walbro 255 pressure at the rail..........?

[mr.prick]

my mechanical gauge on my fuel rail reads 70psi.
i would like to know if that sounds about right
to anyone that has logged fuel pressure with the walbro 255.
please let me know what you ended up using for your IFR values.
i ask because at start up i see 72psi and,
after the car is warmed up i see 70psi and at RPM it gets hard to read,
it will bounce around 68-72psi or so.
i have used 68psi for my IFR values but i am wondering if it is best to
use average or minimum or maximum.
i am using stock fuel rails and injectors if that makes a difference.
thanks.

[redhardsupra]

check the voltage at the pump, they usually draw more current and the stock wireing makes it freak out.

[mr.prick]

check the voltage at the pump, they usually draw more current and the stock wireing makes it freak out.
what do you mean?
i just would like to know what values i should be seeing/using.
like i said i have 70psi more or less.
should it not fluctuate at all?
at rpm it moves , probably because of the injectors are opening more often.....?
basically does 68-70psi sound like it is range for this pump.
i would like to get the proper sensor for logging but it is a little pricey and i don`t want to spend the money
if it`s going to tell me i have 70psi.

[ntae]

Yes all the walbro in tank pumps i have fitted have increased the pressure over the stock holden reg set point i see around 62 / 65 psi

[JezzaB]

So the walboro is installed in the swirlpot with the stock 58psi reg and reads higher? Im curious because I have one too. Think I might have to put a pressure gauge on it.

Jez

[ntae]

i would like to get the proper sensor for logging but it is a little pricey and i don`t want to spend the money
if it`s going to tell me i have 70psi.


where is the world do you live mr.prick there are some good priced fuel pressure senders

[mr.prick]

where is the world do you live mr.prick there are some good priced fuel pressure senders
part #s would be nice.

[mr.prick]

So the walboro is installed in the swirlpot with the stock 58psi reg and reads higher? Im curious because I have one too. Think I might have to put a pressure gauge on it.

Jez
this is one reason i am asking for others with the walbro and know
they`re fuel pressure to say whether or not if it sounds accurate,
if not i will have to buy the Autometer fuel pressure sending unit
(pn 2246) and wire harness (pn 5223)
($101.99) ($37.99)
i am a cheapskate i know but if someone could tell me if my psi
is or isn`t abnormal, i will go from there.
i though it was 60-62psi but i recently noticed it is in the 70psi range.
though my gauge might be off.

[Doc]

That does seem high to me. Are you using the factory wiring or a beefed up setup like the racetronix? The tutorial is really good. From my observations/ logs with the autometer setup I have observed ~62-64 @ idle and ~58 @ WOT. It does vary with load, which makes sense. Probably worth your while/wages to get more accurate readings you can actually log. Look at it this way, you can fire the small Laotian boy you have under the hood watching the gage while you drive.

;)

[mr.prick]

That does seem high to me. Are you using the factory wiring or a beefed up setup like the racetronix? The tutorial is really good. From my observations/ logs with the autometer setup I have observed ~62-64 @ idle and ~58 @ WOT. It does vary with load, which makes sense. Probably worth your while/wages to get more accurate readings you can actually log. Look at it this way, you can fire the small Laotian boy you have under the hood watching the gage while you drive.

;)
LOL:hihi:
i have just the pump.
now i`m wondering whats is going on with my fuel pump.
guess i`ll have to spend more money;)

[redhardsupra]

That does seem high to me. Are you using the factory wiring or a beefed up setup like the racetronix? The tutorial is really good. From my observations/ logs with the autometer setup I have observed ~62-64 @ idle and ~58 @ WOT. It does vary with load, which makes sense. Probably worth your while/wages to get more accurate readings you can actually log. Look at it this way, you can fire the small Laotian boy you have under the hood watching the gage while you drive.

;)

how does your fuel pressure hold up on wot at lower vs high rpm? do you have any logs with this stuff logged?

[mr.prick]

no i just have a gauge tapped in the fuel rail.
it drops to about 68psi under throttle, and idles at 70psi.
i imagine the lower value is probably the one i should use for
the IFR table.

[Doc]

LOL:hihi:
i have just the pump.
now i`m wondering whats is going on with my fuel pump.
guess i`ll have to spend more money;)

No kidding, I started out with the Racetronix kit and then hooked up the Autometer gage and crapped my pants when I saw the first readings. My alternator (stock) was not up to the task of supporting my LC-1, N20 stuff. This lead to a bigger, better, more expensive alternator.

http://www.alternatorparts.com/Extreme%20Duty%20Dual%20Rectifier%20CS-144%20type.htm

Only catch with this puppy was the CS-144 case style. It fits no problem. The holes for the mounting hardware are another story. A really good friend, (screen name tunedportCJ5 on this board) helped me make a custom bracket to accomadate it.

[Doc]

how does your fuel pressure hold up on wot at lower vs high rpm? do you have any logs with this stuff logged?

Sure, I am at work right now and I didn't bring my laptop today. Do you mean "How does FP hold up when going to WOT from low rpm VS. High?"
Sorry, I've got a bunch of whiney Engineers crying right now.

[redhardsupra]

yea, according to my calculations a walbro 255 should be running out of flow on higher rpm's, i wonder how visible it is, and also i wanna see if i could estimate the dynamic pressure, as the fp sensor only captures static one.

[BowlingSS]

Will EFIlive check fuel rail pressure without special gauges?

Bill
:master:

[Doc]

Will EFIlive check fuel rail pressure without special gauges?

Bill
:master:

Look in the tuning tool under Help> Tutorials>LS1 FP sending unit

Not that hard.

[BowlingSS]

Look in the tuning tool under Help> Tutorials>LS1 FP sending unit

Not that hard.

Thanks.
Bill
:cheers:

[billyjo]

RHS,

I have several logs with fp data @ the rail and I'm using a 255. I've also got an Aeromotive fp regulator after the rails to try and control the fp, and if it makes a difference mine is also super charged.

Bill

[mr.prick]

RHS,

I have several logs with fp data @ the rail and I'm using a 255. I've also got an Aeromotive fp regulator after the rails to try and control the fp, and if it makes a difference mine is also super charged.

Bill
well what is your fuel pressure!

[billyjo]

I have a adjustable regulator after the rails and I set it to 58psi

Bill

[TAQuickness]

70psi sounds a bit high for just a fuel pump swap. 60psi - 65psi is what most folks see.

After my Racetronix install (pump & harness) I average 63psi at idle. WOT's another story...

[mr.prick]

well now i`m wondering what would give me higher fuel pressure.
maybe the sock filter fell off in the tank or a bad relay?

[DrX]

Have you tried a different gauge? 70 psi sounds high unless you are using a voltage booster and it is always on or the intank FPR has been modified/messed up.

[mr.prick]

i am using a mechanical gauge.
i `m not sure what could go wrong with it to show 10 psi
more than it should, but i guess it`s a possibility.
and i swear that i was seeing 58-60 psi before but
maybe i was reading it wrong LOL. (increments of 20):bash:
i just have the pump , no hot wire kit.
also my voltage is 13-13.5 i`m pretty sure thats normal.
i also found out you don`t want to go around corners really hard
with just 1/16 of a tank of gas .:eek:
this is NOT a new pump. (28,000 miles)

[joecar]

If you're sure that you saw 60 psi on this pump and now see 70 psi, then the FPR may be faulty (as DrX said) or the return pipe may be restricted (located on the outlet side of the fuel filter and goes back to the top of the pump assembly where the regulator is located).

[mr.prick]

i hold pressure with the car off and have 60PSI with the key on......?

[joecar]

i hold pressure with the car off and have 60PSI with the key on......?Holding pressure with engine off means: regulator is not leaking, injectors are not leaking.

Key on is not sufficient since pump runs only 2 seconds each time key is cycled to on... would have to cycle it at least 5 times... but FPR is static after pump stops running (i.e. it dumps a little pressure and then stays static)...

you want to see pressure while engine is running, because then FPR and pump are under dynamic conditions...

your pump is probably good, but your FPR may be sticking or the return line may be retricted... but they may also be ok... I said may...

[mr.prick]

oh man i don`t want to drop the fuel tank:mad:

[joecar]

Thinking Out Loud (TOL)...

you might be able to check the return line by disconnecting it at the T and blowing clean compressed air regulated to say 72 psi... if air can go in then FPR/pipe should be ok, if air seems to not want to go in, then FPR/pipe may be stuck...

(warning: service manual says that fuel pressure must not exceed 75 psi otherwise damage may occur)

I don't know if this warning is refering to damage to [GM] pump, regulator, or nylon lines.

Does anyone think 70 psi might be ok, a little on the high side, but ok...?

Are you sure your pressure gauge is reading right...?

[billyjo]

I have a mechanical Autometer FP gauge that went bad and read way higher than my actual pressure when it happened, so gauges can go bad.

Bill