AAN Engine transplant into VW T3 Transporter

[UrS4boy]

Ahah ok, I'll see if I've got another G28 kicking around or maybe swap the G28 and G4 over? I presume that that would create other faults if the G28 is dead? Weeping injectors.. that's all they are. They're not being fired by the ECU.
MG

As stated before, you need a good signals from the G28 engine speed sensor, the G4 crank sensor and the G40 cam position sensor (all three) before the ECU will activate the fuel pump, injectors and coils. One of them not working = no start.

[RS2]

As stated before, you need a good signals from the G28 engine speed sensor, the G4 crank sensor and the G40 cam position sensor (all three) before the ECU will activate the fuel pump, injectors and coils. One of them not working = no start.

Ok thanks.

MG

[RS2]

Another frustrating morning...

One new crank sensor later, same problem. Tried it in replacement for G28 and G4.

By earthing out the injectors one by one and then trying to start it, I can get it to just about tickover for 5 seconds. Whilst that's going on, I've been looking for a signal from the ECU to drive the fuel pump relay... Nothing. The highest rpm I've had register within Vag-com is 600rpm but still nothing from the ECU.

Getting fed up now...

MG

[UrS4boy]

Another frustrating morning...One new crank sensor later, same problem. Tried it in replacement for G28 and G4. By earthing out the injectors one by one and then trying to start it, I can get it to just about tickover for 5 seconds. Whilst that's going on, I've been looking for a signal from the ECU to drive the fuel pump relay... Nothing. The highest rpm I've had register within Vag-com is 600rpm but still nothing from the ECU. Getting fed up now... MG

I imagine that you are getting fed up. However, don't give up. There is a solution, you (we) just haven't quite found it yet. Here a few things.

1. Try having someone spray diesel starting fluid (ether) into the throttle body (open the throttle plate a bit) while you are cranking the engine on the starter. If it is fuel injector issue, but you are getting spark, the engine should catch and run on the ether until you stop spraying. (Have whoever is doing the spraying wear a glove and stand to the side a bit in case there is a backfire). If it does catch, it is a fuel injector issue. If nothing happens, there is still an issue with the G4, G28 and G40 sensors and/or the ECU.

2. Any chance of trying another Motronic AAN ECU in case it is an ECU issue? Did you ever establish that you don't have an immobilizer ECU? AFAIK, with an immobilizer ECU, you need the key in an immobilizer-equipped ignition switch which then completes the immobilizer circuit, allowing the engine to be started.

3. Not getting a voltage signal from pin 3 output from the ECU, normally used to energize the J17 fuel pump relay is bothersome. I points to either an immobilizer or a bad G28. It would be good to test the G28 to see if it is generating a signal.

4. You haven't established that the G40 cam positon sensor and G4 crank position sensor are working. Either would stop the engine from starting. But they do not influence the Pin 3 signal so I think you need to focus on why you aren't getting at least that signal.

Try no. 1 first.

Dave F.

[RS2]

Thanks Dave,

It does run an Immobiliser but I've got that running along side with a key, correctly coded into it (Vag-Tacho!).

Having had the engine running (almost!) just on fuel sprayed into the engine by earthing out the injectors, I know that the spark is there and near enough in the right place for it to run.

Having tried a new G28 crank sensor and having used the same new sensor to swap over with the G4, I can rule both of those out too. I also checked on the resistance of both G28 and G4 sensors and had just under 1000 ohms between 1 and 2 and no connectivity between 1 and 3, or 2 and 3 which is correct according to tests on the net.

I then checked the resistance on the G40 and found no connectivity... nada between any pins. Looks like that's next on the list.

I never heard this engine run and it had been stood for a few years in barn so I expect that this may be why it was there and not driving around. Hopefully this is what is stopping it from running and everything else will be perfect... haha!

MG

[UrS4boy]

I am not convinced you have spark. Please try the diesel starter fluid-spray trick to confirm.

[RS2]

You might not be convinced but I am.

This should help.

http://youtu.be/CCU5qUmAmms

MG

[UrS4boy]

Consolidated AAN Cam and Crank Pulley and Flywheel Timing Mark photos and diagrams

You might not be convinced but I am. This should help. MG

Maybe. What I saw there is an engine that is out of time as well as one that isn't getting fuel. Can you check that the timing marks line up?

You need to check the position of the cam relative to the crank, using the external marks and the mark on the edge of the flywheel, as shown here:

http://forums.quattroworld.com/s4s6/msgs/136943.phtml

[RS2]

Can anyone confirm if the Hall sender is supposed to have resistance between any pins please?

MG

[UrS4boy]

Can anyone confirm if the Hall sender is supposed to have resistance between any pins please? MG

Not sure. VAG doesn't say anything. I'll check the Bentley. In the interim, this *might* help:

http://forums.quattroworld.com/s4s6/msgs/22580.phtml

[UrS4boy]

Okay. I checked the Bentley. It has a diagnostic procedure for the cam position sensor ("CMP" in Bentley-speak) but it involves lots of VAG tools and connection boxes.

I think it is better to use an LED between Pins 2 and 3 as has been suggested previously by Paul N. (S2central.net) and Marc S (a4quattro) at EFI Express.

The harness connector between the G40 hall sender/cam position sensor is under the plastic fuel rail cover (if still on), at the front of the engine. There are 3 pins in the connector. In the harness, Pin 1/3 is the 5V feed from the ECU Pin 12/55, Pin 2/3 is the return signal from the Hall sender to ECU Pin 8/55 and Pin 3/3 is the Ground/Earth (back through the harness). Wire colours are as shown here.



As per Marc S. at EFI Express, you need to connect an LED and a resistor across pins 2/3 and 3/3 at the G40 connector to ECU harness connector in order to watch the generation of the Hall sender signal (once every two crank revolutions). Marc's instructions are here:

http://www.efiexpress.com/catalog/article_info.php?articles_id=11

Photo courtesy of EFI Express

[RS2]

Thanks Dave,

LED ordered (with correct resistor). I'll get this rigged up and see what we get.

I'll also double check on the crank/cam timing.

I'll be changing the timing belt as I've no history as to when it was last done so a new G40 sensor wouldn't be that bad to do at the same time and from what I've seen on the this website, a worthwhile swap as they do go bad.

Oh, has anyone looked at using G40/Hall sensors from other engines which are cheaper and fitting them to our bracket?

MG

[hajbed]

Looked on the forum a link to a german seller who sell only the defectuous part of the hall sender for 10 times less than price of the oem entire piece.
I've ordered 3 pieces and mounted one on my AAN. It's runing ok.

http://www.hallsensors.de/Hall-Vane.htm

[RS2]

Excellent... I'll look into that. Thank you !

MG

[UrS4boy]

Looked on the forum a link to a german seller who sell only the defectuous part of the hall sender for 10 times less than price of the oem entire piece.
I've ordered 3 pieces and mounted one on my AAN. It's runing ok.
http://www.hallsensors.de/Hall-Vane.htm

Those Hall Effects vane senders are the same ones that were the subject of at least one group buy here and as now (as of last week) sold by EFI Express (US$10 plus shipping (postage)). Click HERE

The one you want from the German dealer is the CYHME301 which is the replacement for the Siemens HKZ101 that you would get on a new bracket from the dealer.

With the CYHME301 (or BBHME301 from EFI Express) you can use this procedure written by Imquattro (Nate P) on my home forum to install the new sender on the bracket and on the engine:
Click HERE

which is part of my G40 Hall sender post:

http://forums.quattroworld.com/s4s6/msgs/22580.phtml