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2.5 TDI ACV fuel pump timing - your wisdom please

1.7K views 5 replies 2 participants last post by  Or_GazM  
#1 ·
Hi all, hope you can help please. Appreciate its been covered a fair few times before and i've scoured many a post on the forum for the answer but can't find it.

Setting the timing up on the diesel fuel pump post cambelt change. I'm having the usual cold start problem, so it takes forever to eventually fire with lots of smoke, but its fine once up to temperature. Drives perfectly once running.

I don't have access to VAGCOM/VCDS, so took it to a VW independent who set it yesterday afternoon, but this morning when starting from cold its still an absolute pig to start so back to square onw. Having questioned the specialist he advised it was within spec at somewhere around 47-52 (reterded if i'm correct)

I believe the best number to achive is 55 if correct on measuring block 2 from what i can read up. How critical is this 55 number when it comes to the cold starting. A few posts have mentioned running slightly advanced will assist in cold start issues, so how far past 55 would be sensible if this is the case?

No inference to the repairer as they appear very knowledgeable and have been very helpful, but i appreciate some on here may have more experience in the subtleties of things like this than others and want to make sure we're 100% as good as can be on the fuel timing before i start looking elsewhere.

Thanks in advance :)
 
#3 ·
Thanks for the reply T: , i'm looking to get it but understand it needs a dedicated standalone laptop to run?

No prior issues at all with anything including start up before belts were changed, it started every time all the time, so not looking to glow plugs as of yet but will certainly consider once timing is ruled out.

When you say 'sweet spot' how much outside of it is ok before it becomes a problem? Would the numbers the inde mentioned cause issues?

Any ideas on the retarded/advanced part of my post on how this affects cold start up?

Thanks again

Si
 
#4 ·
Retarded causes starting problems.....a few degrees low makes a big difference.
Too advanced, makes it sound like a tractor!

You don't need "dedicated" laptop.
I have an OLD XP laptop with VCDS (registered at $99) on it, (50 quid on ebay, with a 10 quid lead) that I keep in the van (also have 12v adaptor for it).
I also have VCDS on my Windows 10 laptop as a backup.....both work, I just like to keep the "cheap one" in the van.

Small (free) program, but you will need to register it to do timing.


With the amount your timing is out, I would think you could adjust that using the tensioner pulley.
If that is already at maximum adjustment, you'll need to move the belt one notch, and start from there.
 
#6 ·
It also depends upon what your "specialist" used to measure the timing.....I:

VCDS will NOT allow it to be displayed until the engine is at 90C (option to lower that in the settings).

MY "local" garage had a system that showed the timing at a steady 54.......(STEADY)
Putting MY VCDS on, it showed it was moving between 48 and 53.....(at correct temp)

After some "discussions", they tweaked the tensioner, and got it to be between 54 and 56....so, average 55.T:

They'd been using a "rattle gun" on the pulley, and moving that.....NOT the way it's supposed to be on a 2.5 (But fine for a 1.9TD...)


BTW....
You don't even need a laptop, as long as you have a long power lead for your home PC and monitor... LOL:

(Honestly, been there, done that!!!....for another vehicle.)