Replaced Coilpacks, Car "pauses", Black Smoke. Wtf!

[buckets]

Hey guys

I don't post of here often, I look alot. I'm in need of some help but guys. My R33 had a problem a while ago where it would really badly missfire (even on idle) to the point where the car shook a bit. I services her (plugs, fluids etc) and it hung around. So I figured it must be the coilpacks. So I bought some R34 Gtr ones and they have a built in igniter so they pop in. Fixed it. She was running great! Strong smooth power. Then the other night, stomp my foot down, boost pressure builds and starts pumping, 4000-5000 revs the car stops. Not stalls, just like it paused for one second then kicked back in.

Did a bit more driving, decided to slowly feed the power on now to see at what rev range the pause kicked in. It was literally a pause. Thrown forward in my seat for a second then back on. It didn't do it. If I wind out the boost (feed it on slowly) she's fine. However, the issue now is. Since the pause, I've got alot of black smoke coming out the exhaust. It only seems to be on boost but. Not normal driving.

I'm thinking (and hoping) it's my AFM? As I'm hoping the turbo is fine. But the boost is still as smooth as it was at the moment even with the smoke.

Any ideas guys?!? I'm Uni student too so I'm praying it's not gonna cost me an arm and a leg

Thanks guy

Help me fix my girl

[buckets]

Sorry guys,

Car has a manual boost controller (set to 9psi), pod filter and 3inch cat back exhaust

Might help

[Moodles2]

Set the boost to minimum and see if it still does it.

[buckets]

I'm gonna reset the ecu tonight with the old paper clip trick. See if it brings up errors codes/ take it for a spin on a resettled ecu

[89CAL]

Turn down boost to 7psi see if it helps, or run 5 psi by running a boost line from actuator to boost pickup point

did you put the earth for the coilpack harness back on when you put it all back together?

[buckets]

Yeah. I replaced the coilpacks 2 months ago. Why I'm curious as to whats going on now though. I've also re bolted my battery earth as the bolt sheared off a while ago. So that's sweet too. No idea what's going on

[89CAL]

sounds like ECU limits, mine did this on stock ecu. try lower boost setting just to see if it helps

[mad082]

+1 for winding the boost down. I'd put money on you actually running more than 9psi (despite what your gauge says). cleaning the Afm may help the situation, but the problem is that the ecu is seeing too much airflow for a given rpm and load. I used to have this happen to my 33 on cold mornings.

[buckets]

I'll give it a go boys. Only thing is she has been running 9pound now since about 3-4months ago. So I don't know why it would do this all of a sudden?

[buckets]

By the way. Always remains at 9pound 24/7. It's never been wound up or down since I set it. Manual boost controller too so just a t peice with a bung

[mad082]

I'll give it a go boys. Only thing is she has been running 9pound now since about 3-4months ago. So I don't know why it would do this all of a sudden?

Cold air is more dense, so the ecu compensates.

As for running 9psi, as I said, your gauge may be reading 9psi, but you may be running more. Comes down to the brand of the gauge (some more accurate than others) and where you have it hooked up to.

I'd start by cleaning the afm, then if that does nothing, wind the boost down

[buckets]

Is she right to drive? Like without boost? She is my daily driver

[89CAL]

Just plumb the boost line straight to the actuator so it runs 5 psi. Run it like that for a few days and see if the problem disappears. Might be slower but will tell you if that's the problem

[buckets]

Okay so update.

Took the car out last night. Just standard drive. She drove fine. Idle smooth. Power good. I didnt really go near boost though. Checked the ecu for fault codes with mr paper clip. Got a "55" which is "no malfunction"? Huh? This happened the other night and I haven't driven her that much since. So the fault code she still be there?

[buckets]

One more thing to add that I always forget about lol I had to replace the fuel pump on her as the spindles inside went (Christmas day just passed, so f***king great timing). Replaced it with a second hand R34 Gtr pump which has 15,000 genuine km's on it. Contributing factor? It did happen with just, just over a quarter of a tank and I know the fuel pumps on skylines don't like being run low. Possible cause or me being paranoid?

[89CAL]

How about you do what we suggested from the start and wind the boost down and see if that fixes the problem. We are either right or wrong about this but you wont know till you try it.

[buckets]

Hey guys

Sorry I haven't updated in a while. I haven't had a chance to look at my car. Uni is in full swing. However over the last weekend i got around to changing the oil on her (she was overdue by a good amount, and have noticed a slight drop in oil pressure). So new oil and filter. Start her up. She runs smooth as anything. She was full on fuel so I decided to give her a spirted run to flush some new oil through the system.

So I'm driving along after about 15mins of standard driving, touch of boost here and there, feels good, I drop her back to second, balance the revs and plant it. Boost comes on strong and smooth as anything. No kickback just straight in.

Here's the thing though, I did this about 2-3 times and all of those times there was ZERO smoke and ZERO misfire. I also popped the car during this time and hooked up a boost gauge (as I'm running 9 psi and she's pretty much stock as a rock I haven't invested in one yet) and the boost was fine. Still 9 psi. It's a manual boost controller and it's +2 clicks/1psi so I figured it would still be okay. And the ecu is still reading "55" so all clear.

Any possibility that low/oldish oil could cause more fuel dumpage? Is there a sensor or something possibly at the back of the sump that tells the ecu (when using boost due to oil feed to the turbo while low, and the kickback from it) that there's not enough oil. Therefor cutting the power sometimes. Or requiring more fuel? 1st may add up the second I'm still skeptical about

Anyway sorry for the delays guys and thanks for all the help so far. Let me know if you think of anything

[89CAL]

No and no

There is no oil level sensor at all, only oil pressure and even then it won't stop the engine from destroying itself

I say give it time and the problem will return.