I was informed K20 engines went forever, but I didn't have this in mind!

[MattEP3]

Hi guys.

New here and after some advice due to an issue that has me stumped. I'm far from an auto electrician so any advice or even criticism is appreciated.

Car - 2002 Honda Civic Type R
Fault - Engine doesn't turn off.
(Likely) Cause - Jump started after flat battery.

As stated above after a jump start my cars engine no longer wishes to turn off by key. No fuses had been blown. Original thought was an ignition switch fault but even with the connectors pulled car continues to run. Next thought was potential alternator backfeed, again this was unplugged and the issue remains. Main ignition relay was also swapped out and made no difference.

Car runs ok, no EML or other symptoms. I've been getting the engine and ignition to go off by parking up and removing the key from the ignition. Then drop the glove box and remove the main ignition relay. The relay only needs to be removed for a split second and can be put back in. Ignition stays off. Not ideal every time I need to use the car but it's worked for now.

Now for the part that's confused me, when the ignition relay is removed completely. The car starts, drives and turns off as it should. Yet the same relay has to be pulled to get the engine and ignition off so shouldn't that stop the car from starting?

Like I said guys/girls any advice would be hugely appreciated.

Thanks in advance.

Matt.

 

[ruston]

Have you any idea why the battery went flat in the first place?
It certainly looks as the relay is faulty and the systems are being set out of sequence.
Was the jump start carried out by another vehicle or a boost start?
Any chance it had reverse polarity?

 

[MattEP3]

Hi Ruston.

I just assumed it had reached the end of its life to be honest mate, I doubt it was the original but it had obviously been on the car for a very long time.

Jump start was from another car, BMW 116i. Not sure if that will have been reverse polarity. As for the relay being faulty I genuinely don't know as I purchased a new one previously and it made no difference. Unless the one I bought was also faulty, Il get another one to try though.

Thankyou.

 

[ruston]

As long as the leads were put on correctly the BMW would be fine to jump start your car . Were you having the problem before the battery went flat , ie does it seem as this happened simultaneously?
Is there anything been done to your car that may have shorted the relay? Is there any corrosion or water around the holder or fuse boxes?
Has it had any welding ?
A diagnostic may help to be honest , electric faults have so many variables.

 

[MattEP3]

I've jump started quite a lot of cars over the years with no issue but for some reason something didn't go as it should. No until the day it got jump started it was ok, never had a problem like this that's for sure.

As for anything else that could have shorted it, I find it unlikely. 2 fuseboxes are inside the car behind the dashboard and there's 1 in the engine bay. Swapped out the full fusebox and fuses from under the bonnet of a friend's in case it was something in there too.

The last welding the car had done would have been about 18 months ago and the problem only started a couple of month back. Yeah it's kind of looking that way, just thought I'd pop it up on here in case I've completely overlooked something. Initial thought was a live had gone to ground but after removing and replacing the relay to get the engine cut, I ruled that out.

Only other potential option I can think of, is if there's another ignition relay with the immobilizer that's not switching and/or cutting the feed to the main one. Will take everything you've mentioned into consideration though and hopefully figure it out.

Thanks again mate

 

[ruston]

It's Ok , thank you.
It could well be that the relay you are taking out is feeding another relay that is latched .
To Honda's credit I have not worked on many of their cars so I am not familiar with this model .
The only other thing I can suggest is to disconnect the battery for a couple of hours to let the ECU clear any faults that are being held in the memory , not a great description but I am sure you will get the gist.
Good luck.

 

[ruston]

Duplicate.

 

[PEG]

Sounds like a classic diode failure type fault

 

[ruston]

A case of corporal Jones . Do you think it has had a flash of reverse polarity?

 

[PEG]

Who knows...auto-electric issues are the worst type of spaghetti to get involved in...unnecessarily complicated,minimal access,in-built obsolescence and child's toy quality of components.....

Anywho...although the OP's problem could be many things,the symptoms and known history,could point to a diode failure,either in the fuse board or ECU...or,it could simply be possessed by be-elzebub

 

[MattEP3]

Appreciate all the replies guys.

Ruston if it's any help at all, the friend I had borrowed the fusebox off to try also gave me a de-immobilised ecu as his car was off the road while he was doing some transmission upgrades. Will try leaving the battery off this weekend see if anything happens. No chance of the immobilizer locking me out so to speak is there if I try this?

PEG, I'm believing to think there is some witchcraft at play myself. As I said different fuseboxes, relays and ecu yet the problem remained. Mechanical work I can do, electrical is a headache lol