doesnt die when oil cap is pulled

[whitechocolatelove]

ive got a 280zx turbo motor with some running issues. but one thing i noticed is that when i pull the oil cap while its running it actually idles a lil better most of the time if not the same. i checked the pcv valve and it has full movement with no problems. i know the na models are suposed to die with it off but what about turbo models?

[AK-Z]

i know the na models are suposed to die with it off but what about turbo models?

Incorrect. If what you say is true, then I would check to see if there is a vacuum leak/clog somewhere. disconnect one of the vacuum lines and see if it idles better.

[rejracer]

I have an 83 turbo, and when I pull the oil cap or dipstick the idle gets worse. If yours gets better to me it suggests you are running rich at idle, and the unmetered air that is being introduced to the intake charge is leaning it out some bringing it closer to where it should be. I would check the sensors, especially the head temp sensor, injector size, fuel pressure and the adjustments on the air flow meter. Basically anything that can cause it to run fast at idle.

 

I suppose before all that I would check to see if it's running rich at idle to validate if your on the right track.

[AK-Z]

I have an 83 turbo, and when I pull the oil cap or dipstick the idle gets worse. If yours gets better to me it suggests you are running rich at idle, and the unmetered air that is being introduced to the intake charge is leaning it out some bringing it closer to where it should be. I would check the sensors, especially the head temp sensor, injector size, fuel pressure and the adjustments on the air flow meter. Basically anything that can cause it to run fast at idle.

 

I suppose before all that I would check to see if it's running rich at idle to validate if your on the right track.

 

If you say that. I say before anything, check the AFM and make sure that the connectors on it and to it are clean. Might be just an easy fix.

 

Also try adjusting the distributor.

[rejracer]

First off check to see if the crankcase is under vacuum. Simply pull the oil cap and put your hand over it and feel for vacuum.

 

AK-Z has a very good point. I bought this car for 500, and it ran very bad when I picked it up. It needed electrical connectors cleaned mostly. It also needed the fuel system cleaned, but don't think that's relevant here.

 

I would clean the following electrical connectors in this order:

PCM - Made a big difference for me.

AFM

O2 Sensors

Head Temp Sender

Injectors

TPS - helped idle speed.

 

I used electrical contact cleaner, Deoxit D5 followed by Deoxit G5. The first 4 connection points can affect AFR.

 

After all of that I would check to see if the head temp sender is working properly by testing it per the FSM.

 

Based on the limited info available, it appears that the car is running rich, or there is limited / no flow from crankcase to the manifold.

 

Good luck with it.

[AK-Z]

in about 7 out of 10 cases of a stock 280z running rich, is because of the AFM giving of a bad reading (bad connection). the ecu then goes in to "limp mode" telling it to run rich.

 

Not sure with anybody elses, but my wasn't effected by having the temp sensor disconnected.

[hpltree]

My 240 had 94 tags on it when i dragged it out of the garage it was in and i had to clean almost every ground on the car plus unplug and reconnect alot of the harness to get most of the car to come alive. just a thought. i also had to put in a new body groung from the firewall to the neg side of the batt..