Build thread: 1992 Jetta AHU swap

gaets

Member
Joined
Aug 25, 2015
Location
Maryland
TDI
Mk2 Jetta soon to be TDI
Hey guys, my name is Gaets, I’ve lurked TDI club for years with the hopes of some day doing a TDI swap. Things had finally come together to make that happen. Back in August I bought a 92 Jetta with the idea of making it a road trip car. I have a 91 GTI with a 24v VR6 swap, shaved engine bay and lots of other work done to it. I’ve taken it on plenty of 1500+ mile road trips to shows all up and down the east coast but with all the work done to it it’s gotten to be more stressful than fun. My plan is to put together a reliable mk2 that I can take on long road trips and still have fun with at shows.

So more about the Jetta, its a 1992 GL with 128k on it. I’m the third owner and got it with the original window sticker along with most of the service history. The body panels are pretty straight but the paint is pretty much gone. Almost no rust on it, all the trim is where it’s supposed to be. The interior is pretty clean for its age except for a cracked dash and sagging headliner. It’s one of the most complete mk2 I’ve come across. When I bought it, it hadn’t run or driven in over a year and a half.





On the way home with the car I got the wild idea to drive it 1650 miles round trip to Treffensouth in Atlanta which was 2 weeks away. It didn’t need too much to get it back into driving shape, new radiator, belts, and a basic tune up.





The original plan when I first picked up the car was to swap an ABA in it and drive it like that for a while. While on the road trip home from Atlanta I kept thinking how awesome it would be with a TDI. As soon as I got home I was on craigslist and within minutes found a MK3 TDI that would be the perfect donor car. Ended up picking up it later that week.



So like I said, plans for the Jetta is to make it a comfortable reliable driver I can take on long trips. Cruise control and A/C and a necessity on this car (unlike my GTI which is all show). I want to make the swap as close to a factory install as possible. I’m going to keep the body as is, I think the original patina look is cool. It came with coilovers on it’s slightly lowered, at some point I’ll probably put some wheels on it but that’s going to be the extent of exterior modifications.

This past weekend I finally got some time to get started by pulling the TDI out of the mk3. I’m hoping with the long weekend coming up I can get the engine out of the mk2 and possibly set the TDI in place.





I plan on updating this as I go along. I look forward to getting to know and learn from the TDI club community in the process.

Here’s a few pictures of my 1991 GTI in case anyone is interested.



 
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gaets

Member
Joined
Aug 25, 2015
Location
Maryland
TDI
Mk2 Jetta soon to be TDI
I made some progress today.

Last pictures with the 8v





Engine coming out





Swapped the front crossmember to the Passat VR6 and rear subframe to the Mk3





Then got the TDI set in place. Everything will be coming back out to be cleaned up before final assembly. I just wanted to test fit the engine to see how everything fits together.





 
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ToddA1

Top Post Dawg
Joined
Aug 3, 2011
Location
NJ 08002
TDI
'96 B4V, '97 B4 (sold), '97 Jetta (scrapped)
Nice, it should be a quick swap. You'll be enjoying it in no time.

What's your plan for the cluster? You going to run the A2 ac components?

-Todd
 

gaets

Member
Joined
Aug 25, 2015
Location
Maryland
TDI
Mk2 Jetta soon to be TDI
Thanks, hoping to have it done late winter/early spring. The hard deadline is late May, my plan is to take it on a road trip to Montreal for Eurokracy in early June. But that sholudn't be a problem.

I plan on running a mk2 diesel cluster and I'm looking into my options to get everything to work the way I want. I talked to David at fastforward.ca about the digital to analog speedometer adapter hes making. I like the idea of that because then the speed sensor and wiring is factory on the transmission. I'd just have to wire it into the cluster harness. I think that will also help with simplicity for the cruise control, I wont need to wire the VSS in the back on the cluster with that setup. Getting the tach to work correctly should be pretty simple with a signal converter.

As for the AC components I'm also looking into my options. I'm leaning toward running an adapter on the compressor along with the stock mk2 AC lines. Part of the reason for setting the engine in place was to get an idea of how the AC and coolant lines fit.
 
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ToddA1

Top Post Dawg
Joined
Aug 3, 2011
Location
NJ 08002
TDI
'96 B4V, '97 B4 (sold), '97 Jetta (scrapped)
You’re going to need to convert the compressor to fixed displacement.

-Todd
 

ToddA1

Top Post Dawg
Joined
Aug 3, 2011
Location
NJ 08002
TDI
'96 B4V, '97 B4 (sold), '97 Jetta (scrapped)
How’s the stock TXV going to correctly meter the refrigerant?

Do A2s have cold cut off switches?

-Todd
 

Owain@malonetuning

Associate Vendor , w/Business number
Joined
Jul 1, 2016
Location
Vancouver
TDI
PD jetta wagon
Wow, very nice work on the VR swap! That bay must have taken a good amount of time. Good luck with the swap, sure you'll do the car justice.
 

damac

Veteran Member
Joined
Jul 14, 2013
Location
bay area,ca
TDI
none
came across thread by accident. im doing an mtdi alh swap into my golf mk2 diesel chasis and want ac.

i assumed i just had to repair all the chasis parts which i have done after cleaning. i got a replacement alh compressor and thought the cars wiring would just turn on and off the compressor?

i got some converter pieces for the compressor to let the mk2 ac hoses be used in alh's location compressor down low and i can't see a way to hook up the one coming from the front unit, its too short. other one might work but it wouldn't take the stock route and would have to be bent sooner. may not be possible either.

i will check again towards the end of my project, i have to get the turbo mounted and then build myself out i have a special intercooler/radiator.
 

gaets

Member
Joined
Aug 25, 2015
Location
Maryland
TDI
Mk2 Jetta soon to be TDI
You’re going to need to convert the compressor to fixed displacement.

-Todd
Thanks for the heads up. I thought I read that in another thread I came across too. It doesnt seem to be too big of a deal. Is there anything else I need to know?

Wow, very nice work on the VR swap! That bay must have taken a good amount of time. Good luck with the swap, sure you'll do the car justice.
Thank you, countless hours for sure, haha
 

compu_85

Gadget Guy
Joined
Sep 29, 2003
Location
La Conner, WA
TDI
... None :S
How’s the stock TXV going to correctly meter the refrigerant?
Do A2s have cold cut off switches?
-Todd
The same way any TXV in a variable displacement system meters :confused:

Yes, A2s have a freeze switch on the evaporator. That's what cycles the compressor in the stock setup.

-J
 

compu_85

Gadget Guy
Joined
Sep 29, 2003
Location
La Conner, WA
TDI
... None :S
Yes, the 92 had a fixed displacement compressor, TXV, and cold switch on the evaporator to cycle the clutch.

From some of the things I've read you should be able to replace the fixed displacement compressor with the variable displacement one, and leave the TXV alone. The compressor will work to maintain ~30 psi on the suction side. You might not even need to bypass the freeze switch, but you don't want the clutch to cycle on the compressor... it's not designed to like the earlier compressors and will burn out.

-J
 

damac

Veteran Member
Joined
Jul 14, 2013
Location
bay area,ca
TDI
none
how do you disable the freeze switch just unplug it? i already refreshed my box and installed it on my car, can't even remember if i can reach the harness that connects to it with it installed.
 

compu_85

Gadget Guy
Joined
Sep 29, 2003
Location
La Conner, WA
TDI
... None :S
I'd have to look through the circuit diagrams, it will be in line with the signal from the HVAC control head to the compressor clutch. Just join the wires together.

-J
 

Zed.

Well-known member
Joined
Jan 31, 2015
Location
Wales (UK)
TDI
'89 B3 T'die Passat wagon. '95 T4 van (1Z T'die converted). '87 mk2 Golf AHU tdi converted /02a etc. '92 & '95 200tdi Landrover Discovery
I plan on running a mk2 diesel cluster and I'm looking into my options to get everything to work the way I want. I talked to David at fastforward.ca about the digital to analog speedometer adapter hes making. I like the idea of that because then the speed sensor and wiring is factory on the transmission. I'd just have to wire it into the cluster harness. I think that will also help with simplicity for the cruise control, I wont need to wire the VSS in the back on the cluster with that setup. Getting the tach to work correctly should be pretty simple with a signal converter.

you dont need to worry about running the vss from the tdi's gearbox, can use the dash cluster's vss output & feed into the ecu from there. (as vw built for the petrol cruise system)

just fit a 'hall-sensor' in the back of the speedo / dash-cluster & use the cluster's loom to give the ecu its signal:cool:
the mk3 tdi loom has cruise wiring already so just a 4-wire sub-loom to connect the cruise stalk & activate the ecu with vagcom


as to tacometer & also the 'dop' oil warning system, you can use the mk2 td dash cluster & revcounter by adding 1 wire to the engine-loom to supply the alternator's 'W' terminal signal to the fusebox (plug G1 pin 12, remove the ecu's tacometer signal feed to the fusebox by cutting the wire (green/black) & connect a wire to G1/12 terminal & route to the 'spare' position in the 'BLUE' 2-pin connector (by the startermotor / reversing-light plugs) as this connects to a sub-loom between startermotor & alternator to complete the circuit:cool:

this is a common mod when using mk3 tdi looms for T4 / eurovan conversions here in UK:cool:

use a speedo-cable from a 1.3 mk2 golf to connect the tdi's 02a gearbox & the mk2 jetta's speedo

I've done the above on my '87 mk2 golf when converting from 1.8 petrol to 1.9 AHU tdi and have working tacometer & cruise (although I've complicated things by converting the loom to run in a cE1 car :rolleyes: )



Good luck & enjoy, tdi mk2 is a great car, ours is daily driven with 60+ mpg and the torque makes it easy to drive.


Rich.

ps. use the mk3's 'K' frame for the better rear engine mounts
 
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