mTDI / TDI-m VE Injection Pump Question (Cold Start Advance)

[alimotoren]

Hello Vanagon Diesel group,

We are working on an mTDI and had some questions for some of you who have more experience with this configuration.

After the engine had been running for a few months it developed a substantial fuel leak in between the block and pump.

After removal of the pump we found that the lever for the cold start advance (choke) had come loose and the o-ring under it was no longer supported causing the leak when under pressure / running.

Searching for references we have found many example of the VE pump that have this lever assembly blocked off. In the few months it has been on the road the choke has never been used. So the first question is if this can be eliminated, and what the effect on function this would have.

Second question relates to the hydraulic valve that is on the opposing side of this assembly. The person who built the pump said that the electrical connection is not needed, but we are curious about the function.

Thanks for your input Diesel gurus

[?Waldo?]

Who built this pump? It does not seem that they knew much about mTDI injection pumps. That looks like an AAZ pump on all accounts which is *not* the right pump to run a TDI.

There should not be any cold start advance installed on an mTDI pump. It is not necessary and as you found out, will fall apart due to the sharper vibrations from the direct injection combustion event. You can install a block-off plate on that side of the pump but the fact that an earlier IDI cold start advance mechanism and advance piston are fitted would lead me to believe that the wrong advance spring is also fitted. If so, then your timing advance curve is wrong which leads me to answer your next question. You need to supply constant 12v to the solenoid on the other side or your advance will not operate correctly. Furthermore, that solenoid does not allow for enough movement of the advance piston which is required for proper mTDI operation. Given that it appears that all of the advance parts are wrong I would really question whether or not the other correct internal parts have been used. You might be better off using another pump from someone who has a good reputation or sourcing a Land Rover 300TDI or LT28 pump.

[alimotoren]

Andrew, thanks for your reply.

Well, not the news I was hoping for... I've been looking into the LT28 pump also but need to figure out if it's a direct fit to an AHU/1Z motor or what modifications would be required.

[Zeitgeist 13]

This link might provide some helpful insights

http://www.vwdiesel.net/forum/index.php/topic,6427.0.html
_________________
Casey--

'89 Bluestar ALH w/12mm Waldo pump, PP764 and GT2052
'01 Weekender --> full camper
y u rune klassik?

[svenakela]

Like Andrew says, remove it.
But, it is actually OK to run a TDI with an AAZ pump. For future references I saved an old forum post once upon a time:
http://switchamotor.blogspot.se/2011/04/q-is-it-possible-to-run-tdi-with-aaz.html
_________________
Vanagon mirror end caps

[?Waldo?]

The AAZ pump has the incorrect timing advance curve. It has a 9mm plunger which significantly limits fueling. It has the incorrect IDI camplate profile. It has an accelerator shaft with shorter offset which significantly limits fueling. It has a control collar lever assembly with incorrect offset which also sigificantly limits fueling. It has the 17mm main shaft which will cause increased bushing wear with the more abrupt DI injection event and risks snapping at higher fueling rates.

It may be ok, in a gutless, smoky and bad fuel economy kind of way... The AAZ pump will run and it won't hurt the engine, but it will be sad in performance. There are MUCh better options available. It's that type of pump that gives the mTDI option a bad name.

[svenakela]

[?Waldo?]

I guess it boils down to what you consider good/bad performance. As far as my 'smoky' comment, I was referring to the higher rpm haze that will result from insufficient timing advance. With the significant underfueling from the other less-than optimal components I can see how that may be minimal, especially if someone runs the static timing overly advanced (as suggested in the post you liked) to compensate for the lack of dynamic advance. As far as different AAZ pumps, I have seen several. Most have the 'joke' boost pin and some have no boost fuel enrichment at all. I can also see how a European pump may have a decent aneroid setup like the 1.6TD injection pumps and would certainly be better, but still lacking in all the individual components I mentioned before. Considering that there are other readily available alternatives that are much more appropriate with all the correct components that I outlined above, I can't imagine ever opting for an AAZ pump on a TDI engine.

[Waldi]

In Europe there are more than 5 different AAZ Pumps.
A friend of mine is running his 1,9 mTDI even with a stock JX Pump.
It works, but of course a modified Landi (Fiat, Iveco) pump is better.

Edit: if you time a JX, AAZ Pump to smoke alot, you will have a problem with long injection time, which cause overheating your piston.

[svenakela]

[alimotoren]

Thanks for the insight!

Does anyone have experience using an LT28 mechanical injection pump, P/N (0 460 424 138) or (062 130 107) on a 1Z/AHU motor?

[?Waldo?]

Here's a thread with an AHU using the LT28.

[Dieselstuff]

We have a Land Rover pump on our ahu in a vanagon and it works pretty well.
It has the ahu timing piston in it and ahu camplate. I would like to try the Land Rover timing piston but I have lost track of how it is supposed to go togeather it is different than a regular timing piston it has a spring loaded spool valve in the end with the spring. If any one has information on the correct assembly and number of shims that would be helpful I can't even find a picture of a piston like this. The piston is marked -498. Thanks.

[R0Batt]

Resurrecting an old thread here...

Im looking into purchasing a 82 westy for sale in Raleigh, NC. It has a swapped 1Z TDI 1.9L and it comes with a 091.301.103 D 5 speed transmission also from Germany.

I was curious if the M-TDI is still a good route to go based on performance and reliability. Are mechanical pumps still available?

Since this engine is from Germany does that complicate things being in the states?

[ZsZ]

[valvecovergasket]

[Zeitgeist 13]

My 12mm mTDI produces a slight puff of smoke upon cold startup, and then nothing after that. It's a very very powerful pump. I'm officially agnostic about injection systems in these vans, but a manual pump just makes sense, as it's always been my intention to convert the trans from manual to automatic.
_________________
Casey--

'89 Bluestar ALH w/12mm Waldo pump, PP764 and GT2052
'01 Weekender --> full camper
y u rune klassik?