Stumper Question- Starts on Key release into position 2...

Coral Red Syd · 08-06-2007, 02:40 PM

Hello,
Did a search on this one but to no avail.
Have a 1984 3.2L stock engine.
Checked the spark by removing the plug wire and holding it close to ground.
Question - why does the spark fire upon releasing the key from position 3 (start position) versus engaging position 3?
Saw that the engine cranks and turns in position 3, but fires a spark to start when you release from position 3 to position 2. Knowing this has helped me to better start my car, but wondered what's the logic behind it - if any.
Cheers
coral red syd

audi2.7t · 08-06-2007, 05:00 PM

Sounds like you have a weak spark and is only strong enough to jump the plug when the starter isn't engaged..?

2ndTARGA · 08-06-2007, 05:06 PM

CR Syd:

Not sure if I understand - are you saying there is no spark in position 3 and if you hold it in that position it won't start until you let it back to #2?

If that's really the case, then it would seem that your switch is defective (or a PO mis-wired the switch.) I'd have to check the wiring diagram, but in almost all cars, when when you reach the start position, all accessories are disconnected so only the ignition circuits and the solenoid/starter get all the current. This is usually accomplished by wiper contacts inside the switch.

If you only get spark when you release to position two, then the momentum of the engine is keeping things going until the ignition circuit gets hot in position 2 and you (luckily) start. But it should also be hot in position 3.

A 12V test lamp on the switch output or the input to the ignition module will tell you if your switch is losing contact in position 3. If so, a new switch is in order.

Hope this helps.

Ron

Coral Red Syd · 08-08-2007, 12:40 PM

Thanks for the replies.
Does anyone have a DME car close to 1984 that they could pull a plug wire and confirm or deny that this is happening in their cars as well?
Thanks
CRS

Coral Red Syd · 12-16-2007, 07:53 PM

Came to find out the this problem was due to a bad reference sensor / timing sensor.
The sensor finally went 'all the way bad' and then no spark at all. Upon replacing it the car fired at the right spot in position 3. WOW what a difference. Checked the ignition switch and it was fine, but went ahead and put a new electrical portion of the switch in for good measure.
Cheers
CRS

esample · esample's Garage

My car is exhibiting these exact symptoms. I'm not sure if I'm looking at the right replacement part for my '86 Carrera (3.2).

Part number 911-606-215-01-M14

Can anyone confirm this for me? The person who answered @ PP seemed unsure also. Maybe he was sure, but just unconvincing...

These things are expensive, plus I don't want to make a mistake that will cost me time either. Also, is this the same as a TDC sensor? Thanks for the help.

-e.

Thrasher · Thrasher's Garage

Get the BMW sensors. Same part and several here have installed them with no issues: WTB: 3.2 flywheel sensors

DW SD · 06-20-2008, 01:55 PM

Is there a chance you have the power to the DME (computer) hooked up to an accessory locatoin in the fuse panel which is OFF during cranking?

it makes sense to turn off auxillary power consumption during cranking. If you hooked the DME up one of those terminals in the fuse panel, you may exhibit these symptoms.

Use a test light.