rough running sporadic hard starting
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rough running sporadic hard starting
I have a 1990 eddie bauer with the 5.8 it idles steady sometimes and sounds like it has a e303 others an when driving down the road it sometimes feels like it is loosing power biggest problem is sometimes if you pull it somewhere an shut it off it acts like it is out of fuel when you try to start it hooked a fuel pressure gauge to it today it is idleing on 30 psi remove the vacuum to fpr it goes to about 38psi. When i hooked a manual vacuum gauge to the fpr the more vacuum the higher the pressure goes. Also the pressure seems to drop a couple psi whith throttle. And i have a solid 15 on the intake vacuum. I feel like the fpr may be bad but looking for opinions
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Joined: Sep 2002
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From: Gateway to the West
Typical suggestion is to run KOEO and/or KOER tests first. Performance issues will trigger fault codes that will help pinpoint the problem areas without spending a lot of time troubleshooting things that are not the problem.
However, with the research you have already done, the FPR is a very simple device consisting of a vacuum diaphragm and a valve. If there is no fuel leaking into the vacuum side of the FPR, chances are there is nothing wrong with it. Fuel pressure below 40 PSI at the rail is indicative of a poorly performing pump or a clogged filter given that the FPR is regulating pressure down from the maximum pressure coming directly from the pump. Given your 30 PSI at idle, and a mere 38 with no vacuum to the FPR (which should leave the FPR "wide open"), I'd bet the problem is upstream of the FPR starting with the filter (inboard side of the driver's side frame rail directly below the driver's seat).
However, with the research you have already done, the FPR is a very simple device consisting of a vacuum diaphragm and a valve. If there is no fuel leaking into the vacuum side of the FPR, chances are there is nothing wrong with it. Fuel pressure below 40 PSI at the rail is indicative of a poorly performing pump or a clogged filter given that the FPR is regulating pressure down from the maximum pressure coming directly from the pump. Given your 30 PSI at idle, and a mere 38 with no vacuum to the FPR (which should leave the FPR "wide open"), I'd bet the problem is upstream of the FPR starting with the filter (inboard side of the driver's side frame rail directly below the driver's seat).
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Joined: Apr 2005
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From: Longview, TX
FPR
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Fuel Injection Technical Library » Fuel Pressure Regulator (FPR)
Fuel Injection Technical Library » Fuel Pressure Regulator (FPR)
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Joined: Jan 2003
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I replaced all the plastic vacuum lines with rubber hose
My 1990 Bronco used to have all kinds of little annoying issues like that. I replaced all the plastic lines with rubber hose and it made things a lot better.
You might want to look at your plastic vacuum lines..they tend to get brittle and develop little cracks.
You might want to look at your plastic vacuum lines..they tend to get brittle and develop little cracks.
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