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Discussion Starter · #1 · (Edited)
Hi all

Just after a second opinion on something! Lately when I've been hitting full throttle, particularly in 4th and 5th but not exclusively, the car has been misfiring with a big thud and a huge cloud of unburnt fuel from the exhaust. The car was fine on moderate throttle openings and drives normally with no issues. As the problem was getting worse, I had decided to start with new plugs, check the coil pack and harness etc.

On inspection today however, I spotted that this pipe was misshapen and could quite easily be squashed by hand.

Could it be that its closing up completely under load and depriving the car of air?

Would this cause my symptoms?

 

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I think upgrading to a hard pipe kit would be a better option. Them silicon hoses can crack and are prone to leaks and can cause all sorts of air/fuel ratio problem and I have seen them burst under pressure causing over heating too. I don't know if that hose you are pointing at is the source of problem but I would recommend hard pipe kit all the way through. Have you checked wheather all the screw rings are tight? cos loose or burst turbo pipes/ air leak could produce a similar symptom.
 

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Discussion Starter · #3 ·
Jubilee clips seemed reasonably tight, I've re-tightened now. I might try to get a bit of genuine samco hose as the SFS stuff seems a liitle bit softer to me. In the long run a hard pipe might be the best bet as you've said.

I'm not so sure this is the root cause though - car runs 1.6 bar so will demand quite a bit of cold air from the IC. Enough to squash a pipe?
 

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That pipe won't be squashed at full load imho; it'll be under pressure, not vacuum.

The engine doesn't suck 1.6 bar, the turbos blow it! :D
 

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Discussion Starter · #5 · (Edited)
Yes I suppose it will...its feeding air to the I/C through there.

I'll try the plugs next, got stuck before trying to disconnect the PTU as I can't seem to get the rear clip out....off to try again!
 

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Discussion Starter · #6 ·
Right, changed the plugs, still get the problem only under WOT past 3500rpm.

Next thing is coil packs I guess...the splitfires all look fine nothing obviously wrong. I would have thought I'd be getting more of a juddering misfire if it was plugs or coil packs. This is just a big thud and the car has a big jolt go through it as the engine completely misses a beat.

Maybe CAS? Or battery voltage not supplying enough power?
 

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Does it do it at lower boost levels? What ECU do you have?
 

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Discussion Starter · #8 ·
This is Jae's old car Ru, V-Cam, HKS F-Con V Pro.

I haven't tried lower boost - haven't even touched the boost controller since I've had it. I'll give that a whirl as well.

I'll try the basics first but will have to try to get it up to RB if I can't sort it, it seems so violent on the car that it can't be doing the engine any good.
 

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That looks like a straight piece of pipe that someone has "Fanged On"

...Get a proper one with the right angle built into it.
 

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first off, do you know your missing a bolt off the top suspension tower/strut? (i take you have removed the brace to get to the plugs)

I have had pipes collapse before but that was the air intake side. Not the boost side.

Do skylines have a boost cut? Are you hitting maximum boost with not enough fuel and the car is shutting down maybe? Like the supras/ rover tomcats etc?

If so that a harsh cut that makes you head butt the windscreen and then the power returns and keeps repeating.
 

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Discussion Starter · #11 ·
Yes, strut brace off at the time. Pretty sure the pipe thing is a red herring.

Feels a bit like boost cut I'd imagine (always had cars that have a soft limit on the boost controller) - i'll try to get my head around the EVC to lower the setting. Maybe the colder weather is making the boost spike above 1.6 and the EVC hasn't had the cut-off set to a moderate %...didn't think of that I must admit. Difficult to monitor the gauge on my own as the car is so nippy its hard to take your eyes off the road.

Still not sure but will check this next!
 

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This is Jae's old car Ru, V-Cam, HKS F-Con V Pro.

I haven't tried lower boost - haven't even touched the boost controller since I've had it. I'll give that a whirl as well.

I'll try the basics first but will have to try to get it up to RB if I can't sort it, it seems so violent on the car that it can't be doing the engine any good.
Aaah, you're the lucky ****er who got jae's car! :D

Okay, I bet it's the VPro cutting power (not sure if it does fuel or ignition) as you've hit its programmed boost limit.

Happened to mine (until I had the limit raised, lol).

Wind the boost down a bit, as it's obviously slightly too high.

Sorted.

ps hope you're enjoying the car

pps it's violent when it hits the power cut-out, eh!
 

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Discussion Starter · #13 ·
Ru

Thanks very much...just been out with it on setting A about 1.2bar and no problems at all. Yes, very violent...wasn't expecting that. Problem solved though!

Still quick enough so I'll leave it for now. Car is great, I've had all the bodywork niggles done bar the strut tops which I'll do at the end of the summer so it looks great now.

Cheers
Alex
 

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Ru

Thanks very much...just been out with it on setting A about 1.2bar and no problems at all. Yes, very violent...wasn't expecting that. Problem solved though!

Still quick enough so I'll leave it for now. Car is great, I've had all the bodywork niggles done bar the strut tops which I'll do at the end of the summer so it looks great now.

Cheers
Alex

so that is yes a skyline does have a boost cut then!
 

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depends on the ecu i imagine!

he is running a vpro which would have had a boost cut programmed in. it isnt stock
 

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Ru

Thanks very much...just been out with it on setting A about 1.2bar and no problems at all. Yes, very violent...wasn't expecting that. Problem solved though!

Still quick enough so I'll leave it for now. Car is great, I've had all the bodywork niggles done bar the strut tops which I'll do at the end of the summer so it looks great now.

Cheers
Alex
Cool! I know it took me a while to work out when it was happening on mine.

I think jae ran 1.4, or maybe 1.5 bar max, and he seemed pleased with the performance! I never did get a go in it though :(
 

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Power FCs have a boost cut too, and it's like you just dropped a six-ton anchor into the road when it cuts in. I've basically turned mine off.
 

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1.6 bar with all boost and ignition cuts enabled. Because I'm a paranoid lad and that car was WAY too fond of finding new and interesting ways of emptying my bank account. :D Good to know the engine management was doing exactly what it should.

Looking forward to seeing it in full '2010 Alex C' spec :D
 

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lol, I'm sure it'll be sooner rather than later! :D
 
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