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possible fuel system problems


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juli
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Sep 5, 2017, 2:44 PM

Post #1 of 23 (921 views)
possible fuel system problems Sign In

I am working on a 1990 Pontiac Bonneville, it has sat for 3 years, because of dieing issues. I have changed the fuel pump, while observing that the filter sock had broken down and was in the bottom of the tank. It ran good for a while. died again, changed fuel filter noe will not start at all. It has fuel pressure, I can hear the pump, but the car will not start. I am courious if the oil pressure sending unit would cause this problem of if you have any ideas where I should look next I whoul be very greatful.


Hammer Time
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Sep 5, 2017, 3:08 PM

Post #2 of 23 (912 views)
Re: possible fuel system problems Sign In

What is the fuel pressure?



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



juli
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Sep 5, 2017, 3:14 PM

Post #3 of 23 (908 views)
Re: possible fuel system problems Sign In

I will have to get a pressure gauge to find that out. I do not have one available at the moment.


Hammer Time
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Sep 5, 2017, 3:29 PM

Post #4 of 23 (904 views)
Re: possible fuel system problems Sign In


Quote
It has fuel pressure


Then obviously, that is an incorrect statement.



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



juli
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Sep 5, 2017, 3:39 PM

Post #5 of 23 (900 views)
Re: possible fuel system problems Sign In

Yes it has fuel pressure when I push the shrader valve.


Hammer Time
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Sep 5, 2017, 3:46 PM

Post #6 of 23 (896 views)
Re: possible fuel system problems Sign In

That doesn't mean a thing if you don't know what the pressure is.

You could try spraying some starting fluid in the intake and see if it starts on that,



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



(This post was edited by Hammer Time on Sep 5, 2017, 3:48 PM)


juli
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Sep 5, 2017, 3:57 PM

Post #7 of 23 (889 views)
Re: possible fuel system problems Sign In

That would tell me if it not getting fuel from the injectors. But would that be a wrong pump, or pressure regulator, correct? I ordered a book will have it tomorrow, then I will at least have diagrams on which relays are which and I will have the specs I need. I will try to do some troubleshooting then if I can't figure it out I will contact you again. Thank you.


(This post was edited by juli on Sep 5, 2017, 4:00 PM)


Hammer Time
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Sep 5, 2017, 4:33 PM

Post #8 of 23 (872 views)
Re: possible fuel system problems Sign In

The only thing that test will tell you is if the problem is fuel related, period.

You aren't going to isolate anything until you get a fuel pressure reading and injector pulse test.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



juli
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Sep 5, 2017, 4:41 PM

Post #9 of 23 (867 views)
Re: possible fuel system problems Sign In

ok thank you


juli
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Sep 6, 2017, 2:11 PM

Post #10 of 23 (829 views)
Re: possible fuel system problems Sign In

Ok car has almost 40psi while running. With tester hooked up, turn on ignition the pressure is less than 10psi. when shut car off the pressure does not hold steady, it drops to 3psi


Hammer Time
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Sep 6, 2017, 3:38 PM

Post #11 of 23 (798 views)
Re: possible fuel system problems Sign In

OK, fuel pressure is leaking from one end or the other.

It could be leaking through the regulator, through a stuck open injector or back through the check valve in the fuel pump.

Pull the vacuum line off the regulator while engine is running and see if there is any fuel in it.

You will have to start pinching off lines at various point to determine where it is leaking to.



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



juli
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Sep 6, 2017, 5:42 PM

Post #12 of 23 (788 views)
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pulled vacuume line, there was no fuel, there is vacuume. ordered pressure regulator. hope it fixes it or the next thing in it might be a bullet.


Hammer Time
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Sep 6, 2017, 5:52 PM

Post #13 of 23 (784 views)
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Why would you do that? There isn't supposed to be fuel in the vacuum line.



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



juli
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Sep 6, 2017, 6:45 PM

Post #14 of 23 (773 views)
Re: possible fuel system problems Sign In

i pulled the vac line to make sure there was vac, there are no external leaks, so the next thing is the pressure regulator right? the only other thing I can think of is that I got the wrong pump.


Hammer Time
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Sep 6, 2017, 7:00 PM

Post #15 of 23 (765 views)
Re: possible fuel system problems Sign In

You're WAAAAYYY out in left field.

You really need to spend your money on a good tech to diagnose it and stop throwing money away at the parts store.



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



juli
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Sep 6, 2017, 7:11 PM

Post #16 of 23 (761 views)
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well then set me straight please!


Hammer Time
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Sep 6, 2017, 7:13 PM

Post #17 of 23 (757 views)
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I just did.



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Tom Greenleaf
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Sep 6, 2017, 11:56 PM

Post #18 of 23 (745 views)
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juli: Sorry if I missed the clue but there IS NOT supposed to be fuel in vacuum line to regulator. It isn't holding pressure is being lost the sock found off on one fuel pump and replaced still does this? Wrong pump - it should be the check valve or fuel pressure pushed right back to tank backwards.


Other: This era hates ethanol in fuels is a disaster to some plastics and rubber products of fuel systems. ? Old replacement pump if OE still should have worked highly suspect now again or fast leaking injector?


T



(This post was edited by Tom Greenleaf on Sep 6, 2017, 11:59 PM)


juli
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Sep 7, 2017, 12:00 PM

Post #19 of 23 (721 views)
Re: possible fuel system problems Sign In

My biggest problem with this car is that it had started to die 3 years ago and was then parked. When I removed the pump there was a lot of particles from the old screen and the rubber in the bottom of the tank. So it was needed to be replaced. The more I think about it, it may not of been a fuel issue to start with. I don't know the history of the car so it could of been something else in the beginning. I do think maybe I did not get the seal on the pump correct, or maybe the sock fell off. As an intermitent problem I am having a hard time tracking down the original issue. As of now I am going to have to drop the tank again and make sure the pump and sock are correct as well as the o ring seal on the top of the tank. With the new regulator I installed the fuel pressure comes up to normal pressure but as soon as the pump stops the pressure leaks back off.


Tom Greenleaf
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Sep 7, 2017, 12:28 PM

Post #20 of 23 (713 views)
Re: possible fuel system problems Sign In

I'm near sure the pump is what does NOT allow fuel pressure backwards - a check valve of its own.
About whatever dirt/particles and rubber (?) found in tank it might have to go. See if dirt will catch on a magnet it shouldn't. The seal should tolerate the ethanol but at the age maybe original one didn't or other rubber parts about it? It's sounds nuts but "gasoline" and proper rubber is fine. Same old type rubber still was good for gasoline but not some in the alcohol?! Some do problems some don't.


Anyway a true new pump should have been complete with all parts rubber seal, the metal ring even and best with fuel gauge. I can't know how available what is to you a dealer even would probably just use whatever aftermarket came in?


Check out cost of a whole tank if it's junk inside from water back when now moving around with current ethanol blend could be quickly defeating the ONE WAY action the fuel pump does.


Fuel filter if off you really shouldn't be able to blow backwards might be a test I haven't done but would prove it's not working for any reason. Dirts or rust could make a good pump go bad it what I'm suspecting about now most just don't want to repeat that over and over,
T



Hammer Time
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Sep 7, 2017, 1:50 PM

Post #21 of 23 (708 views)
Re: possible fuel system problems Sign In

If there is loose crap in the tank, then it is going to ruin every pump you put in it.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



juli
User

Sep 7, 2017, 2:59 PM

Post #22 of 23 (702 views)
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I did get the tank cleaved out, the rubber was part of the piece that the pump insulstor that comes with the new pump, the other had sat so long it had fallen apart.


Tom Greenleaf
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Sep 7, 2017, 3:23 PM

Post #23 of 23 (700 views)
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"Had tank cleaned" Not really as they have baffles inside you could never get small junk all out like particles of whatever already mentioned. Rubber - never saw one do that exactly but always a first time and that seal isn't really inside so IDK where rubber if so got in there?


T







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