I have been reading the post about ignition modules. My situation is I have the original IM in car. Cold start engine runs fine, around 10-15 min into running engine runs rough under load. Idle is ok. Checked fuel pressures....ok Checked wires...ok. Plugs were replaced recently. Cap and rotor done recently. Fuel pump and pressure regulator changed within a year. Sometimes engine will not start hot but still get spark from coil, Blue with a tinge of orange. Could this still be the Ignition module? Could the IM get hot and thow off the ignition spark so the engine won't start? I just want to be sure because the part cost $130.00 and the car is a 1995 with 172000 miles on it. Otherwise runs great. Enjoy the game today. Thanks for the help.

 

Is it the vortec 4.3L with central port injection??? Is it harder to start after its warmed up??

 

You can remove the ICM and have it tested at various autoparts stores. A failing ICM can definitely cause the symptoms you are experiencing.

The CPI engine was the only engine offered in the 95 Blazers.

 

It is the 4.3 with central port injection, VIN 8 digit W. The hard starting is not constant. It is only a intermittent problem. I have called every autozone in my area and they do not check IM's. I live in Rockland county NY. Does anyone know of a parts store that can do the test it in my area?

 

Found out what the problem was, of course after I installed the new module. The injector wire that go into the lower intake on the driver front of the engine, must be a short inside the plenum. When I went to check the vacuum line from the evap to the throttle I moved the wires and the engine stalled. I pulled the wires out about a 1/4 inch and the engine ran smooth. I am going to take the upper plenum off to check further. Will keep everyone posted........

 

Sure sounds like you found the problem. I can't say that this is the first I have heard of an injector wiring issue, but it is one of the things that gets overlooked by pretty much everyone. Thanks for the check-in! Let us know how the repair goes.

 

Ok. Took upper plenum off last night. Wires were intact, no breaks or bare wires. Continuity was good between connector and injector plug. Only thing I could figure was connector was loose on injector and when I pulled it through the intake, it tightened on the injector and ran fine. So I tightened and cleaned the pins in the injector end as best I could and it seems to be working. I will eventually replace the connector when I get a chance. Thanks for all the input and the great forum. Keep up the good work.

 

Hey if one of the little keeper tabs is broke off the plug they have replacement new ones at oreilly's I broke mine when I was doin the nut kit and spyder Did the inside of your intake look all black with NO washed spots If so your a lucky man If it were me I would still make an EGR blockoff plate Glad you fixed it intermitten problems will make ya pull yer hair out

 

No. Overall I think the plug is a little loose on the injector in the middle of the spyder. Old age a alot of miles. Around 172000 and 15 years old. What do you mean about black with washed out spots in the intake and the block off plate? I used to have issues with the egr evry once in awhile when a piece of carbon would get stuck and make the engine run bad. Always traveled with a screwdriver and 10 mm socket and rachet to fix it when it happended. I eventually put in a button to activate the egr to clear it when the problem hapended.

 

As far as a blockoff plate I took a piece of 1/8in plate steele and traced the end of the egr then drilled the holes out for the bolts Done a lil clean up with a bench grinder and put the gasket on then the plate then the egr It looks functional and its still hooked up but the intake won't get nasty antmore. The washed spots if there are any will be on the left or right Left = regulator Right = nut kit Leaking If its all an even black sooty color then your OK but if its light and you can see the intake aluminium were fuel has sprayed the intake clean its time for the regulator or nut kit to be replaced and usually it'll show its ugly head at 150k + There's posts about it and what to look 4 If you search it you can see pictures My other intakes covered by a foot of snow or I would send ya a pic of what its supposed to look like when its not leakin