LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

Anyone ever have this problem before? (fuel related i think)

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Old Mar 21, 2008 | 11:16 PM
  #1  
Hybrid86Z's Avatar
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Anyone ever have this problem before? (fuel related i think)

when my motor is cold or hasn't been running in a couple hours, I will go to start it, and it'll crank over roughly 3-5 seconds before actually firing up.

once running, its great, no problems. Opti is ok, no problems on the spark side what-so-ever.

I can then turn it off, and start it back up and it'll turn over and fire right away (like it normally should)

It only does this when the motor is cold or hasn't been started in awhile

I'm thinking my FPR is bad maybe? Like it can't hold the fuel from the FPR to the rails for the "cold start"?

The Fuel pump works great too no problems.

I will be getting a fuel pressure tester and put it on to see what the press. is when i turn the FP on during the "cold start".

Buddy of mine thinks there's some "check valve" or something that might be failing?

TIA guys.
Old Mar 21, 2008 | 11:43 PM
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Getting a gauge on there would be a good idea. Pressure should be at 41-47 psi with the vacuum line pulled off of the fpr. If you find that the pump primes as it should and then immediately bleeds off all pressure, there are a few things to check. Either a ripped fpr diaphragm, or a bad check valve in the fuel pump, or leaky injectors. First thing to check is to pull off the vacuum hose to the fpr and look and smell for gas. Another thing you can do is pull up your fuel rail and injectors, turn the key to koeo and see if any fuel comes out of the injectors, if so thay are bad. Good luck with it all.
Old Mar 21, 2008 | 11:46 PM
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Hybrid86Z's Avatar
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thanks for the tip. the injectors are SVO 30's and i bought them used. Will check the other things as well.
Old Mar 22, 2008 | 01:09 AM
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Check valve in the fuel pump. My car does it, mines so bad that I have to prime the car twice then start it. Doesn't effect performance, just starting though.
Old Mar 22, 2008 | 09:40 AM
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Hybrid86Z's Avatar
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Originally Posted by cvccbum
Check valve in the fuel pump. My car does it, mines so bad that I have to prime the car twice then start it. Doesn't effect performance, just starting though.
interesting. does this require replacing the fuel pump? Or is there a part number for just the check valve?

it's a racetronix kit that i bought used (i know i know, buying used stuff leads to things like this lol)

Luckly i did the "trap door" method when I replaced the pump in the 1st place
Old Mar 22, 2008 | 10:04 AM
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are u letting the car completely prime when cold? like are u trying to turn it over while priming or after the fuel pump is done priming?
Old Mar 22, 2008 | 10:19 AM
  #7  
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Originally Posted by Pyrodawg
are u letting the car completely prime when cold? like are u trying to turn it over while priming or after the fuel pump is done priming?
i turn the key to "on" position, wait about 2 seconds (i can hear FP turn on at that time) then go and start it.
Old Mar 22, 2008 | 12:12 PM
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wait until u hear the fuel pump turn off and see how it starts, my car usually is a little harder to start when cold too but its no big deal
Old Mar 22, 2008 | 12:35 PM
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I'm not 100% sure but I believe you have to replace the whole pump. If you only have to wait 2 seconds, I'd say live with it
Old Mar 22, 2008 | 01:07 PM
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Originally Posted by Hybrid86Z
interesting. does this require replacing the fuel pump? Or is there a part number for just the check valve?
As said before, you have to replace the whole pump. If you can verify that it is in fact just the check valve, they you can get away with just priming the pump a couple of times before starting.
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