Engine peters out under load
Thread Starter
Intermediate
Joined: Jul 2011
Posts: 30
Likes: 1
From: Dix Hills, Long Island NY
Engine peters out under load
My restored 454 with rebuilt Rochester Quadrajet has started to lose power under hard acceleration and stops RPM climbing at a certain point.
In beginning it started to lose power at 65-70 mph, then 50 mph , and now at almost any speed when I put the pedal down for full throttle. This is now happening even when parked.
Changed carbs with no improvement. Fuel filter, fuel lines and tank are new and spotless. Fuel pump works. So you might think it was an electrical problem, but there is no misfiring, no back firing, no apparent timing issues and idles OK.
We are going to have to take it apart and look at the distributor gear, maybe the timing chain (although no misfiring).
Has anyone had such a problem?
In beginning it started to lose power at 65-70 mph, then 50 mph , and now at almost any speed when I put the pedal down for full throttle. This is now happening even when parked.
Changed carbs with no improvement. Fuel filter, fuel lines and tank are new and spotless. Fuel pump works. So you might think it was an electrical problem, but there is no misfiring, no back firing, no apparent timing issues and idles OK.
We are going to have to take it apart and look at the distributor gear, maybe the timing chain (although no misfiring).
Has anyone had such a problem?
Thread Starter
Intermediate
Joined: Jul 2011
Posts: 30
Likes: 1
From: Dix Hills, Long Island NY
I had the same problem even after installing my 2nd rebuilt Rochester Quad.
FUEL SUPPLY was the first suspicion and had some black particles in the fuel filter but now the 2nd fuel filter has remained clean and problem still persists.
FUEL SUPPLY was the first suspicion and had some black particles in the fuel filter but now the 2nd fuel filter has remained clean and problem still persists.
Thread Starter
Intermediate
Joined: Jul 2011
Posts: 30
Likes: 1
From: Dix Hills, Long Island NY
I think that the fact that the problem seems to be getting worse (occurring at lower and lower speeds ) should tell me something is wearing out or getting more broken or something!
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Joined: Oct 2008
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From: Long Island
If it's still stock, put a jumper from 12v to the + of the coil and see if it gets better, if it does it's electrical. Resistance wire, condenser or coil.
I agree it appears to be a fuel issue.
I just had a similar issue on my 85, 838 w/carb , my MSD box went bad. Drove me nuts.
I agree it appears to be a fuel issue.
I just had a similar issue on my 85, 838 w/carb , my MSD box went bad. Drove me nuts.
Thread Starter
Intermediate
Joined: Jul 2011
Posts: 30
Likes: 1
From: Dix Hills, Long Island NY
We did the fuel flow check by cranking engine with carb tube disconnected but maybe that doesn't tell us everything that happens under load.
We will install new fuel pump with different Roch Quad carb and see what happens.
We will install new fuel pump with different Roch Quad carb and see what happens.
Is my vette stock?? HAHA
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Put a fuel pressure gauge in there as well. I had a brand new pump fail after a few weeks, only new because of the pressure gauge
Le Mans Master
Joined: Apr 2011
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From: Hermosa
So it doesn't act like it runs out of fuel then recovers then does it again over and over until you back off the throttle? Not sure what you mean by struggles to increase RPM. I was under the impression it was cutting in and out.