Fuel Pressure Spikes Cold Engine

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Oct 25, 2014 | 08:01 PM

ebbnflow

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Joined: Sep 2006

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From: NorCal

For the first 5 minutes of my drive every morning, I see this:

I rebuilt the FPR a few months ago because the pressure was high all the time. Could injector O-rings cause this? Thanks in advance.

Oct 26, 2014 | 08:15 PM

ebbnflow

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From: NorCal

Maybe it's my glow shift sensor, but I've got a feeling something else is going on. Anyone??

Oct 26, 2014 | 09:08 PM

TKegs763

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Joined: Dec 2012

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From: Arlington, Texas

I can't see the video, but my fuel pressure first thing in the morning is 6-8 psi higher than it is after it warms up. I'm curious

Oct 26, 2014 | 10:54 PM

ebbnflow

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From: NorCal

I edited the link. I think it works now. Thanks.

Oct 27, 2014 | 06:08 AM

Tugly

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Joined: Jan 2011

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From: Puget Sound

I can't read the numbers, but I offer a counter-thought. Could your FP be low, and it restores momentarily? That looked like air bubbles in fuel, or a poor electrical connection.

Oct 27, 2014 | 06:12 AM

Pikachu

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Joined: Jun 2004

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From: Amarillo, TEXAS!

You might try putting a mechanical gauge on it as a test to eliminate the electric gauge itself as the problem.

Oct 27, 2014 | 07:47 PM

ebbnflow

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From: NorCal

Thanks for the suggestions. I did the hutch and harpoon several years ago. I've got 2 clamps on the lines at the tank. Quick connects are long gone. I think a little clear tubing is in order.

I wish I had a mechanical gauge to try. That would rule out a faulty pressure sensor.

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Nov 17, 2014 | 04:42 PM

ebbnflow

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Senior User

Joined: Sep 2006

Posts: 258

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From: NorCal

I just wanted to post an update. After 10 months if service, the sensor on my glow shift fuel pressure gauge is the culprit. Confirmed by a mechanical fuel gauge and my multimeter. Glow shift was kind enough to send a free replacement.

I wonder if it failed because:

1. I run 100% biodiesel.
2. I neglected to remote mount it. I mounted it directly to the back of my fuel bowl post filter.
3. It is cheap Chinese c.r.a.p.

So let me ask this:

For anyone running a glow shift 0-100psi fuel pressure gauge. How long did your sensor last? Where did you mount it?

Thanks.