won't turn over??!

[thirsty]

are you gettting oil pressure?

Good point there Capt. I fixed the same problem once with a few qts. of oil.

[2502]

The ECM triggers the Injectors to fire.  Do you have anything disconnected?  Any broken/frayed wires?.  The injectors are tied into the fuel pump and oil pressure switch, are you gettting oil pressure?  Is it connected?  The only other thing I could thing of it the ignition module.

we went thru it today to doublecheck connections and didn't SEE any wires disconnected or frayed, melted etc. when it starts up, nothing abnormal shows in my oil pressure gauge, so i'm lost. i was thinking maybe the ecm died.

but the fuel pump DID die too, i just didn't think it was coincidental that both of them went together. i mean who knows it's an old truck. my friend initially thought maybe the injectors were out but they spray when they have power to them so i'm assuming it's maybe the ecm.

anyway to test either one to eliminate them before i start replacing stuff again that's not broke? lol

[VileZambonie]

You need to verify your fuel pressure and check for injector pulse. If you have correct fuel pressure and no injector pulse you can do a few easy pinpoint tests. Did you check your fuel pressure? Do you have a test light or noid lights?

[2502]

You need to verify your fuel pressure and check for injector pulse. If you have correct fuel pressure and no injector pulse you can do a few easy pinpoint tests. Did you check your fuel pressure? Do you have a test light or noid lights?

no i don't have any of that... maybe i can get a friend that has test lights to come thru and check it out

[2502]

ok tell me what tests to run and i'll do it when my friend gets off work and can give me a hand with the stuff i dn't know how to do

[VileZambonie]

are you gettting oil pressure?

Good point there Capt. I fixed the same problem once with a few qts. of oil.

What did you do that to that fixed the problem?

ok tell me what tests to run and i'll do it when my friend gets off work and can give me a hand with the stuff i dn't know how to do

Verify spark (do you know how to do this?)

Verify injector pulse ( Test light to ground, key on engine off, unplug one injector connector. One terminal should have B+. Now probe the other terminal with the test light connected to B+. Have an assistant crank the engine. Test light should blink

[2502]

are you gettting oil pressure?

Good point there Capt. I fixed the same problem once with a few qts. of oil.

What did you do that to that fixed the problem?

ok tell me what tests to run and i'll do it when my friend gets off work and can give me a hand with the stuff i dn't know how to do

Verify spark (do you know how to do this?)

Verify injector pulse ( Test light to ground, key on engine off, unplug one injector connector. One terminal should have B+. Now probe the other terminal with the test light connected to B+. Have an assistant crank the engine. Test light should blink

i gotta get a test light mine is missing from teh garage go figure.

i'm gonna try this tomorrow i didn't have the extra body to try things out today. i swear it's probably something simple and i just don't know enuff about this stuff to get it right.

[thirsty]

are you gettting oil pressure?

Good point there Capt. I fixed the same problem once with a few qts. of oil.

What did you do that to that fixed the problem?

The oil pressure switch shut the fuel pump off.
The truck would run for a short time and die. I noticed it was 2.5qts low on oil after I added oil it didn't die any more.

[VileZambonie]

Thirsty,

The oil pressure switch doesn't shut down the fuel pump, it enables it. In the event that the fuel pump relay fails, the oil pressure switch would provide a back feed to the fuel pump. So what you'd get is an extended crank but it would still run. You probably had a problem with the fuel pump circuit. Many people think the oil pressure was a protective series circuit but it wasn't. You could drain the oil and it should still start and run.

[2502]

since it was sitting, i did change the oil. that didn't make a diff it still starts up if it's sat, then dies right after.

[Irish_Alley]

dont know why I didnt see this but just now realized its for a 95, are you saying it will start up but will die within seconds. if this is the case a couple things to try would be the pick-up coil or icm. kind of leaning towards the icm, the ecm primes the pump which is why you hear it run from the start, then the ecm waits for a pulse from the icm to keep the pump running, if the icm is good i think you can test them at the parts store then the only thing else i can think of is the pick-up coil i dont know why but for some reason its staying in my head as a possible problem kind of a hunch i hate to suggest something on a hunch but what the heck lol

[VileZambonie]

You're right Irish,

It could be many things including the icm but with a few simple tests he can avoid throwing parts at it uneccessarily.

You need to verify fuel pressure, spark and injector pulse for any of us to really help you out here unless you're willing to just throw parts at it.

[Irish_Alley]

yeah wasting money sucks

[2502]

i was away all weekend and hopefully today a friend is coming to check the fuel pressure i'll let you know in a few hrs

[thirsty]

Thirsty,

The oil pressure switch doesn't shut down the fuel pump, it enables it. In the event that the fuel pump relay fails, the oil pressure switch would provide a back feed to the fuel pump. So what you'd get is an extended crank but it would still run. You probably had a problem with the fuel pump circuit. Many people think the oil pressure was a protective series circuit but it wasn't. You could drain the oil and it should still start and run.

I stand corrected.
Years ago I was told that the oil pressure switch would shut the pump down to protect the motor by someone that I thought I could believe. I was sold on the theory without ever looking into it, even more so when adding oil to that 90' chevy made it stay running.

The best part of this forum is that you get tons of advise and people like Vile will take the time to explain things to everybody when advise is not accurate for your situation.