Audi a4 1.9 Tdi to 1.8T Conversion

Hello guys. I know that this site is dedicated to TDIs but i think it's the most informative one and may be some of you could still help. Although the conversion from petrol to diesel is more common, in my case i want to do the reverse. I have had a lot of trouble with my Ahu engine which sound very rough - took it to a garage and got no faults but the mechanic said that the turbo is going out and that an engine rebuild will have to be done. The problem is that here in Mauritius the parts are at least 3x more expensive and the road tax is so expensive too and I have heard that the diesel we get are poor ant that's why these car suffer here. I will provide a link on my previous post regarding this car. I have recently bought a cheap engine on ebay.co.uk - http://www.ebay.co.uk/itm/271500069411?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649.
The car has a huge mileage but my budget was a bit tight. Can you guys tell me if this engine has everything to go on my car, and what will i have to buy additionally or what you recommend me to change before mounting to the car.
Also, what is you opinion about this engine by just looking at the pictures? Can people with conversion experience guide me regarding other parts that will have to be replaced - for example exhaust, fuel tank pump etc.
Please note that the seller is supplying the key and a transponder ring and advised me to take the chip out of the key and put it in my key with the transponder ring installed.
Thanks a lot guys and tdiforum

The car to be modified: https://www.youtube.com/watch?v=Vv_7-8i94N0&feature=youtu.be

Hi there,

WHile 167k isn't ideal it's not to bad either. I just turned 220k and mines still going strong.

Depending on the body plug harness it could be a very very easy swap. Prefacelift cars and facelift cars have body plug harness' under the ECU. I would see if those match up.

Being that you bought an entire swap it shouldn't be to hard It looks like you got the axles to which you'll need.

The fuel tank is the same all you'll have to do is swap in a fuel pump from a gas car. 1.8t/2.8/2.4/s4 etc will all work so you can probably find one in the used market.

It looks like you've got the downpipe so that'll make things easier. Worst case you have to find an ebay exhaust etc

Depending on gas pedal that may have to be swapped but I know most UK pedal clusters are shared between drive by wire and drive by clutch so you'll have to see what type of engine you ahve bought.

If it were me I would go only replace stuff that is obviously junk now and swap in the entire lump. This would help eliminate variables and make life easier.

Thanks a lot for the reply sir.

"If it were me I would go only replace stuff that is obviously junk now and swap in the entire lump. This would help eliminate variables and make life easier" - do you mean you would replace the diesel engine with another diesel engine?

ziad2006 said:

Thanks a lot for the reply sir.

"If it were me I would go only replace stuff that is obviously junk now and swap in the entire lump. This would help eliminate variables and make life easier" - do you mean you would replace the diesel engine with another diesel engine?

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Haha No I mean on the 1.8t. Lets say you find coolant leak from the thermostat housing etc. That's what I mean

Oh.. When do I have to consider rebuilding the engine? Does that depend on the mileage or the way the car runs (smoke, noise etc) ?

Input from other members are welcome

B5 1.8T's are so plentiful in the states - it would be awesome if you could just trade! anyone here would love to have your OEM B5 TDI which we never got.... pipedreams

A few things i can replace from engine to refresh it please?

Thanks for the detailed advice. My car as well as the donor car both have manual transmission. Did you see the engine picture? do you think the fuel lines, secondary air pump and other parts you mentioned come with it? Please look at the link of the ebay advert. Seems like the whole engine was taken off the donor car with all ancillaries but i dont know if the parts you mentioned are attached to the engine. I also think the downpipe is visible on the engine.

I will look for the parts you recommended me to replaced before swapping, but as I will purchase most of them online (and i know little about mechanics) i hope to get the right parts, as some of them you described do not have names (for example "T" on the back of the valve). May be i will post more pictures when i receive the engine, at the moment it's on a vessel somewhere in the Indian Ocean

Is this tensioner gasket? http://www.ebay.co.uk/itm/FEBI-3229...arts_Vehicles_CarParts_SM&hash=item2c772a1d99

Vacuum hose: http://www.ebay.co.uk/itm/Audi-1-8t...arts_Vehicles_CarParts_SM&hash=item336cf6bca2

Hello again - got the engine but i think i am really unlucky with this car. I received everything as described minus the Immobilizer control unit. I did some research on the net and i found that the cluster of the 1.8T has not got immo - so that box is missing. Any one knows at this point any way to go around the immobilizer problem? If you need any further info to advise me let me know. Thanks

ziad2006 said:

Hello again - got the engine but i think i am really unlucky with this car. I received everything as described minus the Immobilizer control unit. I did some research on the net and i found that the cluster of the 1.8T has not got immo - so that box is missing. Any one knows at this point any way to go around the immobilizer problem? If you need any further info to advise me let me know. Thanks

Click to expand...

Just get the immo flashed out of the ECU, if it even has one. I think most all the B5 USA cars don't have them up until 2001. UK cars do IIRC. Most tuners can flash it out for $50 or so.

Thanks but the problem is that i live in Mauritius and there are not many tuners here - my best bet is probably getting an ECU with imobilizer removed from ebay

Or ship it to rocket chip and have them flash it and send it back.

Hi - i am still struggling to get this car to work. Ecu is now ok. The problem is that when the swap was made, the electrician said that the wires harness from ecu to cluster was not in order and therefore the OBD does not work, i have plugged in a dongle, it lights up - so there is power and the bluetooth dongle pairs but it cannot access the ecu. Now the problem with the car, it starts but can't idle for more than 10 secs, the rpm drops till it stalls. When i floor the gas pedal the rpm rise to about 2000 only. While playing with the gas pedal to try to keep the engine running i found out that i could keep the engine running as long as i want but i have to press-release-press the gas pedal to about a quarter (from a to b in the diagram) continuously. If keep doing the press-release for a few minutes and stop, the car will idle okish for a minute then drop to 500 rpm then drop all the way down till it stalls. Also the air out of the exhaust is not constant but more like a poof-poof-poof. Seems like only the first quarter press of the gas works, if i do the press-release-press at a faster rhythm i can even increase the rpm to 5000 whilst a full press of the gas pedal only revs the engine to about 2000 rpm. Lastly while checking around i remembered that the engine came with black 058133551 injectors but for some reason the mechanic changed them to blue 06B133551 injectors. The throttle was replaced by a used throttle but it did not bring any improvement. I will try to make a video at the weekend to make it easier to explain. Any help is welcome - thanks.


https://s30.postimg.org/hqan3ix69/gas_pedal.jpg