Starter/solenoid connections (1999 1.8K)

[John Vine]

I'm trying to help my son-in-law solve the dreaded click on his 1.8K SS. The snag is I'm currently sitting in SW France and the car is in SW Wales.

 

What do the connections on the starter/solenoid look like (a photo would be great). IIRC, the starter has two terminals: a spade for the energizing control wire and a large copper post for the battery positive feed. There's also (I think) a thick braided cable between the solenoid and the starter. Presumably this is the high-current connection between the two? To circumvent the "click", the car will start when a fly-lead is connected between the battery +ve and this braided cable. Does that make sense? I would have thought that the fly-lead should be between the battery +ve and the control-wire terminal?

 

JV

[Stationary M25 Traveller]

Big red lead from battery to threaded stud on starter. Same terminal also carries cable on to alternator.

 

Small brown/red cable from MFRU (or retrofitted 12V relay) to spade terminal on starter.

 

When 12V is sent down the little cable, it energises the solenoid which is just a heavy duty switch that connects the heavy duty supply cable to the braided cable to fire up the starter motor. It also pulls in the gear on the starter so it meshes with the flywheel ring gear.

 

You can get old grease and grit in the bore of the solenoid, so the piston doesn't slide freely. Easy to dismantle and clean out (easy once you have got the starter off anyway).

[John Vine]

Thanks for that, SM25T -- matches my understanding of how the circuitry is supposed to work. So, am I right that the starter/solenoid has just the two terminals? (S-in-L is not available right now to check.)

 

Two supplementaries:

 

1. Certainly his plan is to remove the starter and strip down and clean the solenoid, but should he grease the solenoid core? I've received conflicting advice on this -- either to use a high melting-point grease such as Castrol LM, or to leave it unlubricated to avoid picking up crud and rubbish.

 

2. How does a fly-lead from the battery +ve to the braided cable energize the solenoid (and start the car)? It strikes me that the braided cable is the wrong side of (and not even connected to) the solenoid coil. Is that correct?

 

ETA: I think I've got the answer to Q2. It turns out that the "fly-lead" was in fact a battery jump-start lead -- in other words, it was bypassing the solenoid altogether, and carrying the full starting current. The car started because all other necessary circuitry (fuel pump, ECU etc) was powered up already. Does that make sense? If so, it points to the solenoid itself as the prime suspect in that the core/piston were not sufficiently free to move. If so, cleaning (or replacing) the solenoid should fix things.

 

JV

 

Edited by - John Vine on 22 Aug 2013 21:56:55

[Stationary M25 Traveller]

I think you have got it.

 

There is a tiny drain hole in a rubber moulding in the solenoid body ... presumably to let water out. Driving in the rain, I guess water can splash in and push grit in. I used emery to clean inside bore of solenoid and outside of piston. Surprising how much scoring there was from grit. Degreased first then lightly greased with LM wheel bearing grease after.

 

Word of warning ...... note carefully and photograph .... how the bits at the far end inside the solenoid go together. It will make reassembling easier !

[John Vine]

Thanks again. Given that the solenoid has two functions: (1) to connect the battery to the starter, and (2) to throw the starter pinion into mesh, I'm still puzzled how jumping between the battery and the thick braided cable can achieve (2). As the solenoid will (should) be energized when the start button is pressed (assuming the relay circuitry works properly), it appears that the solenoid piston is "sticky" and won't throw the pinion. If that is indeed the fault, could it simply be that spinning the starter with the jump lead throws the pinion into mesh somehow (inertia, friction?), even though the jump connection is outside the solenoid circuit?

 

JV

 

Edited by - John Vine on 23 Aug 2013 10:01:12

[John Vine]

My S-in-L has already fitted a bypass relay, which didn't make any difference, so everything is pointing to the solenoid as prime suspect. The factory fitted a "race model" starter in 2004. Can anyone tell me what make/model that might be? (I ought to know as the car was mine from new, but I don't.) Does it have the same solenoid? Once I know the make etc, I can research replacement solenoids. (I think a new one might be a worthwhile investment after all this time.)

 

JV

[Jerry Auton]

Does the car have FIA Batt Cut Off Switch ? - As I have just had a similar issue & it was eventually traced to a faulty switch.

 

 

[John Vine]

No, it doesn't (but thanks for the pointer).

 

JV

[Jonathan Kay]

What is the "braided cable"? The only braided uninsulated leads I know are earths...

 

Thanks

 

Jonathan

[Jerry Auton]

*arrowup*There is a v short braided cable between the solenoid & starter on my Bosh Starter unit JK

[Jonathan Kay]

Thanks, Jerry

 

Jonathan

[John Vine]

Quoting Jonathan Kay: 

What is the "braided cable"? The only braided uninsulated leads I know are earths...

 

Thanks

 

Jonathan

You can just about see the copper (braided) connector between solenoid and starter motor here (right at the bottom of the photo). Sometimes the connector is sleeved, but often it's completely uninsulated.

 

JV

[Stationary M25 Traveller]

You should get away with a clean and grease inside the solenoid. Worked ok on my 10-year old 60,000 mile unit.

[John Vine]

That's encouraging. Let's hope it works for S-in-L!

 

JV