Intermittently not cranking when hot - what could it be?
Intermittently not cranking when hot - what could it be?
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fablu

Original Poster:

34 posts

150 months

Monday 6th September 2021
quotequote all
Hi all
After searching through pistonheads reading about many different kinds of "hot start problems", I'm looking for some clarification

When turning off the car and it being hot, the car sometimes won't crank i.e the starter doesn't engage.
The fuel pump still primes as it should, and the lights on the dash go slightly dim when turning the key.
Locking and unlocking the car doesn't help. (arm, disarm) Wait X minutes, it will start right up and crank strong as normally.

Having had the car in my ownership for over 8 years, it has only happened very very rarely, not even once a year. But this year alone it has happened more than enough.

The car has an aftermarket alarm, Toad Ai606T2 fitted before my ownership, so I would assume the (possibly) incorrectly-wired meta immobiliser has been removed from the car.
I don't have any immobiliser fob-key-thing for the immobiliser connection near the ignition barrel, which doesn't seem connected since it doesn't blink or anything.

Is my first order of business to verify this, and how in that case?

When it cranks no matter from cold or eventually from hot, it cranks strong and it doesn't seem like a frayed cable from battery to starter would give these symptoms?
Is this the case of a sticky solenoid, and would a removal and thorough cleaning of starter and solenoid fix this?

Or could it be something else?

Battery changed a few years ago and always on trickle charge and starter motor was replaced in 2011 according to the service history. (with comment about checking starter circuits and traced it to faulty starter apparently)

Cheers
Fabian

Steve_D

13,799 posts

275 months

Monday 6th September 2021
quotequote all
The most likely is that the starter lives right under the exhaust with the starter solenoid closest. The heat dries out any lubricant that may have been in the solenoid which then becomes stiff.
Hot days and a hot car are just the straw that breaks the camels back.
A new or refurbished starter will likely solve the problem.

The 'Hot start' mods you have seen referred to the use of a relay to deal with the higher currents being drawn by the 'stiff' solenoid.

Steve

citizen smith

781 posts

198 months

Tuesday 7th September 2021
quotequote all
My suggestion would be take the starter off the car, strip it down and clean all of the components including the solenoid - reassemble with appropriate grease plus make sure that the electrical contacts on the solenoid are free from corrosion and all should then be O.K

Did that procedure on a Griff many years ago and never had another issue with it, prior to that the car sometimes failed to start particularly at petrol stations - dead embarrassing!

QBee

21,815 posts

161 months

Tuesday 7th September 2021
quotequote all
If that doesn't work, try replacing the cables from battery to starter.
My car started a lot better once this had been done.
The heat of the gearbox/engine increases the resistance in what are under-specified cables from the factory

fablu

Original Poster:

34 posts

150 months

Monday 13th September 2021
quotequote all
Thanks for the answers!
I'll remove the starter and strip&clean it and the solenoid up as much as I can during the winter and see if that helps.

If that doesn't do it the cable will get replaced with thicker gauge as well, it might happen anyway.

Cheers
Fabian

Belle427

10,841 posts

250 months

Tuesday 14th September 2021
quotequote all
I don’t think your problem will be with the cable, more than likely the immobiliser or sticky solenoid.
It is a good idea to upgrade it though if you do get chance.

jojackson4

3,042 posts

154 months

Monday 4th October 2021
quotequote all
I have the same thing
None standard alarm/ immobiliser
Second brand new starter and still intermittent no turning over
But mine will do it hot and cold
Put a different battery on ( from 330d) and still persists

The only thing that is constant is a jump pack instantly makes it turn over

David Beer

3,982 posts

284 months

Monday 4th October 2021
quotequote all
jojackson4 said:
I have the same thing
None standard alarm/ immobiliser
Second brand new starter and still intermittent no turning over
But mine will do it hot and cold
Put a different battery on ( from 330d) and still persists

The only thing that is constant is a jump pack instantly makes it turn over
Tvrsw will have the answers. https://www.tvrssw.com/contact-us

Belle427

10,841 posts

250 months

Monday 4th October 2021
quotequote all
Maybe rig up a start button from the battery connected to the solenoid terminal so you can try it next time it fails.
At least it will help you narrow it down if it’s the cabling or starter.