S14 KA24DE-T Idle woes

[DDS]

First off, let me apologize for not having a log file to show here. Apparently I lost it somehow, probably didnt save it, customer already gone.


Basically, I am having an issue with the MAF/TP oscillating at idle. With electrical load (headlights/fan on), if I load the power steering then let go, it will oscillate about .3V up and down exactly 4 times then smooth out. During this the idle bounces around a bit, sounds like it will die, and sometimes does. If I blip the gas, it will smooth out a bit, and if I let it fall upon idle slowly, it wont do it at all.

It will also do this coming to a stop. Drive, press in clutch, gear shifter in neutral, it idles at 500 rpm whilst car is moving. as soon as it almost comes to a stop it will begin to oscillate same as above.


The car is a 95, and I believe its a manual ECU in there. Type 4 board with 70F00. Stock MAF, SR 370cc injectors, and every other part of the tune is spot on and holds well except for dying on decel. Ive had this issue with some others and tuned it out with the fuel cut/fuel recover rpm, but I don't see these in there. Are there any additional things I can add to the address file to have more options? Or is it possible that this could have been an auto ECU and that has something to do with it.

Thanks in advance! Anybody???

[Matt]

Question would be did the problem exist prior to the Nistune and the upgrades? Difficult when you have the customers car there usually upgraded and then notice the problmes

Sounds a bit like an electrical issue rather than something to tune around?

[DDS]

No, we did the Nistune over a year ago, and ever since its been like this. Really the only mods made were converting to blow-thru MAF and swapping the injectors to 370ccs, and the tuning for boost. As far as i can tell, the MAF isnt getting any reversion according to logs after letting off boost.

[Matt]

Yeah not sure without the log files unfortunately (stream mode) to see what is going on. Normally if I can see the problem and repeat on the bench here then it assists with narrowing it down

[BlueRB240]

No Filter on the maf?

[DDS]

It ended up being the idle screw needed to come out 2 turns. The jumping up and down in MAF voltage was from one of the other idle valves turning on and off. After some more air gets in, it slows down the decel so much that this no longer happens

WOOHOO!

[Matt]

good stuff. mechanical issues can always throw a spanner in the works