My Blazer started running like it had bad gas, then was hard to start, then DEAD! I checked the "PCM", Brain, and no power to "red" or "blue" ports. I checked the ICM-Ignition Control Mod, and got 11.96volts in to the ICM at the Ign 1 and Ign coil control wires, but have not checked the wires going out am about to check this toaday and the "CPS" crankshaft position sensor. The other thing is when it was running like crap, the check engine light was on so I unhooked the battery, I know wrong thing to do, but the Balzer ran great until I runned it off and then will not start. Sounds like timming is off and backfires through throttle body. ???? Any ideas. THANKS

 

Probably a dead fuel pump. Can you you here it when you turn key on?

 

I would check the fuel pump fuse and the fuel pump relay first. I believe that both are located in the engine compartment fuse block on the drivers side inner fender. If the fuse is good and the relay is clicking when the key is turned on, then it is a pump problem. If it will run, spit/spudder, then die, it's mostlikely a pump problem, but it never hurts to check the simple/cheap things first.

 

I would test the battery and the electronic control module. Take them both to your local autoparts store.

The ECM controls the spark timing, if it is shot you can still get spark and the truck might still run, although it will seem like the timing is off.

 

Thanks for your reply, the battery is good and is the ECM the same as the ICM? I was looking up things on ALLDATA and thought that that they are the same part, just called different names? May just have to pay the BIG bucks to have a garage check it out. Need to get it running. Will let you, and the others know when I find out what the problem(s) are. Thanks again.

 

I have now tried to pour some gas down through the throttle body and it still didn't start. Do you think it could still be the fuel pump. Also am trying to find the crank position sensor, any idea where it's at on my 2002 LS. Thanks.

 

Check your fuel pressure at Napa or AZ...should be 55-62psi @crank/idle...our Blazers eat fuel pumps...

 

lovetheblazer, where would this reading be at in the fuel system. I know that there is a spot to check the fuel pressure down behind the throttle body. Is that where the psi you told me about should be checked? Thanks, 57

 

It buzzes for a few seconds and then shuts off like it's suppose to. It may just be going out. Am going to get the pressure checked to see if it measures up. First I'm going to change the fuel filter, even though I changed it about 3 months ago. Thanks, 57

 

All right then, I believe you can rent a fuel pressure guage at CARzone. Good Luck 57Chevy. Git R done!