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Argh! Impossible Idle/trans/timing Issue!

Emrarrr

By Emrarrr,
in General Maintenance

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Emrarrr Enthusiast

Emrarrr

Posted
Posted

Hey Guys,

I have previously posted a thread in regards to my series 2 r33 and very rough idle problem. I am seriously going to end up in a mental asylum! I have been trying to figure this out for so long and have checked and replaced so many things!

I decided to grab an OBD scanner and I used ECUtalk which show the gauges in real time and this is what I discovered.

When in Neutral or Park the timing fluctuates erratically between 0 degrees and 20 degrees?? As soon as I put the car into park it sits steadily on 20 (auto trans). Does anyone know what would cause this?? In drive it is fine just not in P or N. The idle also jumps around 700-850 constantly. When I hear the car miss on idle the timing fluctuates harder so it has to be related. But why only in P and N?? Prior to looking at the software I changed O2 sensor, coolant temp sensor, cleaned AAC/IACV, cleaned throttle body, replaced AFM, checked vac leaks but still some keep appearing so maybe it is that??, did coil power test, spark plugs (bit dirty), etc etc. Maybe it is the throttle position sensor for auto?

If anyone has any idea what the relationship between the trans and timing is I would love ur help!!

thanks

Em

89CAL Grand Master

89CAL

Posted
Posted

Does the ecu register its in neutral? Also the tps has 2 functions, one is an analog sensor measuring actual throttle position and the other digital (on/off) that tells everything if the throttle is open or closed. This will effect wether the car is in idle map or normal map and may be the problem, so worth checking out. Is the voltage at 0.40v or there aabouts with foot off the pedal? I think the spec is actually 0.44

Ben C34 Grand Master

Ben C34

Posted
Posted

The ecu adjusts the timing when at idle to maintain a smooth idle, at the correct rev.

If the idle is set too high,the ecu will pull timing to get it right, what is your idle at in neutral?

Emrarrr Enthusiast

Emrarrr

Posted
  • Author
Posted

Hey Cal :) is the bottom brown plug the TPS and the grey one for the auto? I actually got 3.8 to 4.0 volts when tested I actually don't think there was anything on grey but need to double check.

Thing is sometimes the car dies when the bottom brown plug is pulled put out and other times the car stays on?

Also wondering if it has something to do with the trans? I can't seem to set idle properly with adjustment screw it doesn't seem to change too much?

Hey Superben :)

The idle fluctuates which I could see on ecu talk but it doesn't seem to hunt on the cars gauge? At one point I did set idle too high because the screw seems to be retarded! Am I supposed to pull the TPS when doing this?

Thinking ECU now doesn't have control over idle but why only in neutral/park?

I am pretty sure have vac leak still locating but would this only happen in park??

Thanks for answers!

Ben C34 Grand Master

Ben C34

Posted
Posted

Ok. Simple things first.

Check timing and vacuum leaks. Simple things first. (Don't use the loop when checking timing use a plug lead between the coil and plug and disconnect the tps)

95% of people that buy ecu talk only confuse themselves with the info. (Fact made up by me, but I am pretty good at making up facts)

Ben C34 Grand Master

Ben C34

Posted
Posted (edited)

I was told Autos are 20deg at idle, manuals are 15deg....

Unless that's a r33 thing, my neo stage a is definitely 15.

I should add that is in neutral, I haven't bothered looking at what it does in drive.

Edited by superben
89CAL Grand Master

89CAL

Posted
Posted

I'm pretty sure to adjust the Idle screw you have to have the AAC valve unplugged. I think only one of the 2 plugs but cant remember which one. Because you have already adjusted it, you might find it is too far in our out so might take a bit of playing around to get the car to idle with the AAC unplugged.

You say you keep having Vac leaks? where are the Vac leaks? Because they will effect how the car idles.

Emrarrr Enthusiast

Emrarrr

Posted
  • Author
Posted

You guys are awesome thanks for the help! I will reply to any questions in a sec so that maybe it will help just thought I would quickly mention what I have done and another thing or two I have noticed.

Last night I pulled all the air intake out and re did the hoses and put good clamps etc and its still doing it. I can still hear this whistle sort of almost electronic whistle sound when it spools up my stock BOV is pretty loud for an auto but checked line etc. I've got the idle to drop which is good and pulled TPS as per manual. When I unplug brown plug on aac unit the revs change so that's good but when I pull the purple plug on the unit nothing happens? Does that mean anything?

Also it makes this funny sound like you know the sound when u put the car in reverse its a high pitched whining winding noise? It does that when accelerator depressed and used to sort of rev on its own? Wondering if that could be related? If it is the auto trans I will be doing a manual conversion sooner so not too bad!

VLSteve Enthusiast

VLSteve

Posted
Posted

Random stab In the dark (I'm thinking of RB30 stuff here) but does the auto take a vac signal from the back of the manifold.. next to where the brake booster hose goes? Remove hose and block the nipple and see what happens?

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