Hi all,
In Corvette Central's catalog it is suggested to increase your fuel pressure you should disconnect the vacume line off the fuel regulator and plug it. I did this and increased the fuel pressure from 34lbs to 44lbs! Is this a good idea or will it cause problems? Any thoughts or advice?

Thanks

 

Problems, not really. Benefits, not really.

 

Thanks Lee,

I am a little confused though. I thought increasing the fuel pressure increased power out put. I first looked at adjustable fuel regulators and their costs$$$ and then saw this vacume tip in the catalog. So are you saying increasing fuel pressure has no benifits and adjustable fuel regulators and the like are just snake oil?

 

On a mildy modified engine - maybe. On a highly modified engine - yes. On a stock engine - no. No matter how much you increase the pressure the ECM is still going to regulate the amount of air/fuel that engine gets. Increasing the pressure does not relate to horsepower gains indirectly.

 

Thanks again Lee!

My L98 engine has a Hypertech ignition and chip installed in it from the owner before me. I also found an air foil installed in the intake. So it does have some mods. I was trying to increase the fuel pressure for more HP,of course, but, I also was trying to increase the fuel pressure to solve a loping at idle when hot problem. It starts fine, runs well, then when hot it surges or lopes at idle and some times kills. It seem like it starves for fuel at idle when hot. Although acceleration from stop is great with no hesitation. I even did a compression check on all cylinders. Lowest 205Lbs and highiest 211Lbs. Engine cold.

Any other thoughts?

 

you need to hook it up to a computer & run a check on every thing . mine was doing something like that & the tps was out of range .

 

I have a Hypertec Thermomaster - its junk. The ONLY difference it might make (the chip that is) is at WOT. Other than that, the stock chip is just fine. Biggest waste of $200 I have spent on my car. Wish I would have known better to begin with.

 

Increase fuel pressure by plugging vacuum line only will make your engine run rich and deteriorate fuel economy. The pressure regulator is there for a purpose, it is engineered for for proper fuel pressure under all vacuum conditions. Idle has higher vacuum, hence lower fuel pressure, full throttle has low vacuum, hence higher fuel pressure. Your loping problem could be several things, 1st and foremost, check for vacuum leaks around intake with a can of carb spray. Lightly fog it around with the plastic tube that usually comes with it. 2nd, check and clean the throttle plates on the back side and clean the throttle bore. Try those first, I am assuming there is no trouble codes.

 

Thanks Mech259,

I'll try your suggestions and let you know the results. Also there ars no codes recorded. Another thing I just found left over from the last owner is he has the MAT sensor unpluged with some sort of resistor plugged into the receptical. I should mention the car ran good when I first got it about 2 years ago with 27K miles on it. It now has 32K.