Intermittent Low Idle, Stalling
06-20-2017, 08:25 AM
#22
Another thing that just dawned on me. I have a Walbro 400 in the tank, inline filter/regulator, then fuel rail.
My pressure at the rail is about 50-55psi when the key is in the on position and the fuel pump primes the system. When the car is running, the gauge is pegged out at 100psi.
Is this not another indication that my regulator is failing since I thought it was supposed to regulate at about 58psi to the fuel system?
My pressure at the rail is about 50-55psi when the key is in the on position and the fuel pump primes the system. When the car is running, the gauge is pegged out at 100psi.
Is this not another indication that my regulator is failing since I thought it was supposed to regulate at about 58psi to the fuel system?
06-20-2017, 06:58 PM
#24
TECH Senior Member
iTrader: (7)
People have reported issues with the Corvette filter/regulator when used with high flow pumps. Perhaps it was fine for a while and then went caput? Maybe swap it out for a new AC Delco part? Seems cheap enough...
Andrew
Andrew
06-21-2017, 09:29 PM
#26
I replaced the filter regulator with a Wix part. Still have the RPM flux every time I go into neutral from driving.
But..now, there's a power cut when I'm under acceleration. If I get on the gas, the engine kicks back on power bad then revs up a bit and kicks back again then goes. It's never done this before.
Now I'm wondering if the Walbro 400 pump is crapped out.
I don't have a MAF by the way, it's density tune.
Thoughts?
But..now, there's a power cut when I'm under acceleration. If I get on the gas, the engine kicks back on power bad then revs up a bit and kicks back again then goes. It's never done this before.
Now I'm wondering if the Walbro 400 pump is crapped out.
I don't have a MAF by the way, it's density tune.
Thoughts?
06-22-2017, 12:57 PM
#31
I just read through the thread again....I don't think what's happened so far points necessarily to a fuel system problem. Mind you - I don't know what's wrong, but there are lots of other issues that could cause the symptoms you're having with the fuel system working just fine. If pressures are indeed varying while driving (...and you don't know that for certain...), why wouldn't the system throw codes as it's trying and failing to run properly and maintain appropriate a/f mixtures? The vast majority of the time, my experience has been that electric fuel pumps either work or they don't. I've never experienced any intermittent issues with them (I'm sure others have...). When stuff comes and goes, it's usually an electrical issue of some sort.
06-22-2017, 04:41 PM
#32
If you watch the video, you'll see that my fuel pressure is at 58 psi pretty solid. I slowly rev the engine at first and things are fine. Then at :28 seconds, I punch it and you an hear the super charger wind down then bang, it backfires. If I punch the gas, the engine starves...but fuel pressure stays solid....why? No CEL and no background codes on computer.
What do I need to look at next?
06-22-2017, 05:04 PM
#33
I just read through the thread again....I don't think what's happened so far points necessarily to a fuel system problem. Mind you - I don't know what's wrong, but there are lots of other issues that could cause the symptoms you're having with the fuel system working just fine. If pressures are indeed varying while driving (...and you don't know that for certain...), why wouldn't the system throw codes as it's trying and failing to run properly and maintain appropriate a/f mixtures? The vast majority of the time, my experience has been that electric fuel pumps either work or they don't. I've never experienced any intermittent issues with them (I'm sure others have...). When stuff comes and goes, it's usually an electrical issue of some sort.
And I think the video I posted is fairly indicative of a properly functioning fuel system...at least up to the fuel rail. What's happening with the injectors or air fuel ratio and the computer is still to be determined.
06-22-2017, 09:06 PM
#39
At the suggestion of my father, I pulled the plug from the throttle body and started the car. It ran like crap...kept wanting to stall but kept itself alive. Ran for about 20 seconds. Plugged the throttle body back in and started it up and for about 30 seconds or so, it seemed like the symptoms were gone. I was able to rev the engine with no hesitation and good power....then the symptoms kicked in again. I did get the CEL for TP circuit A and B high and low (P0122 and P0223) but figured they were only caused because I pulled the throttle body connector.
Confused.
Confused.
Last edited by leblanc1; 06-22-2017 at 09:37 PM.