EFI relay unplugged

[rcb280z]

Right? I hope.

[240260280z]

Not sure. I can't recall what I observed years ago.

When you rev the voltage may go up and in turn the fuel pump will put out more but the fpr should regulate. I am not sure what range it will regulate at under different demands.

[rcb280z]

My gauge is faulty. I just ran your test again with the engine off and got nearly 38 psi.

[rcb280z]

I will post tomorrow on the cold start results. Be watching

[rcb280z]

No change on cold start!! I'm going to unplug the cold start and see how it fires up tomorrow morning. Maybe it's dumping too much fuel. I don't quite know which direction to go in next. AFM adjustments, calibration have changed nothing. Kind of lost now

Edited February 19, 2012 by rcb280z

[240260280z]

Don't feel bad...we all are.... this is a tough one... I think your CSV idea is great however! It is an elusive gremlin for sure.

[FastWoman]

RCB, you should probably check the static pressure of your fuel pump, both cold and after warm-up. The way you do it is to disconnect the line from your fuel filter to your fuel rail and to attach your gauge there (i.e. with the fuel rail completely disconnected, and with the fuel line dead-ending into the gauge). You should get at least 45 psi, as I recall. When my fuel pump failed, its failure was apparent only after it had been running for maybe 30 min. Then the pressure would start sagging.

You should also check to see how much volume your pump puts out. Reconnect the fuel rail, and connect up a clear vinyl hose to your FPR's return outlet. Put the other end of the hose in the tank's filler neck. Now run the pump, and see how much fuel flows through the hose. In the case of my own pump, fuel flow would start out OK and then slow down as the pump warmed up. Return flow would eventually come to a halt at the regulated pressure, and then the pressure would slowly sag from there (i.e. still with no return fuel flow).

Make certain your electrical connections to your fuel pump are solid. At one time I had a crusty and arcing connection in my main harness firewall connector (passenger side). I eventually snipped out the wire and reconnected with a bullet connector.

I doubt your CSV could result in a lean condition, or perhaps I'm misunderstanding. It's only active for a very short time (assuming the thermotime switch works properly), so it is not responsible for much beyond the start. It's true that it can stick open, but when that happens, the mixture will be rich. Of course if it sticks closed, it can result in a hard start condition.

FAIW, I would calibrate the AFM's clockspring via Blue's method, so that vane movement is correct to the airflow through the device. Forget about mixture. Then add the potentiometer and calibrate O2 on the dyno using THAT adjustment.

[rcb280z]

Fastwomen, I was just thinking on the lines of checking fuel pump operations myself. As far as the CSV goes, if my problem is a rich running condition on cold start up then unplugging the cold start valve prior to start up might tell me something. I'm looking for her to fire up and idle at 1300 (+/- a couple rpm) like she should on a cold start. The problem here is it doesn't start up right after sitting over night. But if I run her in the am and later, say 3-4 hrs later, I start her up she immediately hits that 1300 rpm spot and warms up as expected without me manipulating the throttle. I have to manipulate the throttle on an over night cold start up. I hope you are following me. I should be able to reach in, in the morning and start the car and it idle with no problem. No, I have to throttle it up for about 10-15 seconds for it to stay at that 1300rpm range during warm up. But only for an over night cold start up. Doesn't make sense. I think I'm chasing my tail and missing something that is actually a simple fix. Maybe?

[FastWoman]

I understand, and yes, it sounds logical. I didn't realize you had a problem with the first 10-15 sec of a cold start.

[rcb280z]

Yeah, and it's driving me nuts. Something so simple isn't working. Everything has tested good so far. Unless I am missing something. I'm debating taking my Z to a well known Z shop in southern Ca but I don't want to. I took it for a short drive a little while ago and I am not happy with the way it's running. It feels lean. A little loss of power. Coasting to a stop it's popping through the exhaust. pop.pop...pop....poppop..popopop....pop. Running warmer than usual (lean). When we put it on the dyno yesterday it was rich, 1.8% co. Not too bad but by CA standards not good. And I talk to people that have no trouble with they're Z running at CA standards, 0.5% co's. Sorry if it seems like I am rambling on. If I could erase everything and start from scratch I would.

[Captain Obvious]

xubuntu, Point taken on the AAR issue. I don't think anyone here knows just how much adaptability the ECU has to compensate for something that is really out of whack. Theory is that the AAR can't possibly affect mixture ratio, but it wouldn't be the first time that theory differed from real world.

rcb280z, Sorry that doesn't add anything to your quest, but I wanted to get that out there.

[rcb280z]

I don't think anyone believes the AAR "affects" mixture ratio. It just adds more air to compensate for the richer condition at "cold" start up. At this point I wish there were someone out there that had the same problem and fixed it.