LT1 fuel pressure testing in-progress, will report results
Thread Starter
Le Mans Master
Joined: Feb 2002
Posts: 7,858
Likes: 2
LT1 fuel pressure testing in-progress, will report results
Car has been sitting all week, so gauge read zero when connected, but immediately pressurized to 41lbs at key-on. Timing it now for potential bleed-down, then more tests to follow...
Thread Starter
Le Mans Master
Joined: Feb 2002
Posts: 7,858
Likes: 2
Re: LT1 fuel pressure testing in-progress, will report results (Lone Ranger)
15 minutes drops to 36psi
10 more minutes drops to 33psi
10 more minutes drops to 31psi
10 more minutes drops to 29psi
-------------------------------------
total: 45 minutes drops from 41psi to 29psi
Start engine drops it from 41psi to 37psi and holds steady @ 37 while idling
Pull vacuum line off FPR while engine idling brings it up to 45 or 46psi
Engine was not at full operating temp for the above, going to drive it for awhile and re-test w/ hot engine.
Not going to do the gauge-on-windshield driving observations yet, perhaps tomorrow if it seems necessary.
[Modified by Lone Ranger, 1:38 PM 4/26/2003]
10 more minutes drops to 33psi
10 more minutes drops to 31psi
10 more minutes drops to 29psi
-------------------------------------
total: 45 minutes drops from 41psi to 29psi
Start engine drops it from 41psi to 37psi and holds steady @ 37 while idling
Pull vacuum line off FPR while engine idling brings it up to 45 or 46psi
Engine was not at full operating temp for the above, going to drive it for awhile and re-test w/ hot engine.
Not going to do the gauge-on-windshield driving observations yet, perhaps tomorrow if it seems necessary.
[Modified by Lone Ranger, 1:38 PM 4/26/2003]
Team Owner
Joined: Apr 2001
Posts: 22,267
Likes: 3
From: Dallas TX
Re: LT1 fuel pressure testing in-progress, will report results (Lone Ranger)
There's going to be pressure drop.. it's a matter of how much. I changed out my stock injectors for 30# SVO's after i could watch the pressure go from 45psi to 0 in less than 30 mins. it could also be your fuel pump, btw.... but injectors fixed mine.
Thread Starter
Le Mans Master
Joined: Feb 2002
Posts: 7,858
Likes: 2
Re: LT1 fuel pressure testing in-progress, will report results (GlockLT4)
Ran the test with the engine hot, and got a little bit different results:
Key-on pressurizes it to 41psi, 15 minutes later she's still holding 41psi-- no bleed-down drop apparent on the gauge. I didn't wait any more, since it appeared that with the system hot it holds pressure with little or no bleed-down (at least for fifteen minutes).
Engine start-up and idle dropped it from 41psi to 36psi-- no major difference from the cold test. Engine idling and pulled vacuum line off FPR caused it to go up to 44psi, about 1 psi or so less than when the engine was idling 'cold' (warming up).
All of the tests both cold and hot seem to be within spec, AFAIK.
How come it holds pressure better when hot than when cold, anyone know?
[Modified by Lone Ranger, 5:57 PM 4/26/2003]
Key-on pressurizes it to 41psi, 15 minutes later she's still holding 41psi-- no bleed-down drop apparent on the gauge. I didn't wait any more, since it appeared that with the system hot it holds pressure with little or no bleed-down (at least for fifteen minutes).
Engine start-up and idle dropped it from 41psi to 36psi-- no major difference from the cold test. Engine idling and pulled vacuum line off FPR caused it to go up to 44psi, about 1 psi or so less than when the engine was idling 'cold' (warming up).
All of the tests both cold and hot seem to be within spec, AFAIK.
How come it holds pressure better when hot than when cold, anyone know?
[Modified by Lone Ranger, 5:57 PM 4/26/2003]
