'94 TDI Avant Injection Pump Timing

Needs to get out more Joined: Mar 02, 2011 Posts: 113

Having had the head off the Audi 80 TDI a few weeks ago, for a bit of DIY porting and top end rebuild (the cam belt had jumped, so I took the opportunity while the head was off), I finally got round to re-checking the injection pump timing in VAG COM last night, and it looks a bit retarded, (retarded, but still on the bottom corner of the chart) although the engine wasn't getting warm enough due to the cold weather... I suspect that means it's even more retarded than VAG COM is telling me, as if anything I'd expect it to run more advance when cold (although maybe it's not that sophisticated).

This ties in with what I suspected, because the car feels a little bit sluggish, and the fuel economy is a bit off from what it was, at around 45mpg, driving sensibly / 75mph on the motorway. Previously I was getting 50mpg, on a head with slightly pitted valve seats, and the usual gummed up inlet manifold/EGR. I've also blanked off the EGR while the head was off.

The new cam belt was put on using the proper locking tools, and freeing off the cam pulley to fine tune the cam timing, so I reckon that's right.

I had a look at the manual (I've got a Haynes for an Audi 100/early A6 that covers the 1Z TDI) it says 'slacken the adjustment bolts and adjust the pump), without anything so helpful as a diagram or marked up picture of where the adjustment bolts are. I guess it's meant to be obvious then!

I've had a look on the TDI Club forums, but can't find a guide for the 1Z. Some of the later models seem to have a vernier type pulley on the injection pump, but from memory of taking it off to do the head, there's just one bolt in the pulley on mine.

Any top tips and pointers gratefully received, on
1. Where do I find these adjustment bolts
2. Which direction of adjustment to advance the timing?
3. Any other top tips??

BTW, if anyone local to me wants their pump timing checked, then drop me a PM and I can easily do it in VAG COM - takes 5 mins on a warm engine. Adjustment *may* take a little longer [lol]

Posted: Fri Jan 13, 2012 11:22 am

Mike here you go:
Setting the Injection Timing - Injector Pump Mechanical Adjustment - A VW specific scan tool such as VAG-COM is required for this procedure. It cannot be done by any other method. The mechanical adjustment technique used for previous generations of VW diesels, which used a mechanical fuel pump without electronic control, is not suitable for the electronically controlled TDI injector pump.
With the engine warmed up and idling, connect the diagnostic tool, and select the engine control module. At this point, one of two different procedures is necessary, depending upon whether you have the proper factory service manual for your particular vehicle.

If you have the factory service manual, select "Measuring Blocks", group 0, then select "Basic Settings". The glow plug indicator lamp will begin flashing at this time (this is normal). Do NOT forget to go into "Basic Settings" because this procedure is completely invalid if measurements are taken outside of "basic settings". Take note of the 2nd and 9th numbers in the display. Locate the chart in the factory service manual which shows the proper relationship between these two numbers. Go across the chart with the 9th number then up the chart with the 2nd number and make sure it is within the shaded area. It has been found through experience that these engines have better cold starting characteristics if the setting is within the upper half of the shaded area. If it is good ... don't do anything further. If the second number is below the recommended range, you need to make a mechanical "advance" adjustment (see below). If the second number is above the recommended range, you need to make a mechanical "retard" adjustment (see below).

If you don't have the factory service manual, select "Measuring Blocks", and go to group 4. Do NOT use "basic settings" for this method. The displays show the requested injection timing, the actual measured injection timing, and the duty cycle of the advance solenoid. At warm idle in neutral, requested timing should be between 0.4 and 2.0 degrees BTDC. If the actual timing is not more than roughly 3.0 degrees BTDC, and the duty cycle of the advance solenoid is not more than 10%, the timing is good ... don't do anything further. If actual timing is more than 3.0 degrees BTDC, you need to make a mechanical "retard" adjustment. If the duty cycle is more than 10%, you need to make a mechanical "advance" adjustment.

If you have an A3 or B4, you need to rotate the body of the injector pump "forward" to retard the timing and "backward" to advance the timing. Stop the engine. Remove the upper timing belt cover. Rotate the engine by hand (shifting trans into 5th gear and pushing the whole car works) such that the two nuts at the rear and bottom of the injector pump flange can be reached through the access holes in the pump pulley. Loosen these two nuts by 1 turn, loosen the bolt at the top front of this flange 1 turn (accessed from outside, not within the pulley). Loosen the bolt located at the opposite end of the pump below the four injector lines. With a 17mm wrench, loosen by 1/2 turn the injector lines on the end of the pump. Now you can rotate the entire pump housing in the required direction (make VERY SMALL adjustments) then tighten and reassemble everything and recheck the timing.

If you have an A4, you need to remove the upper timing belt cover and adjust the relationship between the inner and outer parts of the injector pump pulley. To advance the timing, the inner part of the pulley (together with the pump shaft) needs to move "forward" with respect to the outer part of the pulley. To retard the timing, the inner part needs to move "backward" with respect to the outer part. The 3 bolts which secure the two parts of the pulley together may or may not be "stretch bolts" that must be replaced every time you do this ... so it's a good idea to get 3 new bolts just to be sure. Make all the adjustments using the original bolts, then replace the old bolts with the new bolts and torque them one at a time.

http://tdiclub.com/TDIFAQ/TDiFAQ-7.html#k

Needs to get out more Joined: Mar 02, 2011 Posts: 113

Cheers. That looks like what I need.

I'm interpreting that as 'forward' means away from the engine, so to advance the timing I rotate the pump towards the engine. It makes sense that way too, if I think of it like advancing a distributor on an old school petrol engine.

Posted: Fri Jan 13, 2012 11:40 am

yes mate, sorry its from an american forum and is written for the passat running the 1z engine, found this when i was having problems with mine, the garage that had fitted the pump and belt on mine before i bought it obviously never knew how to set the timing and the injection pump properly

Posted: Fri Jan 13, 2012 11:46 am

this is the whole page from them http://tdiclub.com/TDIFAQ/index.html

Needs to get out more Joined: Mar 02, 2011 Posts: 113

Thanks - I was searching on their forum and didn't spot the FAQ. Very useful!