M

mikeadams1985

Active Member
After doing the head on my d2, (it has sat for about7 months) I fired it up and it has developed a fault where it will fire before I get the key to the crank position, So when it is on accessory live it fires up.

I have had the BCU out and that's dry as and looks absolutely fine inside.

The fuse board below the drivers side did look a little funky, so took that out and cleaned it up.

The problem is, if I leave the car a few days and then try, it doesn't do it and fires as it should in the crank position (the windows also work as they should...)

Once its ran for a bit if I turn it off and return and try again, the problem has returned. The windows also refuse to operate when this problem appears.
before I change the fuseboard has anyone got any suggestions?

I have been running a commercial dehumidifier in the car for a bout 4 weeks now to remove any moisture in side as the sun roof is a little leaky. The car is now dry as can be inside
 
If the cranking symptom comes together with windows misbehaviour it's most probably the IDM fusebox hurt by corrosion, no other way to rule it out than replacing it with known good one which comes from same modell(facelift ot not)
 
repalcedd the IDM fuseboard,

no change, still happening.

I disconnected the barrel, sent 12v through it and tested all outputs and they all read as expected when disconnected.
key in but no turn, 0v on all, turn once get 12v on accessories, turn to crank position and 12v coming out on ignition feed

connect the barrel back up to the fusebox and suddenly I'm getting 12v output to started in position 2

Ive ruled out the fuseboard,

so I'm not sure where to go to next ?

bcu looks fine and dry


after leaving the IDM fusebox, where does the 12v ignition signal go to?
 
mikeadams1985 said:
repalcedd the IDM fuseboard,

no change, still happening.

I disconnected the barrel, sent 12v through it and tested all outputs and they all read as expected when disconnected.
key in but no turn, 0v on all, turn once get 12v on accessories, turn to crank position and 12v coming out on ignition feed

connect the barrel back up to the fusebox and suddenly I'm getting 12v output to started in position 2

Ive ruled out the fuseboard,

so I'm not sure where to go to next ?

bcu looks fine and dry


after leaving the IDM fusebox, where does the 12v ignition signal go to?
Click to expand...
From the ignition switch, it goes through fuse 23 in the IDM. From there it goes to the engine bay fuse box and is connected to the starter relay. There appear to be no other connections so it should be fairly easy to trace.

Good luck.
 
Quite odd symptom though based on that
mikeadams1985 said:
I disconnected the barrel, sent 12v through it and tested all outputs and they all read as expected when disconnected.
key in but no turn, 0v on all, turn once get 12v on accessories, turn to crank position and 12v coming out on ignition feed

connect the barrel back up to the fusebox and suddenly I'm getting 12v output to started in position 2
Click to expand...
it's still possible that the ignition switch harness is at fault and it misbehaves only under load when conncted cos the multimeter has no load hence the good readings
 
Unplug the ignition switch's brown plug on the fusebox and give +12V with a wire to where the yellow wire goes from the switch, then to green/white and report the result.
 
mikeadams1985 said:
Sorry not sure what you mean?
do you want me to run 12v through Yellow (pos 1) and test for voltage out from green / white?
Click to expand...
No, unplug the switch's brown connector and give 12V with a wire to the fusebox's pin where the yellow wire was connected from the switch and see if it cranks that way or not then the same test to where the green/white wire goes if you see what i mean cos then you emulate the switch's output on aux and second position cos it should crank only when it gets power to the white/red wire .... btw try to the white wire as well then to both white/yellow together
 
Last edited:
sierrafery said:
No, unplug the switch's brown connector and give 12V with a wire to the fusebox's pin where the yellow wire was connected from the switch and see if it cranks that way or not then the same test to where the green/white wire goes if you see what i mean cos then you emulate the switch's output on aux and second position cos it should crank only when it gets power to the white/red wire .... btw try to the white wire as well then to both white/yellow together
Click to expand...
Right, tried this and still fires on accessory.
New fuse board so can pretty certainly rule that out.
clearly an issue further down the line, I have noticed a clicking noise like a relay is going off and on in the fusebaord, happens with both fuse boards. even with no ignition being turned on.

I tested the terminals at the fuseboard with Igntion cable disconnected.

this is what I was getting from the terminals..

Brown - 12v (as expected)
Yellow - 0v
White - 0v
Igntion 8.4v (fluctuates 8.2/8.4v) - This I believe should be 0! So not sure why its getting 8.4v.
 

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then the engine bay fusebox must be replaced and pray to be that before chasing some hidden short circuit in the harness or rewire that circuit which can be a nightmare
 
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