R33 Gtst Cutting Out Intermittently

[Sinesweep]

I have searched and read many of the misfiring and cutting out threads.

I apologize for the new post / long post but I want to describe my own circumstances before I go chucking in new coilpacks if I don't need to, or if i should try something else, and just for your general help.

I have a bog stock auto Series 1 1995 R33 gtst (K&N pod) on 175k kms.

A couple of weeks ago when I was going around a roundabout she threatened to stall. By that I mean she cut out once or twice in quick succession, got over it, and continued on happily.

It reminded me of when I got water in my coilpacks after an overzealous engine wash - it's that type of "cutout".

Assume low revs and low speed and virtually no boost as I was on a roundabout. Engine was warm and A/C was on.

Next day, I suffered a similar cutout on a straight road.

Took her to a mechanic and described the cutout problem. They asked me if I wanted to up the boost while it was in the shop and I said "why not?".

So I got service / tune which included plugs, plus a Walbro Fuel pump and a bleed valve installed.

When I asked how much boost I had he said ~12-14 psi. (I thought stock ECU / heat on stock turbo wont like that but was assured its ok and let it go). Stock boost gauge showed close to +7 mmhg

Then shes running quite nicely - until (seemingly intermittently) at max boost / 3000rpm she "cuts out" again.

So now I don't know if its my original problem, or the ECU / fuel pump / whatever saying "screw 14 psi" and hitting me with over-boost cut, or a bit of both.

Told the mechanic Monday, he says car shouldn't have that cutout, but winds the bleed valve back to ~11 psi. Now I can hit "max boost" no problems.

Except...

yesterday and today I have intermittent cutout, once per day, at low revs / off boost.

So I'm back to square one.

I will take it back to the mechanic and ask about 0.8mmm plug gaps and suggest dirty / stuffed AFM or coilpacks, maybe even tell him to take the bleed valve back (although the extra boost is nice of course).

If anyone can shed any further wisdom it will be appreciated on my ECU, coilpacks, max boost, other and most importantly my intermittent cutout.

Cheers

edit: adding link to this post for ref - similar problem - but I get cutouts with and without much load. http://www.skylinesa...out-under-load/

Edited March 7, 2012 by Sinesweep

[Bsa]

First it could be coil packs they are old and will almost be def be worth doing. Sounds like ignition cut is your timing set correctly? Could be cas related. I would give the afm a good clean with contact cleaner and see how she goes also check timing

[Sinesweep]

Thanks BSA - I will continue down the AFM / coilpack path, add timing to that, and hopefully get some more responses too

Also for what its worth the mechanic did something with the the fuel pump to try and help (earthed? direct wired? sorry cant remember what he said but this post reminded me

http://www.skylinesaustralia.com/forums/topic/393815-rb25-dies-under-load-lean-out/page__p__6262476__hl__coil+packs__fromsearch__1#entry6262476)

Can I tell the mechanic I definitely have a boost (fuel) cut on my stock ECU or is it model dependent - and if so what is max boost it should handle?

[SargeRX8]

You've done your reading so you might be aware of r&r which your car does have. elaborate on your definition of cut though... Do revs fail to climb? Does the engine sound like its misfiring? Does it sound fine but run like shit? Failing coils will misfire, the car will move and sound like shit. Hitting r&r is an instant loss of power, too much boost will cause this. f**ked afm will cause the same situation, as will a stuffed cas(but this also gives other symptoms as will a failing afm...). Honestly there could be heaps of reasons... diagnosing this online isn't going to be easy, we need details.

[Sinesweep]

I agree sarge - I kinda expect the mechanic to know his stuff, but after 3 visits Im just looking at taking him some suggestions / facts from people who do know Skylines.

It's an instantaneous cut - one or two in quick succession, then instant recovery., like R&R, or wet coilpacks, or some protective boost, electrical or fuel limiter.

The thing thats throwing me is I cant get it to do it again no matter how hard I try to replicate the conditions I think it happened under. (hot / cold / a/c, revs / boost).

All I could replicate was single cut at +7 mmg - which from here suggests that it was just R&R/ECU and it should never have been set to 14psi.

Thats ok now at 11 ish - and my current (and probably original) cutout is at low or no load/boost like accelerating from 55 to 60, or taking off gently from coasting (eg merging into traffic)

If I can only run 9psi and I need coilpacks then the plugs, fuelpump and bleed valve were a waste of money that should have gone into coilpacks.

/e

Do revs fail to climb? Nope revs freely and no issue in neutral - or on a dyno (apparently...)

Does the engine sound like its misfiring? Nope, no regular miss, no hunting.

Does it sound fine but run like shit? Nope 99% of the time its normal, just the once or twice a day (20kms) "cutout"

Failing coils will misfire, the car will move and sound like shit. This bothers me as it may not be the coils

Hitting r&r is an instant loss of power, too much boost will cause this. Yes at 14psi but got me stumped at 0-1psi

f**ked afm will cause the same situation, as will a stuffed cas(but this also gives other symptoms as will a failing afm...). I dont think I can cite any other symptoms - just the intermittent cutout.

/e linking myself to a max stock turbo boost thread

http://www.skylinesaustralia.com/forums/topic/355039-how-much-to-boost-stock-turbo/

Edited March 7, 2012 by Sinesweep

[Bsa]

If it where me I would get a proper boost Guage. Turn the boost down to 9 and check timing also clean the afm oh I would look at a new mechanic also one that has knowledge of fixing rb engines they can be a pain to fix and will give you grief

[Sinesweep]

Yeah this is a new mechanic with a Dyno and race / Falcon turbo experience got me stumped how he couldnt see this on the dyno.

I dont know why but I coming back to thinking my coilpacks have been stuffed from 2 weeks ago and the 14psi R&R in the middle was just a red herring to annoy and confuse me.

Is there anyway to test coilpacks before throwing $400 at a set of Yellow Jackets?

I will clean my AFM tomorrow.

Oh and for what its worth I have full fresh 98 RON fuel.

linking myself to R&R Threads

http://www.skylinesaustralia.com/forums/topic/328005-is-it-rr/

http://www.skylinesaustralia.com/forums/topic/292243-r33-gtst-problem-getting-a-constant-boost-level-causing-rr/ (post 15 interesting)

[GTSBoy]

I think it is electrical in origin, and I'd bet the CAS is a bit stuffed. Dirt on the wheel or worn shaft/bush/bearing surfaces. But, it could just as easily be a loose or corroded pin in the loom connector at the CAS (or at the coils or at the AFM), or a dry solder joint inside the AFM. When it is really really intermittent like this it is hell to try to find it. The best you can hope for is that you can go around and do everything you can think of in the hope that you make it better (which is usually a good thing to do as you often find and fix a lot of other little problems waiting to jump up and get you) or that it gets worse quickly so you have a decent problem to chase.

[SargeRX8]

Wrap your coils up in nitto tape or heat resistant silicone. If this has absolutely no effect, your coils are probably fine. I really doubt its the coils... If you did have a coil issue, you will be misfiring and you will know about it. I still think afm/cas. Especially it happening down low too. Very strange. Every time you take it to the shop it cost you money, you gotta diagnose at home. Simple easy things, try borrow some parts(people here are very helpful and generous), don't spend more money until you know what to spend it on.

[Sinesweep]

Yeah this is pissing me off now. I just went for a drive and took my Digital camera to video it but its too dark and too intermittent.

As soon as I took off It cut out 3 times - imagine just taking off "normally" and counting "One-and-two ..."

It cut out 3 times on each "half count" then ran fine for the next 5 minutes (when the camera was rolling of course)

Boost was interestingly at zero on stock gauge (not vacuum, not boost, but zero).

/e

Yeah thanks Sarge - will try that - the mechanic is pretty good about it so far hasnt charged me for return visits - then again probably should never have given it to me running 14psi...

Edited March 7, 2012 by Sinesweep

[AngryRB]

i notice its an auto, just a thought but could the auto cause any other these symptoms? like torque converter? ive noticed before that low oil pressure or lack of enough oil in the box can make it to be jerky or even stall at low speed.

is the battery old or have loose connectors?

[Sinesweep]

Not sure about Auto - battery is only a couple of years old.

Today it worsened (heat maybe?) to the point where once hot it seemed ok so I hit the A/c and still ok.

Then, chug chug chug and ok again.

Then chug chug chug and finally STALL.

Couldnt restart for about 5 tries - then started very chuggily so I took off and it ran like utter shit. As if I was stomping the accelerator randomly (but I wasn't) I will try to post a video later fwiw.

Made it home and cleaned the AFM.

Let it sit a while but it was by no means cool.

Drove another 3 kms and stalled slowing down for a roundabout.

Now I could restart it but it would die immediately before even idling.

Waited 5 minutes, started and made it another 5 kms to the mechanic pretty much without incident.

Intermittent shit is the worse - I wish something would just explode so I knew what to replace...

[Bsa]

Try the cas I think

[Manuel Kasko]

My sisters car is doing this exact thing!

Exactly how you described it!

They have done the following

-cleaned AFM

-new fuel pump

-new fuel filter

-new plugs

-new plug leads

No one can diagnose her problem either

Not a skyline either it's a Kia Rio

[Manuel Kasko]

Anyone mind telling me what a CAS is?

I know noob

[Sinesweep]

Thanks BSA

Kasko I believe Cas is the cam angle sensor http://www.skyline-o...le-sensors.html or http://en.wikipedia....position_sensor

Post back here if you find out what fixes it. I hope my mechanic can work it out tomorrow. No car + long weekend = grrrr

Heres my sad vids for your viewing pleasure / amusement / sympathy - sorry they are about 6-7MB each and renamed from mkv to mp4 so photobucket could see them.

No, I am not pumping the accelerator (except when trying to stop it stalling after it finally starts. That is smooth and steady pressure.

A few minutes before it stalled the 1st time

http://s127.photobuc...BeforeStall.mp4

trying to restart it

http://s127.photobuc...tafterstall.mp4

the worse cutouts yet - everything before this was just one or 2 then ok.

http://s127.photobuc...dafterstall.mp4

Edited March 8, 2012 by Sinesweep

[Bsa]

Crank angle sensor controls everything needed to make the motor work I have one somewhere kasko if you need one

[Manuel Kasko]

Thanks BSA and Sine

Are they interchangeable? She has a Kia Rio

[Bsa]

Def not haha I thought it was a skyline my bad

[Bsa]

Dosnt read your post all the way