Hot Start Problem

[outhausollie]

Hi there, I really hope someone can help me with this frustrating starting problem I have. I don't know if it is one problem or 2 separate issues.

Vehicle is a 1970 US Microbus with a 1600TP in it. Standard apart from Pertronix electronic ignition and Flamethrower coil.
Newly fitted recon starter, all connections are clean.

Basically, it starts fine when cold but when it's warmed up the following happens:

Starter turns very slowly
Will not fire (presumably because it is not turning the engine fast enough)
Take key out and the starter continues to turn
So I have to disconnect the battery (if I disconnect the +ve side and reconnect the starter no longer turns - if I disconnect the -ve side and reconnect the starter continues to turn)


I have tested the alternator when running and it's producing 14 volts or more (can get an exact figure tonight). I tested this at the battery terminals.

I had a Durite split charge relay for my leisure battery which is now all removed (last starting battery began to boil over when charging and I wondered if the relay was knackered following several jump starts from leisure to starter batteries, somehow allowing the battery to overcharge).

The starter will also turn slowly with key removed when the engine is cold but only when the battery is a bit flat. I found this out on the last battery. It never does it when the battery is fully charged and the engine is cold.

I understand that there is a hot start relay that you can buy if the engine struggles to start when hot. What does this do and does it sound like the fix I need? I am concerned by the fact that the starter will turn when I switch off and take the key out. I don't believe that it's a dodgy ignition switch as it stops when I disconnect the battery and reconnect. Also when cold it ONLY happens with an empty-ish battery, not a fully charge done. I have read about micro welds on the plate in the starter but it seems odd that it only happens when the battery is not fully charged.

Any pointers would be most appreciated.

Cheers,
Ollie

 

[outhausollie]

Also, I should point out that I think there is some kind of drain on the battery. I have bought a battery kill switch to combat this while trying to figure out what's causing it.

I mention this because in Ninove this year I couldn't start the bus early in the morning when it was pretty cold. It had to be jumped and then it fired up fine.

It really does feel like there is a short somewhere which is actually draining the battery as the engine runs, as well as when it's switched off. I had just driven how ever many miles to Belgium and then it appeared that the battery had gone flat overnight.

 

[Trikky2]

First thing I would check is the ignition switch.

 

[outhausollie]

Thanks. Ignition switch is fine.

Have fitted a hot start relay, no change.

Starter feels quite hot to the touch. Is this normal? Am thinking it's getting too hot and the resistance inside is too much??

It seems once it drops to a certain temp it starts no problem at all. Its doing my head in!

 

[Trikky2]

Well if your engine continues to run when you have switched off the ignition it's clearly still getting power to the coil. Therefore, if your sure the ignition switch is not at fault, then it's back feeding, due to a wiring fault. Such a fault cannot be diagnosed remotely. Only hands on with a meter or test light will trace such a fault.

 

[aircooledkatie]

Just had the same problem today, slow turn when hot, so checked earths then to rule out wiring I popped underneath and shorted starter motor out (I know I know) made no difference, still slow. Swapped starter off another van (half hour job) spins over all day. People I know have binned the hot start relay , as nearly always bad earth or starter. I've got a hot start relay if you want for post cover. Cheers..
ps. Just stripped starter and bad wear on the brush com.

 

[Scoote]

Hope you don't mind me jumping on the hot start band wagon! - Took a trip out last week, stopped at the garage after a 10 minute drive got back in and the bugger wouldn't turn over, slow at first then nothing, had to bump it in the end. Did the usual checks, which all seems fine, however only getting 10v at the braided wire on the solenoid when turning it over...so.... Im thinking the lack of 12v (which I'm thinking it should be?), coupled with the heat is causing the problem, especially as intermittent. Would now be the right time to fit a hot start relay, or should I be taking a better look at the wiring...? Should I be getting a 12v measurement on the braided wire......

 

[outhausollie]

Hi guys, have only just checked back here.

These are my findings and hopefully they will be useful for anyone else searching at a later date.

I fitted a hot start relay and it made no difference.
I removed the key from the circuit (hot wired it) and it made no difference.

I fitted a starter from an auto (therefore no pod to go into the brass bush) and, hey presto, no problem at all even after driving 4 hours to Skeg Vegas. It started straight away every time, hot or cold.

My conclusion is that the push rod was not retracting from the bush and so the starter is turning with the flywheel all the time. This would, I think, explain the extremely hot to touch starter motor as well as the fact that I think that if the push rod is out, the solenoid and starter are energised which I'm fairly sure would create heat.

Hope this helps or please tell me if you think I'm wildly out of touch here

 

[outhausollie]

Just come back from the pub and re-read this.

'Pod' should read 'rod'

and

By 'push rod' I don't mean an actual push rod but the bit that shoots out of the starter to engage the gear on the flywheel, whatever that's called.