my z is getting way to much fuel
 

my plugs are coated in lots of gas, i installed a walbro 255 i have no idea if thats the problem or could it be the fpr, or dampner the car is a 1990 na tt swap 92 motor

If it's every cylinder, test your fuel pressure with an inline gauge. I suspect your pressure is too high.

yea it is but whats causing that?

what do you think regulates fuel pressure??

You're now throwing in A LOT more fuel with no other adjustments....

ooh ooh! I know!!! A fuel pressure regulator???? :D

... yahtzee!

i have switched it and hooked up a after market one and that had little effect

What's the fuel pressure at?

125 or so......

... that's the problem. Fuel pressure at idle should be 44.1psi. lol

Go get a *new* fuel pressure regulator.

Just out of curiosity, was the needle on the gauge pretty steady or did it shake? If it shook or varied pressure erratically, your dampener is shot too.

TO recap:

Question: Why is my Z getting too much fuel?

Answer: Because your FPR is shooting out over 300% more fuel than it should be.



I love simplifying :D

You could always decrease the pulse width of each injector instead of properly regulating the pressure. :D

If you wanted to make things *really* complicated... lol

the pressure was jumping around i tryed hooking up my na fpr and dampner and a after market fpr noting worked, but i gess ill order a new fpr and dampner, is it a good idea to get an ajustable fpr? or just a oem one>?

OEM one is fine. The only time you'd need an adjustable one is if you needed to squeeze more fuel out of a smaller injector... but if that were the case, I'd recommend just getting larger injectors.

For your sake, I hope it's not the Walbro fuel pump causing the problems (or perhaps a poor wiring job on the pump causing it to run on high all the time). Why do you even have that? The stock one will pump more fuel than most Z32 owners will ever need, so the only reason I can see buying an aftermarket one is to be cheap, because they cost less than stock. If that's the case (you bought a Walbro to save some money) and this keeps happening, I'd like you to ask yourself if it was really a great idea to save that money on the pump.

Is there any chance that the pump, putting out 125 psi, could be blowing out the fpr or dampener? Doesn't the stock pump go a little over 80 psi? The diaphragm in the fpr might not be suited for the high pressure.

And ....... most standard f/i fuel line is rated to 125 psi. All hose before the fpr will be constantly pressurized to 125 psi, no matter what the fpr regulates it down to afterwards. I wouldn't want to be at the hose pressure limits all of the time (I'm aware of designed safety factors) Besides, leak potential x10.

In summary, I'd go back to a stock type pump, or I'd go to an appropriately upgraded fpr and higher rated f/i hose between the pump and fpr.

On another note, the return fuel line to the tank, might not be sufficeint enough, or might have a restriction to where all of the fuel can't return to the tank at the rate that it needs. If this is the case, then even with a properly working fpr, the pressure at the injectors will be too high.

Just considering the various possibilities here...... :)

This is definately a possibility.

This is a good point as well (the restriction in the return line part, not so much the insufficient part). However, it's not common for fuel line to clog unless it's being run without a filter (it'd have to be a pretty big obstruction). I'd suggest the possibility that the return line might be pinched, having the same result.

Either way, 125psi is NOT acceptable, and you need to figure out why you're getting 125psi. If you've tried multiple FPRs, I'd suggest checking the return line. If the return line is fine, I'd question if your pump is killing your FPRs. Again, might it be wired improperly? The stock TT pump has 2 speeds because, obviously, at different RPMs you want more/less fuel, so I'd wonder if your pump is stuck on a high speed as if you're hanging at 5000rpm.

If you want a sure-fire way to fix it... get a new stock fuel pump, new FPR and Dampener, and make sure the return line is clear.

For a little clarification, it appears that the TT has a 3 speed pump controller and the n/a has a 2 speed controller. :)

FUEL PUMP CONTROL ------ bottom of the page.

You know, that's what I kept telling the bastards on tt.net, but they kept arguing with me that the TT was 2 speeds and the NA 1 speed, so I just stopped arguing when I couldn't find proof. But it appears you are correct. Thank you.

go back and rub it in there dirty faces then.

thread's closed... and apparently someone did correct them after I stopped paying attention to the thread.

ic, and ummm... 125 psi.... that seems a little out there, lol, are you sure your measuring it right? using the right type of instrument to read it place in the right spot? you said you tried using an aftermarket one and the na one? anything else? and its still reading 125..... i dont see how it could do that. let alone i dont see how the fuel pump could make that much pressure, only thing i could think of is kinked line on your return or clogged since you did a swap correct? and does the walbro even have different speeds do we know? its not an oem one after all, or is teh speeds externaly regulated like an ESC sorta set up? in which case how could he have hooked it up wrong since i doubt he would have touched it

that actually crossed my mind too... did you actually test the fuel pressure? If so, did you do it right?

Is your flux capacitor working properly?

Sorry..couldn't help it....125 psi is just about as assinine as a flux capacitor.

the rubber lines will burst beyond 62Psi. so I will asume the reading is off. noway in hell the Injectors can take that much pressure let alone the O-Rings. get a Nismo FPR and call it a day.