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Hey Guys,

Just trying to gather some information on the basic setting everything should be at on a RB20DET in my R32.

Things like AAC value (%) when warm and timing are most important to me. But if you know the working ranges for anything else please do tell!

Anyone know this information? I would like to compare mine to someones who's running properly as I'm trying to diagnose a problem.

Cheers.

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AAC should be lower than 30 (ideally lower than 20) when warm. too high and have stalling etc issues. if its too high, often can be brought down by turning idle screw whilst watching it. stop turning once it stops going down (then maybe a slight turn back to where it starts going up again). thats the quick and dirty method without timing light and so on.

Whats ur issue

Very Simply, I'm having idling issues. I know these are common but i have done everything I;ve read in all of these threads on here that i could find and do myself.

It might take me a while to explain it, but i think i have a faulty AAC valve if thats possible! Other possibilities are faulty CAS, fuel regulator, ignitor module, Dirty Injectors, dead knock sensor/s and 02 sensor. Lol think i covered everything possible there. haha

AAC should be lower than 30 (ideally lower than 20) when warm. too high and have stalling etc issues. if its too high, often can be brought down by turning idle screw whilst watching it. stop turning once it stops going down (then maybe a slight turn back to where it starts going up again). thats the quick and dirty method without timing light and so on.

The weird thing about my car is that once warm the AAC valve will sit on 10% and idles fine but then randomly will start not idling and start moving back up. I have screenshots below that I'll explain.

Actually this is a great idea.

Hoping it'll help others too.

I have cleaned the AAC. Have looked at the air regulator. Checked for vacuum leaks. Check spark plugs and gapped to 0.9mm cause they seems fine when accelerating (just thought while i was there id gap them). Coils looks good (hard to tell i know) but there was no signs of cracking. Fuel Filter been changed. Running stock airbox.

So these are the screenshots i got... I know nothing about this software and have no knowledge so if i sound dumb please bare with me! :)

-------------------------------------------------------------------------

The first is at idle when the cars idle started to drop...

post-74745-0-17962100-1302411634_thumb.jpg

Now this is after i play with the throttle a bit. Blipping it tiny bits and then the idle all of sudden goes rough and starts acting like its gonna stall (and it will if i dont give it some gas)...i got this screenshot right at the beginning of it and didnt have time to get another one. The timing starts going nuts too when the idle starts to drop. It goes from a steady 15 and drops (hard to keep track of it). Im not sure what the AFM sould be reading and all that either. So have a look at everything please and let me know if something looks suss.

So not sure what the stats did after this. But i had to rev it to keep it from dying...also i had to actually drive the car to get the idle back to normal...just reving it wasn;t enough! It would keep falling back to the rough idle...funny thing though is this doesnt happen all the time! It did this a few times in the early part of my drive yesterday then never did it agin for the remainder! Not that i was stopping much though (wasmainly highway cruising)

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Next scenario is cruising at around 60km/h. Got two screenshots of this.

post-74745-0-10478300-1302411831_thumb.jpg

post-74745-0-85937000-1302412035_thumb.jpg

Now this one is where its gets interesting i think? The AAC valve starts to go back up! Is that right when cruising?

In fact when i was on the highway doing 110km/h the AAC went right up to 90%. Now not sure about that?

--------------------------------------------------------------

The last screenshot is accelrating pretty hard in second gear.

post-74745-0-41180600-1302412060_thumb.jpg

Dont really notice much here apart from AAC again? Timing even?

Sorry for the long post...thought i'd get as much detail out there as i could...prop just scared everyone off lol..

Anyway thanks for any help. :thumbsup:

Edited by L0Ki

you have no speed reading, you havent cut the speed sensor wire or anything have you? im not sure what impact this will have given ive never done it.

try turning the log checkbox on before showing gauges next time, then you can post the raw logs that show all the readings. e.g. the time the RPM drops to 600, really depends what the AAC is doing before/after as to whether it looks like ECU is trying to catch the RPM fall or not.

when timing is a solid 15 shows that ecu isnt pulling the timing back to reduce idle rpm (which it will do if idle screw set too high, think it will also add/remove fuel to reduce rpm to some extent).

you have no speed reading, you havent cut the speed sensor wire or anything have you? im not sure what impact this will have given ive never done it.

try turning the log checkbox on before showing gauges next time, then you can post the raw logs that show all the readings. e.g. the time the RPM drops to 600, really depends what the AAC is doing before/after as to whether it looks like ECU is trying to catch the RPM fall or not.

when timing is a solid 15 shows that ecu isnt pulling the timing back to reduce idle rpm (which it will do if idle screw set too high, think it will also add/remove fuel to reduce rpm to some extent).

I just assumed that was because the r32 speedo is cable opperated? I just ticked all the guages available lol. But if theres a wire ic an connect it'll prob help the power steering as that uses the speedo sensor i think.

The timing starts to drop and fluctuate when the idle starts playing up and the AC goes up from 10%. Ill make sure i log the data next time...i logged the data from the highway cruise section but nothing happened on that cruise so not really useful!

the speed sensor input to the ECU is normally seperate to the gauge cluster.

I had a quick search today on the forums for what the wire looks like and all i could find is that its wire 53 from the ECU (thats green with yellow stripe)? But im thinking if it has been cut it'll be under the steering wheel somewhere.

So the speedo gauge (in ECUtalk) should work on an r32?

you have no speed reading, you havent cut the speed sensor wire or anything have you? im not sure what impact this will have given ive never done it.

other than the 180 k speed limiter all it does is increase the idle whilst moving. should run fine without it, mynes never been connected and i've never had any problems.

yes the speedo gauge should work, green with yellow stripe is correct, it should plug into the body loom from the ecu then go to the speedo

Okay heres a log of the idling/almost stalling...didnt let it stall though as im affraid its putting too much pressure on the valvetrain.

Im slowing extracting all the idles out of the excel sheet so its easier to find.

I'll uplaod them one by one as i find them. And i have to use something other than this forum as it doesnt allow u do upload excel format documents :S

Here the first one: http://www.filesonic..._of_the_day.csv (when you see the revs go up thats me revving it slightly not the car doing it)

Last one of the day: http://www.filesonic.com/file/650611774 (I blip the throttle and it begins to die...turn the car of and start again and just goes to the same thing so turn it off again) The AAC numbers start to get really high when the problem is at its worst. So thats why im thinking its a fault AAC?

Any help in understanding why its doing it would be great.

Cheers

Edited by L0Ki

AAC going up means ECU is trying to raise idle, so good that theres probably no issue with CAS etc.

is your minimum O2 sensor voltage always 0.4v? any logs with it lower? can you try disconnect it and see what the effect is. hard to tell if the AFR is never getting lean enough for it to read lower, or just (more likely) its old and needs replacing. hard to know if it's a direct cause.

most likely cause would be AAC or other idle air valves etc (not sure what other things the skyline has). that it sits on AAC 10% and idles fine (when it is fine - i did you get logs of this period of operation?)

i thought you can post zip files here...

is your minimum O2 sensor voltage always 0.4v? any logs with it lower? can you try disconnect it and see what the effect is. hard to tell if the AFR is never getting lean enough for it to read lower, or just (more likely) its old and needs replacing. hard to know if it's a direct cause.

Yea the lowest readings going by the logs is 0.36V (at what id call a normal idle (above 600rpm)

most likely cause would be AAC or other idle air valves etc (not sure what other things the skyline has). that it sits on AAC 10% and idles fine (when it is fine - i did you get logs of this period of operation?)

When its idling fine the AAC valve sits on a steady 10%

Edited by L0Ki

yeah id get a new one, especially if you dont know when you last changed it (or never have). may not fix it but it rules out one potential cause if it doesnt. but try disconnect it first just to see what happens.

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