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Engine Specific Info and Questions => IDI Engine => Topic started by: fourstar on February 02, 2011, 06:04:09 am

Title: Cranking when hot engine
Post by: fourstar on February 02, 2011, 06:04:09 am
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?  ???
Title: Re: Cranking when hot engine
Post by: truckinwagen on February 02, 2011, 09:56:40 am
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
Title: Re: Cranking when hot engine
Post by: fourstar on February 02, 2011, 12:22:15 pm
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!
Title: Re: Cranking when hot engine
Post by: truckinwagen on February 02, 2011, 12:34:38 pm
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.
Title: Re: Cranking when hot engine
Post by: fourstar on February 03, 2011, 09:05:55 am
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!
Title: Re: Cranking when hot engine
Post by: rabbitman on February 04, 2011, 12:26:42 am
Advance the timing a little bit and it should help. Or just pull the cold start every time.
Title: Re: Cranking when hot engine
Post by: fourstar on February 04, 2011, 02:14:56 am
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.
Title: Re: Cranking when hot engine
Post by: theman53 on February 04, 2011, 05:37:29 am
what is max?
Please tell me you have a dial indicator.
Title: Re: Cranking when hot engine
Post by: fourstar on February 04, 2011, 06:26:40 am
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.
Title: Re: Cranking when hot engine
Post by: fourstar on February 05, 2011, 06:06:17 am
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!
Title: Re: Cranking when hot engine
Post by: theman53 on February 05, 2011, 06:39:09 am
If you don't have a dial indicator then the hard hot start could be too much advance. IP timing is important :D
Title: Re: Cranking when hot engine
Post by: fourstar on February 05, 2011, 07:17:06 am
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!!
Title: Re: Cranking when hot engine
Post by: theman53 on February 05, 2011, 09:21:19 am
Glad you know what it is now.