Poor starting when hot

[raydrink]

Hi all,

 

Since I've had my 5 I've done some extensive work on the PI system to get it running smoothly from cold, coldish and warm starts. But I've always had a problem starting it from hot, such as when you've pulled up for petrol after a motorway run. Starting it after this short stop can take several turns of the key, whereas when it is cold it (now) starts first time.

 

It runs like a dream when hot and does not cut out. I've read the archives and I suspect, but don't know, that there is a fuel vaporisation issue which is OK to live with because the engine always starts eventually. However, my query is this:

 

When the engine is hot, the battery appears to discharge quickly when I try to start the engine and if it doesn't start within say four 5 second bursts, then the battery appears as dead as a do-do. It will not turn the starter. After this happens, I let the engine cool down, and do nothing to the battery in the meantime, yet when I come to start it, say 90 mins later, the battery is full of beans again and starts the engine with plenty of gusto, first time.

 

So, it seems that something is making the battery appear flat when the engine is hot. Am I right in thinking this is likely to be starter related? Maybe poor connections or something in the solenoid which has a resistive path to ground when hot, but not when cold? The vaporistion problem (or whatever it is) I can live with so long as the battery doesn't give up the ghost prematurely.

 

The alternator had a new rectifier pack fitted 18 months ago and the ammeter always sits in the middle, neither charging nor discharging (apart from a few seconds after running the pump before starting). So I don't hink there is an issue with the alternator.

 

Any help would be most welcome.

thanks

Ray

[jonlar]

Hi Ray, this does sound like an alternator or electrical connection problem, if the fuel pump isn't giving the M/U enough juice, it ain't going to start, I'd suggest thoroughly checking battery and earth connections, spade connectors to the alternator, and then go on to starter connections and solenoid. If you start fiddling around with connections behind dash, please disconnect battery first!

[raydrink]

Hey whoopee do!

 

It's fixed. I had a new solenoid and brushes fitted to the Lucas starter (the original solenoid had 02 68 stamped on it so it was probably the original) and it now starts within 0.5 sec when cold and 1 sec when hot. Fuel vaporisation - I laugh in the face of it - just a crappy starter. I also took the opportunity to devise and fit a heat shield to deflect the heat from the exhaust downpipes - wow, I didn't realise they were so close to the starter.

 

One happy camper looking forward to the Highlands and Islands tour with renewed enthusiasm................but I wonder what can go wrong between now and June? Mmm...

 

Ray