Starter motor refuses to disengage.

[IamWedgend]

Hi all,

With your help, I just got the car through her MOT, brilliant.

I park for petrol on the way home and when I restart the car the starter motor refuses to disengage. The revs jump, then drop massively and the motor screams and it repeats this process. If I try and kill the engine, it just keeps running. When I shift into gear (it's an auto) and it either slides into gear fine or stalls.

This happens about 50% of the times i try and start it.

As far as I understand there could be two sources of the issue, the solenoid staying electrocuted and keeping the pinion pushed forward, or a dodgy spring on the pinion refusing to return it.

As I can't turn the ignition off, it seems likely that current is still driving the solenoid and engine, rather than the spring. Is that correct?

For some context, the guys in the garage rewired my ignition to go around my immobiliser as it was playing up. Is it possible that they shorted something?

Cheers!
J

[nwarner]

IamWedgend said:

Hi all,


As far as I understand there could be two sources of the issue, the solenoid staying electrocuted and keeping the pinion pushed forward, or a dodgy spring on the pinion refusing to return it.

As I can't turn the ignition off, it seems likely that current is still driving the solenoid and engine, rather than the spring. Is that correct?

For some context, the guys in the garage rewired my ignition to go around my immobiliser as it was playing up. Is it possible that they shorted something?

Cheers!
J

I would say you are correct in your surmise especially as it has been rewired to get round the immobiliser.

Nige

[Boosted LS1]

Could it also be a faulty ignition switch?

[Penelope Stopit]

IamWedgend said:

Hi all,

With your help, I just got the car through her MOT, brilliant.

I park for petrol on the way home and when I restart the car the starter motor refuses to disengage. The revs jump, then drop massively and the motor screams and it repeats this process. If I try and kill the engine, it just keeps running. When I shift into gear (it's an auto) and it either slides into gear fine or stalls.

This happens about 50% of the times i try and start it.

As far as I understand there could be two sources of the issue, the solenoid staying electrocuted and keeping the pinion pushed forward, or a dodgy spring on the pinion refusing to return it.

As I can't turn the ignition off, it seems likely that current is still driving the solenoid and engine, rather than the spring. Is that correct?

For some context, the guys in the garage rewired my ignition to go around my immobiliser as it was playing up. Is it possible that they shorted something?

Cheers!
J

Was the wiring altered on the same day as the MOT?

If yes, ask the garage to take a look

[adam quantrill]

Could be that they wired the cranking wire to stay live, if so that would explain your symtoms.

Were YOU having problems with the immobiliser yourself before the MoT?

[IamWedgend]

All good questions.

Never had any issues with it before at all. Have had starting issues before so maybe knackered it with all the cranking.

Was rewired on the day of Mot so it does seem like it could be linked.

One more thing, when it gets stuck, after I stall it it has so far reliably worked the next time (2 attempts). If it was electrical, wouldn't it be a problem every time?

Cheers,
J

EDIT: Sorry @adam, misread your Q. The immobiliser has turned itself on at least once before and the alarm system has behaved very strangely recently, so I believe them

Edited by IamWedgend on Monday 18th November 23:03

[Penelope Stopit]

Boosted LS1 said:

Could it also be a faulty ignition switch?

There is always the above possibility and it's a coincidence that the problem started after some wiring was altered

Fist port of call is to ask whoever altered the wiring to take a quick look, even if there is nothing wrong with the altered wiring the ignition switch can also be easily tested

[IamWedgend]

Hi guys thanks for the help. Does appear to have been the starter itself. I've replaced it and the issue has gone. Cheers!

[adam quantrill]

The old one will probably be fine with a lube-up inside the solenoid. Some solenoids have a rubber button on them you can get the lube in there easily enough, others just have a hole.

In the past I have used copaslip to do this, others have said it is slightly abrasive but so what? It never stuck after that.

[Adrian@]

I rebuilt all my cars starters recently. After pulling it off I could see the 280i was suffering from the solenoid starting to rust internally and so sticking, you can see the rust marks even when it was cleaned, they are simply enough to rebuild/replacing the solenoid.


HHG tested.

A@

[IamWedgend]

Interesting, I'll take my old one apart and see whether I can get it working.

While on the topic of electrics, I've noticed that the plug on the back of my alternator is missing its back and is disconnecting occasionally when driving. Anyone know where I can get another plug? I'm going to wrap it up with insulator tape for the moment.

[nwarner]

IamWedgend said:

While on the topic of electrics, I've noticed that the plug on the back of my alternator is missing its back and is disconnecting occasionally when driving. Anyone know where I can get another plug? I'm going to wrap it up with insulator tape for the moment.

Is this what you're after https://www.carbuilder.com/uk/alternator-plug If not they have other types.

Nige

[IamWedgend]

Cheers, that was exactly what I needed!

On the subject of the starter motor. The issue is still occurring even with a new starter motor, albeit much less frequently. Where is the next place to look?
- Double check the electrics?
- Check the flywheel?

[adam quantrill]

If it's intermittent then I would run an indicator wire from the cranking wire (white/red usually to the starter) to an indicator bulb on the dash - just rig something up temporarily. Then you can see if it's energised while cranking (yes) or while the fault manifests (maybe) and work back from there to the relay, or the bodged wiring.