Revs dropping when stopping

[Ziltyy]

Hi all, I’m new here and new to skylines in general. I just got an R33 GTS-T RB25DET.

The previous owner only had it for about a year and wasn’t very mechanically minded and couldn’t tell me much of what was done to it by the owner before him. Long story short I’m having an issue with the revs dropping when I’m coming to a stop with the clutch in. Neutral or in gear makes no difference. The revs slowly drop as per normal but 1/4 times they just go all the way to zero and it stalls. The car runs perfectly fine otherwise. This leads me to believe it’s a sensor issue. I have taken the air box out and cleaned the filter (looks pretty clean and new anyway) and I have sprayed about half a can of cleaner through the AFM. This made the car a bit smoother in the lower gears, but the stalling is persistent. I’ve read many things here before posting this, I’m really at a loss as to what to do. Reset the ECU? Check and clean more sensors? I don’t know.

 

as far as I am aware the mods done are:

- 3” straight through turbo back exhaust

- 14psi boost

- A front mounted intercooler has been fitted

- turbo timer

 

any help is appreciated, thanks.

 

[admS15]

Try removing and cleaning the iacv valve. Google for instructions. quite easy.

[GTSBoy]

2 hours ago, admS15 said:

Try removing and cleaning the iacv valve. Google for instructions. quite easy.

This.  It will be this.

[Adam91]

I’d start at your blow off valve man. If your running a vented bov with air flow meters it will play with air/fuel ratios on decel. System should be plumbed back if you have afms. Also try iacv as suggested

[Ziltyy]

Going to try the iacv first, will test It out, if that fails I’ll look at the bov. Thanks all

[rb30gtr]

yeah bov or iacv.

[Ziltyy]

Just an update for anyone else who might have a similar issue. The BOV was deleted and all the lines clamped. I replaced it with a stock intake pipe to the turbo with recirculating BOV and reverted as much of these dodgy amateur cable tie mods as I could back to their original stock parts and it runs ultra smooth with no issues now

Im even getting an extra 100km per tank on average, for a total of about 380km per full tank!

I never ended up cleaning the IACV, it’s on my to do list though. Cheers.

[Dose Pipe Sutututu]

Replace the O2 sensor with a fresh item and get even more economy

 

[drunken0elf]

Yeah bov may make a big impact. My GTR had the same issue and after swapping back to oem bov recirculating setup it was way better.