Audi A4 B7 2.0T swap to V8 4.2

[apigo200x]

hi everybody
i have swap my engine 2.0t AT to 4.2 S4 MT... i have buy a salvage audi s4 B7 4.2 MT i have remove the engine and some parts to put it in my A4 .
Now i have some problem with ecm module coding to change MT to AT and when the ignition is on the fuel pump, spark plug, injector dont not turn on!!
i have check all fuse and all relay is ok... the engine no crank... and before the swap I did not have any code in any module but after the swap my stop light come on when ignition is on without press the brake and all module have a code... But the most urgent for now is engine start first
you can help please
thx

[Nollywood]

Sounds like you're missing a ground connection, either engine to chassis, or engine harness to chassis.

The pictures aren't working, it would help if you could fix them, so we can see what you can see.

[Nollywood]

Engine will crank even if the ECU is not connected, as the starting circuit is completely independent. A missing earth / ground connection may well cause this, or one of your connections under the ECU (body connectors) is incorrect, or missing.

[BB6-B6]

Could be security. The ecu is not original right?


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[apigo200x]

thx Nollywood
just one ground is been connected to chassis in engine compartment.... but the ecu have the coding for manual trans and vagcon reject the coding for auto trans even when i have not faut in ecu

[apigo200x]

Could be security. The ecu is not original right?


Sent from my iPhone using Audizine

Hi BB6
yes is original ecu and ecu for working fine i have start the s4 engine before the swap
thx

[apigo200x]

Sounds like you're missing a ground connection, either engine to chassis, or engine harness to chassis.

The pictures aren't working, it would help if you could fix them, so we can see what you can see.

im sure that engine harness ground is connected to chassis but im not sure for engine to chassis i will check it
thx

[apigo200x]

Sounds like you're missing a ground connection, either engine to chassis, or engine harness to chassis.

The pictures aren't working, it would help if you could fix them, so we can see what you can see.

Actually I had forgotten to connect the ground from engine to chassis ! i have connected it but same problem ...
but i have see that the S4 have not fuel pump module and A4 have one this may be the problem?
thx

[apigo200x]

Someone to help me please

[vce1232000]

IIRC you have to the dash cluster also. Because its coded and immobilized to the ECU of the S4 donor you did the swap from. That or immobilize defeat the ecu

[apigo200x]

IIRC you have to the dash cluster also. Because its coded and immobilized to the ECU of the S4 donor you did the swap from. That or immobilize defeat the ecu

yes ! i dont have immo problem... i think that i have buy the bad engine harness wiring because my vin is waugl78e37a130743 and my engine harness part number is 8E1971072SG For automatic transmission vehicles up to VIN 8E-5-600 000 - Split is in the 2005 model year but now i want try 8E1971074EB For automatic transmission vehicles from VIN 8E-6-000 001 - Split is in the 2006 model year

[Nollywood]

Immobiliser active state won't cause a non-crank condition. Something else is missing.

Was this S4 an automatic, or manual?

[Nollywood]

Of all the engines you could have opted for a swap...you chose one of Audi's most unreliable motors, the chain-driven 079-series V8.

[vce1232000]

i have swap my engine 2.0t AT to 4.2 S4 MT... i have buy a salvage audi s4 B7 4.2 MT

Was this S4 an automatic, or manual?

Op states it was a MT

[07AudiA42.0T]

Does the v8 engine bolt up to the a4 transmission? Thinking about doing the swap lmao

[Nollywood]

Op states it was a MT

Then there's a possibility the automatic transmission starter lockout hasn't been defeated. Clutch safety / neutral switch...

[apigo200x]

Immobiliser active state won't cause a non-crank condition. Something else is missing.

Was this S4 an automatic, or manual?

convertion to auto in my in A4

[apigo200x]

Then there's a possibility the automatic transmission starter lockout hasn't been defeated. Clutch safety / neutral switch...

now im sure i have engine harness wiring problem... i have the harness 8E1971072SG and is not fit my for engine... the correct parts is 8E1971074EB

[apigo200x]

Does the v8 engine bolt up to the a4 transmission? Thinking about doing the swap lmao

yea a4 and s4 share the same transmission just the oil cooler line different
thx

[apigo200x]

Of all the engines you could have opted for a swap...you chose one of Audi's most unreliable motors, the chain-driven 079-series V8.

sorry but It was the only engine V8 that i had as an option :P

[Nollywood]

Audi's likeable B6/7 is placid as a 1.8T
Stonking as a 2.5/2.7/3.0 TDI
Unmatched in oil thirst and chain guide appetite as an S4.

[Okedokey]

Audi's likeable B6/7 is placid as a 1.8T
Stonking as a 2.5/2.7/3.0 TDI
Unmatched in oil thirst and chain guide appetite as an S4.

huh?

[apigo200x]

audi a4 b7 and S4 B7 have the same interior chassis harness wiring configuration?

[apigo200x]

hi i need help please
1- A4 B7 and S4 B7 have the same interior harness wiring posotion ? because i think i have a big electric problem, when i plug the red connector and i turn the ignition to on the taillights come on and still on ( like if you press brake pad) and with vagcom i can acces to ecm i dont not have any fault but i know why but ecm give the power to throttle body just dont not give the power to fuel pump, injector, sparkplug, engine speed sensor and more... before the swap i have starter the S4 engine without any problem

photo libre

[Nollywood]

Pinouts are different.

You need wiring diagrams for both the S4 and your car.

[apigo200x]

Pinouts are different.

You need wiring diagrams for both the S4 and your car.

thx i have bentley A4/S4 b7 ... What section of the diagram I have to look for ?














heberger image

[apigo200x]

The guys I'm really blocked i need ur help please please

[ADCS]

Wait so you didn't alter the V8 engine wiring to match the B7 chassis plugs!?!?!? really!???
You should have tons of ECU fault codes... didn't you scan it before starting?

1. Pray that you didn't fry something by plugging the harness into the chassis without altering the pinouts.

2. Print the engine wire diagrams for the 2.0t

3. Print the engine wire diagrams for the 4.2

4. Make an excel sheet with all the pin outs.

5. Matchup the corresponding connections.

6. Repin the engine harness to match the chassis or create a jumper harness in between chassis and engine.

7. Defeat the IMMO or adapt the ECU to your cluster. Need the SKCs for this.

8. Start car.

[apigo200x]

Wait so you didn't alter the V8 engine wiring to match the B7 chassis plugs!?!?!? really!???
You should have tons of ECU fault codes... didn't you scan it before starting?

1. Pray that you didn't fry something by plugging the harness into the chassis without altering the pinouts.

2. Print the engine wire diagrams for the 2.0t

3. Print the engine wire diagrams for the 4.2

4. Make an excel sheet with all the pin outs.

5. Matchup the corresponding connections.

6. Repin the engine harness to match the chassis or create a jumper harness in between chassis and engine.

7. Defeat the IMMO or adapt the ECU to your cluster. Need the SKCs for this.

8. Start car.

Ok thx ADCS
Yes! i have a lot of fault codes and im not expert in electronic without guide to match V8 engine wiring on B7 chassis
you have a DIY for this ?
thx

[ADCS]

I just gave you a DIY. :-)
You need to get the wire diagrams for both engines, match the connections, modify your engine harness (or make a jumper harness between them).

[blitz2190]

if they came from the same model years, unless they changed in the b7 (speaking from b6 experience here) they body pins will be Identical, in the b6 all chassis have the same pinouts regardless of the engine. I'm not sure you said this but did you get the 4.2 auto harness? If not your missing the tcu. also as mentioned, you will need to either swap the clusters or have your new ecu adapted/defeated.

Edit*
Seems from your pictures that you are in fact trying to use the MT harness, this won't work without a major rewiring of the tcu or far easier pick up an AT harness for a 4.2

[apigo200x]

I just gave you a DIY. :-)
You need to get the wire diagrams for both engines, match the connections, modify your engine harness (or make a jumper harness between them).

ok but I can not read the diagram correctly
you can help me with it ?please

[apigo200x]

if they came from the same model years, unless they changed in the b7 (speaking from b6 experience here) they body pins will be Identical, in the b6 all chassis have the same pinouts regardless of the engine. I'm not sure you said this but did you get the 4.2 auto harness? If not your missing the tcu. also as mentioned, you will need to either swap the clusters or have your new ecu adapted/defeated.

Edit*
Seems from your pictures that you are in fact trying to use the MT harness, this won't work without a major rewiring of the tcu or far easier pick up an AT harness for a 4.2

thx Blitz.. Yea i have harness wirinf for AT.. and i have the original ecu cluster key...
thx

[blitz2190]

Im confused i thought you said the 4.2 was a MT if that is the case you will need a 4.2 AT harness, you can most likely use the stock TCU.

[apigo200x]

yea before the engine swap it was A4 B7 2.0T AT and S4 B7 4.2 MT after the swap it A4 B7 4.2 AT

[blitz2190]

OK I understand that but do you have the automatic transmission engine harness for the 4.2 not the one that came on in and not the one from your 2.0, you need an AT 4.2 Harness which you don't have unless you got it separately, You cannot use the manual harness that came with the 4.2, unless your converting the car to manual.

[apigo200x]

yes i have the engine harness wiring 4.2 for Automatic transmission but the problem V8 engine wiring harness dont not match to B7 chassis plugs pinouts

[Nollywood]

B7 and B6 have different body connector pin outs. Yes, even if both cars are factory S4's, with manual transmission.

I just realised something - your B7 2.0T was an automatic, the B6 S4 is a manual. For some reason, I assumed you were converting your car to manual. Do I take it, you're trying to run the BHF motor as an automatic, but with a manual wiring harness? Where is the TCU? Let's assume you grab an automatic S4 harness, and matching ECU. I don't think the S4 automatic ECU will be compatible with the B7 2.0T automatic TCU.

I would suggest you either use the S4's manual gearbox, harness and ECU. That way, you only need to deal with the chassis connector re-pinning. Or, get hold of an S4 automatic transmission, TCU and matching engine harness. Again, you'd then only have to deal with the body connectors. Either way, I would suggest you get the electrics - harness, ECU / TCU from a B7, your life would be so much easier.

Don't forget, the B7 cluster (Bosch RB8) is very different to that of the B6 (Bosch RB4). It's likely running the B6 electrics, may mean some of your cluster functions will either be lost, or have limited functionality.

[ADCS]

ok but I can not read the diagram correctly
you can help me with it ?please

I can tell you from experience when putting a 2.7t into a B6 it will take many many hours going through the diagrams to understand it and match all the connections.

As for reading the diagrams, look in the legend for anything that says 'connector station Ebox'. Those will be the chassis plugs the harness connects to. Each connector will be described using the format Txxn where 'xx' is a number, 10 or 17, and 'n' is a letter such as i, d, p, o as well as a colour. On the diagram itself, when it says Txxn/yy the 'yy' is telling you the pin #.

So as an example from the diagrams that you posted, the first one you posted you can see T17d/17 off to the center-right of the diagram. This is telling you connector T17d (red connector), pin #17. The diagram shows it goes to pin #2 of J17 (J17 is the fuel pump relay according to that diagram). It also shows the other side of that connection goes to [43]. This is telling you it goes to Trace #43. At the bottom of the diagram you can see incrementing numbers. These are the trace numbers. If you go to the diagram that has trace 43 you will find the other end of that connection. You need to find the same connection on the 4.2 diagrams and note which connector and pin # does the same function. If they are in different locations you will need to modify your engine harness to match the chassis pinout. If you are lucky there will be many common connections...

[blitz2190]

guys I don't know why you keep saying its gonna take re-wiring, he wants to put a B7 4.2 into a B7 Chassis. OP The pictures you showed seem to be a MT harness as the TCU is missing unless the TCU has been moved back into the chassis, I'll pull up elsawin in a bit today and look but I'm willing to bet the body pinout is the same between a B7 A4 and a B7 S4.

EDIT*
After doing a bit of research I can't seem to find a definitive answer on where the TCU is, but seems to be inside the transmission itself, that being the case it would explain why we dont see it, as for the TCU it can probably be recoded for the 4.2