Mysterious problem with my 96 blazer

[dwitczak]

I have a 96 blazer with 4 door, 4wheel drive. The engine was replaced 30k miles ago with a jasper engine.

The truck runs well, but the last two days, while driving, the truck's engine stops running. After it stops running, I try to start it and it will turn but not start. about a minute later it starts running agian. Yesterday it did it twice, the 2nd time was only 1 mile after the first time. I then turned the ac off and when it started again, it drove for about 5 more miles (it did not stall again). I drove it directly to the mechanic and he could not get it to stall.

He did say that the fuel pump was alot loud then any he heard before. The fuel pump was replace 30k miles ago. It always made this much noice. Also, the fuel filter was replaced 15k miles ago.

Also, the distributor cap rear screw housing mount is broken, however, the mechanic and I have it rigged pretty well with zip ties.

I need this vehicle for work and I drive it alot and I do not know what is wrong with it and neither does the mechanic.

Also, the service engine light does NOT come on.

When it stalls it fells like it runs out of gas. It does not buck or hesitates, it just stops running.

The mechanic left it running about an hour an took it for an 11 mile drive and it did not stall. The humity in PA for the last 2 days have been very high, as soom of you might be aware.

[DINO55]

When you have the no start problem, does your fuel pump whine when you turn the key to the on position? Do your dash cluster lights lite up? If you answered no to these questions, you have a bad IGNITION SWITCH HARNESS. Follow the link...

http://www.automotiveforums.com/vbul...gnition+switch

[BlazerLT]

Sounds like a pump problem.

[dwitczak]

Yeh, I think it is the fuel pump too. I just hate replacing parts and not having a decent level of confidence that I am fixing the problem

Yes, electrically everything works fine when it stops running. It starts fine. Even the mechanic said the fuel pump is by far the loudest whining fuel pump he ever heard, especially based upon other blazers. It has always whined loud!. I owned it for one year and the previous owner just replaced the fuel pump before I bought it.

Also, I do not know if this has anything to do with the fuel pump but when I am on a down hill (nose down) I run out of gas with a 1/4 tank. I really hate that.

[BlazerLT]

Originally Posted by dwitczak

Yeh, I think it is the fuel pump too. I just hate replacing parts and not having a decent level of confidence that I am fixing the problem

Yes, electrically everything works fine when it stops running. It starts fine. Even the mechanic said the fuel pump is by far the loudest whining fuel pump he ever heard, especially based upon other blazers. It has always whined loud!. I owned it for one year and the previous owner just replaced the fuel pump before I bought it.

Also, I do not know if this has anything to do with the fuel pump but when I am on a down hill (nose down) I run out of gas with a 1/4 tank. I really hate that.

Your fuel sending unit is out of whack.

[dwitczak]

Is the fuel sending unit part of the fuel pump assembly?

I drove it today about 180 miles and it did not die until the end of the day. Is it normal to run for that long then get screwed up?

[MT-2500]

Originally Posted by dwitczak

I have a 96 blazer with 4 door, 4wheel drive. The engine was replaced 30k miles ago with a jasper engine.

The truck runs well, but the last two days, while driving, the truck's engine stops running. After it stops running, I try to start it and it will turn but not start. about a minute later it starts running agian. Yesterday it did it twice, the 2nd time was only 1 mile after the first time. I then turned the ac off and when it started again, it drove for about 5 more miles (it did not stall again). I drove it directly to the mechanic and he could not get it to stall.

He did say that the fuel pump was alot loud then any he heard before. The fuel pump was replace 30k miles ago. It always made this much noice. Also, the fuel filter was replaced 15k miles ago.

Also, the distributor cap rear screw housing mount is broken, however, the mechanic and I have it rigged pretty well with zip ties.

I need this vehicle for work and I drive it alot and I do not know what is wrong with it and neither does the mechanic.

Also, the service engine light does NOT come on.

When it stalls it fells like it runs out of gas. It does not buck or hesitates, it just stops running.

The mechanic left it running about an hour an took it for an 11 mile drive and it did not stall. The humity in PA for the last 2 days have been very high, as soom of you might be aware.

Time for some proper testing.
Does it lose spark or fuel or both?

For fuel 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.
Do not leave home without it.
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.
Post back fuel pressure readings.
MT

[dwitczak]

I finally found a good mechanic. He had it for an entire day and he drove it 4 times with equipment hooked up and could not get it to stall. So I am assuming he was checking fuel pressure.

[MT-2500]

Originally Posted by dwitczak

I finally found a good mechanic. He had it for an entire day and he drove it 4 times with equipment hooked up and could not get it to stall. So I am assuming he was checking fuel pressure.

Ask him what the pressure reading was?

[BlazerLT]

Originally Posted by dwitczak

I finally found a good mechanic. He had it for an entire day and he drove it 4 times with equipment hooked up and could not get it to stall. So I am assuming he was checking fuel pressure.

I wouldn't assume that.