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Discussion Starter #1
hello,
not got a video of my car but I have found a few that are exactly the same. links below...
I have changed the plugs to the ngk bcpr7es copper gapped to 0.8 this did not solve the issue. it only happens on WOT at around 5k.
the engine has forged pistons and rods as number 6 let go when this happened before! I have the stock turbo with a free flowing exhaust, fmic and hard piping. I still have the stock 2 stage boost installed however it seems to be boosting to around 11-12 psi when this happens. driving yesterday in the wet it was fine all night until the temp dropped a little this it started doing this again :muy:
is this a max out on the afm? if so what's the best way to stop it happening?
I have checked the base timing and I will check this again to be sure it is okay however my rev counter is out so I cant guarantee this is at 650 rpm.. does this matter?
any suggestions would be great as I don't really want another rebuild on my hands.

https://www.youtube.com/watch?v=9dS2YNim3Cs
https://www.youtube.com/watch?v=u-LtEHuMMTo
 

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Sounds like it could be either det, and the ignition is being retarded by the ECU, or coil packs breaking down, has the ECU been remapped/chipped? as this could be the reason if boosting to 12psi or more.
 

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Discussion Starter #3
Hi Ricky,
I'm hoping it isn't det but as soon as I hear it I come straight off so hopefully no damage has been done! When I bought the car they said it was stage one mapped however bells have no record of this so I'm going to say no to mapped. I am wondering is my wastegate is getting stuck as even unplugging the 2 stage it's hitting 11 psi so for something that shouldn't go over 8psi that seems a bit too much for me
 

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I had a similar holding back/stalling issue on mine shortly after I bought it. Wouldn't pull cleanly through the revs, really struggled with it...

Change of plugs to NGK's copper gapped at 0.8 it still happend. Next thing to swap was coil packs . Expensive but given age of the car and mileage at the time (12yr old and 60,000miles) it seemed logical step.

Set of splitfires fitted and back on rollers, all cured! Was running the boost earthing mod at the time too, where you perminantly Earth the white wire to the chassis to run the higher boost all the time. Low boost being 0.5 and above 4000rpm it ups too 0.8bar I believe...

I was going to suggest coil pack amplifier also, if your coils are ok. But really you need to check with another set of coils. Or wrap your old ones throughly in insulation tape! As a get you by mod....
 

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Discussion Starter #5
That's the thing, there is no holding back. It's so odd! I thought the high boost was less than that around 8psi. 0.8bar is 11-12psi. It's so odd! I'll try gapping the plugs again as well as checking the timing and taping up the packs and see if that helps at all. I did try and move my wastegate and it seemed a bit stiff so I have a feeling it's over boosting and throwing the map values out
 

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"A Skyline with 4 doors?"
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It's hard to match up exactly what was happening to the boost gauge with sound. But was your boost dropping back to vacuum when you were one throttle. Some of the video sound reminds me of an issue I had once with an intercooler pipe. The pressure from the mounting would keep the hose in place, but when I hit a certain boost pressure the hose would separate all pressure dropped, missed and once I backed off it'd go back to normal.

Probably a long shot but worth checking
 

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Discussion Starter #7
I don't seem to be dropping any pressure it stayed at 11-12 until I backed off the throttle it went back to 8 and pulled straight past it. Then when you go WOT it builds instantly back to 12 and happens again :(
 

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I'd of said spark blow out, coilpack breakdown. The easiest way to check is to hold partial throttle all the way to the redline and see if she pulls through without the break up. Partial throttle means you are controlling the boost and it should be around half of the max 11-12psi or a little more.

If your car revs through with no break down then it's spark / coil related, there are four things to check and I would do it in this order, least expensive first!

1) Coilpack Loom - Check all plugs to the coilpacks, next Untape the loom and check the common earth wire, it's one thick cable with each branch (6 coils) crimped inline, over time these crimped cables break due to removal and replacement of plugs and heat cycles. Usually a few strands of copper here and there weakening the earth, if this is the case you will want to repair or replace (No solder! Crimps only).

2) Spark Plug gaps and condition - the blackest will be the one where the break up is occurring, as the plug is being fouled.

3) Coilpack Ignitor / Amplifier if Series 1 - test per FSM

4) Coilpacks - Test per the FSM and make sure each one is within spec.

 

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Discussion Starter #9
thanks niz I will get on that this weekend. I can go through the range up to the top at 3/4 throttle pushing around 7psi of boost with no hesitation or break down just the normal pop/ burble when I come off throttle due to a vta bov.
ill have to get a wire brush and clean them up then I will be able to see exactly where it is however I don't really want to keep having to hit it as last time I done this it resulted in loss of a piston :(
I have a spec 2 engine so this will be skipping step 3 right?
is the fsm test for the coils across the plug pins or pin and bottom if the coil as it says 1-2 which is labelled as the plug but the picture has it probing the bottom.
 

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As it's spec 2 yes you can skip number 3, the spec 2 has the igniter on plug, so your coil packs has this built in.

The testing of pins 1 and 2 is for the coil windings, you put the earth / black cable from your tester to the spring / output of the coilpack and test pin 1 and then the same for pin 2. You are looking for the same range on both winds 0.6 ~ 0.9 Ohm.

There's an article on servicing the ignition system here
 

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Discussion Starter #12
Thanks niz I'll be going over them points at the weekend to see what's going on :)

As for the plugs. When I took them out they was eerr black. Think I'll just other a new set of plugs
 

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Reasons for black sooty plugs....
in no particular order.

High fuel pressure
faulty lambda sensor
faulty ECU coolant temp sensor
plug too cold a heat range
bad map
air leaks on boost
faulty or leaking injectors
incomplete combustion/misfire
 

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Discussion Starter #15
Regarding. The plugs I will be getting a new set and seeing how they turn out as although black it doesn't wipe off on anything so this could be the normal colour that's plugs go. My fiesta ones came out the same.

Just a quick update I will be looking at all the listed items on Sunday and seeing what the outcome is however I'm going to be shocked if it isn't the coils giving up under high load and just not supplying enough of a spark.
My reason behind this thiught is that at the moment I just got in from a drive and its 18degrees outside and very little moisture in the air. The roads was too busy to test 5th however through 1-4 never skipped a beat pushing 12psi. Last night however the air was quite a bit colder around 8-9 degrees and was quite moist. Last night the problem happened today it's gone! Seems to me denser air, more pressure in the cylinder and it's getting blown out.

As for the 12psi of boost I found out it has an uprated wastegate so that's why!

I will still go through the motions to be safe however I'll be borrowing a set or rb Motorsport coils to see if it's any change
 

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Reasons for black sooty plugs....
in no particular order.

High fuel pressure
faulty lambda sensor
faulty ECU coolant temp sensor
plug too cold a heat range
bad map
air leaks on boost
faulty or leaking injectors
incomplete combustion/misfire
Yeah. Basically what he said. Covered most of not all the bases

Sent from my SM-N910G using Tapatalk
 

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Regarding. The plugs I will be getting a new set and seeing how they turn out as although black it doesn't wipe off on anything so this could be the normal colour that's plugs go. My fiesta ones came out the same.

Just a quick update I will be looking at all the listed items on Sunday and seeing what the outcome is however I'm going to be shocked if it isn't the coils giving up under high load and just not supplying enough of a spark.
My reason behind this thiught is that at the moment I just got in from a drive and its 18degrees outside and very little moisture in the air. The roads was too busy to test 5th however through 1-4 never skipped a beat pushing 12psi. Last night however the air was quite a bit colder around 8-9 degrees and was quite moist. Last night the problem happened today it's gone! Seems to me denser air, more pressure in the cylinder and it's getting blown out.

As for the 12psi of boost I found out it has an uprated wastegate so that's why!

I will still go through the motions to be safe however I'll be borrowing a set or rb Motorsport coils to see if it's any change
Good indication is usually brownish ...

Sent from my SM-N910G using Tapatalk
 

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Discussion Starter #18
So I followed niz's list apart from the plugs as I lost my spark plug socket :/ my multimeter didn't get down that low to be able to check them so I went and borrowed a set of rb Motorsport coils. The problem has dissapeared so much have had a weak spark! When the new plugs arrive and I get a chance to fit them I'll let you know about the condition
 
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