imloggedin

after i did my fuel pump rewire .. ive finally drove my car enough and i noticed today (only drove it a few time since rewire) that its running VERY rich.. and its not idle'ing well.. and when i boost it hops from 0 to 8 in like a second still.. grrr very annoying.

imloggedin

in the subject i typed wrong.. i meant RICH WTF.. lol oops

HAILERS

Just a word that may/may not apply to your problem...........the fuel pressure in the rail will not increase due to a *fuel pump rewire*. The fuel pressure regulator on the rail determines the fuel pressure in the rail. That's if you have a stock fuel pump.

IF you have a aftermarket pump with some huge volume/pressure output...then it's possible the fpr can't deal with it and the pressure in the rail might very well increase.

But with a stock TurboII pump, no way. 9volts or 13.5volts, it matters not, the fpr will regulate the pressure.

imloggedin

well what in the world could make that happen.. before it was always right between stoich and rich.. now its almost all the way rich on the gauge.. like two notches from being all the way

imloggedin

bump

Slacker7

iTrader: (2)

How bad rich is it at WOT and how bad is it at idle? did you check your fuel pump voltage before and after the install?
When I'm at WOT my car runs pretty rich both at idle an WOT

imloggedin

at idle i adjusted it with the thing on the passenger side in the engine.. i forgot what its called.. but its running about a bar or two from stoich, running rich.. when im driving.. when i get on it.. its like a bar away from fully rich.. maybe 2 away, much too rich.

neevosh

You know those 1 wire A/F guages are anything but accurate.

imloggedin

according to some of you that is true.. according to others its not. none the less, what i see on the gauge is what the ecu is seeing also right? they do what they do.. and from what i can tell it is running too rich. i just want a reason for that, or some help about howto fix.

Slacker7

iTrader: (2)

Err... sounds normal to me. You using an autometer gauge? What kinda boost your running? Or is your car n/a? Although I have one of those, I don't think it's accurate enough to judge off it.. However if you want a comparison with another car... my A/f meter showed the same readings when my car was stock. Now at 10psi based on the gauge, it's running a little leaner but still in the rich zone of the autometer A/F meter.

I really don't think that gauge helps much in letting you know what's happening but just FYI I posted what I noticed.

NZConvertible

Not entirely correct. The only signal to the FPR gets is manifold pressure. It can't respond to any other changes. So increasing the fuel pump's output will result in slightly higher fuel pressure, because manifold pressure hasn't changed so the FPR's internal piston hasn't moved.

Still, it shouldn't have a dramatic effect on mixtures.

imloggedin

before i did that i was running right at stoich/rich when i got on it.. after i did it, now its waaaay rich.. seriously its 1 bar from being maxed out rich on the gauge. these gauges are reading the same thing the ecu is reading coming from the o2 sensor.. right? correct me if im wrong. so why would it feed the ecu bad information? since the AF gauge is reading the same thing, and its information is bad (you say).

neevosh

The O2 sensors reading isn't used by the ECU under load. Just under cruising, where the throttle position hasn't changed.

I remember with my FD, A/F ratios between 10:1 and 11.5:1 didn't make a difference on my guage. It didn't even show full rich on the guage.

I'm not saying it won't show anything, I'm just saying it's not very accurate at anything but near stoich conditions. Even less so on an old O2 sensor. Plenty of people have popped their motors by throwing mods at their cars and thinking they were still safe becuase their A/F guage says so.

You probably are running richer after your rewiring and your guage shows that. But who knows by how much. It could be a lot or a little. Does your car stumble at all? Backfire? Get lower gas milage? Maybe your pump wasn't seeing full volatage before and now it is.

imloggedin

it has straight exaust.. its always backfired. i know its running richer.. when i did that rewire the engine started running worse.. my turbo spools funny and it doesnt idle right, until i adjusted the idle mixture. why doubt me when i say "its running richer".. how about some suggestions about howto get a little leaner or why my turbo is doing that. alls ive got from this is "its your gauge" well i used my nose and my brain and its not my gauge.. so how about real suggestions?

HAILERS

Well if your so all fired curious why don't you put a fuel pressure gauge on the damn thing? Too see what is happening?

A factory pump puts out 64 to 85 psi at idle. You rewired the puimp for a constant battery/alternator output. Sorry, I don't see that causing a rich problem.

02sensor is used only during cruise by the ECU.It's not used at idle by the ECU. It's not used at pedal to the metal conditions by the ECU. If it's not a wideband gauge its useless under less than stoic conditions.

imloggedin

im not talking about you hailers.. im talking about the people saying its the gauge.. ive posted previously about my boost being funny and everyone gives me run around answers.. the only good answers i get are from people with 4k posts or more. my gauge was constantly at stoich/rich when i got on it.. did a FUEL PUMP rewire and now its at very rich when i get on it.. "your gauge is messed up".. what kinda answer is that.. it makes sense that it would be richer, i just didnt know it would make that much of a difference.. but that doesnt solve my problem of.. how to lean it out, or maybe why my turbo is doing that. is it possible that because of too much fuel there is combustion in the turbo or whatever that those people do to make their turbo spool up faster?

NZConvertible

Here's another possiblity. You've made a mistake in your rewiring and the pump is receiving 12V all the time. This will cause exactly the problems you're having.

I know from my own testing that the ECU doesn't increase voltage to full until 3-4psi, so most of the time it runs at low voltage and the ECU's maps will reflect this. Running full voltage all the time will result in rich mxtures.

Test the voltage for us.

neevosh

You're the one that's focused in on your guage. I'm telling you it's not an accurate reading. Maybe if you'd give more info instead of arguing, you could get your question answered.

Which rewiring method did you do? There are 2 different ways of doing it. One retains the factory relay so voltage doesn't go up at idle. The other method just runs a wire from the battery, to a relay, and then to the pump, which will give you full voltage all the time.

I'm guessing you used the second method, which would cause you to run richer at idle. I did mine this way and I noticed an increase in fuel pressure at idle. Also, maybe the wiring was old, and you weren't seeing full voltage at WOT. After the rewire, you're getting full voltage, causing you to run richer.

Slacker7

iTrader: (2)

I asked you if you checked your fuel pump voltage before and after the install. I did not get a reply. We actually need more information.

You need to check the fuel pump voltage at idle and WOT. At idle, below about 3.8k rpms or while cruising while under vacuum fuel pump should be getting 9V. At WOT, partial throttle or when boosting(above a certain level), fuel pump should get 12V.

What you could do is to wire the fuel pump up to a voltmeter and drive it around. It would be safer to get a buddy to read the voltmeter.

If you are getting 12V at idle then you have potentially found your problem while the car is idling. As far as WOT goes... not sure what it is but it should mean that before you did the rewire your wiring was really flaky.

imloggedin

thanks for the response.. i was thinking about that also, ill check it again and see where i stand. anyone have any thoughts on the turbo thing?