Differences between an A3 & A4 TDI?

dhh72

Active member
Joined
Aug 10, 2000
Location
No.Va
In my ever continuing pursuit for an engine and information for my pending A1 Rabbit GTI swap.... I was wondering what the major differences were between the A4 G/J TDI and the A3/B4 TDi engines?

Is the pump on the A3/B4 Passat mechanical or is this all controlled by the ECU/DBW assembly on all TDi models?

Essentially what I'm thinking is that IF the pump on the A3/B4 cars is mechanical that would make my life a bit easier when it came time to put the engine in and trying to hook up the electrics. Think the later I get the worse the wiring nightmare will be.



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David
Formerly 1975 Peugeot 504 GLD w/1985 505TD engine, 5 spd, gone, but still running
Currently 1997 Jetta GLX VR6, Garret v.ll, GTI 5 spoke rims
1983 Rabbit GTI(new project)
 

dhh72

Active member
Joined
Aug 10, 2000
Location
No.Va
bttt

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David
Formerly 1975 Peugeot 504 GLD w/1985 505TD engine, 5 spd, gone, but still running
Currently 1997 Jetta GLX VR6, Garret v.ll, GTI 5 spoke rims
1983 Rabbit GTI(new project)
 

GoFaster

Moderator at Large
Joined
Jun 16, 1999
Location
Brampton, Ontario, Canada
TDI
2006 Jetta TDI
If you want to put this package in an older chassis, your best bet is the A3 engine for sure. The engine mounts are in completely different places on the A4 models.

Jason Crabtree is the resident expert on engine swaps, he put a '98 A3 TDI engine/transmission into an A2 Golf. There were a lot of headaches, but engine mounts weren't among them. There's pictures in the Golf section...

The pump is electronically controlled (via drive-by-wire) on all TDI engines A3 and A4, but I've heard that a TDI engine will work with the mechanical injection pump from a 1.9 regular TD (engine code AAZ). I have not seen this with my own eyes, though. I know the injection pressure is a lot higher with the TDI, and I don't know how the older style pump would deal with this.

Expect the following problem areas:
Wiring harness to ECU and instruments
Pedal box (for drive by wire)
Hydraulic clutch versus cable
Intercooler mounting

Brian P.
'96 Passat TDI
 

Jason Crabtree

Veteran Member
Joined
May 17, 1999
Location
Ontario, Canada
The A3 is the easiest way to go. It doesn't mean to say that an A4 TDI wouldn't fit. People put 1.8T in A2 Golf's & Jettas, although I think that they don't use Passat ones. Also the ability to find an A3 engine is greater than an A4 (although they aren't too common). I think Johnathon Bartlett is trying to get his Passat TDI engine since that car is totalled.

Since they aren't too common, finding one cheap will be difficult. I got mine from RPI (604-944-0494) and they may even have one in stock. They had one not too long ago. It won't be cheap (but then neither are 1.8T engines).

Diesel Des is also doing an A2 swap and is really pushing the envelope in TDI swapdom.

I too have heard that you can hook up a mechanical fuel pump, it has been mentioned on the forum a number of times.

My swap uses drive by wire set up (a pain) and a 98 Jetta relay panel. I know the wiring is a pain but swapping looms is a pain for the most part in any swap. Definately what sorts the men from the boys.

J
 

Beowulf

Veteran Member
Joined
Jan 17, 2000
Location
Lovettsville, VA, USA
TDI
A3 Jetta, 1998, Green
I'm seriously considering swapping a TDI into a VW Rabbit down the road just because I think it'd be cool and a good learning experience.

Right now I only have the barest of mechanical knowledge? Do the swap experts have any URLs/books/etc where I could start reading up on this topic?

Thanks, Steven

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The TDI Owners' Premium Diesel Fueling Station List:
<A HREF="http://www.geocities.com/svenfoucault.geo/tdi/premdiesel.html" TARGET=_blank>
http://www.geocities.com/svenfoucault.geo/tdi/premdiesel.html</A>
 

dhh72

Active member
Joined
Aug 10, 2000
Location
No.Va
Thanks for the info.

The swap is going to be a major PITA. I found an engine a while back for $1700 w/a one yr warranty on it. Should have bought it then, but I didn't know if it had the wiring harness and pump w/it. Think I can find the same deal again if I look.

Does anyone know what problems I would encounter trying to get the car to run on a mechanical pump?



------------------
David
Formerly 1975 Peugeot 504 GLD w/1985 505TD engine, 5 spd, gone, but still running
Currently 1997 Jetta GLX VR6, Garret v.ll, GTI 5 spoke rims
1983 Rabbit GTI(new project)
 
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