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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.







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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 by paradime
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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.

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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.  

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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.

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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.

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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.  

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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 

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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.

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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 by Stoffregen Motorsports
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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


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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.

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