T4 ACV 2.5 TDI injector pump errors

[fargo]

Hi. I have a malfunctioning T4. Was running well then one day wouldnt start. Now it starts sporadically, idels fine, runs a bit rough. Then wont start. Sometimes smokey, then other times no smoke. Put "launch" on the ODBII & it spits out "sporadic fuel metering valve errors. Mechanic advised that car not worth putting new pump on.
Anyway, I noticed(front of motor between block & belt cover) the arm on the injector pump belt tensioner really jumping around a lot. Touched the arm lightly & the engine stopped straight away. Pulled the cover off & found the belt had 30-40% of the teeth missing & I was unable to spin the tensioner but able to spin the idler. The belt looks in extremely poor condition having only done around 60-80k km. I am wondering if the tensioner is seized & that is the clicking noise that I can hear & also a kind of light roaring noise when the motor is revved?
My main question is , can the belt cause the errors on the fuel metering solenoid? I would hate to go through the process of doing the belt to find that the pump is actually stuffed.

Thanks in advance.

[Umai Naa!!]

I'd be putting new pulleys and a belt on it, re-setting the timing, then see how it goes.

Chances are, it's only throwing that code because the timing is miles out.

[fargo]

I'd be putting new pulleys and a belt on it, re-setting the timing, then see how it goes.

Chances are, it's only throwing that code because the timing is miles out.

You mean new tensioners & pulleys or jsut tensioners?

[Umai Naa!!]

I'd do all the pulleys. If one is stuffed, the others won't be far behind.

[fargo]

I'd do all the pulleys. If one is stuffed, the others won't be far behind.

So CAm pulley, injector pump pulley, idler pulley & tensioner? Are you thinking that one of the teeth on the pulleys has crapped out & is destroying the teeth on the belt?

[Umai Naa!!]

No, no. Cam pulley should be fine.

[Snail Style]

You can buy the kit direct from VW and will come with the belt, tensioner and roller. Make sure you know what your doing if you plan to do it yourself.

[fargo]

You can buy the kit direct from VW and will come with the belt, tensioner and roller. Make sure you know what your doing if you plan to do it yourself.

I think the belt completely let go today. We tried to start & it was actually stuck until teeth were gripped.
Seems like the biggest problem with changing it the belt is finding the timing marks & then fine tuning the timing.

[Snail Style]

Yup that's right, main issue is getting the timing spot on. First one you do will drain your life, and then once you understand the system it will become quite easy to set/adjust the timing quite fast.

Most people change the cam belt and never touch the injection belt, and then eventually it craps out.

[Seano]

All that needed to happen for the belt to get in that condition is dodgy tension (which is spectacularly easy to do) and then it'd shred in a heartbeat. Replace the belt,tensioner, pulleys AND the bolts, get it timed up and it should run fine...fingers crossed. The belt itself only has a mechanical influence on the pump, not electrical so it won't affect any solenoids etc.

By the by, it's not really a DIY job unless you know what you are doing both physically and computationally...and have all the right gear.

[fargo]

All that needed to happen for the belt to get in that condition is dodgy tension (which is spectacularly easy to do) and then it'd shred in a heartbeat. Replace the belt,tensioner, pulleys AND the bolts, get it timed up and it should run fine...fingers crossed. The belt itself only has a mechanical influence on the pump, not electrical so it won't affect any solenoids etc.

By the by, it's not really a DIY job unless you know what you are doing both physically and computationally...and have all the right gear.

Going to give it a crack myself. I have already sourced aftermarket(genuine) parts. $150 from Imparts. tensioner, idler & belt.
Read a bit about the procedure. I think I will try it without pulling off the rocker cover & jsut going off TDC1 on the flywheel.
I've ordered a USB-ODBCII & I have downloaded VCDS Lite ready to upgrade to use the timing plugin.
having trouble finding pictures on line of where the timing marks ae on the pump.
Could probably do with workshop manual on that section too if anybody knows of an online source for that.

[jets]

I think I will try it without pulling off the rocker cover & just going off TDC1 on the flywheel.

I agree, no need to remove the rocker cover. There should be a plug in the hole so that you can see the flywheel mark. This can sometimes be difficult. The pointer is cast into the gearbox housing & is hard to see looking from directly above. The timing mark is also hard to see & I worked on one where there was no mark at all. We had to make a mark by removing an injector & turning the crank until the no1 was at TDC & observing the movement of a screwdriver inserted in the hole.
I can't help with the timing mark on the inside of the pump pulley. I know there is one but I don't know what it is supposed to line up with.
When I remove that belt I lock the pump so that it can't move. You don't have that luxury but I will have a look & see if I can find any info on the T4 Forum.

[fargo]

Thankyou jets

[jets]

Go to post #3 on this link.

injection pump timing on 2.5tdi - VW T4 Forum - VW T5 Forum

Here's another link.

Pump timing advice please ? acv engine - VW T4 Forum - VW T5 Forum

And another.

T4 1999 2.5Tdi Error 17656 / Timing - VW T4 Forum - VW T5 Forum

[fargo]

Thanks Jets. I put the parts on over the weekend. Fired first kick & running fine now.
I read a few different articles & I have a few discrepancies. I found 2 articles that stated the fron tensioner bolt to be tensioned to 15nm & the rear to 20nm. Then I read another that suggests 70nm for both.
Also, not having done this before I was unsure as to how to fit the idler. I rotated the idler until the inside casting bracket pushed against he engine & could spin no further. The instructions for the front tensioner were straight forward in lining up the marks. However I am concerend that perhaps i have not nough tension on the tensioner bolt & idler nut & also if I have too much tension on the belt.