GU 2.8TD - Starting Problem Resolved
Submitted: Saturday, May 08, 2004 at 17:14
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Member - Hugh (WA)
Hi Forumites,
There have been a number of posts discussing problems with starting GU 2.8TDs, namely continued cranking post glow plug light going out - particularly when engine is warm. Some excellent
feedback also, with some common issues being 1)a mod to fuel pump (fitment of shim to take up tolerance shift when pump is warm), 2) glow plugs, and 3) battery on the way out (despite plenty of cranking power). Perhaps others too - the above from memory.
This problem has been bugging my GU for the past 2-3 months. I wasn't keen on spending $ on a pump mod so spent some time diagnosing the issue. Glow plug resistance was OK so I didn't think they needed replacement. I found that if I left cranking until a while after the glow plug light went out the engine started OK. Reading manual shows that glowplugs are heated for a fixed time, pending coolant temp i.e. less heating time if engine is warm. Also, the glow plug light is only on for a short fixed time and glow plugs continue heating for sometime after. Also note that the glowplug circuit is only on for a finite time i.e. if you leave key-on for ages then crank the engine won't start because glow plugs will have cooled down.
So this made me think it was an electrical supply issue. I never did measure battery voltage though suspect it must have been low, hence needing longer time to get heat into the glow plugs. The battery seemed to be in good health with plenty of cranking power so I was beginning to think it might be the pump.
Well so I thought until the battery died during the week. Fitment of a new battery has solved my starting problem. The engine now starts when cranked directly after the glow plug light goes out. Also noted that cranking time to first fire is markedly reduced.
So thanks to those that have posted about the battery being a potential root cause - it was for me.
I thought I would post this for other people's
information. I note that the new GU III 4.2TD has an electronically controlled pump (similar to 2.8TD). Owners may wish to make a mental note in case similar symptons occur.
Regards,
Hugh
Reply By: Diesel Do - Sunday, May 09, 2004 at 18:32
Sunday, May 09, 2004 at 18:32
Thanks for the
feedback Hugh. Appreciate it very much.
Interesting problem this. Does anyone have a suggestion as to why a new battery fixed my (and Hugh's) problem, and yet a shim on the fuel pump can have the same effect? I'd be very interested to find out if an "old" battery (same as Hugh and I had) will still start the engine easily if the shim is installed? Can't think how to
test this unless you actually have a starting problem that is fixed by the battery, and at the same time be able to install the shim. Any ideas?
Seems to me that when the battery reaches a certain undefined age/condition again both Hugh and I (and possibly others) will return to having starting problems. Just a thought - is there any chance that the starting problem was fixed when the battery was replaced simply because the computer was powered off for the first time (possibly ever)?
Anyone - is there a mechanical explanation please?
Regards,
AnswerID:
57872
Follow Up By: Member - Hugh (WA) - Monday, May 10, 2004 at 00:20
Monday, May 10, 2004 at 00:20
Thanks for the comments DieselDo. I am going to look into this a little further. From what I have read today, I think that the shim is adjusting pre-load on the injection timing piston. I need to do some more fact finding but I wonder if, being an electrically controlled mechanical pump, that pump timing may be affected if voltage is lower than ideal. Could be an electrical/mechanical interaction, solved by either - perhaps.
Only some thoughts - I'll see what I can find out and let everyone know.
Hugh
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