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Discussion Starter #1
Hi all,

After belts replacement (and also cylinder head cover gasket), I got a long cold start on my 2.5 TDI (AXL) T4. When the engine is warm, it starts fine (but with different sound than before the replacement). The problem appeared exactly after the replacement (when the mechanic did the test start).

The man who did the replacement told me that before the timing was wrong (but I hadn't any problems with start), and now he set the timing how it should be, and it has a long cold start, and it looks like normal for him.

Could he up somehow with timing even if he was sure that it is right?
Or can it be that some other problems (like plugs or something else) were hiding while the timing was wrong? (sounds really stupid)

Last time timing belt was fixed in October (it was slipped and the van lost power and didn't start), so the service fixed it but said nothing about wrong timing or something like that. Not sure if it could slip again just for a bit (mechanic said it was wrong by 1 tooth).

Is it possible to check somehow if the timing is right? I have a chinese cable and vagcom, and obd adapter with Torque app.

Or maybe better to go to another shop and ask them to check the timing.
 

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Pump timing is probably not right, i would guess the mechanic has set it using the locking pin tool or a dial gauge at best, it needs to be set by checking with vagcom and then adjusting and checking again until its right. If he is not used to working on t4's then thats the likely issue.
 

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Discussion Starter #3
Pump timing is probably not right, i would guess the mechanic has set it using the locking pin tool or a dial gauge at best, it needs to be set by checking with vagcom and then adjusting and checking again until its right. If he is not used to working on t4's then thats the likely issue.
I guess I can check it as in the video below? I'll try it tomorrow.

https://www.youtube.com/watch?v=CfYQOl4n4tk
 

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Discussion Starter #6
You need registered VCDS (VagCom) to do timing.
Yep, already tried and was disappointed. Went to the shop and asked if they checked the timing through vcds, and they don't even have it :D Said that maybe another guy has it and need to come on Monday.

Do I need a full registered version or VCDS-Light will be enough?
 

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Discussion Starter #7
Can someone explain why wrong timing only affects the cold start and completely fine with warm engine?

It definitely looks like the colder the engine, the longer the start.
I guess with very cold weather it wouldn't start at all.
 

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You don't need "FULL" VCDS....just the registered version of the software ($99).
Timing "sweet spot" is 55 (on VCDS graph).


Even at -20C, WITHOUT glowplugs, this lump will eventually start.

Working plugs, perfect timing, less than 2 rotations before it wakes up!!! (Key in, turn to start, count to ONE and the engine is running).

The whole thing depends upon those 2 words...."Perfect Timing".... I:

Anyone with a VW T4 2.5TDi should have VCDS.
I never even leave my drive without the 50 quid XP laptop/software/cable under the rear seat..... T:
Total "Tool" cost...150 quid.....could save you that 1st time you have a problem and need to go to a garage (who may NOT have it anyway!!!).
 

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Discussion Starter #9
So. I visited garage ant mechanic checked the timing. Though he checked through Delphi (not vag-com/vcds), it shows 1.5-1.6, which is way too far from 0.55. Although he wasn't sure if it's bad or ok, he said the problem of cold start could be because of glow plugs (I don't think it is, because it was ok before belts replacement).

Also, if it can help somehow, I have white smoke during the cold start, when I have to crank a lot. When the engine is warm, there is no smoke (maybe need double check with a camera near exhaust). Which is also can be because of glow plugs I guess? But again, there was no problems with smoke/cold start before replacement.
 

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So. I visited garage ant mechanic checked the timing. Though he checked through Delphi (not vag-com/vcds), it shows 1.5-1.6, which is way too far from 0.55. Although he wasn't sure if it's bad or ok, he said the problem of cold start could be because of glow plugs (I don't think it is, because it was ok before belts replacement).

Also, if it can help somehow, I have white smoke during the cold start, when I have to crank a lot. When the engine is warm, there is no smoke (maybe need double check with a camera near exhaust). Which is also can be because of glow plugs I guess? But again, there was no problems with smoke/cold start before replacement.
You have the answer there, 0.55 is where it should be so its way off and causing problems with start and smoke and probably stealing bhp too, get him to adjust it.
 

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Hello - sounds similar to an issue I had - van 2.5 TDI 88 started fine before belt change then took a long time to start from cold afterwards, producing smoke at the same time as the long start. Once warm it started fine with no smoke. I took it back to the garage who said the pump timing was out - they had set it at 53 and so reset it at 63!- it did start a lot better but I was not happy with this being so far from spec so took to another garage who according to their notes "reset the valve timing as 3 teeth out on flywheel ". since then its been fine for 3000 miles.
thanks - Dunk
 

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0.55 is the "sweet-spot" when using VCDS.
Who knows what the Delphi readings are/should be?

I wouldn't trust ANY garage that doesn't have the VCDS software.....even the FULL version (that costs a lot) would be a "proper tool" for a garage.

10 quid cable, 50 quid 2nd hand XP lappy, and $99 to get a "registered" VCDS is probably the best tool anyone could buy.
I don't even drive to the local shops without my lappy in the van!!! I:

My "local" garage (that has only around 1000 customers in total), borrows MY VCDS to do timing.
They also borrow the £850 (Chinese Clone/Hacked) MB Star system that I bought for the 2x Smart (Mercedes) cars I have.
MB Star (genuine) costs around £15,000, and £1,500 per year subscription.......
Small garages can't afford that, nor can they buy "illegal" systems.....but they have NO PROBLEM borrowing mine to sort a problem Rasp:
 

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Discussion Starter #13
0.55 is the "sweet-spot" when using VCDS.
Who knows what the Delphi readings are/should be?

I wouldn't trust ANY garage that doesn't have the VCDS software.....even the FULL version (that costs a lot) would be a "proper tool" for a garage.

10 quid cable, 50 quid 2nd hand XP lappy, and $99 to get a "registered" VCDS is probably the best tool anyone could buy.
I don't even drive to the local shops without my lappy in the van!!! I:
I checked it with vag-com 409.1 ("registered") and it shows something weird. In measuring blocks it shows about 50, which would be fine, but in TDIgraph it shows 0 and "Timing is too retarded to be plotted".





Is this timing adjustment is an easy DIY job? It looks easy but I'm afraid I can f*ck it up somehow if move it too much.
 

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Discussion Starter #15
You cant do any harm with the pump timing, worst case it just wont start until you adjust is some more.
I'll try it tomorrow. According to this wiki https://www.t4-wiki.de/wiki/Förderbeginn_(TDI)#Info:_F.C3.B6rderbeginnnachstellung_.28Quick_and_Dirty.29, don't even need special tools, looks like 10 minutes work for someone who did it many times, so I think it's a good job to learn.
Also, didn't find any videos with adjusting, so maybe it's a good idea to make one, in case of success. Or probably there are no videos because it's impossible to record something in such a closed space.
 

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Discussion Starter #16
Tried to advance it today, but it was already full, couldn't move it more, only back. Probably marks are set wrong.
 
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