Engine starts (but doesn't stop!)

MadDogMoggy · #1 18th September 2011, 13:20

After much umming and ahhing I've taken out the Z-cars ECU and loom and fitted a Hondata system.

I've wired it up with help from Rich Hope's wiring diagram which was a fantastic help (cheers Rich)

I've loaded the factory standard K20A map, and turned off multiplexing.

Engine starts and runs lovely, however ....
when turning off the ignition it continues to run

I'm pretty sure that my wiring is ok, but I could have made an error, or there may be something in the map that I've not tunred off/turned on?

It would appear that the main relay coil is earthed by the ECU (pin7 on ECU E connector) on start up, and should stop being earthed when switching off.

When turning the ignition on and off this is the case, but if the engine is started, when turning the ignition off the coil remains earthed, and the engine continues to run.

Any thoughts?

Thanks
Tim

bigrich · #2 19th September 2011, 20:34

Hi Tim,

I had similar prob with my 1.6K back in 2006 - see thread below....perm positive where there should have been a switched.

http://www.madabout-kitcars.com/foru...read.php?t=595

HTH

Rich

MadDogMoggy · #3 20th September 2011, 21:31

Thanks for the reply Rich: an interesting thread.

My suspitions too are that I've wired it wrong somehow, but I'm sure I followed Rich H's diagram closely!

Hondata people pretty much said the same thing, so I'll have a good lokk to see if there are any permanent lives that shouldn't be.

Unlike your problem, the rest of the car wiring funtions ok - even the instuments turn off with the key, just the engine runs on.

What's wierder is that it all behaves as it should voltage wise if you turn the ignition on and off - it's just after you've cranked the engine and got it running that the coil doesn't turn off the main relay.

I'll keep digging!

Thanks again
Tim

Chris Cussen · #4 21st September 2011, 06:38

I had something like that when I wired up an alternator and took the output to the wrong side of the ignition switch. Once the alternator was running turning the switch off didn't make any difference as the alternator kept the circuits live.

alackofspeed · #5 21st September 2011, 23:24

Just to confirm my understanding. When the ignition switch is turned to the run position, the input to E9 goes positive, and when the ignition switch is turned to the off position, E9 switches low, whether the engine is running or not?

MadDogMoggy · #6 22nd September 2011, 12:02

I haven't checked with a the engine running, so I'll do that by getting a probe on pin E9, but:

With ignition off, pin E9 supply = 0v
With ignition on, pin E9 supply = 12v
With ignition off, pin E9 supply returns to 0v

As I said, I'll check whether this is the case when the engine has started and then the ignition is switched off.

With ignition off, pin E7 is at 12v (ie not earthed)
With ignition on, pin E7 is at 0v (earthed) and fuel pump primes
With ignition off again, pin E7 returns to 12v, not earthed
With engine running, pin E7 is at 0v (earthed) and fuel pump pumps
With ignition turned off (aftger engine running) pin E7 stays at 0v, engine continues to run, but rest of electrics (eg instruments) are off

Cheers
Tim

MadDogMoggy · #7 25th September 2011, 11:41

OK - done a bit more checking:

With ignition off, pin 9 on ECU E connector is at 0v

With ignition on, engine off it's at 12v

With ingnition on, Engine running it's at 12v

With ignition off, but engine continuing to run, it's at about 6v!

This sounds as though they may be some current 'leaking' through from the altenator, but I'm not sure how!

Any suggestions?

alackofspeed · #8 25th September 2011, 19:41

Only thing I can suggest is to gradually remove elements from the wiring loom (pull the fuse / disconnect / unbolt) until the offending element is isolated.

The good news must be that the ECU is working as it should!

MadDogMoggy · #9 26th September 2011, 12:37

It's a bit of a puzzler:

The ignition switched 12v supply to the rear of the car (one feed wire) which is used to supply the ECU, Engine Harness, a water temp sender and the O2 sensor is all 6v after turning off the ignition but the engine still runs.

It appears, as was suggested, that with pin 9 on the e connector still having voltage, that the ecu is not cutting the earth to the main relay (pin 7 ECU E connector) and therefore the engine keeps running.

Whats interesting is none of the other switched 12v supplies exhibits this tendancy, so the instruments turn off etc. I've managed therefore to jury rig another relay from a switched supply at the front of the car to earth (coil) and from the coill of the main relay through the switched side of the relay to earth (instead of to the ECU E connector pin 7).

This works, as the relay cuts the earth to the main relay. My only concerns are whether this is likely to have an adverse effect on the ECU and why I seem to be having the issue in the first place. As someone else suggested it seems as if the alternator is supply current when the engine is running.

I spent ages yesterday checking the Alternator wiring and it all seems fine!

Thanks everyone for your thoughts

Tim

Chris Cussen · #10 26th September 2011, 17:15

Tim,

If the output from the alternator goes to the switched side of the ignition wiring then it will remain 'live' when the engine is running.

I've made a sketch, lots of detail missing like earth connections and alternator warning/energising connections but it should give you the idea.

MadDogMoggy · #11 28th September 2011, 14:47

Thanks for taking the time to do the drawings, Chris.

I'm pretty sure what I have is right, as the main connector on the alternator loom goes straight to the battery terminal (ie before ignition switch) with the direct feed to the starter.

I've disconnected this wire and gone straight from battery to alternator, and the car behaves the same.

The six pin connector into the engine loom from the alternator loom appears to be wired correctly, ie the 4 pin connector from the alternator goes into it, along with one pin from the sender in the block by the alternator (one pin is not connected). The other 1 pin connector on the alternator loom is also correct, being the supply to the startet solenoid.

Thanks for your input.
Tim

MadDogMoggy · #12 3rd October 2011, 12:06

Just a quick update from me:

The rear switched +ve of the loom was staying live (approx 6v) after running the engine and then switching off the ignition.

I thought therefore that somehow the ECU was still being powered through this, as this connected to Pin 9 of the E connector.

I used a switched +ve feed from the front of the car to a relay to earth Pin 7 of the ECU E connector independantly, which worked.

I used the same feed from the front to use a relay to turn on the ECU through Pin 9 on the E connector. Again this worked.

I then thought, 'Hey, I don't need the relay, I'll just connect the switched +ve from the front of the car directly to Pin 9 on the E connector'. This didn't work.

Based on this then, it appears to be the ECU that is causing the normally switched +ve to stay on when the engine has been running, and I'm completely mystified!