Cranking when hot engine

[fourstar]

Hi!
I have Golf mk2 1.6 GTD. Cold engine starts instantly even in -10C with some rattle for 10-30 seconds, but when engine reaches operating temperature and is left shut off for 5+ min, engine is hard to start, but when engine cooles down it starts instantly! I swapped my old leaking ip to other ip from 1.9td xantia and changed throttle leaver and head o-rings. Engine is running better, but still cranking when hot engine. I cleaned and lubed starter and swapped battery for bigger one(98 Ah), engine cranks faster, but nothing changed. No air in fuel lines! Could be injectors leaking?  

[truckinwagen]

its low compression.

not really low, but low enough to be a pain without glow plugs.
when the engine is hot it knows it and does not run the glow plugs, making it hard to start.
when the engine is cold the glow plugs get full cycle which masks the low compression issue.

I have unplugged the temp sender for the glow plug circuit on motors that start hard hot before, and it helps because it fools the glow plugs into running even on a hot start.

-Owen

[fourstar]

Yeah I red about same situation and glow plug mode on tdiclub, but they didn't mention low compression!
Thanks Owen, I will give it a try!

[truckinwagen]

well, if compression is good it will start no trouble hot without glow plugs.

as the compression drops(from many miles of running) the first thing to notice is hard start hot.

[fourstar]

It worked, now engine fires up when it's hot! But it is a temporary solution.
Thats true, engine got lots of miles on it!

Thanks for your help Owen!

[rabbitman]

Advance the timing a little bit and it should help. Or just pull the cold start every time.

[fourstar]

I already advanced timing to max, it didn't help at all, still long cranking. I'll give another shot with advancing timing.

I don't have manual cold start, it's vacuum operated because ip is from Citroen Xantia.

[theman53]

what is max?
Please tell me you have a dial indicator.

[fourstar]

I tried different variations of static timing. I will try again soon, but this time I will reset all timing on crank, cam and ip.

[fourstar]

I did reset timing on crank and cam, but I didn't check ip timing because I couldn't borrow a dial indicator. Still the same long cranking when hot engine! I suppose it's low compression. Someday I wil check the compression.

Thanks for help and advices!

[theman53]

If you don't have a dial indicator then the hard hot start could be too much advance. IP timing is important

[fourstar]

Yes I know timing is important, but with too advanced timing it will smoke as hell and had that detonation sound, but I'v got neither of these! I tried to retard timing, nothing changed, as I mention before I tried different settings of timing, nothing changed when engine is hot!

Today I talked to an old timing guru and he told me to check the compression, he said if there is a slight difference in compression between cold and hot engine, then the engine is weared out and thats the cause of hard start!!

[theman53]

Glad you know what it is now.