5.7 Bogs at full throttle when warm
September 13th, 2018, 10:17 PM
#11
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Sorry been busy. Still don't have it fixed but here's an update.
This is turning into the weirdest problem. The bog on throttle problem is directly connected to fuel pressure. When the fuel pressure is near 60, it runs great, when the pressure comes down, usually bottoming out around 52, the problem comes back. It has nothing to do with engine temperature. The other night, it stayed at 60 Psi for 10 minutes after starting, fully warmed up and all. Then something happened and it slowly dropped to 52 psi, causing the problem. When I started it tonight, it had the lower fuel pressure at startup (cold) and stayed that way.
What is causing my fuel pressure fluctuation?? This is gonna drive me crazy. I suppose I could just swap the fuel pump, but that's a lot of work if it doesn't fix it... Also, I've been trying all this with just under a quarter tank of gas, I should probably trying filling it up to see if that helps?
This is turning into the weirdest problem. The bog on throttle problem is directly connected to fuel pressure. When the fuel pressure is near 60, it runs great, when the pressure comes down, usually bottoming out around 52, the problem comes back. It has nothing to do with engine temperature. The other night, it stayed at 60 Psi for 10 minutes after starting, fully warmed up and all. Then something happened and it slowly dropped to 52 psi, causing the problem. When I started it tonight, it had the lower fuel pressure at startup (cold) and stayed that way.
What is causing my fuel pressure fluctuation?? This is gonna drive me crazy. I suppose I could just swap the fuel pump, but that's a lot of work if it doesn't fix it... Also, I've been trying all this with just under a quarter tank of gas, I should probably trying filling it up to see if that helps?
September 29th, 2018, 10:06 PM
#13
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Well, the fuel pressure regulator is actually inside the intake manifold. Took me just under an hour to get in there.
But that WAS the problem!! I didn't replace the FPR, I just found out that there was so much GUNK in the intake manifold, it clogged the vaccuum port on the FPR!! Cleaned it out, put it back together, realized I forgot one O-ring, took it all back apart again, back together again, and FIXED, no more hesitation / bog on throttle!!
Now what's weird is, the fuel pressure is still at 52 lbs at idle, but now when throttle is applied it shoots up to 60+ momentarily, whereas before it would drop a psi or two.
Thanks everyone for the input.
But that WAS the problem!! I didn't replace the FPR, I just found out that there was so much GUNK in the intake manifold, it clogged the vaccuum port on the FPR!! Cleaned it out, put it back together, realized I forgot one O-ring, took it all back apart again, back together again, and FIXED, no more hesitation / bog on throttle!!
Now what's weird is, the fuel pressure is still at 52 lbs at idle, but now when throttle is applied it shoots up to 60+ momentarily, whereas before it would drop a psi or two.
Thanks everyone for the input.
