Fuel pressure jumps!!
 

I was wondering what you guys think??I have an electronic fuel pressure gauge and lately it has been reading a litt;e higher than usual after i downloaded a weaker tune from adrenaline. So do i was amazed on my way home a 40 mile trip it would even go below 15 usually it would go maybe 14 or 13 because there are some big hills. So i let off the gas and the gauge went crazy 20,25, 30 psi i was like wow there is somthing wrong i got back on it and it managed to stay at 22-25 at idle but was bouncing back and forth. What do you guys think?? Is it anything to worry about??


Thanks in advance Brad

We need to know details about the installation.

Could be a bad/intermittant ground.

Do you have a needle valve to dampen the pressure spikes from the VP-44? If not, I would get one on there right away or you could bugger your guage. The needle valve should be just cracked (as in almost closed).

I have now idea how it was installed i bought the truck with the gauge.. I'm just hoping its the gauge not the truck..I know its a glow shift and its a electronic gauge.. It only dies it once on deceleration and it seems to increase when the brake is applied... I just hope i'ts not the vp pump..

Well, if anything, it will likely be the lift pump...

As I said before, youll have to do some investigating under the hood and maybe take some pics of the setup, connections if you want a thorough answer.

I believe your sender isnt installed properly and is causing the trouble here. Its probably lacking a needle valve.

The FIRST thing to look at is to make sure the guages are grounded good...you will want bare metal (as in not painted) at the grounding spot and if there are more than 1 guage grounds tied together, you could try seperating and grounding each guage seperately.

Ok tomorrow i will get a picture for sure..Sorry.. Well i have came to a conclusion that my electric sending unit might be bad for a few things i have read. On the way back to school tonight it was fine until the truck warmed up. Than it was going to 20, 25. I noticed that when i applied the break that the fuel pressure went up to 30 plus. If this helps at all the fuel pressure sender unit is installed on top of the thing that holds the fuel filter canister.

It definitely sounds like an electrical issue and not a Fp issue. Check all the wiring and let us know.

Does anyone know of a place that has instructions on how to install an electronic fuel pressure gauge on my truck??Pictures of how mine is installed will be up this afternoon.

If it is a glowshift I'd look here:

http://www.glowshiftdirect.com/pdfin...w7/fuelpsi.pdf

Well i want to know where i should hook the sender unit up at.

Well, I can answer that for you Brad....you can hook your sender up to the front port of your fuel filter canister, as seen in this pic (I would personally go this route):

Attachment 53867

heres another version of it:

Attachment 53868


Or, you could use the test port on the VP-44, as seen here:

Attachment 53869

If I were you, id go out and get myself a mechanical fuel pressure test guage and anytime the electric guage hiccups, check the fuel pressure with a mechanical guage. OR, trash your electric and install a mechanical guage.

You can find test guages, and all the fittings you would ever need at Vulcan Diesel Performance offers DDUSA twin turbos, FireBall injectors, DrawStraws, Big line kits, FASS fuel pumps, Parker bio fuel line, Quadzilla products, DTT Transmissions, Isspro gauges, High Tech Turbos , Veg pumps, metric adapters & fittings,



In fact, heres the test guage setup:

Fuel Pressure Tester w/ Schrader Connection

I hope this helps.