kennybiv

Hello can anybody help me?
I've got a 95 chevy S10 4x4 blazer w/ 4.3 w engine CMFI That will not start. Symptoms when quit running were rough running then smoothed out. Went to start next day hasn't started since.(5 days) At first i thought it was coil so inspected coil even took to parts shop had it checked it was ok. Also checked ignition module and connector according with Haynes and Chilton manuals. It showed to be good.Even replaced with new and no difference. Ran checks for spark at plugs, which I have, replaced plug wires as coil wire was questionable so replaced all as a set. Replaced all plugs. They were in fair condition but dry like no fuel. Check fuel pump. It was working but would put up 61 psi when running and as soon as pump stop would fall to 0. So troubleshoot fuel pump and components according to Chilton manual. Pinch fuel pressure line off after pump stop and held pressure so replaced pump. Now 61 psi when pump running and holding 58 psi when shut off. While cranking about 58 psi fuel pressure. Connect noid light to injector wire harness and have fire at plug while cranking. Checked injector side of plug showing 2.0 ohms. Haynes manual says 1.37 to 1.77 ohms.
Replaced camshaft sensor rotor cap and distributor cap. Rotor cap post was broken in two. Replaced fuel filter. Replaced battery as old one was weak. There is no fuel smell as if getting fuel and not firing. Could timing be out? Something wrong with CMFI unit or some other problem. As far as codes the only way I could retrieve any was with Autoxray scanner on OBD II generic and I did have a P1351 code set then clear. also showing P0700 and P1100 codes pending? I did troubleshoot the 1351 code and didn't find any problems.Haven't been able to find out what other 2 are for. The Transmissiom was changed out 2 0r 3 years ago.
Any help would be very much appreciated

jackass#1

seems like youve done everything. tried timming? is fuel
comming uot of injecters to to plugs?

kennybiv

I've checked timing with timing light to what look like pointer and mark on harmonic balance (only notch in balance) while crnking engine and it's showing in time also when had dist cap off rolledengine to #1 cly at cap and notch was lined up to timing mark. Didn't pull plug and check for #1 tdc though maybe should do that. 1 other question. You have to pull air plenum to get to cmfi unit which means all components are unplugged. If you crank engine will you still get fuel to poppet valves or will something have it linked out? Something not getting singnal to fire injectors.? Could it possibly be the cmfi unit even though pressure checks indicate good. This is probably high $ item and if not problem won't be able to return parts. Haha.What about oil pressure swith. Saw where it supposed to be linked to fuel system also. But seem like if not getting signal shouldn't be getting fire to injector plug? Haven't tried starting fluid to see if would even hit really don't want to try either but may have to. Any other ideas? thanks again.

BlazerLT

You always test fuel pressure with the key on without starting the engine.

Should be minimum 56psi.

The other codes seem to be computer related.

Remove the top IMTV valve and check for washing in the upper plenum.

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1995 Factory Blazer Service Manual for sale, PM if interested.

Fireplug

Spray some carb cleaner in the intake and see if it trys to start. That way we can pin point if its a fuel or spark problem

kennybiv

Ok tried the starting fluid ( very little) and would hit but no start. Seems to be leaning toward the cpi unit everything else workin so gotta be it.
Anybody know if GM has had alot of problems with the cpi units?

BlazerLT

hehe, yea, you could say that.

Do a search here for CPI injector.

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1995 Factory Blazer Service Manual for sale, PM if interested.

kennybiv

yippee!! Got it running and runs good put in new cpi unit. Come to find out was fuel pump and cpi unit. Fuel pump wasn't holding fuel pressure and cpi injector not spraying. Only found out by troubleshooting fuel system again cause presssure good after changing pump. Parts are high though. This might help somebody else now or in future.
Thanks for the replys.

BlazerLT

Excellent, glad to see you up and running.

__________________
1995 Factory Blazer Service Manual for sale, PM if interested.