Running too rich? fouling plugs between hard shifting?

I have had my car professionally dynotuned with nistune +ebc etc.

However it seems to drop a cylinder or two if i dump into second at full stick.

I havent normally taken much notice as it only lasts about 5 ~10 seconds though it happened again this morning but didnt recover for about a minute of normal driving.

possibly unrelated, but what does the limit switch on the gas pedal do? i noticed it was bent out of place a couple months ago, so i bent it back... however it wasnt tuned with this in place.

I had checked the plugs on the weekend and they dont even look used. no sign of browning or white soot. just look new even after 6000kms.

anyone have any ideas what might be going on? boost leak? faulty mass airflow meter? faulty oxy sensors?

 

Does it go psstishhhh between gears?

If it does that might be why.


Otherwise take it back to the tuna.

 

nah it goes SUTUTUTU lol
just kidding. though it does have turbosmart plumback bovs. though a little noisy, i guess it would mask any other sounds.
looks like i may have to take it back to the tuna. hopefully i can get a day off next week.

otherwise, how hard is it to hook up a pc to the nistune? if it hooks up to a db9 port, could one make their own cable?

 

apart from the obvious boost leaks, maybe the PTU is also failing and you're losing spark?

 

If you are good you could make your own cable. I just bought mine, buy a quality one, i have had cheap ones in the past that have died.

Yes you can still hook up consult with a nistune. I fixed mine the other night.

Plumb back you should be ok, it wont be why you run rich.


Make sure you call the tuna to let them know this is happening as early as you can. but still check for airleaks everywhere.

 

it is a 1st gen ptu, so I guess its possible.

Don't know what symptoms that would have or what would induce it to fail like that. Is it possible it isn't providing enough voltage to overcome the resistance from the extra boost? No idea :S

Easy to test those or would you have to test with a new one?

 

S1 PTUs will fail randomly. I used to drop a cylinder occasionally and then it comes back.

One day it died all together. Change it and rule it out first since it's something you'll have to do one day anyway.

 

You suggest the plugs are fouling but say they're clean, is the fouling just a guess? I'd be more worried that its running too lean if the plugs don't look used.

 

thats what I first thought when I saw the plugs...

with fouling, I'd expect them to not work under load... but if its lean, then I wouldn't have thought the plugs would stop working under load.

I assume the tuna would have been conservative and gave me rich mixtures, as I immediately noticed black soot collect on the rear bar. Though the clean plugs confused me. I could do a plug chop when I induce it to bog... though is a little bit of a pita to do on the side of the road.

Possibly blocked injectors maybe?

Seems like wild guesses in the dark without doing any tests.

 

Also, where's the best place to get a new ptu? Do I need to install new plugs on the loom or is it just plug + play?

 

Changing out the PTU would be warranted if it's faulty.
Where did you have the car tuned?
It would be sensible to talk to the tuner before you change out parts or make any type of adjustments.

 

Unique Autosports in Seven Hills.

I'm hoping they keep a save file for the settings that maybe they can pull up and have a look... but probably not.

I'll give em a ring in a minute... though I'll probably have to bring the car in next week.

Its been like this for months, however I never really noticed as I'm rarely on full throttle as it has bugger all traction.

 

The mech is thinking it might be the BOVs. Even though they are supposed to be plumb back... something screwy might be going on there.

I'll just have to putt around on low boost for a while :/

 

The gas pedal limit switch you are referring to will be the power mode override switch for automatic vehicles. If your Z is manual then it was likely once an auto.

 

I got new ptu set up with extra

http://www.ebay.com.au/itm/Nissan-3...263515?hash=item4aeea35d1b:g:N5UAAOSwLnBXWrHz
But still played up so had all wires solder together with heat shrink tubing
BEAUTIFUL :br::zlove:

 

well. something is failing. was cruising low boost on the m4 on the way home tonight... 90% 40~60km/hr... and in the last 5 minutes or so it dropped a cylinder. Revving it out didn't seem to help much. Got some speed up on the off ramp and it started to clear up. I guess it might be possible with the ptu or my ignition wiring.

I had noticed that when I had reassembled after doing the timing belt, it was running on 5 cyl. I reseated the ignition harness under the balance tube and cleaned the connector for that injector. Was running back on 6.

I should have checked them individually. But i multimetered the ignition plug, ground and power was fine. Couldn't check the signal wire though. Might get a light bulb tester on there.

What would be the most likely? need new connectors, loom and / or injectors? The contacts on the injectors are disgusting. I did my best to clean them, but I think the corrosion is too far gone.

e85 upgrade time?

Gunworm, yeah, I don't think I'd like to trust my crusty old connectors either. I think I should also relocate my existing ptu away from any heat sources and vibration. Does anyone recommend this?

 

90TTZ... *Raises hand* i'm responsible for that hack job. Gave the slosh box to john at unique auto. With the commuting I've had to do lately... I almost miss it

Would that switch by any chance go into the nistune? I'm assuming it doesn't have slosh box features :s

MagicMike, this is also possible I guess. What do you think would be happening after touching limiter? Doesn't it only cut spark for that split second? Or do you think maybe unburned fuel is throwing my narrowband out? (not even sure if mine uses one).

 

replace those injector plugs. check the coilpack wiring, give the wiring a good strudy wriggle while its idling and see if you can cause the problem with movment.

I would next check the resistance on the coilpacks, inspect them for splits/cracks, make sure they have the small tip inside them ( sort of like you can see on this random coilpack
)