Idle Issue

[jyu]

Hey guys, having some trouble here and am wondering if anyone can help me out. I've looked around and tried almost everything but can't figure it out.

So on my 1990 Nissan 240sx s13 Auto > Man (KA24E) I'm having some idle issues. Whenever I come to a stop I throw the car in Neutral and just coast to a stop which is fine, but once I actually get stopped the idle drops to about 500-600 and just bounces between. It's almost like the car wants to die on me but it just holds on and doesn't ever.

I've replaced all the brake and vacuum lines, cleaned out the MAF, after doing so replaced the MAF with a brand new one, tried playing around with the idle control and so on. Still no fix though.

Now on my stock air intake, it does have a huge hole in it and I've got tin foil and duct tape covering it until tomorrow which I'll be replacing with a brand new stock one and I am running the auto ecu still in my manual swapped 240. My question is could this poor idle be from the hole in my intake hose or possibly because I'm still running the auto ecu? I know that leaving the auto ecu allows me to have no speed governor, rev limiter and no fuel cut off but I'm wondering if it's causing this low idle at stops.

Any thoughts would be greatly appreciated, thanks for you'r time and if this post is annoying or isn't in the right spot I'm sorry feel free to delete or report it.

[PapaSmurf2k3]

It shouldn't be from the auto ecu. Having a hole in the intake after the MAF will have you run lean at idle, and that is no good.
Fix the hole, and clean the idle air control valve.

[jyu]

It shouldn't be from the auto ecu. Having a hole in the intake after the MAF will have you run lean at idle, and that is no good.
Fix the hole, and clean the idle air control valve.

Thanks a lot for the help, car won't be running until that part shows up tomorrow. After installing it I'll be sure to clean out the IACV and update ya on how it goes. Once again thanks. Cheers.

[PapaSmurf2k3]

Good deal. You might still have an issue, but its always good to cross the easy things off the list first.

[jyu]

Good deal. You might still have an issue, but its always good to cross the easy things off the list first.

Yeah no doubt. Well a days gone past and I thought I should update you. After replacing that air intake tube, and cleaning the throttle body the idle issue is kind of solved. Now at idle it sits around 800 and doesn't bounce around like it did before. It's still a little low but at least it's consistent.

Unfortunately now I'm running into more problems. I was just going for a test drive around the block after fixing it and it just cut out on me, straight up stalled it self. I tried starting it back up and nothing but crank, I was getting spark and everything looked fine. Oddly enough after cycling the keys a few times and waiting a couple minutes it turned over. Held an idle fine long enough for me to bring it home. I'm thinking either fuel pump related, or ignition coil or switch possibly. I might also just throw that manual ecu in to because that could also be another possibility I'm hoping.

Ahhh gotta love the life of owning a 240

[PapaSmurf2k3]

Well if you are sure you were getting spark, it shouldn't be anything ignition related.

[jyu]

Well if you are sure you were getting spark, it shouldn't be anything ignition related.

Yeah I was just throwing out possibilities. I ordered a new fuel pump so hopefully that will solve the issue. Do you know if I would have to do anything in particular if I changed the auto ecu to a manual one? I kind of want to try it but don't wanna screw anything up.

[PapaSmurf2k3]

I don't believe so. I know they can be run... there might be something dumb like wire the park position sensor to the clutch button to trick the ECU to thinking its in park or something.

[Hijacker]

An auto ECU can run a manual car no problem. It's a plug and play affair. The other way around is an issue. There are kickdown switches, the TPS has extra wiring, and there are interfaces between the ECU and ATCU. So basically, if you have a manual car (or one that's been converted), use either ECU. It doesn't matter. If you have an auto slushbox, you need to stick with the auto ECU.

[jyu]

An auto ECU can run a manual car no problem. It's a plug and play affair. The other way around is an issue. There are kickdown switches, the TPS has extra wiring, and there are interfaces between the ECU and ATCU. So basically, if you have a manual car (or one that's been converted), use either ECU. It doesn't matter. If you have an auto slushbox, you need to stick with the auto ECU.

Thanks for the help guys still kind of confused with it though. I have a auto to manual swapped 240. So it is a manual but the car thinks it's still an auto. I just want to know if I'll have to make any modifications to run a manual ecu that I picked up a while back? I believe the auto ecu is going bad and instead of buying a whole new auto ecu I want to replace it with my manual ecu. Would I run into any problems?

[PapaSmurf2k3]

no.