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Discussion Starter · #1 ·
Hey guys, I recently bought a k20 swapped civic coupe from my friend and recently I have had some starting issues. Car runs perfectly when it starts, no misfires or anything, but when it won’t start it’ll just keep turning over without catching, obviously. By no means am I a mechanic but I’m working towards becoming one and this is what I know so far: I’ve ruled out fuel delivery (pressure tested it and listen for the fuel pump in KOEO position) and battery because it doesn’t feel or sound like it’s weakening when I have to try and start it several times. Also, had all of the relays and fuses tested to make sure that wasn’t the issue. I will say, that green key light that comes on the dash when I put my key in no longer comes on (ever since this issue started happening) which I’m told could be an immobilizer issue but it also won’t connect to the autel scanner I tried to use so I’m not really sure where to go from here. The friend I bought it from is more than willing to help me but I would like to learn and do some research on my own first. Any suggestions would be greatly appreciated! Thank you.
 

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Arouse the DAMPFHAMMER!
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Any suggestions would be greatly appreciated! Thank you.
Welcome to K20a.org @Koupe20.

I run out of time today, but you may read this Please help.car cranks but wont start | Honda / Acura K20a K24a Engine Forum. We have tons of threads to that topic as the electric form the Honda K-series is a weak link at this very good performing Honda K-series.

What always helps, check out:
  • crank speed exceeds 200 rpm
  • if battery has more then 11.5 V during cranking this would help
  • fuel spray pattern for all should have the same pattern
  • every spark plug should fire viewable
  • compression test result of all should be within 0.5 bar (Honda allows more, I am not ;))
  • how does exhaust gas smell? After fuel would be good...
  • ...
 

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The immobilizer light not coming on anymore and the scanner refusing to connect may or may not be related. If the immobilizer disabled the engine, it will have no injector pulse or spark. Next time it won't start, see if the spark plugs and fuel injectors are firing.
What ECU does it have? If it has Kpro you could try disabling the the immobilizer and see if that makes a difference.
 

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Discussion Starter · #4 ·
So it’s an automatic transmission and the guy I bought the car from says that kpro won’t work because it is an automatic. I know for sure it has spark and Fuel pressure to the fuel rail. Haven’t checked the actual injectors yet because I don’t have the tools required to do it unfortunately. I can ask him (the friend I bought the car from) what ecu it has but I’m fairly certain that it’s just the standard rsx type s ecu. When I tried connecting a scanner it kept saying it can’t connect and I’m not sure if that because I was putting it in as the civic instead of an rsx. Battery has 12.5 v so I knows that’s not it but I’m happy to try another one if you guys think I should.
 

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So it’s an automatic transmission and the guy I bought the car from says that kpro won’t work because it is an automatic. I know for sure it has spark and Fuel pressure to the fuel rail. Haven’t checked the actual injectors yet because I don’t have the tools required to do it unfortunately. I can ask him (the friend I bought the car from) what ecu it has but I’m fairly certain that it’s just the standard rsx type s ecu. When I tried connecting a scanner it kept saying it can’t connect and I’m not sure if that because I was putting it in as the civic instead of an rsx. Battery has 12.5 v so I knows that’s not it but I’m happy to try another one if you guys think I should.
Kpro won't work with automatic. What engine is in that car? I assume a K20A3 with an RSX automatic transmission? The Type S was never available with an auto.

Use a test light or volt meter to see if the injectors are being fired while cranking. There should be pulses of power at the injectors while you crank the engine. Since it has spark and fuel pressure but still won't start, missing injector pulse seems likely.
 

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Discussion Starter · #6 ·
It’s a k20a2. While I was out there just now, I was able to get it to start, turned it off, tried again, struggled to start again, tried it one more time and it started again. I think I’m starting to see a pattern. When I got it to start, I had it in the KOEO position for a few seconds, saw the CEL blink off, cranked it, and it started. Second time, I tried it without waiting in the KOEO position and it wouldn’t start. So what would that indicate? I have a timer set for 30 mins to go out and try it again and see if it’ll crank again
 

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It’s a k20a2. While I was out there just now, I was able to get it to start, turned it off, tried again, struggled to start again, tried it one more time and it started again. I think I’m starting to see a pattern. When I got it to start, I had it in the KOEO position for a few seconds, saw the CEL blink off, cranked it, and it started. Second time, I tried it without waiting in the KOEO position and it wouldn’t start. So what would that indicate? I have a timer set for 30 mins to go out and try it again and see if it’ll crank again
I think the fact that you have a K20A2 with an automatic transmission is in itself a problem since the base RSX has a K20A3 (the 160HP economy version of your engine), which is significantly different. Your fuel curves, VTEC engagement point, VTC settings, ignition timing, etc is no doubt way off and might even damage the motor. To the best of my knowledge there aren't any tuning options available for the auto RSX ECU, so the only way to fix that would either be to downgrade your engine to K20A3 or swap to a manual transmission and get the proper ECU. Whether having the wrong ECU has anything to do with it randomly not starting I have no idea.

No idea what that could indicate. Possibly a faulty ECU that is slow to initialize? Did you try resetting it by leaving the battery disconnected for 30 minutes or more? If you have the old ECU, you could plug it in and see if your scanner will communicate with it to rule out a problem with the car's wiring.
 

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Discussion Starter · #8 ·
Well it seems I was mistaken, I do actually have a k20a3 not an a2 so now we can rule that out
 

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Well it seems I was mistaken, I do actually have a k20a3 not an a2 so now we can rule that out
That's a tough one. Personally I would start by trying to get a scanner to connect to the ECU. The no communications may or may not be related to why it won't start, but being able to read the codes may give you a direction. You could try entering an Acura RSX on the scanner or try a different scanner. You could also take it to a parts store and let them try their scanner and see if it will connect.

I assume the battery was relocated to the trunk for the swap? If so, you may have a significant voltage drop through the long cables while cranking if it's not wired properly and with proper cables. Perhaps there is enough voltage at the starter to crank the engine, but not enough voltage for the ECU to work properly while cranking the engine.

I would check the voltage at the fusebox while cranking. Put the positive lead of your multimeter on one of the 2 main power feeds of the underhood fusebox and the negative lead on the chassis and see what it drops to when you are cranking the engine. I don't know what exactly the minimum required voltage is for the ECU to function, but if it's dropping below around 11.5 volts I would be looking at the battery and the wiring.
 

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Discussion Starter · #10 ·
Well I’m definitely gonna have to get myself a multimeter since I don’t have one of my own yet but now I’m having another issue where something is drawing power from the battery because I went to crank it up this morning and it was completely dead. I’m charging the battery now with a charger I borrowed from my parents. Any idea if the two issues could be related? (Also the battery is still in the engine bay, not the trunk)
 
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