96 GMC Jimmy is having a few issues with the ignition and the driving performance.?

Dave Myers

New member
Joined
Mar 13, 2010
Messages
1
Reaction score
0
Points
0
My Jimmy won't start on the first ignition attempt, it usually takes 2 times to turn over. Also I've been experiencing sudden hesitations when I'm on the road, usually on the interstate at high speeds. The "service engine soon" light stays on all the time and blinks when the hesitations are severe. I've already changed the fuel filter, the air filter and cleaned the distributor rooter and I've even added fuel cleaning additives to the gas tank regularly but nothing has improved! Do I possibly need a tune-up or a new fuel pump?
 
dont take car advice from a fucking girl. she is wrong
this is what you do go by a bottle of potassium permangante and bronzing powder, mix it together
put it in a pipe with coarse threaded caps on both ends and trill a whole on the top cap, then get a fuse of some kind and run i threw the whole, light the fuse and put the pipe in ur car and run
 
You should check the fuel pressure (the test port is near the firewall at the back of the engine).
For one reason or another, these vehicles absolutely need greater than 55 PSI of fuel pressure or they start hard and don't perform well.
 
You should check the fuel pressure (the test port is near the firewall at the back of the engine).
For one reason or another, these vehicles absolutely need greater than 55 PSI of fuel pressure or they start hard and don't perform well.

Close LeAnne:

You need 3 things.
Compression
Good hot blue spark to all plugs.
Good gasoline and proper fuel pressure. 63-64 lbs.
If you have all 3 then move on to injector pulse to all injectors.
I think each injector is on a separate driver on that one.
Check for pulse to all of them.

It may be weak on fuel pressure . even a couple of lbs low on a cold start will cause a no start. Double check cold start cranking fuel pressure. If under 63-62 lbs you have problems. One test is to give it a squirt of carb cleaner not starting fluid. If it starts then you have a fuel pressure problem.

Run the full fuel pressure test and post back pressures. Here is the guide lines on testing.
Hard to start cold.
* Check cold start fuel pressure.
* Check engine running fuel pressure.
* Check engine running on the road fuel pressure.
Then shut it off and watch for fast leak down.
Pinch off at rubber part or block off return line and check full pressure.
Later V6 and V8 gm engines should have 60-66 fuel pressure.
Cold start should be 64-65 lbs of pressure.
If you do not have full fuel pressure on a cold start the injectors will not squirt fuel.

Engine running should be 60-66 lbs pressure depending on engine load.
Full pressure with return pinched off should be 75-85 or more.
And if it has a fast leak down after shut off you have a leak.
The 75-85 is only a check on the capable full pressure of fuel pump.
If you can not find the rubber return line check full pressure by plugging return line or just or the true full pressure can be taken direct at the end fuel filter.

The other thing also is to check your ground wire to the fuel pump, the ground wire a grounded separate to the frame from the fuel pump sending unit harness. Good luck and hope this helps. :D
 


Back
Top