New to Forum.. I am having problems with 94 blazer full size. V-8, Automatic. All right guys I am writing for my husband... Poor man has been trying like crazy to get this thing running.. He has changed just about everything .. from the computer to pump, TPS,.. you name it.. The truck will run but the RPms are around 1500 if it goes below that it dies.. Will not idle!! Not sure what elese to check.. Any ideas please write back..Thanks!

 

perhaps check the timing? is it carburated? you could adjust the idle as well. just throwing some suggestions out. maybe some help from a mod. would be good

 

Do a fuel pressure test.

 

Has he tried the IAC? Idle air control module. It controls the engine at low rpms, idleing.

Make sure all teh vacuum lines are connected. And since he has changed a bunch of stuff already, make sure they are connected correctly.

Being a '94 it should be fuel injected. Fuel pressure test is a good thing to check.

How is the air cleaner, is it clean?

what about the fuel filter. Strange as this is going to sound, a partially plugged filter could give your trouble at lower rpms.

To get some more specific info it would be nice to know which V8 were talking about.

Anyother thing to check is the injectors, if they are partially blocked it will also run like crap.

I like to start with the simple stuff first.

Another posibility is the Ignition control module, It controls spark timing. EVen if it is broken you can still get spark, just the timing will be off. Most auto parts stores can test it for free.

I would also check for a vacuum leak at teh intake manifold. Get a length of hose. Place one end to your ear and move the other end around the engine comaprtment, careful of the fan blades and hot parts.

You could also srap either (in small shots) around the intake maifold and vacuum lines. If the engine accelerates you have a vacuum leak.

Sorry for rampling in no uncertain order. Sorry for the list of things and nothing specific to your problem.
If you could provide more detail that would help eliminate things.

 

Replaced the ICm and still same problems. Blazer will run at 1500 rpms if your foot is on gas. Seems like it is getting to much fuel. Checked for leaks can not find any. ? I am not sure what else to do.. running low on cash. need truck for work.. Have not changed the ignition module. What about the o2 sensor?? Dad came over and thinking maybe the distributer. The cam shaft sensor??

 

How did you check for fuel leaks? Did you do a fuel pressure test?

*EDIT* - Removed incorrect info...

 

Husband says it is a TPI not a cpi.....?? When we got the Blazer from his brother he said that the people he bought it from replaced the engine.. WE Drove it home from N. Texas. Drove great just had a hesitation in it. How can you tell for sure if it is the right engine. We are now thinking it may be a 91 engine instead of 94.. Lots of black tape underhood if you know what I mean .. Thanks for your reply. We are still trying.. ( Took it in and had a pressure test ran on it.)

 

You could of tested it yourself for free.


Clean the MAf sensor.

 

Sorry, I completely missed the "fullsize v-8"... In that case, there would not be a MAF sensor and yes, it would be a TBI.

When you attempt to start the motor, do you see fuel spray out of the bottom of the injectors (above the throttle body)?

 

yes there is a full spray .