OK! fuel pressure reading on my ka24de-T25

[240sxvaj]

my fuel pressure is reading at 36 psi (sometimes 40psi on a cold start) when im driving, idleing etc....

but then assoon as i turn off my engine my psi will drop from 36 straight to 20 psi to 21, 22 psi

does that mean i have a leak? or can it be something else?

im running 450cc injector, Nismo FPR type B with adapter, only used for nomore than 1,000 miles on it.

[480sx]

Normally you would smell a leak, it would be pretty obvious. Just get your car running and put your nose down beneath the car and see if you can smell any gas. Or its leaking into your manifold, but your car would be running really rich and not very well.

If your pressure is dropping that fast, you probably do have some issue. I know mine takes at least an hour or so to drop down to 20.

My only other thought is the one way valve in your fuel pump is going south, and is letting some of the pressure back out of the line and into the tank.

Theres only a few places your fuel pressure can go so, it shouldnt be to hard to narrow it down. What are you using for a fuel pump, and how long have you had it?

Has the fuel pressure been doing this ever since you installed the FPR? I would try it with the stock FPR and see what that does, just to narrow down what it could be.

[240sxvaj]

th stock FPR went bad and kept on makeing my car sputter and wouldnt let it go pass 4,000 RPM.

im running a walbro 255 pump

it never did this before til now

i will re-check all the lines

and i did kept my lines connected to the fpr and fpr gauge kinda long.

can that cause it?

thanks for the help

[eazye2000]

My car does the same thing bro. I don't know if it's normal, but hopefully it's reassuring.

While Idling, I get 34-36psi. Then when I shut her off, she drops to 20-24psi.

I just had an injector take a crap on me. So I sent them back to Deatschwerks. One coil was bad, and another one was out of spec. So a whole new set is being sent back to me. As soon as I get the injectors, and the new turbo on, I will let you know if anything is different.

[480sx]

Weird stuff, i mean im sure my FP stays peged at 40 when i turn the car off.

The other side to this is simply.. If its not broke dont fix it(kinda...)?

I mean if your not leaking fuel, and your cars running fine, then you really dont have much of an issue.

[240sxvaj]

My car does the same thing bro. I don't know if it's normal, but hopefully it's reassuring.

While Idling, I get 34-36psi. Then when I shut her off, she drops to 20-24psi.

I just had an injector take a crap on me. So I sent them back to Deatschwerks. One coil was bad, and another one was out of spec. So a whole new set is being sent back to me. As soon as I get the injectors, and the new turbo on, I will let you know if anything is different.

Just curious, i have a set of 450cc from deatschwerks. do they usually run bad, i mean how can you tell?I know this is out of subject but i think you know, i'm only running afcneo and my car is rapin me on gas, i was told it wasnt fine tuned on low throttle, the original tune was (-1) through out low throttle and the dyno guy told me to put it at (-15, after letting him know of how much gas is costing me) all across and i did but i felt a huge power loss at boost. and somewhere here i heard you are running e-emance and it is giving you around 29mpg w/good power. that sounds great and thats what i want, but i dont know how much its all going to cost and what i need, so if you can help that would be great. thanks in advance.

[240sxvaj]

alright so this might be a little off topic but then as i boost my car i can see white smoke comming out from my exhaust.

can it be fuel?

[S13FX]

From what you said in your previous post, it looks like your not tuned at all. Do you have a wideband?

if you don't I would not let the car go into boost at all until you are certain you are tuned fine. Also for 450cc injectors you need more like 35% across the board on low throttle not 15.

As for how much an emanace will cost, well I guarantee you from the prices iv seen a Emanace tune costs less then the pos SAFC heh, and its actually tuned for timing too.

[240sxvaj]

i had my car tune twice already from 2 different guys

the first one was sh!tty

and the second one was ALOT better.

as for my fuel gauge i can smell some fuel comming from it, so imma redo it again.

i'll let you know how it turns out

thanks!

[240sxvaj]

One thing i figured out today that when i rev my engine the fuel pressure drops from 36psi to 29 psi right when i rev a little. when i do higher rev then the psi goes 40+psi. ANyone know whats wrong?
Modified by 240sxvaj at 6:00 PM 3/23/2008

[480sx]

Are you sure you dont have the FPR lines crossed? What about a Vac source, where is your FPR vac line hooked up to?

Thats not good that your FP is changing so much.

[240sxvaj]

Are you sure you dont have the FPR lines crossed? What about a Vac source, where is your FPR vac line hooked up to?

Thats not good that your FP is changing so much.

What do you mean by crossed? it looks straight and hooked up right, just extended kinda long and the vac source is the original one used on the stock one just that it is also extended.

I'm thinking it is something else like the fuel pump. i have a hardwire kit for the walbro fuel pump but never did install it. can that be something?

[480sx]

Well, if you have the feed/return lines hooked up backwards it can cause some weird stuff.

IIRC, when i hooked up my fpr i tried it backwards to trouble shoot something and the car still ran.