Mark-87-951

I have the Lindsey fuel rail with an AEM fuel pressure regulator. I've been trying to figure out why my fuel pressure drops immediately rather than as noted at Clark's Garage.

Previous to testing today, I had a mechanical gauge and electronic gauge sensor at the FPR, using a t-fitting off the FPR gauge port. Dave Lindsey suggested that maybe putting a gauge at their damper might be a better location, so I moved the mechanical gauge there.

I used the DME relay bypass and then clamped the hose between the FPR and damper, pulled the relay and still had the pressure go to zero, no waiting 20 minutes, it just starts to drop until it's nothing. I then repeated this and clamped the hose coming out of the front end of the rail and got the same result.

I finally pulled the rail and got it up to pressure and had paper towels over the injectors, expecting a leaking injector(s). Nothing, and pressure still dropped when the relay was pulled.

I put in a new check valve when I installed the new fuel pump. What else could be the problem?? I don't have any visible leaks.

Bri Bro

Clamp the return line and quickly run the pump being carefull not to build excessive preasure. If it drops the zero again, the new check valve ain't working.

Mark-87-951

I'm thinking the line at the front end of the fuel rail is the return line. There really isnt much more to clamp. At least a new check valve is cheaper than new injectors, just a bit more hassle to replace in this weather.

Mark-87-951

And it would figure that a new part would fail for me. The spark plug wires I purchased not long ago failed as well. Paragon was quick with replacing them though.

special tool

Then you are thinking wrong.
The front line is pressure.
The last in line is always the regulator because it regulates by restriction.

You need to check your injectors.

951Saga

The return line comes off the FPR and the feed line enters the damper, (line up front), so clamp the line from the FPR. Sounds like the check valve at this point.

Mark-87-951

Ah, thanks for that info.

I had the rail off, the system up to pressure and nothing from the injectors.

special tool

And a new check valve?????

Mark-87-951

I clamped the line between the FPR and the t-fitting between the damper and the rear end of the rail. Still sound like the check valve?

951Saga

I apologize I'm not too familiar with the LR rail and AEM bits. Can you clamp lines before and after the FPR?

Mark-87-951

Well, I thought the hv fuel pump I got from Lindsey Racing had a new check valve on it. I'm thinking I screwed up

Mark-87-951

Yes I can. I'm thinking I screwed up by assuming the new fuel pump also had a new check valve. Everything hooked up fine but I'm thinking that end fitting wasnt a check valve - doi!

special tool

Do you have a picture of the front of it?

Mark-87-951

The pump?

It's this one here

http://www.lindseyracing.com/mm5/mer...944BOSCHHVPUMP

Bri Bro

They are cheap compared to the cost of the fuel pump.
http://www.paragon-products.com/prod...87.010.536.htm