Overfueling And No Power On Boost

[mle808]

Hi guys,

Haven't been on here in a while, my car has been trouble free for so long. But here I am again needing some sound advice after a massive fail following what should have been a tedious but fairly straight forward spark plug change over the weekend.

-Changed plugs. Went from Iridium BKR6EIX to copper BKR6EYA

-Put all the intake pipes & hoses back together

-Engine would not hold idle. I can hear all sorts of relays clicking on and off, revs were jumping from 800 to 0. Eventually stalls after about 5seconds.

-Take all the piping & vacuum hoses off again. Found the ground wire to the coil pack rails or whatever you call it, had snapped off.

-Regrounded it back and screwed it back on the last bolt of that coil pack holder thing(near the firewall), then put everything back together

-Started car, idles fine.

-went for a drive and Noticed the problem as soon boost is building on 1st. Its like hitting a wall the more you press the accelerator. I get a sudden increase in speed as I back off the pedal. Its almost as if the pedal turns into a brake pedal. This is only when boost is made. Cruising on very light load is ok, no problems.

Then today;

-Checked AFM connection. Unplugged it whilst started, car stalls. Started car with it unplugged, it idles.

-Checked for vacuum leaks or loose pipping, and...I don't think there are any. Checked vacuum leaks with throttle body cleaner whilst on idle. No changes. Can't really hear any hissing noises either but its difficult with an exhaust.

-Checked the coil packs to see if they were secured. They were.

-Checked the plugs, all plugs were blackened apart from the very tip, even the white insulating part, assuming this would be expected from the massive over fueling (are they consider fouled now, or will they self clean so to speak?)

-Put the same plugs back in (was iffy about this, was considering whether i should put the mostly worn iridiums back in, but I didnt)

-Put everything back together, went for a drive. SAME SHIT. Really over it.

Any suggestions on what I can check for? Please note, car was running fine prior to the plug change. Other info;

-I can make full boost according to the gauge (0.7bar), unlike the instance where I had a loose cooler hose and the pressure would not reach the 0 mark. Does this rule out vacuum leak?

-Have a power FC with controller. Any sensors checks to look out for?

-Thinking, whether the ungrounded coils issue in the beginning, causing the engine to stall and relays flicking on n off could burn a fuse somewhere. And if yes, how would it cause this over fueling?

-Could the above, somehow reset the power FC?

-Have checked all connections nearby parts I had removed, and all seem connected.

-I did remove the HKS BOV from the piping, thinking it would help get things off as I also have a strut brace in the way. Probably shouldn't have as there is a metal gasket. I did spray the throttle body cleaner around those joints, and no changes to idle.

-Can the plugs get ruined in should a short amount of time? Idled for about 20mins all up, and drove for a 5mins all up.

Any suggestions are greatly appreciated. Thanks.

[Don Dada]

25det?

[mle808]

Sorry, yes rb25det

[Don Dada]

What boost are you seeing when this happens?

Make sure the actuator is getting a proper boost source and you havent mixed up the vaccum hoses some how

edit...

now saw you have pfc so you can rule out overboost protection by the stock ecu

Never the less make sure all hoses are properly connected

Does it free rev smoothly?

Edited August 30, 2011 by Don Dada

[mle808]

What boost are you seeing when this happens?

Make sure the actuator is getting a proper boost source and you havent mixed up the vaccum hoses some how

edit...

now saw you have pfc so you can rule out overboost protection by the stock ecu

Never the less make sure all hoses are properly connected

Does it free rev smoothly?

Hmm, it varies. Can start before hitting 0. Depends on volume of air coming in I suppose. The more air/boost the worst it gets.

Stationary, out of gear it revs ok. In gear, hard to describe. Its sort of like revs fine until 'too much' air comes in then it feel like i've hit a brick wall. If i continue keeping accelerator pressed I will eventually get smoke out the back. Lifting off the pedal makes the car picks up speed for a split second.

Ok, I'll check the hoses are not mixed and the actuator too, although I'm not going past 0.7bar so I'm assuming that its getting the correct vacuum feed.

Thanks

[KerrodR33]

Hey mate I had this same problem for weeks, completely identical symptoms, I checked piping and pretty much everything else. Then it dawned to me that I didn't properly check the piping connection under the airbox because I am lazy lol. Turns out it was loose and making a minor leak. Tightened it and I was boosting again. Make sure there are no splits, and that they are connected properly and tightened

[SargeRX8]

Overfuelling on boost is generally a sign of a vacuum leak. Check ALL intake connections. Everything leading to boost gauges in the cabin too.

I had a vacuum leak on my old skyline, it was so bad and overfuelling so much I had black smoke coming from everywhere. Fixed slip on the cooler piping and it was sweet again.

[bubba]

If idle and cruise is fine, it would point more to a boost leak than a vacuum leak (a clamp not tight enough somewhere or something opening up with positive pressure).

[SargeRX8]

If idle and cruise is fine, it would point more to a boost leak than a vacuum leak (a clamp not tight enough somewhere or something opening up with positive pressure).

Ahh lol I got my context wrong. This is what I meant sorry.

[Room42]

One of my intercooler pipe clamps broke today and it drove alright but was running at about 12 to 1 on cruise. It ran ok but wouldn't boost very well and was rich as a bastard. Thats what a loose hose will do to your car. In my case it was still sealed up a tiny bit so it was enough to suck through the afm. I have had pipe pop off before and a huge flame came out the back before running at 9 to 1 or richer. It would barely drive like that. Just food for thought. It might help or it might not.

[KerrodR33]

Meh mine runs 9 to 1 all day everyday Lol

[bubba]

That's pretty rich.... mine only dips into the 9's when I have a boost leak.

[KerrodR33]

Yea I need a tune pretty bad. I can't stand to look at the back of my car (white skyline). It still drives smooth and I managed a nice 182rwkw with just exhaust and intercooler but when I had the boost leak I could hardly drive it as it had the same symptoms as the OP so I would like to know how rich mine was with the leak. The guy who dynoed my car said that was normal richness for a 33 with said mods.

What I would like too know is what makes the car hesitate and jolt around like madness with a boost leak? I would assume it would just loose heaps of power. Is it an ecu defense?

[mle808]

Yea I need a tune pretty bad. I can't stand to look at the back of my car (white skyline). It still drives smooth and I managed a nice 182rwkw with just exhaust and intercooler but when I had the boost leak I could hardly drive it as it had the same symptoms as the OP so I would like to know how rich mine was with the leak. The guy who dynoed my car said that was normal richness for a 33 with said mods.

What I would like too know is what makes the car hesitate and jolt around like madness with a boost leak? I would assume it would just loose heaps of power. Is it an ecu defense?

Checked vacuum lines, all in the right places. Tightened up every clamp, no splits. I can hear a small hiss now. But can't bloody find where it is. It's down near the turbo side. I have the engine fan and pod filter going at the same time it's quite hard to even tell if it's normal. Its not the pod sound, but I can hear a muffled down version thru the top intake pipe.

Either way a leak somewhere i didnt touch shouldn't explain why this is suddenly happening. I'm starting to think it's got more to do with the plugs or coils. Are these plug compatible? Do they take more current to spark than the iridums? Both sets are 8mm gaps. Should I try a new set since these ones are now black already? What are your thoughts?

[KerrodR33]

I doubt it's the plugs. They will be black from your overfueling issue. When I had a blown turbo gasket the leak was making a more of a quiet wet fart noise and got louder as I accelerated but it didn't feel like it hindered my performance.

[mle808]

Hi all,

Spent most of sat trying to find this leak. If it exists I can't find it. Tighened every clamp and took a few suspect pipes off just to re-sit and be sure. Nothing.

Also changed the plugs again and taped up the coils. No difference. Want to think of other ideas but will not rule out air leak possibility either.

Something new I noticed is that when I get sudden drop in power(when not on super light load) is that the ignition timing readout on the controller drops to zero. Lifting off, the timing goes back to something that resembles the actual timing map values. This also happens in neutral and giving the throttle a good jab. Thought the power fc wouldn't retard timing automatically like the standard Ecu.

Sorry I forgot to mention that I did the plug change in the place was that my fuel economy was falling.

Any ideas about this timing change on even light load?

Tried searching this forum and google as well, can't find anything specific. Thanks

[Room42]

Hi all,

Spent most of sat trying to find this leak. If it exists I can't find it. Tighened every clamp and took a few suspect pipes off just to re-sit and be sure. Nothing.

Also changed the plugs again and taped up the coils. No difference. Want to think of other ideas but will not rule out air leak possibility either.

Something new I noticed is that when I get sudden drop in power(when not on super light load) is that the ignition timing readout on the controller drops to zero. Lifting off, the timing goes back to something that resembles the actual timing map values. This also happens in neutral and giving the throttle a good jab. Thought the power fc wouldn't retard timing automatically like the standard Ecu.

Sorry I forgot to mention that I did the plug change in the place was that my fuel economy was falling.

Any ideas about this timing change on even light load?

Tried searching this forum and google as well, can't find anything specific. Thanks

Timing going back to zero sounds like tps and/or afm reading wrong. Research, sus it out, clean, check, blah blah blah.

[mle808]

Hi all,

car is FIXED! Just wanted to report back in case this info is helpful to anyone in the future...

Brought it to the tuners and it turns out the tune data got corrupt. Can't remember the exact details, but it was something to do with a corrupt water temp correction map causing ignition timing to drop to negative 80 on load. It dynoed at around 100kw at the time. Values were fixed...somehow.. and its now back to normal! Root cause is uncertain but apparently he has seen 3 r33 gtst power fc tunes get corrupt like so. Am thinking the ungrounded coil packs as described above may have played a part as the problem only started after this.

Anyway. Also, I took it to Powertune in Fairfield because I didn't want to risk driving all the way out to Hitman and I have to say the service was friendly & efficient. Work was promptly done and I don't believe I was overcharged for their time. Chea took his time to explain the issues and was happy to answer questions I had. Will go back again.

Next, need to check PaulR33's power FC FAQ again, and see how I can make a backup of the tune in case I need to reset the thing.

And thanks to everyone for their input and suggestions....appreciate it.