Very odd fuel pressure issue.

[ZX2Fast]

So, at 150,000 miles the wifes car started losing fuel pressure. Since I've put a SVT pump in mine I already know how to do it and it is cheaper then buying a stock replacement. Anyway, I put the pump in and noticed a strange surge when driving. I put the fuel pressure tester on the car and the pressure would drop to 20 psi and then quickly jump to about 40 psi. It would slowly drop to 20 psi and then jump to 40 psi again. It just keeps doing this. The next time I drove it I noticed the issue went away. I thought it just cleared up. Nope, the time after that it did the same shit again. I noticed that if I start the car before the pump stops pressurizing the system (before the 1 second is up when you first turn the key on) it will jump to 80 psi then fall to 20 psi, and start the 20-40 psi cycle again. But, if I let the pump run the whole second (turns off after it pressurizes the system) the car runs like normal and holds normal fuel pressure. I installed a spare pressure sensor and still the same issue. I even installed a spare FPDM and still the same issue. The problem started directly after I put the SVT pump in, but I don't see why the pump would affect the pressure just because I do or don't wait the whole second before starting it. If I unplug the pressure sensor it runs at 60 psi no matter how I start the car. I called the tech at Ford and he says he has never heard of this issue on any car, ever. He even owns a ZX2. So, we just wait the whole second before we start the car. It sure is annoying though. Has anyone ever heard of such a thing?

Here is a vid of it:
http://vids.myspace.com/index.cfm?fuseaction=vids.individual&VideoID=32476985

[scort2498]

i think im fighting the same issue as you... i saw this video a few days ago and i deceided to wait the second like you did in the vid and it went away. however i didn't replace any parts. but when i wait my bogging/surging between2500-3000 went away so idk.

[99S/R]

Timely post. My car is in the shop for the 2nd time in two weeks because it was bucking and the engine was shutting down. Code said high fuel pressure and shop diagnosed as bad fuel pressure sensor. They would tap the sensor and it would read high pressure then next tap the pressure would read normal. All the while the acuall pressure was rock-solid. I was told a bad sensor would shut down the fuel pump trying to regulate the pressure.
I will find out on Mon if its still the same issue.

Bill

[mechtech]

Filter sock problems?
I'd take a look and also try a new fuel filter.
my first guess is the FP sensor, but you said it was checked by replacement. Maybe it it not OK with the new pump.

[ZX2Fast]

I put new socks on it. The filter was replaced last fall but I guess it wouldn't hurt to do it again. Still odd that starting the car before the second is up causes this issue. I have nocticed that I can hear a soft burp, like a squeak coming from the tank after the pressure shoots up to 80 psi. I figure there is some sort of pressure relief in the tank, maybe in the pump. If it is in the pump, that would explain why this issue started when I installed the pump.

[mechtech]

This sure does sound odd.
I hate these type of problems when they come in.
Maybe the controller does not mate with the new pump precisely.
Also a bad seal somewhere.
A bit of work and a PITA, but could you swap controllers or pumps to test it?

[ZX2Fast]

I've already tried my spare FPDM, no success. I'm using this exact pump in my car without issue.