Aeromotive 340 Woes.
11-03-2013, 09:46 PM
#1
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Aeromotive 340 Woes. I've been chasing a rich, rough idle issue for several weeks and think I found the issue...
My idle fuel pressure is 70 psi (used two different gauges on the test port -- same result). The pressure drops immediately to 62 psi when i rev the engine up a couple thousand rpms. When I turn the key on, the pump primes to 62 psi and drops to 54 psi as soon as the pump stops priming. The pressure drops to 54 psi as soon as the engine is shut off. The pressure is 50 psi five minutes after shutdown and 47 psi ten minutes after shutdown.
My plugs read like the tune is good everywhere but idle. The car runs pretty strong at WOT but shakes pretty good at idle as though it was missing (all cylinders are firing normally.
Can 70 psi at idle cause the engine to shake and sound like it is missing?
The short specs are:
2000 Camaro SS, 6-spd, 4.10 gears
383, 11:1, LS6 intake, 42 lb FIC injectors, Stealth 340 pump, Hotwire kit, etc.... 451 rwhp, 443 rwtq.
The engine did not shake or feel like it was missing initially; It started to have issues a week or so after the motor and 340 pump install. I will post some pics of the plugs.
Thanks!
My idle fuel pressure is 70 psi (used two different gauges on the test port -- same result). The pressure drops immediately to 62 psi when i rev the engine up a couple thousand rpms. When I turn the key on, the pump primes to 62 psi and drops to 54 psi as soon as the pump stops priming. The pressure drops to 54 psi as soon as the engine is shut off. The pressure is 50 psi five minutes after shutdown and 47 psi ten minutes after shutdown.
My plugs read like the tune is good everywhere but idle. The car runs pretty strong at WOT but shakes pretty good at idle as though it was missing (all cylinders are firing normally.
Can 70 psi at idle cause the engine to shake and sound like it is missing?
The short specs are:
2000 Camaro SS, 6-spd, 4.10 gears
383, 11:1, LS6 intake, 42 lb FIC injectors, Stealth 340 pump, Hotwire kit, etc.... 451 rwhp, 443 rwtq.
The engine did not shake or feel like it was missing initially; It started to have issues a week or so after the motor and 340 pump install. I will post some pics of the plugs.
Thanks!
Last edited by gixxer9; 11-03-2013 at 10:32 PM. Reason: Add car info..
11-04-2013, 09:21 AM
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Yes. I'm using the stock regulator.
I realize that I should be running a return line system, but it seems many guys are running the single line system without the issues I'm having. I'll have no problem with doing the return line conversion if I know that it'll clean up my idle (roughness and richness).
Do I have any other options?
I know I cannot simply have the car tuned as though it had 46 lb injectors because they only flow more at idle due to the increased pressure but the pressure drops to 62 psi (where the injectors flow 43.5 lbs) when the engine is revved.
I realize that I should be running a return line system, but it seems many guys are running the single line system without the issues I'm having. I'll have no problem with doing the return line conversion if I know that it'll clean up my idle (roughness and richness).
Do I have any other options?
I know I cannot simply have the car tuned as though it had 46 lb injectors because they only flow more at idle due to the increased pressure but the pressure drops to 62 psi (where the injectors flow 43.5 lbs) when the engine is revved.
Last edited by gixxer9; 11-04-2013 at 09:31 AM.
11-04-2013, 10:51 AM
#6
If the changes in fuel pressure are consistent (always drops at the same point) you could tune this out but the correct way is to add a return and aftermarket regulator.
Leaving the stock regulator and tuning is only a short term solution though because the pump will likely fail (most seem to fail in 6-12 months)
Leaving the stock regulator and tuning is only a short term solution though because the pump will likely fail (most seem to fail in 6-12 months)
