Help Needed: Verifying/Re-setting TDC for 1.9 AHU (Injection Pump Re-install)

[Too40gawlf]

Hey Folks,

A friend of mine recently got a 98 Jetta with the 1.9 AHU that had a massive leak from the back of the injection pump. While I have a lot of experience turning wrenches, I have not messed with a TDI motor, but I was eager to jump at the opportunity to work on this car/motor. Anyway, I went over to my buddy's place a few nights ago to remove the injection pump to bring it back and re-seal it (which I have done). When removing the pump, while I did have the cam locking tool, I didnt have the crank locking tool. I marked the timing belt to the sprockets (cam, crank, and injection pump) but I dont believe I marked it to the engine block. In addition, I am not 100% sure I had the engine at TDC (cam tool fit just fine, but I couldnt see any indicator on the flywheel inspection hole, even though I turned the engine over multiple times - so i just go it to where the #1 cylinder cam lobes were pointing away from the valves and the where the cam holding tool fit snug). I guess I could theoretically be 180* out?

I'm going to go back and work on the car next week, but now I'm starting to have doubts as to getting it back to perfect timing. The cam shouldnt have moved because the tool, but Im not sure if the crank sprocket didnt rotate as I was taking the belt off. I have ordered the crank holding tool and will have it with me on re-assembly.

But my main question is, how do I ensure timing is right on if I didnt secure the crank sprocket with the tool prior to removal of the belt and if my marks where less than ideal (it was dark and i was trying to extricate the injection pump to get going)? Secondarily what other tips n tricks would you pass on to ensure that this job is done correctly?

Thanks folks - sorry for the sloppiness - it was cold and dark and I wasnt my usual slow and methodical manner.

 

[Too40gawlf]

Anyway, injection pump has been cleaned up pretty nice though:


IMG_4055 by emanookian, on Flickr

 

[turbodieseldyke]

There is no crank locking tool to find TDC. You look for the flywheel notch in the inspection window at the tranny.

 

[Too40gawlf]

There is no crank locking tool to find TDC. You look for the flywheel notch in the inspection window at the tranny.

I get it. Is it possible that the cam locking tool would go in on the crank but the crank would be 180* off? Like I said, I couldnt see anything in the inspection hole on the flywheel.

 

[turbodieseldyke]

The opposite could happen -- crank at TDC, cam 180 off. Keep looking for that flywheel mark. It flies by pretty fast. Hopefully it's a proper flywheel, not an aftermarket/whatever with no marks.

 

[Too40gawlf]

Appreciate the input.

Let me ask my question a little more simply...

Lets say you walk up to an AHU engine that has the timing belt off, the injection pump off and the cam has the tool in it. What would you do to ensure that you are at TDC prior to re-assembly? Lets say as you look at the inspection port on the flywheel, you do not see any marks.

 

[turbodieseldyke]

Never had that situation, myself. Probably remove glow plug #1 and measure TDC with a dial indicator or a chopstick or god knows what. Someone else will have to give their 2 cents.

 

[starrd]

Be aware that this is an interference engine. Be very careful you do not hit a valve into a piston when trying to find TDC with the timing belt disconnected. You might want to consider removing the camshaft so you can rotate the crankshaft the full 360 degrees to find the mark without a chance of any interference. More involved, but if the timing is out 180 degrees I don't think you can avoid contact any other way.

 

[Too40gawlf]

Never had that situation, myself. Probably remove glow plug #1 and measure TDC with a dial indicator or a chopstick or god knows what. Someone else will have to give their 2 cents.

Good suggestion.

 

[Too40gawlf]

Be aware that this is an interference engine. Be very careful you do not hit a valve into a piston when trying to find TDC with the timing belt disconnected. You might want to consider removing the camshaft so you can rotate the crankshaft the full 360 degrees to find the mark without a chance of any interference. More involved, but if the timing is out 180 degrees I don't think you can avoid contact any other way.

Could you not (theoretically) slowly rotate crank and cam at the same time until TDC?

 

[turbodieseldyke]

You won't break anything if the pistons slowly touch valves by hand-turning, but if you turn them both simultaneously, you'd just be keeping them both misaligned 180 (if that's how they are now).

I think there's a position you can set the crank (i forget how many degrees past TDC), where all pistons are midway down their cylinders, and then you can rotate the cam freely.

 

[starrd]

Here is the best diagram I can find of the mark on the flywheel you are looking for

FlywheelTiming.jpg

forums.tdiclub.com

 

[Nuje]

I think there's a position you can set the crank (i forget how many degrees past TDC), where all pistons are midway down their cylinders, and then you can rotate the cam freely.

Piston1 and 4 move in unison, as do 2&3. 1 and 4 are at TDC every time that mark on the timing wheel flys by - so every 360° of the crank bolt / flywheel.
Piston 2&3 are at TDC (no marks to judge by) 180° away from that.

To help keep straight where you are, when you have the flywheel mark centered, put a paint mark roughly at 12o'clock on the crank sprocket. 6o'clock, then, is when 2&3 are in valve-contact zone.

So, 90° away from 1&4 TDC (3o'clock or 9o'clock) will get all four pistons in the middle of their travel.

With the belt removed, I've always rolled the crank bolt counter-clockwise 90° if/when I've had need to let the camshaft do whatever it wanna do. And then roll forward (clockwise) when I want/need #1 TDC again. I don't think it matters which direction you go with the timing belt off; I'd just suggest doing it the same all the time so you minimize the chance of going the wrong way when going back to TDC (paint mark will help with that as well).

 

[Too40gawlf]

Piston1 and 4 move in unison, as do 2&3. 1 and 4 are at TDC every time that mark on the timing wheel flys by - so every 360° of the crank bolt / flywheel.
Piston 2&3 are at TDC (no marks to judge by) 180° away from that.

To help keep straight where you are, when you have the flywheel mark centered, put a paint mark roughly at 12o'clock on the crank sprocket. 6o'clock, then, is when 2&3 are in valve-contact zone.

So, 90° away from 1&4 TDC (3o'clock or 9o'clock) will get all four pistons in the middle of their travel.

With the belt removed, I've always rolled the crank bolt counter-clockwise 90° if/when I've had need to let the camshaft do whatever it wanna do. And then roll forward (clockwise) when I want/need #1 TDC again. I don't think it matters which direction you go with the timing belt off; I'd just suggest doing it the same all the time so you minimize the chance of going the wrong way when going back to TDC (paint mark will help with that as well).

Exceptional input - thank you!

 

[Too40gawlf]

Here is the best diagram I can find of the mark on the flywheel you are looking for

FlywheelTiming.jpg

forums.tdiclub.com

Thank you! With any luck, I was at TDC when I pulled the belt off and it being dark, I just didnt see the mark.

 

[TDIDaveNH]

A trick for looking for the mark I do is to remove the front passenger wheel, stick a robust flat screwdriver through the caliper and into the brake rotor vent effectively locking that side, then raise the driver's side front wheel off the ground then put the car into 5th gear. This will allow you to rotate the driver's tire by hand which will rotate the engine so you can better examine the flywheel for that mark from the correct side of the vehicle. It's a rusted-over V notch you're looking for. Once you find it, I use a paint marker to draw arrows pointing towards each other on the flywheel through the inspection hole on each side of the TDC mark. Highlighting the mark helps as well after you clean the rust out of it. Good luck and hopefully your flywheel has the mark, not all of them do.

Edit: keep in mind I do this with the TB still installed, as it's easy to spin the engine faster than you can by hand from the crank sprocket side so if you do this with the TB off, it may be possible to damage valves depending on your level of care while doing this trick.

 

[alanack]

I screwed something up and sent a piston into a valve with the starter once.
Crushed the lifter and then tore up the cam shaft...
Didn't really break anything else.... yet

I would just turn the engine over slowly by the crank bolt. Wont damage anything unless really crank on it.

 

[Too40gawlf]

Alright gents, I got the crank to show the mark at TDC, had to turn it over a bit. Can someone show me how the cam is supposed to look at cyl 1 TDC? I have the cam holding tool in and I can see the lobes for 1 and 4 are off the buckets, but I just want to verify.

 

[Nuje]

Google ALH TDC camshaft
First image that came up was this (compliments of this thread, but the image is from myturbodiesel.com.

 

[Too40gawlf]

Thanks, you guys are awesome... I had a couple of hours to work on the Jetta today and I was able to get mechanical timing right on:



IMG_4126 by emanookian, on Flickr

IMG_4127 by emanookian, on Flickr

IMG_4128 by emanookian, on Flickr

 

[Too40gawlf]

However, I ran out of time and wasnt able to get the injection pump lines fastened to the block - one of the lines just wouldnt seat - so I will have to swing by later in the week to see if the car actually starts.

 

[Too40gawlf]

Hey Folks - so its been a few weeks since I was able to get back to the car (she's in a corner of my friend's shop). I have the diesel pump installed and the fuel lines connected to the injectors. However, when I went to prime the diesel pump, I noticed it was completely dry - Im not getting ANY fuel TO the pump NOR do I see any fuel coming out of the fuel filter (the rubber fuel line from the filter to the inlet of the diesel pump was completely dry after turning the engine over numerous times). I was trying to prime the pump with a hand pump AND a vacuum bleeder driven by an air compressor.

Any suggestions on what to check and why fuel is not working its way to the pump?

 

[HardToHandle]

Hey Folks - so its been a few weeks since I was able to get back to the car (she's in a corner of my friend's shop). I have the diesel pump installed and the fuel lines connected to the injectors. However, when I went to prime the diesel pump, I noticed it was completely dry - Im not getting ANY fuel TO the pump NOR do I see any fuel coming out of the fuel filter (the rubber fuel line from the filter to the inlet of the diesel pump was completely dry after turning the engine over numerous times). I was trying to prime the pump with a hand pump AND a vacuum bleeder driven by an air compressor.

Any suggestions on what to check and why fuel is not working its way to the pump?

Have you tried using the vacuum pump to try and pull fuel from the fuel supply line going into the fuel filter?

 

[Too40gawlf]

Have you tried using the vacuum pump to try and pull fuel from the fuel supply line going into the fuel filter?

No - for whatever reason, I didnt try the line going to the filter. But I know the car was running with that exact filter before I re-gasketed the diesel pump.

So if I am able to get fuel via the fuel supply line, then what would that imply my issue is?

 

[HardToHandle]

No - for whatever reason, I didnt try the line going to the filter. But I know the car was running with that exact filter before I re-gasketed the diesel pump.

So if I am able to get fuel via the fuel supply line, then what would that imply my issue is?

I would at least try to see if you can draw fuel from the inlet line going into the injection pump

Basically, its to isolate the source of the fuel supply issue

If you are not able to draw fuel manually from the fuel inlet line to the IP, then the problem is with the fuel supply up to that point.

If you are able to get fuel to the IP, the the problem is downstream of that point, i.e. the IP itself

Out of curiosity, where were you trying to pull fuel from with the hand pump?

Edit: the only reason I mentioned pre fuel filter would be to rule out anything from there back that could possibly be causing an issue. It probably is not that, however knowing that you have fuel up to there would show that there is nothing wrong with the supply up to that point

 

[Too40gawlf]

So - I DID try both ends - the rubber line from the filter to the IP and then at the opening on the other end of the IP where the metal return (?) line and banjo bolt thread into. Bone dry on both ends.

 

[HardToHandle]

So - I DID try both ends - the rubber line from the filter to the IP and then at the opening on the other end of the IP where the metal return (?) line and banjo bolt thread into. Bone dry on both ends.

Like I mentioned, Try to see if you can use a hand pump to get fuel up to the inlet line to the fuel filter, once you have fuel there pump from the inlet line to the IP, after that try to pump from the return fitting on the IP. After that it should be primed enough to get fuel to the injectors

The point at which you can't get fuel will be the source of you're problem