Sluggish turnover when hot...

[mark387mw]

Your experiences please on this problem...
My early Series 2 1985 350i engine is reluctant to turn over when hot. Its fine cold-starting and runs to normal temp but when its been running for about 15 miles and stopped for a few mins its turnover is then sluggish. Its as though the battery is near flat. A bit of encouragement with the accelerator and it'll catch and run fine.
Give it a cooldown period and the battery has no problem starting.
Any suggestions where I should check first?
Battery, Starter motor/solenoid?, ECU hot start??. Should there be a heat shield for the starter motor?
I've searched the forums but most are about (dead) Chimps

Mark

[JMorgan]

Not sure about the rest but are you happy with the starting electrics, testing etc? Don't want to tell you what you might already know.

[sevans]

Wiring to the starter or maybe a bad earth. If that's OK then the starter motor itself.
I would have thought a problem with the battery would be worse when cold.
It's a common problem on chips/griffs that the starters get warm and won't work at all. A heat shield helps here.
Had a similar problem on a Tasmin 200 and it was crappy reconed starter motors that were the problem. Fitted one from a Ford P100 pickup and it was fine.
Cheers SteveE

[Cathelijne]

Hm, sounds a bit like the problem I have with my Tasmin 280i.
When I start it when it's hot, it runs on 3 or 4 legs. After a few seconds the rest runs also. If yours, just like mine, smells like gas you'd better check the ignitionsystem.
At the moment we mixed a cleaner with the petrol and waiting for results

More information:
www.pistonheads.com/gassing/topic.asp?f=13&h=&t=12048

>> Edited by Cathelijne on Thursday 20th June 15:12

[mytvr]

Sounds like either a bad starter motor or a bad earth for sure. Easy way to test earth just put a jump lead from battery neg terminal to engine block, with a good contact try again. Move lead to pos terminal and starter solenoid to test wiring here. Much care needed when doing this though.
Dave

[mrcrappy]

if your car is running lumpy on start up when its hot it may be because the fuel in the fuel rail evapourates and takes a little while for the cold fuel to get back round again(the fuel mixture is then lean, my car did this when i had been in traffic parked up came back 20 mins later and it ran like it was going to cut out for a few minutes), im sure it says something about this in steves bible,

[mark387mw]

Thanks for the advice. The car runs fine when started, just poor turnover when starting from hot. My first check looks like the starter motor then, I'll try to attempt in the week with the fine evenings we're getting

Mark

[Schazzar]

My early series 1 did this. I got fed up turning over the car after filling up before flattening the battery. The only way I managed to solve the problem was to get a bigger battery after a couple of TVR mechanics told me that the batteries supplied by the factory weren't big enough to do the job for such a big engine.

I also checked over the connections too but the bigger battery solved the problem. I would also get someone to check the ECU as they are prone to suffering a few problems with age. One of the easiest ways to cure ECU problems is to disconnect it, clean up the terminals and reconnect it.

Putting a heat shield near the starter motor also works as the heat from the exhaust can weaken the insulation a cause a failure. My car did this too and was fixed by RAC....again after filling up. I wouldn't worry about fuel evaporating etc. Just keep an eye on the connections, battery, alternator, fan belt tension etc and you should be ok.

>> Edited by Schazzar on Tuesday 25th June 07:29

[mark387mw]

Thanks Andy for battery advice, easiest to replace! Anyone know the minimum ampage CCA required, and one that can actually fit the small battery area?

Mark

[Schazzar]

I also had to chop out part of the inner wing to fit the battery which was mega. Some series 2 had that part chopped out too to accomodate the bigger battery. I had to do a bit of GRP work to get the job done which wasn't too hard but was well worth it as it solved the problem.

[JMorgan]

Mines a Bosche Silver 6H battery, 600 amp and fits the 'ole. Spins the motor like there is no tomorrow.