Fuel pressure supply/regulator question

[Beamer]

OK,

I am not getting the fuel pressure that I want under boost. I saw only 58 at 25Lbs boost with base of 43. It should have been 68, and I am sure it was under 60. I am running the Denso pump and thought it would not be the problem and I wanted to check voltages to the pump. I probed into the pump feed out of the relay of the hotwire relay and saw 13.7 volts. I then adjusted my pressure regulator up manually and was able to take it to 80PSI and I then checked the volatge which was 13.6 volts. I believe the pump is adequately supplied with power and is capable of the pressure.

I recently replaced the fuel filter with a new Wix brand and had no change in ability to maintain safe A/F numbers with my car. I am curious if anyone has had issues like I am facing, and what is thought. Attached is the regulator that I am running.

I have the Racetronix bulkhead replacement harness for the Denso pump and the sock is attached to the pump.


Any suggestions are appreciated,
Mike

 

[TRICKSIXPA]

Any kinks in the line or pinches? Did you check with another gauge.

 

[Chuck Leeper]

Leaking at the short hose between the pump and the hanger? Did you cut the reduced nipple off the hanger tube, B4 installing the pump?

 

[bison]

Pressurize the regulator via shop air through an air regulator to the regulator and tee in a good accurate gauge for the air pressure. See if it's 1:1 while idling.

 

[getdowngranny]

Sounds like the regulator is the culprit. Do the test that bison posted and it will give away the ghost before your start dropping the tank and chasing elsewhere.

 

[Beamer]

I was thinking of exactly what Bison suggested and am glad to see him suggest that.

Has anyone else seen a pressure regulator do this before ? Drop off of a 1:1 increase ? I believe there is a membrane in the regulator, could it be comprimised? Possibly rebuilt? Or should I get a new unit if I find it not raising fuel pressure at the proper rate.


Thanks again all !


Mike

 

[Beamer]

Chuck,

I had the tank down a while back and had noticed the hose was short. I replaced the hose and installed double clamps. I am sure it is good. Thanks !


Mike

 

[pacecarta]

whats your MPH?
from your sig " 10.8 still needing traction help" ...might be time for a double pumper

 

[Beamer]

The 10.8 was with my old PT-54 turbo and a weak wastegate with 24 Lbs boost. That turbo went out and I replaced with the CPT60 turbo and have not been back to a track. I need to iron this out and get it tuned better before doing that, lol...


Mike

 

[87GN_70GS]

Your voltage is good at idle. Are you able to check it with the engine spinning high rpm? What I'm getting at is eliminating a possible bad alternator at high rpm as a culprit.

 

[Beamer]

I looked at my data logs and the voltage looks good through the entire range. Great point though.


Mike

 

[Beamer]

Well, I got my neighbors air compressor yesterday which has a pressure regulator. I took a hose and T'd it off to the fuel regulator and boost gauge only so I knew exactly what the pressure was. I started with a 43 Lb base and the fuel pressure went up at a 1:1 rate with air pressure. At 27 Lbs air, I had 70 Lbs fuel pressure.

Now it sounds like my fuel pump is not capable of delivering the quantity of fuel needed. I feel Pacecarta is correct and that is what I was thinking originally, but I had to test and be sure that was the situation. It is looking like double pumper time.



Mike

 

[Ttype6]

Well, I got my neighbors air compressor yesterday which has a pressure regulator. I took a hose and T'd it off to the fuel regulator and boost gauge only so I knew exactly what the pressure was. I started with a 43 Lb base and the fuel pressure went up at a 1:1 rate with air pressure. At 27 Lbs air, I had 70 Lbs fuel pressure.

Now it sounds like my fuel pump is not capable of delivering the quantity of fuel needed. I feel Pacecarta is correct and that is what I was thinking originally, but I had to test and be sure that was the situation. It is looking like double pumper time.



Mike

Get a volt booster. You should have one any way,no matter what pump or pumps you use. I like the boost activated volt booster that Red Armstrong sells. If your pressure rise condition improves with the volt booster,you'll know that the pump is the culprit. It will flow a lot more with the two extra volts if it is good.