Code 17656 on 1.9 TDI (ALH)

[kellarj93]

Hello

8 months ago, I got a "Emissions Workshop" warning in my dashboard with symptoms being extremely slow acceleration and high fuel consumption though no starting problem. I took it to VW, where they told me that the timing belt had to be changed and the injector pump's timing was not right (code 17656), though they were able to fix it. On my way home, the light came up again, but I couldn't turn around as I was late for job so I kept driving. After I was finished at job, I tried to start the car buy it wouldn't start. It cranked and cranked and cranked and finally started after 10-15 seconds of cranking (I know, it was really moronic as lots of white smoke was coming out the tailpipe). So I parked the car and later in the month had it's timing belt, V-belt and glow plugs changed along with engine oil change. The problem was still there, it would crank but not start, it did start with starter gas, but the car struggled a lot at high speeds. None of the workshops used VCDS as they used a software from Bosch, which only showed the quantity being injected, not the timing. 

 

After months of self-learning about the problem and about the car, I went out and had the starting problem diagnosed, which was found to be misaligned timing belt and again! code 17656. The problem was STILL there. So I went out and asked to rent a VCDS and was hopefully able to find one. So We met today, sat in the car and booted up the VCDS. Upon looking at the timing we were shocked. The timing on injector pump was so much advanced (it was meant to be around 60, but it was at 210, look at picture 1 where there is a straight vertical yellow line) that we had to retard it all the way down to 70. Now here was a problem. Everytime we adjusted the timing a tiny bit, trying to get from 70 to 60, it would fall down to zero. And when we tried to get it up to 60, it would suddenly climb to 120 (yes, we did try to move it as little as possible, but wasn't much help).

 

At last we gave up at timing = 69 (picture 2, where horizontal and vertical yellow line is visible), though the warning light would still come on, but at least the car was accelerating much better and could easily get up to speed but the fuel consumption was still high. I did eventually found out that the three bolts around the 22 mm nut are meant to be used only once as they're stretchable so those bolts could be the reason why the timing went advancing while running.  

 

So here is my question. Is there a fault with the injector pump? or the 22 mm nut because of the three 13 mm bolts? I do know that there are 13 ,mm bolts that are reusable, but where can I find them? And how can I reduce the fuel consumption (it used to do 5.2 - 5.8 L / 100 km, but now its doing 9 L / 100 km) because it's not getting economical to drive it now. What shall I do? I have already spent quite a lot on that problem without any success? Shall I just go ahead and change the injector pump or shall I try new non-stretchable 13 mm bolts and try to correct the timing? 

[kellarj93]

Bump. Anyone who can help me out? Still struggling with the problem :(

[mac11irl]

Did you change the bolts yet?

 

How misalligned was the timing belt?

If it was quite off there could be valve damage which may explain part of the problem. Or.. it could just be the injector pump is dying..

[kellarj93]

Just now, mac11irl said:

Did you change the bolts yet?

 

How misalligned was the timing belt?

If it was quite off there could be valve damage which may explain part of the problem. Or.. it could just be the injector pump is dying..

I will perform the bolt change on friday with a friend. According to the mechanic, he said a couple of teeth (for which he charged 400 £ for diagnosis). There isn't any valve damage, just the pump that had the timing problem. But what could be the sign of a dying injector pump? 

[mac11irl]

https://forums.tdiclub.com/showthread.php?t=34497&page=3

 

Its old, but go to page 2, i

O ring in the solenoid can be the issue...

[kellarj93]

7 minutes ago, mac11irl said:

https://forums.tdiclub.com/showthread.php?t=34497&page=3

 

Its old, but go to page 2, i

O ring in the solenoid can be the issue...

I will give it a try, though on friday as I mentioned. I have also ordered an gasket set for the injection pump for 15£. I will let you know how it goes, thank you so much for the tips.

[kellarj93]

Update: 

TLDR: The three new bolts didn't helped at all. Even with them sitting tight and getting the timing right 4 times, I couldn't get it. After 5 mins of driving, the engine light would come back on and the timing was advanced to 255, BUT the bolt itself never moved at all. I don't know what's causing this, but I am considering getting a new pump because I cant pay 50€ every time to rent a VCDS, unless I get some ideas from you guys.

 

Long version: 

We started the day by changing the bolts and trying to get a middle position. After a few attempts, we got the timing down to 53 (from 255) and the VCDS showed "Dead on!". We went out for a drive, and logged inn to VCDS to confirm the timing. When we entered "group 000", the engine started to stutter towards being shutting down, spitting white smoke from the exhaust. The timing had advanced again to 255 while the bolt was still where it was positioned.

 

We then checked the fuel injected quantity which was supposed to be 3-5 mg / str. It was showing in the range of 9 - 11. We tried to lower the IQ by VCDS, but we couldn't do it at all. I didn't went for the hammer mod as I am a newbie with car components. 

 

In addition I also found out that the previous owner had tackled with the car's odometer, It was showing 211000 km when it actually has done 261000 km.

 

I have added photos of reading on VCDS. 

[kellarj93]

Bump! Any help on diagnosing the problem?

[mac11irl]

Rebump... i have no idea...

[kellarj93]

Update

 

It was a defective injection pump. I replaced the pump installed with one refurbished from a German dealer on Ebay. The fuel consumption when idling was 1,6 L/hr with the old pump, it's now idling at 0,4 L/hr (it was originally idling at 0.6 L/hr but I used VCDS to lower it just a tiny bit, from 3,8 mg/str to 3,4 mg/str). It now runs smooth as it was meant to be and the timing is "Dead on!"

 

However the mechanic told me to add approx. 200 mL of engine oil/2-stroke mineral oil to the tank and fill the tank up with diesel as running the car on this blend would lubricate the gaskets in the new injection pump. What do you guys say? I am considering buying a 5 L jug of 2-ethylhexyl nitrate (cetane booster and lubricant) to keep the gaskets lubricated.

 

Edited 21 June, 2019 by kellarj93