Fuel pressure increase?

[Jon89LE]

On the stock fuel rails, is there a way to manually increase the fuel pressure. Any screws to turn? I pulled my plugs and they're whitish which means im running hot. For the past week my cars temp has been creeping up to 220* lately and then it'll drop back down to around 200 so the guage is just backing up the sparkplug reading. So the only thing i could think of is assuming the filter is fine and pump, that the pressure is off. That temp is also with running 93. And by any chance, would anyone happen to know the fuel pressure range that I should see at the fuel rail when at idle and cruise? Thanks

[RidgeRunner]

For which engine?

If it helps any, my '93 3.1 is supposed to be 41-47psi (or that's what Haynes says), and i believe that's with the vac line disconnected from the regulator. Do you have a fuel pressure gauge? They're not terribly expensive, I think about $25 will get you one from autozone.

[Jon89LE]

Its the Gen2 3.1 engine. Ive done internal, head, and exhaust work but i assumed the computer would calibrate itself. Is there any way to increase it?

[geoffinbc]

You need to buy and adjustable regulator. The stock one has the vacuum port right in the top. This makes it impossible to install a screw in this location. Caspers Electronics has what you need.

Stock pressure should be 41 to 47. It should drop 5-10 with the vacuum connected.

[Jon89LE]

If I buy a regulator, where would i put it since the stock rails are under the plenum? You mentioned with the vacuum connected it should drop 5-10 psi. Is it possible to plug up the vacuum hose to get the higher reading constantly or does that vacuum line serve another pupose?

[oil pan 4]

Some guys put a shim in the stock fuel fressure reg. like a dime, nickle or washer.

[LA1 Z24]

You can turn the stock FPR into an adjustable. THere is an awesome thread on here about it somewhere. It involves buying a rebuild kit for a different FPR and modyfinig the stocker.

[geoffinbc]

Yea that could work so long as you get the vacuum line out of the center of the diaphragm.

If you buy an adjustable regulator it simply goes in place of the stock one. It is just a re-and-re

[Jon89LE]

Would doing that coin thing work?

[geoffinbc]

Yea. But it would only be adjustable depending on the shims you use. So every time you needed to change it you would have to remove the regulator and dissamble it.

[Jon89LE]

Well thats fine for me. I dont need it constantly adjustable. Im just looking to see if increasing it will get rid of that mysterious knock im getting that i think is detonation.

[oil pan 4]

When you are stock and start leaning out add a dime. When that's not engough any more replace it with a nickel.
A lot of TPI guys do it over on camaroz28.com

[geoffinbc]

I would be using stainless shimming washers. Not nickels and dimes.

[Jon89LE]

Is there anything that needs to be modified or removed in the regulator to add the "shim" or does the spring sit against a flat surface? Also, to see if fuel IS my issue, could i plug up the vacuum lines to get a constant increase in psi?

[geoffinbc]

Yes you can remove and plug the line. It will increase the pressure under high vacuum where it would normally be decreased.

Inside the regulator you will find a spring that fits into a retainer. Put shims on the seat of the retainer and it will collapse the spring more causing the spressure to increase.