One for Timmus - FSI Throttle Body

Topsie

Member
FSI Throttle Body

I'm currently looking for a new throttle body for my FSI - Mine is no longer working (one of the angle sensors is stuffed) and I've PM'd a couple of people who have given me a price - that's sorted, I just haven't pulled the trigger yet.

My hesitation is that I do not want to put a replacement TB on only to have the same issues - the throttle bodies are lifed items, ie, they will not last forever and they are all pretty old now, I'm 99% sure that the TB is the root cause of 99% of my misfire issues.

The TB is known as the J338 and I'm curious if the TB from a 2006+ A3 1.6 FSI can be used (Link) as both cars use Bosch Motronic MED (All be it different versions) and both use a J338. I've no idea if they are the same diameter, fitment looks similar and has a 6-pin connector much like the early TB's. The TB's for these FSI's is are not expensive as they were made in abundance.

Is it feasible to have a go and see if it works, or am I wasting my time?

Edit: I'm assuming the later TB uses the same brush and track system as the earlier TB's, and not infra-red alignment or another funky method

Nick
 
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I'm currently looking for a new throttle body for my FSI - Mine is no longer working (one of the angle sensors is stuffed) and I've PM'd a couple of people who have given me a price - that's sorted, I just haven't pulled the trigger yet.

My hesitation is that I do not want to put a replacement TB on only to have the same issues - the throttle bodies are lifed items, ie, they will not last forever and they are all pretty old now, I'm 99% sure that the TB is the root cause of 99% of my misfire issues.

The TB is known as the J338 and I'm curious if the TB from a 2006+ A3 1.6 FSI can be used (Link) as both cars use Bosch Motronic MED (All be it different versions) and both use a J338. I've no idea if they are the same diameter, fitment looks similar and has a 6-pin connector much like the early TB's. The TB's for these FSI's is are not expensive as they were made in abundance.

Is it feasible to have a go and see if it works, or am I wasting my time?

Edit: I'm assuming the later TB uses the same brush and track system as the earlier TB's, and not infra-red alignment or another funky method

Nick

Hi Nick,

the TB used in the A2 1.6 FSI is part number 036133062D which is used in the same fitment 1.6 FSI BAD engine in the contemporary VW Golf / Bora and also used in the Lupo 1.4 FSI ARR engine.

The later A3 1.6 FSI engine uses a different part number, 06A133062AT, (in your eBay link) for the TB which in itself indicates that it isn't exactly compatible in some way.
Whether the operation is the same but it is "adaptable" is another matter. If for example the cooling pipe fittings are in a different place so given different hoses it would otherwise work, you would only find out by trying.

regards

Andrew
 
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They are different parts but i’m hoping the mechanics behind there operation are the same. I suppose the only way is to try...
 
... you would only find out by trying.

I suppose the only way is to try...

Hi Nick,

I was slightly alarmed to see my forum name and 'FSI' written together in the thread title, and I'm very glad Andrew got back to you first.

With some sheepish hesitation, I'll admit that the information in my head about Audi A2s is bordering on encyclopaedic, but there is nevertheless one massive, gaping hole: the petrol engines. I know that they have spark plugs, but that's about where my knowledge ends. In all seriousness, I don't even know where the oil filters are located on the 1.4 and FSI engines. That's not to say I couldn't find them, but it gives you an idea of my total lack of familiarity with the petrol engines.

I have, of course, worked on A2s with those engines many, many times, but always for upgrades/retrofits or some repair work away from the engine itself. After all, they have the same bodywork and same interior and same electrics and same suspension and... etc, etc. Maybe one day I'll fill the void, but I've never been especially interested in petrol power, and interest is the driving force behind discovery.

Nevertheless, despite my ignorance, I agree with Andrew. The best thing to do in these circumstances is to bite the bullet and give things a go. I know every last bolt of the TDI engines because I've been prepared to experiment. Sometimes you'll get lucky and find that you're the pioneer of something new, but sometimes you'll find that you've spent money only to find that something doesn't work. However, sometimes a negative outcome can be as informative as a success. So, go for it! :)

Cheers,

Tom
 
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Thanks Tom,

I'm going to pull the trigger, plug it in and see if it operates the throttle body before doing anything else, the chances of the wiring being identical is slim but like you said, sometimes you'll get lucky.

I'll keep everyone posted,

Nick
 
...the chances of the wiring being identical is slim...

Given that both units are made by the same manufacturer (i.e. Bosch), I'd suggest there's a good likelihood that the wiring will be the same. This is something that one ought to be able to establish by studying the wiring diagrams for the A2 and A3 and doing a comparison. As Andrew says, there could be minor physical differences that throw a major spanner in the works, though. Best of luck and let us know the outcome. :)

Cheers,

Tom
 
Just checked with what I could find on google (i'll try elsawin once I'm home) it looks like the wiring shares the same principles - ie. a shared earth, 2 position sensors and a motor through 6 pins. Throttle body should be with me by the weekend and I'll let people know if it at least operates the butterfly without any fault codes!

Nick
 
Okay a bit more detail:

The throttle control unit (J338) pins are the same for the 2006 Audi A3 FSI and the Audi A2 FSI. The next step is to connect and see if the throttle body responds following adaptation in VCDS.

A3 VS A2 FSI TB.PNG

Update: The connector fitted perfectly onto the A3 throttle body and adaptation was carried out successfully. The A3 throttle body works as it should. The next step will be removing the A2 throttle body and making some dimensional inspections. One difference between the A3 and A2 is the crank case suction enters the throttle body direct. In the A2 it enters in the elbow that separates the TB from the MAF. Essentially one will have to be capped, and i'll cap the on the TB and keep it as intended (as much as reasonably practicable).

Update 2: Amazingly, the A3 throttle body fixings have the same PCD of the A2. The throttle body looks of slightly larger diameter but rain has stopped play and i haven't got the A2 TB out just yet. This is starting to look farily straight forward.

(Audi A3 on the left, A2 on the right)
 
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Okay, the throttle body is fitted however i'm going to have to order some hose as the water inlet and outlets are quite different. I'm also getting an error code for an air-leak which may be because the TB is not heated and the air is coming in cooler than expected. It could also be the blanked vacuum line as I couldn't fine a suitable bolt to blank the hose with.

In short, it fits and the engine is running, however not quite 100% yet.
 
Okay,

Finally got around to finalising the new throttle body.

Car feels a fair amount more responsive, the misfire has all but gone and there is no longer any hesitation or surging while driving. I used some 7mm reinforced hose to run coolant to and from the throttle body and some Elring SHF Sealant as a gasket between the TB and the inlet manifold.

All in all, quite happy with the result with total expenditure being £40 ish (I had the sealant already, it's not the cheapest!)

Topsie

IMG_0865.jpg
 
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