# APX/BAM - What is the difference?!!!



## DaveG40 (Apr 12, 2009)

Good Evening All :mrgreen:

First post here after a friend recently acquired a 2000 Mk1 TT - after sourcing a few parts due to the below issues!!! can anyone tell me what the differences are between the APX and BAM engines?

This particular mk1 has a twin exhaust, engine code APX. During the viewing, we noticed it was smoking under load, due to the oil seals on the turbo being worn/shot - A deal was struck and a new K04 ordered along with all the relevant gaskets, nuts and bolts from audi and the work completed by a competent and trusted mechanic.

After the turbo has been run in, the car developed a faulty coil pack number 4, diagnosed by the same mechanic. this has been replaced only to find the car is misfiring under load. VAGCOM indicated a faulty N75, so off we went to Audi, new N75 fitted, and the same issue is occuring of a misfire under load. The mechanic has again been contacted, and advised a replacement mass air flow sensor. This evening this has been replaced, battery disconnected to clear any codes and tested, only to find the same fault occuring.......... [smiley=bigcry.gif]

Slowly the frustration is building....!!! :evil:

Any advise welcomed, but i think a coil pack is breaking down under load, would this be logged in VAGCOM if it is only intermittent whilst driving? As the misfire is not occuring on idle or when revving from idle etc...

Ta Muchly - look forward to seeing you all around the shows and meets - and if you beeped on the M4 today at us - HI!


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## jammyd (Oct 11, 2008)

Hello and welcome...

TBH I have no idea about the difference, but I am sure someone will come along and help soon


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## junkie (Jun 22, 2008)

As far as im aware the misfire will be recorded on VAGCOM


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## SteveS TT (Apr 23, 2008)

I think the APX has a larger ported head. And the BAM has some sort of VVT system... i think!!!!!!!


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## TT51 (Feb 28, 2009)

I've just been reading Wak's guide to Vagcom and you should be able to diagnose an intermittent problem even if it does not show up as a fault code.

Have a read up on this link its very useful

http://www.wak-tt.com/vagcom/vagcom.htm


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## rustyintegrale (Oct 1, 2006)

As far as I know the APX has forged internals and the BAM cast.

APX is the stronger engine but BAM is preferred by software tuners...


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## junkie (Jun 22, 2008)

The BAM has forged pistons and naff rods.


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## T3RBO (Dec 9, 2003)

Welcome to the forum 

The difference between APX and BAM on THIS thread


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## 26ash_tt (Jul 16, 2008)

how much stronger are the rods on the apx then? does that mean apx owners dont need new rods for the big turbo kits


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## Wallsendmag (Feb 12, 2004)

Welcome to the forum


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## Constantinos (Aug 22, 2008)

I think everyone is missing the point here probably because of the misleading question. It is not the difference you want it is the cause of your problems. I am willing to bet that it is either a coilpack on its way out but not being recorded by VAGCOM or bad sparkplugs.

NO not all misfires are recorded on VAGCOM especially the ones that happen under heavy load. Believe me I learned that the hard way.

Best thing to do is have your mechanic pull all the coils and check on the conditions of the spark plugs. Then put the coils back into place and start by replacing the coil on the third cylinder. If the car continues with the problem then you will know that coil 3 and 4 are good (since you already replaced 4) and proceed with changing coil 2 (which is easier to do that is why I said to start with cylinder 3 first).

If the problem persists continue with coil 1 and eventually you will find the faulty coil.

I have had this before. I replaced all sparkplugs and coils under dealer warranty and the car is as strong as ever. Before it used to stutter under heavy load. No misfires were detected on Liquid TT.


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## LuTTon (Jul 18, 2008)

Hi DaveG40 and welcome!

If you have the 2000 model like me you should have the bolt-down coil packs. These are said to be much more reliable than the newer bosch ones but do have a tendancy to cause intermittent faults rather than just failing altogether.
I believe this is because the insulation within the coil starts to crack due to expansion with heat allowing the coil to short when using higher voltages (I.E. when you put your foot down) the result is that you misfire and look silly when trying to show the local Saxo-boys how its done!

If you have the APX engine then the ECU is slightly more limited and will NOT read coil misfires making it difficult to tell which one is causing the problem! As Constantinos said you'll just have to move them about.

Whilst you are doing this though I think it would be worth changing your plugs just to rule that out and also check the wire insulation into the coilpack plugs... You'll find that a couple have probably cracked so I wrapped electrical tape around each one. I had the say problems as you so I'm sure this will solve it! Even before I found the faulty coilpack re-insulating those wires made a very notable difference so I'm sure one was shorting to the engine block.


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## DaveG40 (Apr 12, 2009)

Thanks All!

I think your are onto a winner there with the suggestion of process of ilimination now...

The plugs - is it recommended to use Bosch? And if so what code of plug is required ?

If i grab a full set of plugs and a coil pack - and we can spend a morning testing on each cylinder with the new coil from 3 down the block until we find the problem has been rectified.

Thanks All, will give GSF a shout and see if they are still open or get one in for Monday at least...


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## TT51 (Feb 28, 2009)

You can test the coil packs by just unplugging them one at a time and then drive. When you find the car doesn't feel any worse than originally then you have almost certainly found a faulty coil pack


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## TT51 (Feb 28, 2009)

DaveG40 said:


> Good Evening All :mrgreen:
> 
> First post here after a friend recently acquired a 2000 Mk1 TT - after sourcing a few parts due to the below issues!!! can anyone tell me what the differences are between the APX and BAM engines?
> 
> ...


You can use Vagcom measuring blocks 015 and 016 to record missfires I've just had a go at it myself. This will definately tell you which coil pack/spark plug is faulty.


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## DaveG40 (Apr 12, 2009)

Just been looking online at some parts and Euro seem to be the best for parts at the moment, i'll pop in next week and grab some new parts, plugs, oil and filter and a new coil pack.

I've been told the Hitachi coil pencils are OEM and to ensure when it is purchased to get hitachi, i think i'll steer clear of any later types!!!

Thanks for all the advice, looks like we'll be onto a winner very soon, i'll update this post here and hoopefully we can get it sorted without having to VAGCOM it again by spending some time swopping out and checking these coil packs and plugs.

It'll be good to finally get it running properly after spending so much time scratching our heads and reaching into the wallet!

:lol:


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## Constantinos (Aug 22, 2008)

Good luck mate keep us posted.


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## DaveG40 (Apr 12, 2009)

Just been out and swopped all the plugs for fresh bosch items - 3 + 4 seemed a little oily... 

I sourced a new hitachi coil pencil - swopped it out on all and tested one by one - this took me ALL DAY!!!!! :lol:

Only to find no change what so ever..... [smiley=argue.gif]

Bac to square one - consideringdropping it into the phirm as not too far away - everything else is in order apart from a connector we found diconnected and dangling around under the air box - pic to follow...

Meh - any idea's?


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## Matt B (Apr 8, 2007)

DaveG40 said:


> Just been out and swopped all the plugs for fresh bosch items - 3 + 4 seemed a little oily...
> 
> I sourced a new hitachi coil pencil - swopped it out on all and tested one by one - this took me ALL DAY!!!!! :lol:
> 
> ...


Hey dave

If you don't mind me asking how much were the hitachi coils, mine have done 114K now so am thinking of changing all 4.

Matt


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## mattwarner (Apr 2, 2007)

Sounds like my problem!

Check this out.

viewtopic.php?f=2&t=138894


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## DaveG40 (Apr 12, 2009)

Thanks for the link - probably a very good idea to check all of that - got some more time this weekend so will give it a try...

Here is a pic of the random connector and plugs in order 1,2,3,4...


















I've changed all four for fresh bosch items now and any ideas on the random connector dangling about under the air box???...

The coil pencils were just under £25 each from Euro - Top quality imo - Even got a genuine VAG oil filter for -£4!!!!

The phirm will take it friday - if the wiring is the cause i'll cancel but it needs sorting one way or the other!

Just for laughs - here is me on my day off testing the new coil pack on all four cylinders...








How happy do i look...!!!! :lol:


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## DaveG40 (Apr 12, 2009)

popped into a mate to VAGCOM her and got this:

Address 01: Engine
Controller: 8L0 906 018 M
Component: 1.8L R4/5VT 0002
Coding: 05710
Shop #: WSC 01236
2 Faults Found:
18010 - Power Supply Terminal 30: Voltage too Low
P1602 - 35-10 - - - Intermittent
17743 - Shareware Version. To Decode all DTCs
P1335 - 35-10 - Please Register/Activate - Intermittent
Readiness: 0000 0000

-------------------------------------------------------------------------------
Address 03: ABS Brakes
Controller: 8N0 907 379 E
Component: ESP 20 CAN V005
Coding: 18446
Shop #: WSC 01236
2 Faults Found:
00778 - Steering Angle Sensor (G85)
62-00 - No or Incorrect Adjustment
00668 - Shareware Version. To Decode all DTCs
16-10 - Please Register/Activate - Intermittent

Cleared all down and got the same - lord knows what the 17743 is!!!


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