Grunswald

Hi,

I've had the FC sat in the shop for a bit more than a year cause i had been struggling with coolant issues for a long while.

Now the car is not leaking anymore, getting up to temp at a decent speed and staying at it.

Now i have a new problem. Maybe it was already present but masked by the car running with almost no coolant...
Anyway, when the car is warmed up, i have a very rough idle. basically, the rpm falls down really low almost until the engine stall, then get back up and down.
Before it almost the stall, the AFR reads really high value (16.8).
I have a lightened fly wheel, but it is qualified has "street" so shouldn't have that much of an impact on idle.

At first i thought of air leak but i don't seem to find one. And the turbo pressure reads as normal.

During the coolant leakage fix, there has been plenty of parts removed and reinstalled (the fix was the to change the O-ring between intake and engine).
As such, could there be a screw or bracket that has been reinstalled without the correct setting and then impact the idle rpm ? as with carbs ? Or is everything controlled by the ECU ?

diabolical1

iTrader: (3)

do you still have a functional BAC?

Grunswald

well every part is in place but the belt is not there anymore. (replaced by the twin pulley on alternator)

The hose that connect to the pump is caped. I haven't checked if everything is still ok there.

But if the idle is really rough, it doesnt stall. So i don't know if that could come from the BAC...

diabolical1

iTrader: (3)

well, i'm not sure what you're trying to say about the belts and pump. maybe there's a little miscommunication between us on this.

BAC threads:
https://www.rx7club.com/2nd-generati...estion-855185/

https://www.rx7club.com/2nd-generati...c-valve-47260/

i was looking for some photos of it online, but the only ones i could find are EBay ads, so i'm sorry for that. here's one: https://www.ebay.ca/itm/254127678238

you can also look up any test procedures in the FSM, and you can get a free copy of it from: Foxed.ca

Other ideas

1. are you absolutely sure you have checked everything and found no vacuum leaks?

2. did this issue start after you changed the flywheel?

3. even though you're saying that idle issues begin after the car is warm, you can check the thermosensor, but i really don't think that's the issue. if it were the issue, then i think your issues would be before you get up to temp, but maybe i'm wrong.

maybe give the TPS a check????

Grunswald

Well basically I started the air pump removal and usually the bac valve goes with it. But I stopped halfway through it and went back.

Long story short, the bac valve is almost untouched.

The flywheel was changed 8 years ago so I don't think it's at fault as the issue is quite recent.

It really seems like the idle is too low. But it's fine when it's warming up as the idle is higher.

I believe there is no leakage as the car revs normally and the turbo pressure is at it should be (0.8 bar).

I thought also about the TPS, I don't know if there would be other symptoms associated.

I have a weird guess also. I was due to change the oil but i sent it to the shop and thought they'd do it. I wonder if they haven't done it and the oil isn't thick enough anymore. That would be a long shot but that wouldn't be the weirdest thing I've had with the car...