Fuel Pressure Regulator?

[HellOnWheels]

I have a no-start situation with my 87 and believe it could be the fuel pressure regulator?

Key on (engine off) fuel pressure gauge will jump to normal fuel pressure and will remain there as long as the ignition is on, however, the fuel pump runs continously and fuel can be heard going thru the fuel rail...could it be the FPR?

TIA
HOW

 

[Black Car]

After the key is turned to "on" but engine not running, the fuel pump relay is suppose to run the pump 3-5 seconds and shut off till the engine rpm exceeds 400-500 range.
If the fuel pump is running all the time the key is "on" then you should hear the fuel flowing through the return line because the injectors are (should be) closed.
So I wouldn't think the FPR is your problem.

Gary

 

[wantan87]

I had this problem with my fuel pump staying on also. 2 questions for you does the main 3 lights come on the dash when you turn the key to on the oil pressure light, volt light and service engine light come on? Second question is have you washed your car latley? If you saw yes to the first part all 3 lights come on I don't know. But if they don't check your computer it might be wet and very soapy. This is what happened to me got a new computer and the car starts up right away.

 

[DHarber]

I dont believe it is your non starting issue, but the fuel pump will also stay running if your oil pressure switch is bad internally. Disconect the oil pressure swith which is right above the oil filter and turn the key on. You should hear the fuel pump run for 2 seconds and then shut off as long as the fuel pump relay is working correctly.
If it works right, replace your switch.
I dont believe your your injectors are open with just the key on, or you would have massive flooding. Fuel would be pouring on top of your pistons. You can check your oil dipstick and see if it reads overfull and smells like gas.
Again I dont think that is the case, but if it is the only thing that will cause this is your ECM is shot. Good luck

 

[HellOnWheels]

Originally posted by Black Car
After the key is turned to "on" but engine not running, the fuel pump relay is suppose to run the pump 3-5 seconds and shut off till the engine rpm exceeds 400-500 range.
If the fuel pump is running all the time the key is "on" then you should hear the fuel flowing through the return line because the injectors are (should be) closed.
So I wouldn't think the FPR is your problem.

Gary

Gary, the fuel can be heard running thru the system, plus fuel pressure gauge will hold set pressure as long as key is on, and will hold for a while after the ign is turned off, in other words all seems okay except the fuel pump run on continusly. The engine tries to start. I've cranked it for 15-20 seconds at a time to no avail.

Any help is appreciated,

HOW

 

[HellOnWheels]

Wantan87:

Only seat belt light comes on when ignition is turned on.
Computer is not wet.

Think it may be the ECM?...hope not!
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DHarber:

Disconnected the oil pressure switch, key on pump NOT running.


What next?


HOW

 

[wantan87]

I think it is. Those 3 lights should always come on when the ignition is on. At least on my digital dash it does. I'm pretty sure it is but i'm still new around these TR so I could be wrong. ECM aren't that expensive like $80 their is a guy on here that I bough mine form John his email addy is Rudykz@cs.com I can't think of his s/n off hand.

 

[HellOnWheels]

Originally posted by wantan87
I think it is. Those 3 lights should always come on when the ignition is on. At least on my digital dash it does. I'm pretty sure it is but i'm still new around these TR so I could be wrong. ECM aren't that expensive like $80 their is a guy on here that I bough mine form John his email addy is Rudykz@cs.com I can't think of his s/n off hand.

Is there a way to test the ECM, without a zillion dollar tester?

HOW

 

[wantan87]

Thats a good question but I can't answer that one for you sorry.

 

[DHarber]

You say switch disconnected and pump not running.
You need to listen for the first 2 seconds too see if the pump runs and then shuts off after the key is first turned on.
If it goes off after the 2 second on time then you need to replace the oil pressure switch. This is possibly why your oil/choke light does not come on the dashboard.

 

[Shane]

Originally posted by HellOnWheels
Is there a way to test the ECM, without a zillion dollar tester?

HOW

Not really that I know of. They are decently cheap. You can get them from junkyards for like $40. Search the forum Junkyard Dogs for the cars that the ECM came in. It came in non turbo cars.

 

[HellOnWheels]

Originally posted by DHarber
You say switch disconnected and pump not running.
You need to listen for the first 2 seconds too see if the pump runs and then shuts off after the key is first turned on.
If it goes off after the 2 second on time then you need to replace the oil pressure switch. This is possibly why your oil/choke light does not come on the dashboard.

With the switch disconnected the pump will not run, with key on.



HOW

 

[DOG]

Sorry to piggy back on this thread but i am having the same start issue. (new battery, alternator, charging system good and intact) Sometimes i don't get any fuel pressure to the engine, but other times it cranks up with no problem. Its a crap shoot every time i decide to go out for the day. How do i diagnose this problem? have someone place the ignition to on while i listen under the hood or back by the fuel tank? where is the relay located and the grounds for the fuel system. I have gotten lucky a couple of times and had a friend help me out with some jumper cables, but the GN was reluctant to turn over.

I dont have any issue cruising around town with fuel / oil pressure, its only during the starting when there is no pressure. thank you all for your time.

 

[williamsGN]

clamp the rubber return line with some vice grips and a rag around the line below the FPR, see if you get pressure.