is the CPI unit. There is also a small fuel line connector at the rear of the plenumn on the drivers side when you have the upper plenumn off it will be on the drivers side rear where the hard fuel lines come into the plenumn and attach to the flexable lines. These lines also come loose and leak at this connector also. You should be able to see a clean spot on the bottom of the plenumn valley where any fuel has been leaking. This part is about $50.00 compared to the price of a CPI unit.

Paul (Phatboy)
'93 "W" S-Blazer