Starting when hot

[Carrmonkey]

At the end of a run my S3 wont restart when hot. Its not always the case but about 50% of the time on restart I just get a clonk from the solenoid which is fixed by letting things cool down or rocking the car in 1st gear

I've cleaned the earth, fitted new starter motor and ignition coil and the battery is ok

Any ideas ?
Thanks
Mark

[S2Andy]

Hi

Very common problem with the V6 cars. Had this last year myself exactly as you describe. Clean up all the leads to the starter motor but the problem is undoubtedly the solenoid fitted to the starter. About £30 from Bosch (in my case). No problems since.

Andy

[orange_dodo]

I had this problem but the car could be cold or hot. I imagine the heat is causing the solenoid to distort slightly so more power is needed to move it. My problem was a lack of sufficient power to the solenoid/starter even when cold.

As you have a new starter the things that could cause the problem are:

1. Starter +ve lead - I cleaned and resoldered mine

2. Solenoid +ve lead - I replaced part of mine it was so manky

3. Solenoid itself - It's easy to dismantle and clean up or you can replace it.

4. Starter to bell housing face - The starter is earthed through the bell housing so make sure there is some clean metal on the bellhousing, gasket and starter to lower the resistance. Or you can fit a dedicated earth from the starter. Make sure the engine earth has clean contacts too.

[Bobhon]

Ah the 'old' S hot start problem. I had the same thing on my S2 and even a new starter motor and all terminals cleaned up didn't fix it.
It seems as if the 20 odd year old wire from the fusebox, through the ignition switch (via the yellow connector) all the way down to the starter solenoid builds up a resistance over time. Hence there is not enough power at the solenoid to pull it in properly to crank over the starter motor.
Changing the solenoid might be a good temporary fix but I would expect the problem to return.

The fix I used (courtesy of Phillpot) was to fit a starter relay into the system. It's a 10 minute job for anyone who's reasonably okay with electrics.

Disconnect the battery, then use the current starter motor solenoid feed to the switching side of a normal relay. Piggyback a lead from the starter motor terminal (main feed) to the input side of the relay. Then run a lead from the output switched side of the relay over to the starter solenoid terminal. You also need an earth cable from the switch earth side of the relay down to the chassis earth on the left hand outrigger cross bar.

Now when you switch to starter position on the key it pulls in the new relay feeding direct battery current through to the starter solenoid, avoiding having to run power around 6 feet (approx 2 metres if you're metric) of cable.

No more hot start problems.

HTH

Bob

[Deeman]

Thanks Chaps - I too have had this problem since I bought it - and gone down exactly the same route of new starter motor etc!! rocking it in second gear always does the trick but its a real pain will give this a go too. Most grateful. Pete

[Carrmonkey]

Thanks a lot guys turned out to be a dodgy starter motor which was less than a year old. Neil at TVR Car parts was excellent and sent me a replacement under warranty.

New earth were run and this has also helped the starting sequence

Cheers

[GadgeS3C]

Bobhon said:

Ah the 'old' S hot start problem. I had the same thing on my S2 and even a new starter motor and all terminals cleaned up didn't fix it.
It seems as if the 20 odd year old wire from the fusebox, through the ignition switch (via the yellow connector) all the way down to the starter solenoid builds up a resistance over time. Hence there is not enough power at the solenoid to pull it in properly to crank over the starter motor.
Changing the solenoid might be a good temporary fix but I would expect the problem to return.

The fix I used (courtesy of Phillpot) was to fit a starter relay into the system. It's a 10 minute job for anyone who's reasonably okay with electrics.

Disconnect the battery, then use the current starter motor solenoid feed to the switching side of a normal relay. Piggyback a lead from the starter motor terminal (main feed) to the input side of the relay. Then run a lead from the output switched side of the relay over to the starter solenoid terminal. You also need an earth cable from the switch earth side of the relay down to the chassis earth on the left hand outrigger cross bar.

Now when you switch to starter position on the key it pulls in the new relay feeding direct battery current through to the starter solenoid, avoiding having to run power around 6 feet (approx 2 metres if you're metric) of cable.

No more hot start problems.

HTH

Bob

After a nice drive on Sunday I seem to have a similar problem. Turn the key and can hear the solenoid click but doesn't turn the engine. Couple more turns of the key and it always started but one day...

Haven't had chance to do any checks yet but was intrigued by the starter relay solution. Can anyone point me to an appropriate relay, what current rating does it need?

Also, from a quick look at the starter I guess it needs to come out from underneath?

Sorry for dumb questions, when I get chance to look I know I'll find out but always happy to benefit from the experience out there!

Thanks,
Gary

[Bobhon]

Gary, I just used a 'standard' 5 pin relay, the sort that you get all over most cars. I guess that it's the one that your local Motor Factor would pull out of their drawer if you asked them for a relay?

I just looked over the wiring diagram to try to identify the fuse size and found out that the original wire isn't fused, so that doesn't help to size the relay, sorry.

Bob

[phillpot]

I used a 30 amp relay, this seems to be a fairly general size/rating available "everywhere"

Picked this one up a a carboot for pence, stays in the handy spares bag in the boot



If you can make out the numbers its:

85 existing solenoid feed
86 new wire to earth
30 new live wire from starter main terminal
87 new feed wire to solenoid activate terminal

Why they use these numbers I've no idea but think they are fairly generic across many makes of relay.

HTH Mike

[GadgeS3C]

Thanks Mike & Bob, looks like a standard relay like that is worth a try just to see if it solves the problem. I'll let you know.
Cheers,
Gary