Slow starter cranking once engine warmed up. Why ?

[mongo3528]

Hi guys, does anybody have ideas as to why my starter turns my engine over slowly once its hot.. but is fine when its cold? i fitted the "hotstart" mod.. but i dont think i have that problem, as it hasnt yet not started at all.. it just always sounds like it might not start.. but it always has.. so far ! Would this be a starter motor fault or to do with the cables? I did relocate the battery to the boot last winter but it was the same when the batt was in the footwell.

[rev-erend]

Maybe the starter motor getting too hot - are the exhaust pipes near it ?

[mongo3528]

the exhaust pipes are as near to the starter as they are on any chim i guess.. The starter is only a few years old i believe.

[locodude]

Beginning of the renowned hot start problem?

[JonRB]

I had something similar on my Sagaris and it turned out to be a corroded earth strap, apparently.

Edit: Or, as locodude says, the start of the well-known 'hot start problem'

Edited by JonRB on Thursday 17th September 16:27

[mongo3528]

thanks guys , the earth strap is fine. So the "hotstart" problem isnt just where the starter doesnt turn the engine when hot, it also can cause slow cranking ?

[T_Pot]

I had this exact same trouble, turned out to be earth , added another earth from engine to chassis and chassis to battery and has never happened since

[mongo3528]

Thanks for that idea, il give that a go 1st then

[bigdods]

I suffered this when my battery was on the way out. Explained by soeone who knows as follows:

Battery cold, everything works. Plates are straight.
Battery warmed by charging as car is driven. Damaged/faulty plates bend slightly and touch reducing amp output of batter

Result - when battery is warm it wont crank very fast.

This is very easy to check. Get the car warm, turn off. Attach jump leads to another car. See if it cranks faster. If it does you've probably got a stuffed battery .

[mongo3528]

Hi again , ive fitted a new earth from chassis to engine and the problem is cured, so a big thank you for your assistance, much appreciated !

[T_Pot]

mongo3528 said:

Hi again , ive fitted a new earth from chassis to engine and the problem is cured, so a big thank you for your assistance, much appreciated !

its crazy how that bit of cable fixed it eh ?
id put up with mine for weeks and then was almost annoyed it was such an easy fix lol

[mongo3528]

ha ha , i know , id lived with it since may.. but it hadnt let me down , just always sounded like it might do ! Guess the cables ability to take current degrades over time with the intense heat in that area.

[mongo3528]

ha ha , i know , id lived with it since may.. but it hadnt let me down , just always sounded like it might do ! Guess the cables ability to take current degrades over time with the intense heat in that area.

[nroberts]

Can anyone post pictures of where to attach the extra earthing strap as I have the same problem in my griff.
Cheers

[T_Pot]

nroberts said:

Can anyone post pictures of where to attach the extra earthing strap as I have the same problem in my griff.
Cheers

anywhere mate, as long as you connect the engine, to the chassis then to the battery.

[rev-erend]

You can test it beforehand with a jumper cable .. just clamp it on and see if it fixes the problem.

[domV8]

Hmmm - I have this problem too, and I've just had the engine rebuilt.
Would be really interested in seeing this...

Presumably this new strap has to be touching bear metal, not a layer of paint - so where is a good place to fix it..? I don't really want to be breaking through the paint layer in any old place if I can help it, surely..?

Dom

[domV8]

bigdods said:

I suffered this when my battery was on the way out. Explained by soeone who knows as follows:

Battery cold, everything works. Plates are straight.
Battery warmed by charging as car is driven. Damaged/faulty plates bend slightly and touch reducing amp output of batter

Result - when battery is warm it wont crank very fast.

This is very easy to check. Get the car warm, turn off. Attach jump leads to another car. See if it cranks faster. If it does you've probably got a stuffed battery .

Just an addition to my post above - I have this problem, but have had the alternater and battery replaced on Friday, and the problem started today...
Got the mechanic to test it (cause thought it might be dead battery again), and battery was perfectly strong, and *was* being charged according to multimeter.

Alternator replaced Friday
Battery replaced Friday
Engine totally rebuilt, run-in 500 miles now

When hot, on cranking it sounds like absolutely flat battery (one *very* painful crank every 4 seconds!) - and worryingly I am getting a burning plastic smell - but if left for 15+minutes, starts up again reasonably easily.

Any ideas guys...?

Edited by domV8 on Wednesday 23 September 23:50

[lotusandy]

domV8 said:

When hot, on cranking it sounds like absolutely flat battery (one *very* painful crank every 4 seconds!) - and worryingly I am getting a burning plastic smell

This another indication that there is an earthing issue, the starter motor requires several hundred amps when it is running, power is fed to the starter via a red cable directly from the battery, the return path from the starter is via the metal casing of the starter to the engine block, then via the engine earth strap to the chassis, then via the chassis to battery via another earth strap!
So if any of these earth straps are missing the current will flow via any other earth path it can find.
If the engine has recently been out it is possible that an earth strp has been forgotten.
I forgot to refit one on a mini may years ago & the return path was the throttle cable, which whent into melt down - causing said burning plastic smell.

So check your earth connections & if in doubt add another from the engine block to a clean paint & rust free place on the chassis.

Andy

[domV8]

Briliant Andy - thank you very much

I will get this attended to ASAP.

Anyone got any ideas of locations that lend themselves to natural/easy earthing points between engine/chassis...?

EDIT: this problem started when the alternator and battery were changed over the weekend. Are there any obvious earthing points near the alternator which this might indicate to be the dodgy earth..?

Cheers!

Dom

Edited by domV8 on Thursday 24th September 21:12