Engine Cranking When Ignittion Turned On

[86alexp 2]

So I am in the final throws of my throttle body conversion and am pretty much ready for first start. Only thing is that when I turn on the Ignition the engine is cranking. First of all, this is not the classic issue of swapping the connections in the brown plugs under the steering column. I built the original Mi16 conversion loom for the car about 5 years ago, and at the time I did the classic mistake of getting the ignition and starter muddled, embarrassing I know!

 

So this time round there is no doubt which is starter and which is Ignition, plus I have made this engine loom from scratch so I can compare the loom side buy side with my previous (working Mi16 loom), I have no doubt on this car Pin 9 is starter! I've attached a drawing of my loom so there is no confusion, at the moment both relays are removed!!

 

So what can be going on??

 

If I put a multimeter on the brown plugs the ignition and starter gets 12v when they should.

 

In the ignition position I do see -0.55v on the starter circuit, but this shouldn't operate it?

 

So I am really confused! Has anybody come across anything like this before?

[Anthony 1,003]

Do you have a relay in the starter circuit anywhere or is it wired as per the way it left the factory?

 

If you physically remove the starter solenoid wire from the brown multiplug, does the starter still operate with the ignition on?

[86alexp 2]

Yes the rest of the car is untouched electrically. there is no relay, pin 9 goes straight to the starter as in the diagram.

 

And yes if I remove the solenoid wire the starter doesn't operate

 

Thank you

Edited November 4, 2015 by 86alexp

[Tom Fenton 1,548]

Have you got a good earth from engine/box to the body? Can cause some weird faults if not. After that though, the only way the starter can turn is by sending voltage down the signal wire, so trace that back and check your wiring.

[86alexp 2]

Hi Tom, thanks for the help. Yes I had thought my earths were very good. I think your right though, this is now only going to be solved by first principals. I will post up when/ if I discover the culprit as I hate unfinished threads.

 

I should know the answer to this but... Would the tachometric relay have come out along with the original 8v engine Loom?

[86alexp 2]

All sorted! Thanks for the help.

 

So Sunday evening having had a few beers, I thought it would be a good idea to play in the garage for a bit. Seeing as I had already finished the loom I only needed to tape and tidy it (not too challenging) what could possibly go wrong!

 

Well, to pass the loom through the bulkhead to tape the loom nicely, I took out the 9 brown pins, and put them back. Only somehow, I put them back in reverse order, meaning the ignition feed to the Reverse switch went directly to the Starter.

 

Fortunately no harm has been done! Just pride

Edited November 5, 2015 by 86alexp

[Tom Fenton 1,548]

So this time round there is no doubt which is starter and which is Ignition,

 

Say what?! LOL!

[Anthony 1,003]

You plonker! Still, at least it was an easy fix.

[86alexp 2]

Thank you both!