Pinched fuel return line.. big problem??
Thread Starter
Racer
Joined: Nov 2002
Posts: 471
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From: Queens NY
Pinched fuel return line.. big problem??
While looking for the cause of my above-3000 rpm significant power loss, I changed the fuel filter and noticed that the return line is pinched underneath the fuel filter
Would this be the cause of my crappy performance? :banghead:
Would this be the cause of my crappy performance? :banghead:
Team Owner
Joined: Dec 2000
Posts: 90,675
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From: SE NY
Cruise-In II Veteran
Re: Pinched fuel return line.. big problem?? (CarAteMyMoney)
Put a gauge on the Schraeder valve to see if fuel pressure holds under hard acceleration. You can lay the gauge under the right side wiper so you can watch it.
Le Mans Master
Joined: Apr 2000
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From: DrunkDefender
CI 1-2-3-4-5-6-7-8 Veteran
CI-IV AutoX Champ
CI-IV Burnout Champ
St. Jude Donor '07-'10
Re: Pinched fuel return line.. big problem?? (65Z01)
I had a Yukon in the shop last week that had a pinched fuel return line. Fuel pressure would go as high as 90 psi and it ran rough to say the least. Check your fuel pressure and see if its high.
Team Owner
Joined: May 2002
Posts: 24,337
Likes: 25
From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
Re: Pinched fuel return line.. big problem?? (CarAteMyMoney)
Mine is like this too. I just noticed a few weeks ago. Apparently the moronic previous owner felt ballzy enough to jack up his own car. You can't blame em though, those jacking points are ridiculous. It'd be easy to f' up your fuel lines, brake lines, parking brake cable, nothing important. :rolleyes: Why don't they put a jacking point on the wiring harness while they're at it.
I'm getting a fuel pressure guage soon, I'll let you know what I find out on mine... but I do believe its running rich. I have new 22 lb injectors and AFPR to put in. My 85 came with 24# from the factory.
I'm getting a fuel pressure guage soon, I'll let you know what I find out on mine... but I do believe its running rich. I have new 22 lb injectors and AFPR to put in. My 85 came with 24# from the factory.
Thread Starter
Racer
Joined: Nov 2002
Posts: 471
Likes: 0
From: Queens NY
Re: Pinched fuel return line.. big problem?? (Dr. Evil)
it idles rough but not too bad, it's a little smoother when i put the computer in field service mode
but would the pinched return line effect higher rpm performance?
but would the pinched return line effect higher rpm performance?
Le Mans Master
Joined: Dec 2000
Posts: 7,839
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From: San Diego, Ca
Re: Pinched fuel return line.. big problem?? (CarAteMyMoney)
A restriction raises pressure which enriches the mixture and can cause driveability problems. If it gets high enough (GM cautions going above 60 psi), the regulator will fail. A pressure test at idle and while driving will show whether or not it's a problem. A scan would be a good idea too and if it's been a problem for any length of time, check the plugs for fouling (rough idle), check/change the oil if it has a fuel odor, and check for a restricted exhaust (power loss).
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Re: Pinched fuel return line.. big problem?? (SunCr)
A restriction raises pressure which enriches the mixture and can cause driveability problems.
Because we have electric fuel pumps, the volume output is NOT rpm related. The problem of a restriction in the return line, would tend to ease at higher rpms/loads, as the engine consumes more fuel, and there is less fuel to be returned to the tank. Good luck, and...
RACE ON!!!
1984 Crossfire
Member NHRA
Thread Starter
Racer
Joined: Nov 2002
Posts: 471
Likes: 0
From: Queens NY
Re: Pinched fuel return line.. big problem?? (65Z01)
65Z01,
did you get my Im regarding the field service mode? my computer's been messed up lately, but why does my car run smoother when in FSM?
did you get my Im regarding the field service mode? my computer's been messed up lately, but why does my car run smoother when in FSM?
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