badmfkr

iTrader: (4)

couple ?s on fuel preasure I've never had a FP guage so I don't exactly know what to expect. here are my observations after installing the FP guage stock fuel pump and stock injectors w/ 100K miles.

1.engine cold I usally turn the key on to prime the pump observed 40PSI

2.engine cold started PSI went to 45PSI then started driving climbed to 50PSI

3.stomped on it on the expressway to about 135MPH and it stayed at 50PSI
stayed at 50PSI during regular cruising even at idel.

4. turned engine off let car cool down about 5 minutes PSI dropped to 45 engine not running.

?doe's all this seam normal?

I've read here that normal preasure is 58PSI? doe's the regulator lower the readings?

also I used a few layers of teflon tape around the fitting and snugged it down tight
? if it was going to leak would it have allready happened?

custom guage installation

image of sensor

I'm a little nervous about messing w/ fuel never done this before so
Thanks for any advice from you nice knowlegeable LS1 folks

RKHiPerformance

When dealing with EFI connections, teflon paste is generally preferred as a sealant over teflon tape. The tape can fragment and stick in an injector.
Additionally, the paste is only required on the male threads of the gauge. The rail-side of the Metco adapter uses a flare-type seal.

Your pressure readings are a bit lower than we've seen in most applications. It could just be the calibration of the gauge or sending unit, but it might be worthwhile to check the available voltage at the pump connection when the engine is running.

badmfkr

iTrader: (4)

I checked the fuel pump voltage at the fuse block inside engine compartment
got .0002Vs w/ car running.

can you let me know how to check voltage at the pump?
I have searched and found this.

https://ls1tech.com/forums/fueling-i...fuel-pump.html

koolaid_kid

iTrader: (21)

Just a couple of observations:
If my fuel pressure were off by more than 10%, I would be concerned. On a system that is supposed to be 58 psi, that would be less than 50 psi.
At WOT, I would expect it to be very near 58 psi, and would again be concerned.
AFA using tape vs. paste, if you tape carefully, there is no way that it could enter the fluid stream. Been using it for decades w/o any negative results.
Your gauge, OTOH, doesn't seem to be that precise. IOW, I would use a gauge that is calibrated in 1 or 2 psi increments. I use a Hypertech 4004 which I attach to the fuel rail to check the calibration of in-dash gauges.

badmfkr

iTrader: (4)

I looked at the guage did'nt see anyway of recalibrating it I'm assuming that needs to be done internally from the manufactor.

I am now thinking maybe the tape is interfering w/ the grounding of the sensor even though the tape is mainly on the inside of the threads and gets torn ontop of the threads any thoughts?

can you let me know how to check voltage at the pump?

The car still runs great.

Thanks

charlie c5

iTrader: (6)

Im having your same issue. Sorry, not trying to jack your thread. But, Im only seeing 50 lbs. And I have the racetronix fuel system, bigger injectors and FAST fuel rails. This is killing me.

badmfkr

iTrader: (4)

no hi jack just waiting patiently for feedback from nice knowlegbable LS1 experts that are willng to share the knowlege.

BTW Nice c5. how are you mearsuring the FP what guage ?any drop off in power? I haven't noticed any.

I'm now thinking the stewart warner FP guage is a turd on accuracy, please someone step up and say it's a turd if it is I'm thinking SW is a well respected manufator in all guages for over 100 years they must be doing something right, right?

the SW sells for around $100. the autometer entry level starts at $200. so is the SW a complete piece of crape.

I'm now thinking of getting a actron to see if there's any differnce if any. http://www.smarter.com/fuel-system-c...i-3612700.html
this thinking process dos'nt make much sence $ wise the actron is only $32. ? am I way off base?

Then if the actualle reading from the SW is 10PSI low then my 50PSI I see will actually be the desired 60PSI.

Thanks LS1 experts for the feedback.

salemetro

iTrader: (5)

It is......just kidding. Truthfully, I don't know. AutoMeter seems to be the "standard" these days, IMHO. Twice the price....we'll you know that saying about getting what you pay for. I think that SW is made in China these days??

charlie c5

iTrader: (6)

Thanks for the nice comment. Im running the AutoMeter FP guage, and the pressure never really moves, sits on 50, and has since day one..

badmfkr

iTrader: (4)

update on current observations

couple days ago just cruiseing regularly FP went to 54PSI just for a short period of time then back to the constant 50PSI.

today did the same stomp test on the same section of expressway this time only 3/4 throttle FP creeped up to 55PSI stayed around 54PSI even at idel then back down to the 50PSI.

I usallally change fuel fliters (fram) at 22K or 25K miles current fuel fliter has 13K considering changing and maybe upgrading to a Wix.

would still like to check voltage at the pump anyone here know how this is done are the wires under the car or inbetween the car body and fuel tank?

charlie c5

iTrader: (6)

Yes sir, thats easy. Check the voltage coming out of the battery, then check the voltage at the alternator, then, pull off your driver rear wheel, and the inner fender cover towards the front of the driver rear wheel well, and youll see the connectors for the fuel pump. Check the voltage there. And between the three places there shouldnt be TOO much of a drop. If you DONT have the "hot wire" kit for the fuel system, then you may only see around 12.4 at the fuel pump.. Good luck buddy. Post back your results..

badmfkr

iTrader: (4)

update increase in FP PSI now at 59 60ish after the lucas fuel injector cleaner I beleive this used sender I bought had fuel inside of it and it gummed up sending a boguy signal (who knows how long this fuel was in there only the seller who won't respond).

anyway the SW guage seams to be acrate.

what I'm observing now is at idel the FP has increased however under the slitest load it drops but only to 55PSI -56PSI then rises back to near 60PSI thanks Lucas I beleive the sender is getting degummed and also the fuel pump is getting lubercated.

edit:just before the increase in PSI I observed the guage peg to way over 100PSI so I bliped the throttle and now it seams to be working fine.

charlie c5 I did'nt take the wheel off just looked inside and did'nt see a panel cover for FP wires this is a WS6 not a Vette.





I am wondering if the amount of fuel in the tank has anything to do w/ the amount of preasure like a full tank will have more preasure than a 1/4 tank would have?

Thanks for the surport

Racetronix

iTrader: (2)

The worst location for placing the pressure sensor is above the engine. These sensors tend to drop the pressure reading when they become heat-soaked. For accurate pressure readings it is best to use a QUALITY analog gauge.

If you are running the Racetronix harness then it is pretty safe to say your fuel pump is getting all the voltage your electrical system can muster. It is advisable to check your battery voltage with an accurate digital voltage meter under WOT. You should see apx. 13.2-13.6V with a fully charged battery with moderate accessory loading. We do not recommend probing / piercing the Racetronix harness because this can lead to moisture infiltration and failure.

badmfkr

iTrader: (4)

can the sensor be insultlated w/ like a convelluted tubing like I used to insulat the sensors wire?

will I get more accurate pressure readings if I relocate the sensor off the fuel rail away from the hot engine
I have a 18" braided brake line for this relocation however it will still be inside the engine bay.

What do you think about the sensor becoming degummed w/ the fuel cleaner and giving more accurate pressure readings?

PS I've only read good stuff about the Racetronics fuel pump and hot wire kit when my stuff completely fails I'll be in touch w/ Lonnie for a up graded replacement.
Thanks

Racetronix

iTrader: (2)

It would be best to relocate the sensor off to the side of the engine bay. Do not use any solvents on the sensor w/o checking with the manufacturer.

charlie c5

iTrader: (6)

So you guys reccomend putting the fuel pressure sending unit some place other then the port thats on the driver's side fuel rail.? Not doubting you, but Ive literally seen THOUSANDS of cars with the exact same set up, and have 56 - 58 lbs of pressure. Im not trying to argue, I just dont like having 49-50 lbs of fuel pressure with nearly 80K invested in the car, to have the best of the best...

MadIceV8

iTrader: (12)

Analog fuel pressure gauges are not allowed inside the cabin of the car. Nor would I recommend doing it this way. I have never seen or heard of this heat issue when using a quality gauge like autometer. This is not to say anything against a quality analog gauge mounted at the end of the rail.

Racetronix

iTrader: (2)

It is a well documented problem with select sensors particularly from Autometer.

charlie c5

iTrader: (6)

Well, damn, Im gonna move that sucker and see what happens. Thanks for the info. Hopefully this works..