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Fuel Pump Rly highlighted red and lean with a/c on.

Posted: Wed Aug 03, 2011 2:25 pm
by treese88
Hey,

Just have a couple questions for my Z32.

One thing I noticed the other day is in the consult vehicle display the fuel pump rly is highlighted red at all times. I swapped the relay and there was no change. I am wondering what this means because I am actually attempting to figure out why I am having low fuel pressure, maybe this has something to do with it. Idling at ~30psi (goes up to ~40 psi with vacuum removed from fpr). I assume the fuel pressure is staying low when driving because my a/f is running lean and doesn't seem to want to go below 12.5...which is a problem. Currently I am leaning towards the fuel pump as the issue but I am unsure because if I clamp off the return line the pressure will go up to 60psi and it doesn't make any noise. Any other ideas of things to check would be great to know. The relay and pressure issue both popped up recently and maybe even at the same time but it is hard to say.

Also, when I turn the a/c on my a/f will go up about 1.5 points...say 14.5 it will go to ~15.5-16 (most notable at idle but effects driving as well) I'm guessing this is something to do with my iacv valve but if there is anything that may be affected with nistune that would be good to know.

And finally (just remembered while writing!), my temperature will only display in Celsius even though I have checked for Fahrenheit. I tend to consistently end up at 81 when idling after fully warming up, which only makes sense if it is displaying Celsius. Off the top of my head I am not sure what it goes to when driving.

Thanks!

Re: Fuel Pump Rly highlighted red and lean with a/c on.

Posted: Wed Aug 03, 2011 4:15 pm
by Matt
consult vehicle display the fuel pump rly is highlighted red
This is normal. Red means that the relay is active (powered on)
when I turn the a/c on my a/f will go up about 1.5 points
Nissan ECU should open the IACV when the air cond is on. Check this is occuring by checking the solenoid functions when AC switch is pressed. This will introduce extra air (should be metered) and also check Air Cond input inside consult is flagged when this is used
my temperature will only display in Celsius even though I have checked for Fahrenheit.
Run the latest 0.10.10 version and let me know if still and issue. I fixed this a while ago and also fixed the log recording/playback for Farenheit

Re: Fuel Pump Rly highlighted red and lean with a/c on.

Posted: Thu Aug 04, 2011 2:21 am
by treese88
Thanks for the quick reply Matt. I guess I never noticed the relay light up because I wasn't having fuel issues. I'll update versions as I am currently using 0.10.1 with a build date of May 24, so hopefully that will fix that issue.

When you say to check the a/c solenoid function how do I go about that?

Re: Fuel Pump Rly highlighted red and lean with a/c on.

Posted: Thu Aug 04, 2011 2:32 pm
by Matt
Check the FSM (Factory Service Manual) for details

1. Put a multimeter on the soelnoid and check it shows voltage when AC is on
2. Remove solenoid and plug hole whilst testing. Check solenoid goes in/out when AC on/off