M-TDI ALH into a MK2 swap

[libbydiesel]

Also any suggestions on where to tap in a MK2 temp sensor?

On my '91 ALH Vanagon install, I made a simple adapter plate for the end of the head and used an aluminum coolant flange from a Mk1/Mk2 that already had the temp sensors for gauge a glow plugs.

[fatmobile]

I found one flat spot on the ALH waterneck and it just happened to be on the only thick part.
 The rest was really thin.
MTDItempsensor by vwfatmobile, on Flickr

It's also near the top so easy access for plugging it in.
 
 It still didn't work so I pulled the cluster and both the gauge mounting bolts were loose.
 They provide electrical contact.
 So the stock ALH sender might have worked, I still kinda doubt it.
 It works now,.. but it looks like the thermostat needs changed
 because the needle won't go into the center of the gauge.
 Won't go above the first mark.
 TDIs are supposed to run at the same  temp as the IDIs right?

 Going to move it back to 12 BTDC and get a new thermostat.

[libbydiesel]

In looking at the picture of the flange, my memory was jogged a little.  For future reference there is a sender that works in the stock ALH or AHU location.  It is a two-part sensor and allows temperature readings for glow plugs and for gauge - two pins each from a 4-pin sensor. 

I also worked on an ALH of mine last weekend and realized when looking at it that despite the angle of the pump, the back of the pump bracket would prevent removing the back dynamic advance cover. 

The normal operating temp should be about the same.  The TDI's take longer to warm up, though. 

[fatmobile]

 My engine has the 4-pin sender.
 I hooked it up.
 Used the wire that read close to the MK2 sender in resistance
 and the ground wire for that part of the sender was grounded to a bolt on the head.

 Unfortunately the bolts holding the gauge to the circuit board were loose.
 So the contact was bad.
 I assumed it was the sender not working with the gauge and unhooked it.
 When it still didn't work with the stock sender I tracked it to the gauge nuts.

 So that 4-pin sender which is probably meant to feed info to the ECU
 might actually work with the MK2 gauge.
 I wondered what the other 2 wires were for.
 Side note: That's a pretty expensive temp sender.

 In true VW fashion
 the thermostat is the same as the one used in the MK1 and 2.
 I had a stash of old tested thermostats and swapped one in.
 Temp rides right down the middle.
 
 I noticed the injection pump's back timing cover being blocked too.
 
 Maybe put a seal in another front cover so I can see if a pin moves when running.
 There is almost no pressure behind that cover,
 in fact it's connected to the front of the pump.
I've been wanting to build something like it for awhile anyway.
 So I can see the piston moving.

 Might be the turbo too.
 It should be building more boost.
 I'll tie the vanes closed just in case the exhaust flowing through it is causing the vanes to open.

 It starts great even when cold.
 Jumps to life. Without glow plugs.
 Has great low end grunt.
 But EGTs climb too fast and boost not fast enough.
 At 1200 boost is only at 10psi.
If I step on it EGTs run up to 1500 and boost doesn't climb past 10psi.
 Torque drops off.

[libbydiesel]

There are several 4-pin TDI temp senders that are not the same.  The part number of the one that works correctly is 357919501 (green ring).  That sensor is two sensors in one and gives the correct resistances on either in order to run the gauge or glow plugs.  The correct connector and pigtail is readily available for cheap, often sold as an "VW A/C Connector".  Here's one for $5:  https://www.ebay.com/itm/A-C-Pressure-Switch-Pigtail-Plug-Cable-Connector-For-Audi-A4-A6-A8-VW-Passat-B5/332918478538?fits=Make%3AVolkswagen&hash=item4d837cd6ca:g:3yAAAOSwV0RXrS3R

When you say you have considered placing a seal in the dynamic piston cover, I assume you mean the outer dished one.  The spring side (outer) of the dynamic advance piston has a channel to no pressure.  The plate side (back of pump toward the block/head) has a channel to internal pump pressure.

Ah, I thought that you had fastened the vanes in the closed position.  If the vanes are able to move, they will move to the fully open position.  If they aren't totally stuck, exhaust flow is definitely enough to push them open. 

[fatmobile]

I did have a rod on it earlier.
 But it wasn't hooked to anything.
Just a foot long piece of allthread.
 I thought the weight of it would hold the lever down, vanes closed.

 I'll make sure it's held firmly in place and try again.
 It should over boost easily, like the rabbit.
 I have a controller built for it but haven't mounted it or the rods.
 
Thanks for including the temp sensor info in this topic.
 It won't help me with this engine but I'm trying to get all the info in one thread
For others thinking about an ALH MTDI build.

It's also nice to be able to look back on my old threads to see how much I forgot, he he.

 

[fatmobile]

 It's running great.
 First refill at 1/4 tank and it got 46 MPG.
 That's with some beating on it,
lots of in town driving
and chasing down an air in the fuel problem that required lots of idling.

 I used a 12mm pump from Andrew so it's a little clackity.
Some white smoke when taking off so I might advance the timing.

[fatmobile]

 Got around to hooking an 02A trany to it.
 Shifter and cables along with shift tower and linkage swapped from a later MK4.

 Peddle cluster from a Corrado, with the pin-mount for the clutch.
 So the clutch master had to be for a Corrado and mounts with the pin.
 
 Engine bay, bracket for the brake booster, with built-in clutch master cylinder bracket,
came from a B4 passat.

 I had heard that the K-frame or rear crossmember had to be swapped to the MK3 one.
 The difference between the rear engine/trany mounting points, on a MK3 and MK2 frame, isn't the trany mount.
 is the passenger side mount and it's welded to the K-frame.
 Easier to swap crossmembers, than to cut both off and weld it onto the MK2 frame.
 
 Because I made a custom rear motor mount to clear the VNT and bolt to the MK2 mount,
 I could just keep the MK2 rear crossmember.

 The front crossmember doesn't sit at the same angle as the MK3 front motor mount.
 I heard the B3 Passat front crossmember is the cure.

It running good.
 Still too much fuel for this turbo so I can't really floor it, got to watch the gauges.
 
Getting some more parts together now.
An intercooler and better flowing intake from a BRM TDI to install.

AAAnd some more body work to do.