Fuel system will not prime?????
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From: http://www.mphparts.com 800-364-1975
Originally Posted by SmoothFRC
I thought of trying this (with disconnecting the return line) I am just waiting to get the line tool off my buddy...
When i started this post - the car was not holding pressure at all during the priming process - Now the car is, but inconsistantly, so i have to think there is still a checkvalve of some sort in the system... But why it is inconsistant??? I dont know......
If you're not holding pressure DURING the priming process, either your pump is not pushing fuel or your regulator is letting it go right back to the fuel tank. The check valve, while important, should not do much for you during priming (based on my experience of running around for a few months without a check valve).
Thread Starter
Melting Slicks
Joined: Dec 2002
Posts: 2,480
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From: Middletown DE
This has been my thinking and my buddies also...
We are thinking pump issues or maybe a bad regulator - but the only thing that changed was the pump - everything was working peachy before that.
$5 is $5
Since there is now 3" of snow on the ground with like 5 more on the way tonight - i am in no rush to get the tool, but will have it in hand shortly.
We are thinking pump issues or maybe a bad regulator - but the only thing that changed was the pump - everything was working peachy before that.
$5 is $5
Since there is now 3" of snow on the ground with like 5 more on the way tonight - i am in no rush to get the tool, but will have it in hand shortly.
Thread Starter
Melting Slicks
Joined: Dec 2002
Posts: 2,480
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From: Middletown DE
I am being told there is NO checkvalve in the newer cars because the regulator is in the filter (which i think i heard before on here), but.... The car held pressure fine before i changed the pump - and now since it is inconsistant, i am skeptical at that being the case.
Melting Slicks
Joined: Jan 2003
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Don't take this the wrong way but...When I installed the Racetronix I found it confusing when wiring the new pump. The polarity is reversed so the ground wire becomes the hot wire and visa versa. Did you use A&A's instructions for the install? Because it is clearly outlined there. The pump may pump, but poorly if wired wrong. It's just a suggestion.
Melting Slicks
Joined: Mar 2002
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From: Tx
Originally Posted by SmoothFRC
I am being told there is NO checkvalve in the newer cars because the regulator is in the filter (which i think i heard before on here), but.... The car held pressure fine before i changed the pump - and now since it is inconsistant, i am skeptical at that being the case.
If there is not a check valve, the pump must just naturally hold presure. I have a 2002 car and swapped to the 97 rails and return line. I also put in a 97 filter. Pressure drops to 40psi as soon as the pump turns off, but seems to bleed down very slowly from there (it would take hours to drop to 0). It behaves just like it did when I had the '02 rail and filter on.
Pulling off the return line and seeing if any fuel is going back to the tank seems like the next logical troubleshooting step.
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From: http://www.mphparts.com 800-364-1975
FWIW, everything I have ever heard indicates that there is a check valve on late model fuel systems. My car is an '02 and when my fuel system was redone at Norris Motorsports, Mike explicitly told me that there is no longer a check valve in my system because all that gear was replaced.
I came back later on and added an Aeromotive check valve immediately before or after my fuel filter (I don't remember which).
I came back later on and added an Aeromotive check valve immediately before or after my fuel filter (I don't remember which).
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Thread Starter
Melting Slicks
Joined: Dec 2002
Posts: 2,480
Likes: 62
From: Middletown DE
Racetronix Explicitly explained to me that there is NO check valve in the pump.....
I asked him to send me the PDF for the 99-03 fuel system to see if the feed line from the tank to the filter is the same, which would indeed include the checkvalve. (still waiting on this)
I did pick up the tool last night, and i went out, hooked the constant up and the car read 0 - did 1 prime and murphy's law of course, car primed to 56-8 psi and dropped to 40ish once the pump shut off... Maybe if my check valve was sticking.... as it is not holding more time then not.
I am still going to pull the return line and see how it primes with that disconected (into a bucket of course) It should still hold the 40psi with the regulator in place. I am sure it wil bleed off some, but that is to be expected.
The replacment pump was pre-wired, all i had to do was plug in my fuel level sensor and it was done, so there is no chance i wired it wrong. (but i sill use a&a's instructions for reference) I could do this swap in my sleep at this point.
I asked him to send me the PDF for the 99-03 fuel system to see if the feed line from the tank to the filter is the same, which would indeed include the checkvalve. (still waiting on this)
I did pick up the tool last night, and i went out, hooked the constant up and the car read 0 - did 1 prime and murphy's law of course, car primed to 56-8 psi and dropped to 40ish once the pump shut off... Maybe if my check valve was sticking.... as it is not holding more time then not.
I am still going to pull the return line and see how it primes with that disconected (into a bucket of course) It should still hold the 40psi with the regulator in place. I am sure it wil bleed off some, but that is to be expected.
The replacment pump was pre-wired, all i had to do was plug in my fuel level sensor and it was done, so there is no chance i wired it wrong. (but i sill use a&a's instructions for reference) I could do this swap in my sleep at this point.
Melting Slicks
Joined: Dec 2002
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From: Friendswood, Tx
Originally Posted by IM QUIKR
Don't take this the wrong way but...When I installed the Racetronix I found it confusing when wiring the new pump. The polarity is reversed so the ground wire becomes the hot wire and visa versa. Did you use A&A's instructions for the install? Because it is clearly outlined there. The pump may pump, but poorly if wired wrong. It's just a suggestion.
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From: A dealer near you.
The pump would not produce much pressure if it was wired in reverse. The C5 systems come with the pump pre-wired from Racetronix.
According to G.M.'s tech site your 2000 C5 does have a checkvalve built into the plastic feedline coming off the module.
The G.M. part number and description for the feedline on your 2000 C5 is different from the 1997-1998 C5's. The 97-98 part lists the feedline as having a checkvalve and the 2000 does not.
Conflicting information from G.M.
According to G.M.'s tech site your 2000 C5 does have a checkvalve built into the plastic feedline coming off the module.
The G.M. part number and description for the feedline on your 2000 C5 is different from the 1997-1998 C5's. The 97-98 part lists the feedline as having a checkvalve and the 2000 does not.
Conflicting information from G.M.
Thread Starter
Melting Slicks
Joined: Dec 2002
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From: Middletown DE
For the past few days the car has been priming and holding pressure with no issues..
One thing that is worrying me... I initially thought i had something wrong with my FP gauge because it was not sweeping like it usually does (and now does) but i am thinking that the gauge was actually fine, but maybe the pump that was not building any pressure during the priming process... the gauge would just rest at 0 during this process and would not move... Unlike when it primes properly, the pressure will jump to 60 and immediatly drop to 45-ish and slowly drop from there... So i agree that it is impossible for the pump to prime the system and the pressure drop to 0 in a matter of a 1/2 second.....
I am going to knock on wood for now and hope it was a glitch with the new pump break in - but i dont really get the warm and fuzzy feeling from it.
One thing that is worrying me... I initially thought i had something wrong with my FP gauge because it was not sweeping like it usually does (and now does) but i am thinking that the gauge was actually fine, but maybe the pump that was not building any pressure during the priming process... the gauge would just rest at 0 during this process and would not move... Unlike when it primes properly, the pressure will jump to 60 and immediatly drop to 45-ish and slowly drop from there... So i agree that it is impossible for the pump to prime the system and the pressure drop to 0 in a matter of a 1/2 second.....
I am going to knock on wood for now and hope it was a glitch with the new pump break in - but i dont really get the warm and fuzzy feeling from it.
Le Mans Master
Joined: Aug 2001
Posts: 7,064
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From: Arizona
Originally Posted by Busa196
I didn't know that this was possible- I thought if it were wired incorrectly, the pump simply wouldn't work. So, it is possible to wire the pump wrong and for it still to work?
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From: A dealer near you.
Originally Posted by ICULUKN-C5
It will work.. just not well. I would check to wiring just to eliminate that possibliity.
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From: A dealer near you.
Originally Posted by SmoothFRC
For the past few days the car has been priming and holding pressure with no issues..
One thing that is worrying me... I initially thought i had something wrong with my FP gauge because it was not sweeping like it usually does (and now does) but i am thinking that the gauge was actually fine, but maybe the pump that was not building any pressure during the priming process... the gauge would just rest at 0 during this process and would not move... Unlike when it primes properly, the pressure will jump to 60 and immediatly drop to 45-ish and slowly drop from there... So i agree that it is impossible for the pump to prime the system and the pressure drop to 0 in a matter of a 1/2 second.....
I am going to knock on wood for now and hope it was a glitch with the new pump break in - but i dont really get the warm and fuzzy feeling from it.
One thing that is worrying me... I initially thought i had something wrong with my FP gauge because it was not sweeping like it usually does (and now does) but i am thinking that the gauge was actually fine, but maybe the pump that was not building any pressure during the priming process... the gauge would just rest at 0 during this process and would not move... Unlike when it primes properly, the pressure will jump to 60 and immediatly drop to 45-ish and slowly drop from there... So i agree that it is impossible for the pump to prime the system and the pressure drop to 0 in a matter of a 1/2 second.....
I am going to knock on wood for now and hope it was a glitch with the new pump break in - but i dont really get the warm and fuzzy feeling from it.
Thread Starter
Melting Slicks
Joined: Dec 2002
Posts: 2,480
Likes: 62
From: Middletown DE
I understand what you are saying... What i am thinking about is that when the car is supposed to be priming - the pump should push 60-ish psi to the rail regardless if there is a checkvalve in place or regulator.... and this should be reflected on the FP Gauge, when the pump shut's off, you should see the pressure fall on the gauge..
What i am saying is - from what i recall, the gauge never budged, stayed at 0 during the priming process, which leads me to beleive the pump was actually not priming the system at all... And the car would not start in this condition - just crank for a while until the pump actually pressurized the rail.
Granted, it seems to be working now, but nothing has changed...
What i am saying is - from what i recall, the gauge never budged, stayed at 0 during the priming process, which leads me to beleive the pump was actually not priming the system at all... And the car would not start in this condition - just crank for a while until the pump actually pressurized the rail.
Granted, it seems to be working now, but nothing has changed...
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From: A dealer near you.
Originally Posted by SmoothFRC
I understand what you are saying... What i am thinking about is that when the car is supposed to be priming - the pump should push 60-ish psi to the rail regardless if there is a checkvalve in place or regulator.... and this should be reflected on the FP Gauge, when the pump shut's off, you should see the pressure fall on the gauge..
What i am saying is - from what i recall, the gauge never budged, stayed at 0 during the priming process, which leads me to beleive the pump was actually not priming the system at all... And the car would not start in this condition - just crank for a while until the pump actually pressurized the rail.
Granted, it seems to be working now, but nothing has changed...
What i am saying is - from what i recall, the gauge never budged, stayed at 0 during the priming process, which leads me to beleive the pump was actually not priming the system at all... And the car would not start in this condition - just crank for a while until the pump actually pressurized the rail.
Granted, it seems to be working now, but nothing has changed...
Thread Starter
Melting Slicks
Joined: Dec 2002
Posts: 2,480
Likes: 62
From: Middletown DE
I can only assume that if air is getting into the lines, that i would have quite a fuel leak on my hands...
And like i said - the system seems to be working fine now - and i have not touched anything besides playing with the gauge to have it on constant power to see how the pressure is acting during the powerup sequence.
I agree, it is a wierd one - It is not like this is the first time i am changing the pump in this car, it is straight forward and there are no leaks.
And like i said - the system seems to be working fine now - and i have not touched anything besides playing with the gauge to have it on constant power to see how the pressure is acting during the powerup sequence.
I agree, it is a wierd one - It is not like this is the first time i am changing the pump in this car, it is straight forward and there are no leaks.
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From: A dealer near you.
Originally Posted by SmoothFRC
I can only assume that if air is getting into the lines, that i would have quite a fuel leak on my hands...
And like i said - the system seems to be working fine now - and i have not touched anything besides playing with the gauge to have it on constant power to see how the pressure is acting during the powerup sequence.
I agree, it is a wierd one - It is not like this is the first time i am changing the pump in this car, it is straight forward and there are no leaks.
And like i said - the system seems to be working fine now - and i have not touched anything besides playing with the gauge to have it on constant power to see how the pressure is acting during the powerup sequence.
I agree, it is a wierd one - It is not like this is the first time i am changing the pump in this car, it is straight forward and there are no leaks.
