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New 620 guy with KA24 swap


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So I'm new to datsun and the forums. Picked up A 73 620 already with a KA24 swapped BUT is very hard to keep the car on specially when cold. It will crank no problem but it will just sputter off. After trying and trying for while (30 mins) it will stay on and will smooth out once warm. Any help will be appreciated before I start chasing the problem. Thanks 🤙🏾

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1 hour ago, datzenmike said:



Does this have the EFI or was it 'converted' to carburetor?


Don't be shy posting pictures.

Thanks, it's fuel injected and there's a few mods ill be posting pics. I just brought the truck home today so haven't really poked at it.

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Did you check the ECU light for error codes. Depending on year if its pre obd2 then the ecu has a light on it that will flash a series of short and fast blinks to give an error code. The newer ones might need a tool to read the codes, cant find my other ecu at the moment to check though.

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Here are some pictures of what I'm dealing with. Hope you guys can see it I was having a hard time uploading pictures. I'm wondering if whoever built this out in the SF bay area is on here? Truck seems to have some good bones hopefully I can get it running soon.

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DE from an S13/14





Maybe someone knows but normally the valve cover vent does not go to a filter like this. Isn't it connected to the air pipe between throttler body and the MAF???


Poor cold idle.... maybe look at the AIC idle air control valve.

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definitely check for codes.


You have an obd1 ma24de, it is fairly  simple. 


Turn the ignition on and turn the screw on the ecu to the right and count the flashes.

you can google for the full procedure and code list.


Mike has a good suggestion as well. The idle air control system is what acts as the ‘choke’ as part of its function 

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Vent tube is fine.  Checking codes is a good start.  Also check and see if the ilde air control stuff is wired up.  Redeye would know about that :). There are two idle air control valves.  One that is similar to a chock, it just gets constant 12v while it warms up it shuts a "air leak" which then idles down the engine.  The other is controlled by the ecu, if the alternator clicks on or in stock form the power steering pump engages, it needs a few more RPMs it can make it happen.  Technically there is a 3rd for the AC but you don't need to worry about that one.  Usually a purple plug.  

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Looks like an S13 because 3 head bolts and looks like an external coil.


Check your air intake tube. Looks like it is sitting right on top of the dizzy wires. I know from experience that after a while it chafes and causes headaches.


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Thanks everyone 🙏🏽. So started to poke around and got the codes. Calls for

34-knock sensor,

12- air flow meter.

13- temp sensor.


I'm replacing those and doing a good tune up. Surprisingly I get the car on without the MAF sensor on but as soon as I plug it in car stalls. Also planning on removing the gas tank and cleaning it out. Since its been sitting and its an old truck.  I'll keep you guys posted. Thanks for the help.

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1 hour ago, ]2eDeYe said:

knock sensor will cause acceleration issues. 


MAF issue is weird, i wonder if something was bypassed or shorted

I think there was a ton of stuff bypassed, none of the gages work, and I have an ignition switch thats connected to a relay box that buzzes when its turned on. But definitely there's some weird stuff happening with the wiring I think.

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Reset the ECU and see what the new codes are.


When the engine is running, spray carb cleaner all around around the intake area and listen for engine changes. If you have a vacuum leak, it will show up because the idle will jump up slightly as it sucks cleaner into the leak. Vacuum leaks need to be fixed.


Make sure that little hose that goes into the intake pipe right before the throttle body is not kinked, broken or disconnected, its hard to see from the video. See the youtube video below.


Google IACV KA24DE. Your idle air control valve might be dirty or blocked - tons of info on line about how to clean it. Idle Air Control Valve.






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  • 2 weeks later...

Thanks everyone for the support. After a few hours of chasing the possible problems Turns out my fuel pressure is too low. I managed to keep it on when pinching the return line and it kept running smooth for as long as the line was pinched. Will order a new regulator and will test it again.

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  • 2 weeks later...

Happy new year everyone.... so I'm back to square one. Truck ran after I fixed the fuel pressure regulator and now it's back to doing the same it turns on but won't stay running. 

Checked for vacuum leaks and nothing even took the intake manifold off to make sure everything was properly installed and nothing. 


One thing I did notice was some wires are ripped off maybe will do some wire replacement next. 


Thanks for the help... cheers

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