KA24DE (NA) swap no start condition.

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620brian
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KA24DE (NA) swap no start condition.

Post by 620brian » Mon Aug 19, 2019 7:11 am

Sorry this isn’t technically turbo KA related but this forum seems to be very knowledgeable. And I do plan on going turbo..after I get it running NA that is.

First time poster - long time lurker.

Over the past year, I have entirely rebuilt a 96 KA24DE and swapped it into a 79 Datsun 620 620.
It has the standard KA/240 5 speed behind it (also rebuilt).
Wiring specialties harness custom made for this application and a 96 KA ECM.
Everything is plugged in and terminated per wiring specialties documentation.
Grounds all over the place, chassis, body, starter, alt, ecm.
Brand new battery.
Triple checked the timing - i.e. - I put it at TDC with the finger in the #1 hole trick, long ratchet extension dropped in plug hole is at its top movement, the crank pulley is on 0deg, the #1
Cam lobes are pointing out at TDC.
Proper S14 dizzy.
Good spark on all 4.
Walbro 255 FP and a Tomei FPR set at around 40psi.
I removed the fuel rail and rigged up water bottles under each injector. They all spray while cranking (a LOT actually).

I just cant get it to start.
If I spray starting fluid it WILL start and actually sounds like it running for about 30 sec.
I'm pretty sure its in time or close if I can get it to run on fluid - please correct me if I'm wrong.

What am I missing?
Any help is greatly appriciated.

Theory - Its almost like the injectors are spraying TOO much and flooding the cylinders - like its not presenting an nice atomized spray on the compression stroke - its more like a giant puddle that the plugs cant ingnite? I dont know.



NOTE - I do have another S14 ecm and a another S14 dizzy on its way from the ebay.....thats only thing i can think of trying.

620brian
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Re: KA24DE (NA) swap no start condition.

Post by 620brian » Mon Aug 19, 2019 2:29 pm

This pretty much proves I’m timed correctly yes?

https://vimeo.com/354748629?ref=tw-share‬

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p00t
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Re: KA24DE (NA) swap no start condition.

Post by p00t » Fri Aug 23, 2019 3:29 pm

Sounds like you're heading in the right direction diagnosis-wise. If you unplug injectors and it can momentarily start on carb clean then your ignition is at least good enough to start.

Sounds like you need to look at those injectors closer.

Are they stock? Does your ecm have a custom tune? The only other thing that would affect starting pulsewidth is coolant temperature sensor. You can try unplugging that and letting it use failsafe value.
KA24DETT still alive
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p00t
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Re: KA24DE (NA) swap no start condition.

Post by p00t » Fri Aug 23, 2019 3:29 pm

Also you verified fuel pressure with a gauge?
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620brian
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Re: KA24DE (NA) swap no start condition.

Post by 620brian » Fri Aug 23, 2019 3:34 pm

I have a Tomei FPR that I’m trusting.
Set at 40 psi.

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Re: KA24DE (NA) swap no start condition.

Post by 620brian » Fri Aug 23, 2019 3:38 pm

Good tip - I was unaware the CTS effected pulse.

I’ll try that and test the CTS per the FSM.

The 2 wire one is the ECM feedback one if I remember correctly? the single wire is just for gauges..I think?

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Re: KA24DE (NA) swap no start condition.

Post by 620brian » Fri Aug 23, 2019 3:41 pm

Stock red KA injectors (as far as I know).
Stock ecm. I have 2 identical so I’ve checked that.
I do have some purple injectors but I think they’re for an SR - I assume those would flow too much?

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Re: KA24DE (NA) swap no start condition.

Post by 620brian » Sat Aug 24, 2019 11:18 am

Got it running by unplugging the CTS (it’s bad), new plugs and turning the FPR down to 10psi.
I’m going to order new injectors I guess?
Not really sure what the fuel delivery problem is.

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Re: KA24DE (NA) swap no start condition.

Post by 620brian » Sat Aug 24, 2019 12:20 pm


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p00t
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Re: KA24DE (NA) swap no start condition.

Post by p00t » Thu Aug 29, 2019 6:52 am

Glad you at least got it running. Having to turn the FPR down to 10 is aweful. There must be an input causing the ECU to drive the injectors that hard... Do you have consult or similar to see the live data?

How are your voltages at the ecu, at the alternator, and at the battery? If your ecu is reading less voltage than at the injector it will drive it harder.

I am also assuming we can rule out the MAF which should only affect running condition...

I would not assume that wiring specialties is flawless you might want to check sensor voltages according to FSM with a multimeter. Also make sure all ECU pins have grounds that should. Some are power grounds others are for sensor circuits in the ECU.
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