KA24ET

[Away8777]

Hello everyone first thing I want to say is thank you to everyone on this site for helping me get my 82 720 pickup running good the community here is great. I recently picked up a 85 with a KA24ET swap. I was told that the truck was NA and ran great for the longest time. The previous owner decided to throw a turbo on it and now the truck won't stay running I have been chasing down vacuumed leaks left and right on this thing. When I do get the truck to idle it stays at about 2k rpm I have pictures and a short video of how everything is ran and would like some input on the set up it has stock fuel injectors factory 240 MAF and stock ECU I'm wondering if it is possible to at least get this to stay running for now without getting the bigger injectors and tune that is needed to drive it.

https://imgur.com/a/PL3r0MI

https://imgur.com/a/8ytWG5C

https://imgur.com/a/fu1RtiF

https://imgur.com/a/v1VeZtD

https://imgur.com/a/PvXOMis

https://imgur.com/a/X9J15Lp

[paradime]

Have you checked the idle air control valve? Is it a stock or modified/reflashed ECU? Does it have an O2 sender and gauge? If it still needs larger injectors to run it safely, it sounds like it has a ways to go all round. I would wait until all ducks were in a row before trying to get it to idle right as is sits.

Edited July 15, 2022 by paradime

[Away8777]

I have adjusted the IAC it helps a little and as far as I know the ECU is stock the 02 sensor is hooked up the ECU is throwing no codes when the turbo is hooked up I tried bypassing the forced induction system by simply hooking the intake, IAC line, and mAf back up to the throttle body and it still would not idle and would throw a MAF code.

[Icehouse]

Maf is to close to the turbo.  Get that sucker 18" away and it will run great

[Icehouse]

Also stock injectors will only do a couple PSI of boost.  So when you get the idle and cruise good and it cuts out under full throttle it will need bigger injectors.  

[Away8777]

Ok I wasn't sure if the MAF was an issue as it wasn't throwing a code with it so close I will try relocating it tomorrow and get back to you guy I appreciate a response you guys are great.

[datzenmike]

2 hours ago, Icehouse said:

Maf is to close to the turbo.  Get that sucker 18" away and it will run great

 

Nissan usually mounts it on the opposite fender well away from the plenum and any flow disturbances.

[Away8777]

So Mike are you saying I should have it by the throttle body after the BOV ? I figured that would give false readings due to the forced induction? 

[datzenmike]

Try to move the MAF as far from the turbo inlet as you can.

[Away8777]

10/4 thank you👍

[Away8777]

So I just ran a temporary test pipe for the intake with the MAF about 25in away from the turbo inlet the truck still does not want to idle or stay running any thoughts?https://imgur.com/a/UlEVBVA

[Away8777]

Icehouse this also has one of your can/am boxes in it with some scary wiring not sure if that's the problem or not I went over it and looked also sent some pictures of it to ]2eDeYe to look over when we were talking about the motor mounts he makes and he said everything looks fine.

[Icehouse]

If there are no vacuum leaks and the engine ran good in the last chassis it should idle perfect with the MAF unplugged.  If it doesn’t you still have vacuum leaks.  Only wiring issues I can imagine are no idle air control wiring or maybe a bad ground.  Should be two on the back of the intake manifold.  Not bolted together.  

[Away8777]

I can't get the truck started with the MAF unplugged. The previous owner stated that he was driving the truck every day then got the idea to turbo it and that's when it stopped running good I will check the IACV wiring in a bit. I have read all over forms about the PCV and valve cover vent causing vacuum leakes but then other people saying it won't cause any issues it seems there is no definitive answer. Right now the valve cover is to atmosphere and the PCV is ran to a port on the intake manifold after the throttle body not sure if this is right 

[Stoffregen Motorsports]

Try clearing all the codes and start over.

 

Try plugging the IAC just for testing.

[Icehouse]

Yeah what codes are we getting?  Also are you sure it has stock injectors.  

[Away8777]

I'm not getting any codes I did get a MAF code when trying to bypass the turbo by going straight to the throttle body with some intake piping I had laying around. But I reset the ECU by following the procedure with the dial on the ecu .at least I believe I did it right. I would assume that the ECU resets when the battery is disconnected as well correct? And as for the injectors they look like the factory 240 sx injectors and I was told they were stock by the previous owner.

[Away8777]

Does anyone know what this is in the image ? It's between the intake manifold and the injectors it's plumbed into the same line as the IAC?https://imgur.com/a/82h576l

[Stoffregen Motorsports]

Is it a coolant hose?

 

This guy talks about the IAC circuit - https://240sxguide.wordpress.com/2014/04/06/1995-1998-240sx-ka24de-iacv-idle-air-control-valve/comment-page-1/

 

Some ECM/ECUs will not reset by simply disconnecting the battery. This changed around the time of OBDII. Did you say if it was a factory ECU? Or is it aftermarket? Aftermarket ECUs will allow you to delete the IAC. Changing the idle up is done in the tuning software.

Edited July 20, 2022 by Stoffregen Motorsports

[Away8777]

I believe it's an air line as it tees off the hardline under the intake manifold that the IAC is connected too and it is a factory ECU from a 1990 240 sx

[Away8777]

It seems like some sort of air diaphragm I outlined it here and the red line is the line that is connected to the hard line that is also connected to iac

[Stoffregen Motorsports]

Could it be some sort of idle up solenoid for A/C? I thought those things were controlled by the IAC, but I'm not too familiar with the modern Nissan stuff.

[thisismatt]

8 hours ago, Away8777 said:

Does anyone know what this is in the image ? It's between the intake manifold and the injectors it's plumbed into the same line as the IAC?https://imgur.com/a/82h576l

 

Iacv-Air Regulator

 

https://www.nissanpartsdeal.com/parts/nissan-regulator-assy~22660-40f00.html

[Away8777]

Thank you Matt this is obviously part of the IAC system by what I can find is it's for cold start ups and cold weather if I get this weekend I'm going to start tearing into it the more research I do and the more Info I get from you guys I'm starting to lean more towards a vacuum leak or an issue with my FPR. I know that without proper vacuum on the FPR the engine will not stay running thanks again I will keep everyone updated

 

[Away8777]

Well boys I figured it out turns out I had a huge vacuum leak. Something so stupid and I overlooked completely thinking I had more serious issues...... The vacuum reference for the break booster was disconnected because there is no booster in it!!!!! I feel like an idiot but glad I figured it out the truck now stays running under 1000rpms but sputters and chatters at idle now. I'm going to do everything every one has said on here moving the MAF further away resetting the ECU and messing with the IAC a little bit will keep everyone updated on my findings.