Will pcm from anything else work on my 95 blazer?

 

1995 was a crossover year using 2 different fuel delivery systems & 2 different computer control systems, they are NOT interchangeable.

Where is your PCM located?
Do the plug wires attach to the distributor cap horizontal or vertical?

 

Yes i have definatly come to realise the hard way that 95 is a ... Screwball ... Year for the blazer. This one has the pcm behind passenger side kick panel. Two computers actually. Not sure what other is? And it has the standard vertical style dist. Cap... Allow me to pick your mind for a minute if u dont mind , as i see from reading thru this forum u seem to be very knowledgeable about these trucks... I bought this truck which is an absolute creampuff, after sitting for seven years. So one thing after another then another has led to a list of new stuff i.e. Fuel pump ,spider injector, then no ignition.... So new coil ,icm,pick up coil ,plugs, wires, cap n rotor...and a few things im sure i forgot... Anyway i hav solved my ignition problem and almost have fuel problem fixed except now i have no triggering signal to my injector. I do however have 12 volts to it. I can even wire it to battery and manually open and close circuit and it works.... Any ideas as to why this could be?

 

You have an early production '95 using OBDI computer controls and HEI ignition.

Does this vehicle have, or did it have, an aftermarket security system or remote starter? If so, that may be what's causing the problem. If not, continue on...

The PCM uses data from the ignition pick up coil to determine when to fire the injector. Your vehicle does not have a crankshaft position sensor, so make sure you have a good hot blue spark at each spark plug, and at the coil tower, while cranking. If that checks OK...

The ECM/IGN 10 amp fuse supplies voltage to the fuel injector through the pink with black trace wire when the ignition switch is in the CRANK & RUN positions. The PCM supplies ground to the injector through the dark blue wire to open the injector. The connector at the injector is known to have "issues". Heat inside the plenum can cause the connector to become distorted causing the terminals to lose contact with the injector. Most auto parts stores have, or can order, a new connector. Here's how to test the circuit: Using a digital volt meter, hold the positive probe to pink black trace wire terminal in the injector connector and the negative probe to the dark blue wire terminal in the injector connector. While cranking the starter, the volt meter should show a pulsed ground. If that checks ok, the connector needs replacement. If there is no pulse, check for it at the PCM. The dark blue wire runs directly from the injector connector to the PCM connector "C2 pin A18". There are no connectors inbetween. Post your results.

 

Hook, how can find if my truck had a security or remote start. I do see a "black box" under driver side dash just left of steering column...but it looks to me to be factory?. Also i got my hands on another pcm yesterday and hooked it up with no positive results... Is it my understanding as someone xplaind to me that it has to be reprogramed if disconected?

 

Check the black box for a GM part number, and post an image of it. If you post an image of the RPO code sticker, (in the glove box) I can tell you if it was originally equipped with a security system, (other than the standard Passlock system). The PCM/VCM only needs to be flashed if you replace it. The original PCM/VCM was flashed when the vehicle was built. A used, new, or rebuilt PCM/VCM must be flashed to your VIN.

 

i thank you for the info you have been sending... however im looking at my pcm now trying to establish the c2 pin A18.. im not sure quite how to read that. of the two plugs on pcm one is A the other marked E and both only numbered up to 16. ???

 

also... so my original pcm , would it have to be re-flashed if it was disconnected from truck or is it still good to go?

 

Data that is specific to your vehicle is not affected by disconnecting the PCM. If you replace the PCM with a different one, it needs to be flashed.

No C2 pin A18, hmm ok, is there a dark blue wire and a pink with black trace wire at the injector? If so, can you identify them in any of the PCM connectors?

 

hey there. ok so im sitting here with my meter hooked up to the pcm to what im pretty sure is the blue wire at injector if im correct its the #16 pin on the red connector,does this sound right? anyway with key off i have a little over 12 volts ,soon as i turn to run position it drops to .15 volts and when trying to crank it shows .45 ish...?