4.3 Vortec CPI Question

**apmech** · 04-27-2009, 07:50 PM

My winter beater a 93 s10 blazer with the 4.3 Vortec CPI is having a on going issue I need some help with. It started with it missing at high speeds then not wanting to start inttermently, die ing after about 15min of driving and now not starting. Here is a list of fixes I have done sence then: Intake manifold gasket; plentim fule lines; plugs; wires; cap rotor;. The timing is goodand good spark so now I am thinking fuel injector but I want to be sure because it is a expensive shotgun item. I checked the resistance of the injector at the connector just outside the intake plentium and I am getting 400k ohms. My buddy has the same truck that runs great so I checked his and it is reading 1.6 ohms.
The resistance is really high in my injector...bad injector. I am almost 99% sure it is the injector but I would like to here some thoughts and ideas.....Thanks

**Badbrad469** · 04-28-2009, 06:52 AM

the spider injectors in those trucks were notorious for blowing the fuel pressure regulator. also, if the injector does not see i think it's 62psi of fuel or something like that it WILL NOT start. when u take off the upper intake if you see "washing" on the drivers side, the nut kit(fuel lines) need to be replaced. but, if u see "washing" on the passenger side of the intake, the regulator has gone bad and the entire thing needs to be replaced. while you're at it, go ahead and pull off the egr valve and clean it really really well. that's another problem with these motors. if u can find the screen type gasket for the valve do it, because you will get a lot of carbon in the intake and it will clog up the valve itself. hope this helps ya a little

**apmech** · 04-28-2009, 06:04 PM

I just did the lower intake manifold gasket and when it was off I cleaned all the builtup carbon out. I did the fuel pump just before thhe intake gasket. I have a solid 61psi. I did the plastic fuel lines in the plentum about a year ago. I changed the psi regulator a few months ago when I did the fuel pump.
That is why I ohmed out the injector. I was hoping someone else with the 4.3 CPI could also check the resistance of there injector.

**GaryL** · 04-29-2009, 10:50 AM

I had this same problem on my wife's old 92 S-10 Blazer. It was intermittant, so it was hard to track down. I finally found it to be the ignition module. I kept telling myself it wasn't, because I had spark. But after I replaced the module, I never had the problem again. Give it a try, it's cheap.

**Badbrad469** · 04-29-2009, 11:31 AM

Originally Posted by GaryL

I had this same problem on my wife's old 92 S-10 Blazer. It was intermittant, so it was hard to track down. I finally found it to be the ignition module. I kept telling myself it wasn't, because I had spark. But after I replaced the module, I never had the problem again. Give it a try, it's cheap.

ya i forgot about that one. i also had the problem too with mine. you can take the ignition control module up to autozone or oreilly and they can test it for you.