Hot start issue

[anonymous-user]

Car has just developed a hot start issue.
Car starts perfectly from cold. Run car for 15 mins return home, turn off go to start, starter will not turn engine . Struggles big time .

I have swapped the battery for a known good one, the one original on there is 1 year old anyway. Battery reads 12.6 at cold start. Dips to 10.5 under starter, filers up and goes to 14.1/14.3. Its a 12 month old upgraded starter motor.
I have run a solid earth battery negative terminal to engine and this is no better. Same symptoms good when cold wont budge when hot .



Any previous experience of this appreciated .

[citizen smith]

Perhaps the internals of the starter motor are all gummed up.

I had this problem with a Griff years ago - quite embarrassing after re-fuelling at a petrol station. Hence, when I got home I took the starter motor apart and thoroughly cleaned it, the re-assembled and never had a problem again.

[m4tti]

Have you earthed the starter directly David. I had all this. Seems even the slightest oxidisation caused hot start issues.

I even cleaned the starter mating face.

[Penelope Stopit]

9.6 Volts is the cut off point for battery voltage during cranking, your battery voltage being 10.5 Volts during cranking points to your starter not drawing enough current and that could be caused by bad negative or positive leads, if the leads check ok then you definitely have a bad starter
Low starter current draw can be due to bad commutation (brushes to armature commutator) and temperature does make a difference with this fault

To check the leads - During cranking...

Check voltage drop between battery negative and starter body - Should be no more than 0.25 Volts

Check voltage drop between battery positive and starter solenoid positive terminal - Should be no more than 0.75 Volts

[pcameron]

I had the exact same problem. TVR Power fixed it for me, I think the key thing was putting an uprated starter motor in.

[Chim450]

If you’ve earthed directly from battery to engine and it is still playing up, then my money is on a knackered starter motor.

[anonymous-user]

All earth's checked. Battery checked on a drop meter. Alt checked. Starter motor ,9 months old checked all connected and we'll earthed. Alt is making volts. Battery is getting the volts. Starts cold will not crank hot. Big battery ,600 amp hours. 70 cold crank. Can starter motor have failed and I can't see it by visually examination ?

[Penelope Stopit]

cliffords said:

All earth's checked. Battery checked on a drop meter. Alt checked. Starter motor ,9 months old checked all connected and we'll earthed. Alt is making volts. Battery is getting the volts. Starts cold will not crank hot. Big battery ,600 amp hours. 70 cold crank. Can starter motor have failed and I can't see it by visually examination ?

Do you mean you have the starter in bits to do a visual on it...that may cost you the warranty. You can't find a faulty armature or coils by looking at them, the armature needs growler testing

[anonymous-user]

No, just took it off the car to look at .
I have refitted with an additional earth to chassis . Try again tomorrow it will start fine in the morning but lets see after 15 mins run.
Although I took lots apart today and cleaned lots of earthing points , I have not actually found anything wrong

[PetrolHeadPete]

https://www.pistonheads.com/gassing/topic.asp?h=0&...

[Penelope Stopit]

Penelope Stopit said:

9.6 Volts is the cut off point for battery voltage during cranking, your battery voltage being 10.5 Volts during cranking points to your starter not drawing enough current and that could be caused by bad negative or positive leads, if the leads check ok then you definitely have a bad starter
Low starter current draw can be due to bad commutation (brushes to armature commutator) and temperature does make a difference with this fault

To check the leads - During cranking...

Check voltage drop between battery negative and starter body - Should be no more than 0.25 Volts

Check voltage drop between battery positive and starter solenoid positive terminal - Should be no more than 0.75 Volts

If you have checked the above when the starter is hot and failing and the results are within these values.....The starter motor is faulty

[anonymous-user]

Well I have discovered the problem it appears when hot there is a high resistance between the body of the starter and the engine. I have added an earth lead from one of the starter mounting bolts directly to the chassis and the car starts perfectly even when hot

[Penelope Stopit]

Nice find