Hello guys,
I was driving the truck, and all of a sudden, it stalled as I was going 45 MPH. Many years ago, that happened to me on an old van, which turned out to be a mechanical fuel pump failure. So that was the first thing I checked, but the fuel pump is getting power, and it is working. So the engine just turns, and nothing happens. Any suggestions or ideas of what it can be? The truck is a manual, V6 4.3L engine.
Thank you
As a '96 truck it should have OBD2 communication from the engine computer. So is your check engine light on? What are the error codes (in the form P1234)?
If it has no check engine light and just died, the crankshaft position sensor has failed. It cost $25 and is located in the distributor.
Try spraying starter fluid into the intake while cranking the engine. If it starts and runs as long as you spray, it IS a fuel supply problem. If it doesn’t it is an ignition problem. Try hooking a timing light to any spark plug wire, if it flashes while cranking, you have ignition.
Post back with answers to the questions and we’ll go from there.
It all boils down to air, spark, and fuel. Sounds like you’re getting air and spark.
How are you “testing” the fuel pump? I know Chevy/GM trucks of this vintage were notorious for having bad fuel pumps, with little or no warning.
There was no check engine light on. I was having a problem because the fuel pump would run even with the key out. I was able to start the truck without the fuel pump relay being in place, which means I have a short somewhere, and unfortunately, it is not on that relay box (I took it apart, and it is clean). So would undo the battery when not driving the truck. I checked for power by the fuel pump, and I am getting power, and I can hear the pump, and still, someone suggested checking if I am getting fuel by the fuel rail, so I thought of checking that. The crankshaft position sensor was replaced last year.
To check for spark, take any spark plug you have laying around and plug it into the end of any spark plug wire on the engine.
Lay the spark plug on the engine to ground it.
While someone is cranking the engine over, watch the end of the spark plug.
The spark should be bright blue in color.
If there’s no spark or the spark is more of a yellow color, there may be a problem with ignition control module.
Tester
And compression.
Without compression, an engine can’t run.
Tester
You said it would run with the key out, even with the fuel pump relay removed???
Is the vehicle starting or not??
Edit: Did you take the relay apart or the fuse block assembly a part?? not sure if you are calling the relay a box or what it plugs into a box…
Davesmopar,
The deal about the truck starting without the fuel relay is before my new problem of the truck now no starting at all. I mentioned it as background information…
Did you fix the old problem or is the new problem a continuation of the old problem that has gotten worse??
And if old problem fixed, how long ago was it??
I did the spark plug test three times because I am NOT getting any color spark. I was sort of hoping I was not grounding the spark plug correctly, but no matter what I did, I had no spark. I used an old spark plug for this test, so all I did was remove one of the spark wires and plug in the old spark plug.
I have not yet fix the old problem because it seems I may have to run new wires all the way to fuel pump.
I use an old spark plug with about a 0.060 to 0.080 gap with a wire (insulation removed at plug) wrapped around the threads of the plug taped on so it doesn’t fall off and an alligator clip on the other end connected to a known good ground… if it will jump a .080 gap you have spark…
I’d be looking at a bad ignition module.
Tester
Thanks for your reply,
Just curious because I replaced the ignition control module last summer, so I was wondering if there is no spark, is there anything else that could be the culprit? Is there a way to test this module? How about the ignition coil?
Thanks
If you have consent power to the fuel pump with the relay and key out and the issue is getting worse, you have wires melting together somewhere and have a possible fire hazard…
It could be anything in the secondary ignition system that can cause a no-spark condition.
But I base my answers on what is the most common cause that I’ve seen over the years of repairing vehicles.
Just because a component was replaced a short time ago, don’t dismiss it not being the problem.
Something else I’ve learned over the years.
Parts stores use to be able to test ignition modules. But since today’s vehicles no longer use ignition modules it’s become an obsolete practice.
So, the spark plug test is used instead to determine if might be the ignition module.
Tester
Yes, the original problem that you said was never resolved…
So I tested the ignition coil, and I got a spark, I then unplugged one of the wires from the distributor cap and I had no spark. I tested a different distributor wire for spark, and nothing. I removed the the less that one year old distributor and to my surprise, there is a white rust looking film on the contacts, and the distributor has an actual burn mark. I was expecting a longer live span on these parts.
Suggest to replace distributor cap, rotor, the spark plug wires, and the spark plugs. I own a similar vintage Corolla, started ok, but had to replace all that stuff before it would pass an emissions test.
Ideas what’s causing the burn marks
