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.