Need some pump timing help

I searched and couldn't find the answer I was looking for.


1998 Jetta, AHU.
Starts right up and runs pretty well. I have fixed a couple issues and there are no codes remaining. I haven't had the car long and have been working out bugs.

I am attempting to check the timing of the pump.
I had it all warmed up and VCDS hooked up, looking at the timing graph.

I get only the vertical yellow line with the note that it is too advanced to plot. The timing sets at "255" and doesn't change.

Ok, I think, assume, it's advanced too much.
I loosen the bolts to adjust the timing. It's advanced, so I pull the pump towards me to retard it.
I have to move it a good bit before anything changes. When it does, it drops to "38" (retarded), then jumps back and forth from 38 to 255 without any stopping in between. It runs a little rough during this and starts putting out a good bit of grey smoke.

That is the only two options I can get: Steady at 255 or oscillating from 38 to 255.

Does that make sense?
Any suggestions?

there is a drop down menu to select your engine, you do have the right engine elected? you will see a green, a red and a blue line and your yellow line that moves around so you can time it in REAL time. if you only have the yellow line, your selection is wrong or the vcds is not installed right or something with your drivers is messed up. try a different usb port too, i had an issue with my 3.0 usb and my usb that defaults for bluetooth and mouse port on my old laptop.

you will be able to tune it in real time to whatever you want. Try it again. make sure your selecting the right stuff, its been a year since my timing job so i might be a bit fuzzy on the line colours but i do remember issues with selection and usb ports.

Yes, I have chosen the correct engine. Everything else is working fine.
I should have noted. I have timed many TDIs before and know my way around VCDS pretty well (I've been using it for about 15 years).
All of the correct colored lines are there. Just the yellow (timing) line is off the chart when I first started.

I've just never ran into this issue before.

i had this problem a while back, i forget what exactly was the problem. other than 1 check all pump electrical connectors, should be 2, if there was any 'looseness' or otherwise electrical problem/disconnection, its most likely there would be carbon build up at connector(s). in either case use some electrical spray and reconnect. if there is dark/carbon build up the spray alone may not be enough. like a thin special file, or other small filing/scoring device,tool.

Mongler98 said:

your yellow line that moves around so you can time it in REAL time. if you only have the yellow line, your selection is wrong or the vcds is not installed right or

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one question i had for him was did he have the right engine code selected in the drop down menu. but i mean your kind of rough and insistent in your recommendations mongler.

a yellow line indicates more advance than the graph shows, or needs to show. just a (hard to see)yellow dot at the bottom of the screen is retard, again at the edge or off the graph. if timing is in graph range you will (iirc) see one yellow line coming up from bottom, this intersects at a point with another yellow line coming from the left of the graph. (iirc both bottom and line from left are yellow, intersecting at a yellow point or dot. this is your timing mark.)<as you know.

iluvmydiesels said:

a yellow line indicates more advance than the graph shows, or needs to show. just a (hard to see)yellow dot at the bottom of the screen is retard, again at the edge or off the graph. if timing is in graph range you will (iirc) see one yellow line coming up from bottom, this intersects at a point with another yellow line coming from the left of the graph. (iirc both bottom and line from left are yellow, intersecting at a yellow point or dot. this is your timing mark.)<as you know.

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That is correct.
I didn't mean that the vertical yellow line was the only line on the graph, just that there was no corresponding horizontal yellow line as well. Meaning that it was advanced off the chart.

But, when I pull the pump back (toward front of car) the timing retards to 38, but jumps to 255 and back to 38 pretty quickly.

yea as i said i had a similar problem not that long ago. iirc some how the upper electrical connector on mine was not connected. that happened when i finished adjusting the pump(timing) i now snugged all 4 pump bolts/fasteners, and had the lines off, both to get to pump body bolts/fasteners, whatever, and to have the lines loosen. in doing so that upper 3prong connector needs to be disconnected, well in restarting the car and verifying timing, so happens i seemed to forgot to plug connector back in, was a real headache to figure out what would set it (VCDS timing) back right. as like yours it would jump from about timed to wayy advanced, like yours may have read up to 255. i forget h what i did to get to settle down timed, so id say check your connectors, clean, and perhaps reset codes, perhaps disconnect battery, then recheck mechanical timing, after warm back up and see if you can get pump timed. before disconnecting battery (-) make sure, of course you have code--

iluvmydiesels said:

one question i had for him was did he have the right engine code selected in the drop down menu. but i mean your kind of rough and insistent in your recommendations mongler.
a yellow line indicates more advance than the graph shows, or needs to show.

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I agree, especially when he doesn't know what he's talking about.

The Vag-Com is working correctly, the too advanced or retarded both show up as the same thing, which can throw people off. Once you start adjusting the pump to where it'll just show up on the range, it'll go back and forth between the two. Either keep going in the same direction or go the other way and it'll show up on the graph and be stable. Since it was running rough in that direction, go the other way.

Good luck.

Abacus said:

. Either keep going in the same direction or go the other way and it'll show up on the graph and be stable. Since it was running rough in that direction, go the other way.

Good luck.

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I will try that tomorrow. Maybe I was moving it the wrong way and I just needed to go farther the other way.
Thank you!

I have also had that moment when i realize i forgot to plug in the IP harness!

Out of curiosity, did you center the pump, prior to setting the timing?

I realize you used the tools and have done this before, but the possibility the timing is still off, exists. I’m typically used to seeing too little advance and the IP gear needs to be skipped 1 tooth CW, when looking at it from the ps. Pretty easy to loosen and do.... I’ve needed to do it a couple times.

Give it a shot, if you need a Hail Mary.

-Todd

ToddA1 said:

Out of curiosity, did you center the pump, prior to setting the timing?

I realize you used the tools and have done this before, but the possibility the timing is still off, exists. I’m typically used to seeing too little advance and the IP gear needs to be skipped 1 tooth CW, when looking at it from the ps. Pretty easy to loosen and do.... I’ve needed to do it a couple times.

Give it a shot, if you need a Hail Mary.

-Todd

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I haven't had the belt off yet. The belt looks good and I wanted to make sure all was running great before doing the belt. I got the car like this.

I plan on trying again this afternoon. This time I will start with checking the mechanical timing and make sure the belt is not off a tooth.

Thanks guys!

Shikaroka said:

I haven't had the belt off yet. The belt looks good and I wanted to make sure all was running great before doing the belt. I got the car like this.

I plan on trying again this afternoon. This time I will start with checking the mechanical timing and make sure the belt is not off a tooth.

Thanks guys!

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I can understand why you would want to perform the timing operation as a practice but in fact you will have to do this all over again if you change the belt immediately following the VCDS timing adjustment. The pump will not maintain the timing you set now once you replace the belt.

Abacus is correct, a heavy advance / retard situation will appear in the VCDS as the same thing so if performing the timing change as per Bentley with the engine running, if you should happen to advance and not get any where with that you need to try retarding the pump to see if you can get it to show up properly.

Todd also makes a valid point, although, I've never been a full tooth off in the setup, but I have had to lean on the lock pin a tad when trying to get the belt installed, specifically when installing the section from the crank that wraps over the intermediate shaft pulley on onto the IP sprocket.

Good luck in your work.

Steve A