R33 Gtst Cutting Out Intermittently

[wilderboy]

hey guys i am a second year mechanic and its my girlfriend with the kia rio and just yesterday i cleaned the throttle body and cleaned out the tps and she runs great no stalling no hunting for revs nothing doesn't stall when turning corners or uphill or anything so i would recommend cleaning the tps senor and see how that goes

***tps = throttle position senor

also on the subject of misfiring im running 10psi boost and around 4500-5500 my car misfires when im sticking the boot in but when i do it softly it doesn't misfire and i have just replaced the fuel filter and spark plugs so im thinking old fuel pump cant keep up or coil packs any ideas?

[Bsa]

R33 I'm guessing turn the boost down.

[wilderboy]

yea a r33 s2

[Bsa]

It's hitting r&r turn the boost down see if that fixes it.

[SargeRX8]

I think he did, made no difference. Damn man sounds tough to diagnose. It could be the gearbox, auto gear boxes work in weird ways. I'm still thinking cas, but now thinking about it, it could be the tps... Something you can try is tap a volt meter into your tps, leave the ignition on and open and close the throttle. It should increment nice and smoothly from about .33v to about 4.06v. My car can increment it literally .01v at a time (or .1 can't remember). Don't know how you test the cas but you are having starting, stalling and power issues which could all be related to the cas.

Edited March 8, 2012 by SargeRX8

[Sinesweep]

Thanks guys.

I cant understand if it's boost related anymore though - you can see from the videos i am under stuff all load and essentially zero boost?

Some of the posts / mechanics opinion is that Coil packs or CAS would be a lot more regular (less intermittent) too. But it feels so similar to wet coilpacks and as you say CAS controls so many things (so does ECU I guess...)

I am also leaning towards heat as a contributer - it may be coincidence - and it does play up when cool (1/3rd temp) but It does seem to be worse at full op temp / hot day / A/C on. Also seems to behave better in the first few kms of driving - usually.

My engine bay feels hotter too if that makes sense. I notice it because I have an unprotected pod so I notice it from a potential heat soak point of view.

Basically I open my bonnet and think "shit that's hot - I should do something about an air box" - and lately I have been thinking shit thats really hot ... (but car is not overheating in any way)

/e boost should be down to about 9pounds now - I gave it another click when I cleaned the AFM - but wasnt too fussed because I seem to be dying on zero boost..

Edited March 8, 2012 by Sinesweep

[SargeRX8]

Wet coils will misfire, if you aren't misfiring, why would the could be an issue? I really don't that in that moment the spark is too weak to ignite the mix but not weak enough to blow out..

[Bitsushiti]

Intermittent hesitation when rolling on the throttle, jerks around and surges unexpectedly? Sounds AFM related.

The solder from the afm plug to the pcb inside it lets go after a while (especially after 13+ years of heating/cooling/vibration) and can lose connection when hitting bumps etc. Eg. fine one minute, pain in the ass the next.

I had a very similar problem a while ago and followed this tutorial which completely cured it: http://www.skylinesaustralia.com/forums/topic/113284-fixing-your-rb26-afms/ applies to RB25 AFM as well)

Even if the plug looks fine, solder it anyway while you've got it opened up.

Cheers

Edited March 9, 2012 by Bitsushiti

[Sinesweep]

Yeah Sarge I don't think the coilpacks are wet I was just looking for a way to describe the cutout.

Will look at the AFM again over the weekend thanks Bitsu.

Today - mechanic drove a bit no issues, I drove home 15kms (nice cool evening) no issues.

3 days to play and see if I can get stranded (I mean locate the problem) or at least a way to "make it occur", or gauge if it is getting worse, or something.

Mechanic and a few other "Office mechanics" are saying "electrical". Should i be considering an auto electrician?

Edited March 9, 2012 by Sinesweep

[Sinesweep]

Update - more stalling.

In addition to the daily but intermittent cutouts - I have stalled during deceleration a few times (eg slowing for roundabouts / corners etc)

half the time it restarts immediately, the other half it will not. If i let it sit for 2-5 minutes its starts again - and of course runs fine for the ensuing drive.

In frustration I just revved the shit out of it on th elawn after it conked (and restarted immediately) on my driveway.

1st time - hit rev limiter, stalled

2nd time - car only went to 4k rpm (I had foot down) , lost power and stalled.

couple of times i revved to 5 or 6 k and let foot off - stalled

a few times - behaved normally - but on some of those I heard minor backfiring (popping)

getting ready to service it with a jerry can and a cigarrete lighter. ...

[scotty nm35]

So you soldered the AFM? Or can you test with a different one?

[Sinesweep]

Yeah I did.

Just did it again (cap is only on with friction fit old silicon) , and hit up the PCBs and AFM element thingy with some contact cleaner.

Noticed some discoloration that looks like minor corrosion, or solder resist, or something.

I cant access a test AFM, but Im South of Adelaide if anyone has any names of places I could get one, or more advice.

Dunno whether to mess with the Auxiliary Air Control or Throttle position sensor.

Also turned the bleed valve down 2 more clicks whatever that equates to.

photos below

http://i127.photobuc...et/P1000682.jpg

http://i127.photobuc...et/P1000681.jpg

http://i127.photobuc...et/P1000683.jpg

Edited March 18, 2012 by Sinesweep

[ads47]

Hi Sinesweep, did you end up getting a solution the the intermittent cut out issue you were having? Everything that you described that happen to you is more or less happening to my R33 GTST.

[Sinesweep]

I ended up cleaning the AAC as well as rewetting all the AFM solder joints and the old girl came good.

I'm not sure which (if either) fixed it, but my money is on the AFM dry joints.

Have also since taken out the Boost Tee.

AAC cleaning here - http://www.skylinesaustralia.com/forums/topic/110431-diy-aac-valve-cleaning-idle-reset/?hl=%20aac%20%20clean.

[ads47]

Thanks for the help Sinesweep, I took apart my afm and found that all the solder joints had broken off.

A quick resolder & put it back together, then took it test drive.

Drove like there was never a problem, thanks heaps mate.

Edited June 7, 2014 by ads47

[Sinesweep]

Good to hear mate