ka24de 270cc to 380cc floods at start

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modulation
 

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ka24de 270cc to 380cc floods at start

Post by modulation »

I have a NA ka24de with a n60 maf (maxima.) It's been running great! I have no idle air control, or butterfly valves and that definitely cause some of my frustrations, but I think it can be worked around.

I put some 380cc injectors from a Q45 on it today. I used the "change injector" option and fine-tuned the K-constant and everything is good when it's running (idle, WOT) etc..

But its difficult to get it started. I either have to floor the gas pedal when starting (do Nissans have a anti-flood like GM?) or I end up having to pull my electrical injector harnesses's and starting the engine, letting it die and rinse and repeat a few times until it finally runs. After just 2-3 cranks the AFR memter reads like 10-11:1.
I've changed the throttle enrich table down to nothing for the coolant temps I'm hitting, and have also zeroed out the crank enrich and a few other tables.

Once it's running it's fine, but what can I do to like cut the injector pulse-width while cranking?
modulation
 

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Re: ka24de 270cc to 380cc floods at start

Post by modulation »

What is the engine crank offset table?
Does it deal with fuel enrichment?
modulation
 

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Re: ka24de 270cc to 380cc floods at start

Post by modulation »

I messed with the engine crank offset table and it didn't seem to do anything.

I guess even when the car idles at the proper AFR's it doesn't run 100% right. It seems to miss or something and then I get pops in the exhaust. When driving around though everything is fine so it's not a spark problem. I think the air just doesn't get high enough velocity to aerosol the fuel properly, I'm sure the swirl control valve would help with this but it kills top-end power.

I'll probably go back to the 280cc until I go turbo.
modulation
 

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Re: ka24de 270cc to 380cc floods at start

Post by modulation »

I might be even stupider then I thought.
I assumed since they were both similar generation Nissan injectors they would have the same latency, but I found a couple of post that they don't.

720us vs 520us

I'll try this out tomorrow.
modulation
 

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Re: ka24de 270cc to 380cc floods at start

Post by modulation »

Well I gave up and am back on stock injectors.
Fixing the latency made idle way better, but starting was still a pain.

When I took off the new injectors to go back to stock, a few of the injectors had the bottom O ring sliced so I think I might have had at least one if not two fuel rail leaks so maybe that was causing my starting problems so I'll probably try the upgrade again in a week and this time I'll put some vasoline or motor oil on the bottom O rings so they don't get cut.
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Re: ka24de 270cc to 380cc floods at start

Post by Matt »

Crank Enrich table is the one to modify

Currently S13 KA24DE is
78 78 66 54 42 31 20 15 12 10 8 7 7 7 7 7

You need to pull out 27% of the values in this table for these particular injectors to make it crank leaner
modulation
 

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Re: ka24de 270cc to 380cc floods at start

Post by modulation »

Thanks Matt, I'll give that a go next weekend when I try to swap injectors again.
modulation
 

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Re: ka24de 270cc to 380cc floods at start

Post by modulation »

I got new orings and used a tiny bit of Vaseline to lube them before putting the 370cc injectors back in this time.
That made all the difference. The first thing that I noticed was even when cold unlike last time when I had the orings sliced and fuel rail leaking the car would idle perfectly.
There were also no pops on down-shifts or de-accel so I can tell the fuel rail isn't leaking.

Thanks Matt for the data! Looks like I had it pretty close all along and it turned out to be a mechanical problem (sliced lower fuel injector orings) not a software problem.
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