Sputtering/Power loss over 14psi

[TwIzTeD_3kGt]

I've been turning up the boost on the VR4 over the past week. I had been running 12psi on 19T's on stock injectors with no issues, roughly 300whp.

Installed PTE 550's, scaled them with FlashECU, turned the boost up to 14psi. With no other adjustments, had clean logs for a few days, and was up to roughly 350whp.

So I turned it up to 16psi, and with no other adjustments had 2 clean pulls at roughly 400whp. Then it started breaking up in the 4-6k range, though the logs were still clean with minor 1-2 knock counts here and there which could be tuned out by pulling timing back.

I swapped in some coppers gapped at .032", no effect. I pressure tested and found one major leak and a couple minor ones, seemed to help slightly.

I turned the boost back down to 14psi and 95% of the sputtering is gone. AFR's are right where they should be throughout all of this.

I'm thinking maybe the coils are tired? They're probably original. Would that make any sense? Any thoughts?

19t-L
pte 550's
hotwired Supra pump
fmic
flash ecu

[Chris@Rvengeperformance]

gap all the way down to .024 to see

[R/T93]

I bought new coils as I suspected weak originals. They had the same resistance as my new ones with 125k :(

Do what Forest said.

From the phone.

[Greg E]

Weak spark.

Might be time for an ignition amp and new coils.

[TwIzTeD_3kGt]

gap all the way down to .024 to see


I bought new coils as I suspected weak originals. They had the same resistance as my new ones with 125k :(

Do what Forest said.

From the phone.


Weak spark.

Might be time for an ignition amp and new coils.

Ok, just wanted to make sure I was on the right track. I'll try gapping them down further, if it helps I'll see how far that gets me, then ign. amp/coils. Thanks, I'll update the results.

[Pensky3thousand]

I had the same issue when I went from 14 to 16 psi with 16g's and stage 3 heads. I ran out of spark even with brand new ignition components.
Get an HKS DLI and you'll be good to go.
I hit 27.9psi the other day on my DR750's with a DLI, plugs gapped at .025, new stock coils, MSD wires.
The DLI works great.

[TwIzTeD_3kGt]

Uhhh. What caused this?:

http://i39.photobucket.com/albums/e200/twizted_3kgt/20130516_203243_zps08397d61.jpg

Cylinder 1. All the rest were exactly as I put them in a few days ago.

[R/T93]

Daaamn, lol. Maybe you crashed it while installing it? drug it across the valve cover or something? That is a lot of gap.

[Chris@Rvengeperformance]

Can you see any disturbed carbon on the piston dome?

[TwIzTeD_3kGt]

Daaamn, lol. Maybe you crashed it while installing it? drug it across the valve cover or something? That is a lot of gap.

At this point I don't know. It would be a first for me if it was installer error, but I can't think of any other reason it would be that way. Not just a lot of gap, but bent off to the side as well. Unless launch control or NLTS could do something like this? I've been having trouble with NLTS where I'm on/off/on/off the limiter (my fault) and it sounds pretty rough on the engine. I doubt it's that though.


Can you see any disturbed carbon on the piston dome?

I didn't even look. Scared I guess. I just chalked it up to installation error, bent tip back into position and gapped it down to .024" like the rest of them. I don't exactly trust that plug now that it's been bent around so much, so I'll pick up a new one tomorrow.

All misfires gone, I'm up to 17psi with no problems other than it knocks over 6000rpm. Pulls hard, I think I could pull off a high 11 or better as it sits, but I won't get ahead of myself. Pulled timing back a degree or two in the area it's knocking, but didn't seem to cure it. I'll have more time tomorrow to play with it, but any ideas on that? I feel like I've seen a number of threads on that same issue over the years, but that was before I was into tuning anything.

[Chris@Rvengeperformance]

What afr are you running up top?

[TwIzTeD_3kGt]

What afr are you running up top?

Wideband is reading low 10's up top. Stock AFR map with about 40psi fuel pressure. Want to be rich while I'm messing with it.

[J-Groove]

I'm trying to think of other ways that could have happened.

I mean your cylinder chamber is very hot, metal on the spark plugs are made to take it but they are also soft and easy to bend.

Maybe it was just a weaker than standard spark plug and the heat caused the metal to move?

-John

[TwIzTeD_3kGt]

I'm trying to think of other ways that could have happened.

I mean your cylinder chamber is very hot, metal on the spark plugs are made to take it but they are also soft and easy to bend.

Maybe it was just a weaker than standard spark plug and the heat caused the metal to move?

-John

I don't know, I bent it back and haven't had issues yet, plus the others didn't bend. It's getting replaced today just in case. I was thinking, maybe there was a hot spot in the cylinder that pre-ignited or something on the plug when I put it in that ignited. Idk, seems far fetched. The most likely thing is that it happened when I installed it, I just really don't see how. But that's why they call them mistakes.

[J-Groove]

I don't know, I bent it back and haven't had issues yet, plus the others didn't bend. It's getting replaced today just in case. I was thinking, maybe there was a hot spot in the cylinder that pre-ignited or something on the plug when I put it in that ignited. Idk, seems far fetched. The most likely thing is that it happened when I installed it, I just really don't see how. But that's why they call them mistakes.

I agree, it does seem very VERY far fetched. But all things considered, without any damage on your piston or a miss install I don't see what else it could be.

-john

[SpdDmnVR4]

Wideband is reading low 10's up top. Stock AFR map with about 40psi fuel pressure. Want to be rich while I'm messing with it.

Low 10's is quite rich. I know this sounds counter-intuitive, but lean it out just a little. maybe high 10's and see if knock gets worse or if it goes away. on multiple occasions with my car i have seen high rpm knock at 17+ psi and an almost overally conservative, rich AFR (10.0-10.2). leaning it out actually helped cure up the knock in most areas. I chalked it up to more complete combustion.

[TwIzTeD_3kGt]

Low 10's is quite rich. I know this sounds counter-intuitive, but lean it out just a little. maybe high 10's and see if knock gets worse or if it goes away. on multiple occasions with my car i have seen high rpm knock at 17+ psi and an almost overally conservative, rich AFR (10.0-10.2). leaning it out actually helped cure up the knock in most areas. I chalked it up to more complete combustion.

Ill give that a shot, I was half thinking that might be it.