ABF engine died

[h100vw 0]

Fingers crossed for you Roger :mrgreen:

[goodridge 0]

So far as i can see no-one has yet mentioned the Digifant ECU relay. Can't remember the no. of the top of my head but definitely worth checking.

[RW1 0]

Yes, that was the next check.

 

The relay is in position 3 and marked 109. Part number 357 906 381A which happens to be the same as the VR6 ECU relay.

 

The check is above 9 volts or above on pin 87 of the relay when it switches over with the ignition on and there should be battery volts always available to pin 30. Should be possible to get the relay to sit high on the panel and carefully put the meter prob on the relay leg BUT be careful not to short the earth to it while on voltage. There is no fuse protection of the supply to pin 30!

 

Substitution of the relay is safer option.

[Roger Blassberg 0]

Thanks, I'll try that. I now have a multi meter, (and a VR6 from which to borrow a relay !!).

 

By the way, the CPS was not the problem but at least we now have a pristine one and a new ignition switch.

 

Best wishes

 

RB

[Roger Blassberg 0]

the relay in position 3 on the Passat is part nr. 165 906 381, marked 30, and has a different pin arrangement to 109. I tried 109 but it buzzed madly and I pulled it out again. Any further thoughts? If not I'll do the meter test.

 

Best wishes

 

RB

[Roger Blassberg 0]

Pin 3 CPS connection to engine ECU 33 is 1.5 ohms max

Check pin 1 goes to pin 33 on the engine ECU and resistance less than 1.5 ohms.

RW1, just to double check, do both of these, the CPS and the Hall sender, go to pin 33 on the ECU.

 

There was a good voltage between 1 and 3 on the CPS wiring with ignition on.

 

Pin 3 on the CPS most definitely has no connection to pin 33, so if it is supposed to then that is the fault. I trimmed the insulation on the wire to pin 3 and tested that for a connection to pin 33, to check for a poor connection at the CPS plug and it was open also.

 

Pins 1 and 2 were exactly as you said

 

The ECU relay passed the tests.

 

There is a good voltage at the Hall sender wiring.

 

I'll be glad when I've had enough of this......

 

Best wishes

 

RB

[RW1 0]

OK, I think I understand what you have found so here is the confirmation.

 

Check Hall Sender pin 1 (Wire colour – Brown with white stripe) is going to ECU pin 33 (Wire colour - brown with blue stripe).

 

The ECU – pin 33 (Wire colour - brown with blue stripe ), CPS – pin 3 (Wire colour - brown with blue stripe) and the Intake Air temp - pin2 (Wire colour - brown with blue stripe) earths all meet in the loom. If all three of these wires are the colour stated, then they should all connect together and each should connect to the car’s chassis earth. Do this with ECU, CPS and Intake Air Temp plugs separated from the components.

 

Cos you have 12 volts across the Hall Effect Sender and CPS connector pin 1 & 3, therefore it looks like the ECU has lost earth on pin 33. So just to check……….

 

If ECU pin 33 does not go to chassis earth and the wire is the colour stated above, then there is a break in the loom between the ECU and the internal loom earth joint. Firstly I suggest you check the back of the ECU plug in the covering cap for a wire break. In the loom somewhere all three wires are joined and go via 4th brown wire to earth out of the loom binding onto a stud mounting, not far from the engine connector. So look down the loom from the large engine loom connector on the left hand side around the engine block area. This earth stud should connect to ECU pin 33 with the ECU, CPS and Air Temp plugs separated from their component connections.

 

Given the relay substitution, ie. not the same part, if the wire is BROWN WITH A BLUE STRIPE on pin 33, AND ONLY IF IT IS, make a jump lead into the back of the ECU connector and take pin 33 to earth nearby. Quick check between CPS pin 3, and chassis earth and ECU pin 33 to make sure the earth circuit is now there. Now see if the engine will start up and run. Remember your battery may be too low in voltage for the ignition electronics to work (below 10 volts while the engine is turning on the starter is about the low voltage limit, so the battery could do with a charge if it is a lower than 10 volts while starting).

 

If all is well with the jump earth lead, you have a fault in this wire in the loom probably at the internal 4 way joint. The only way to find that is a small bulge and hope it is the joint in question.

 

Next question is why has it happened???

[Roger Blassberg 0]

OK RW1. This has been above and beyond the call of duty, especially at 2 o'clok in the morning !! Many thanks.

 

I now have no more time to sort this out as I am away for a couple of weeks, fortunately not dependent on the Passat, so I'll pass it on to my local specialist with your notes.

 

It sounds as though I could do with a decent set of wiring diagrams, particularly for the pin connections to the plugs including the ECU. Where can I find these?

 

I am slightly confused by one thing; if there is a battery voltage between pins 1 and 3 of the CPS plug, how is it that there is no connection on that plug to pin 33 on the ECU?

 

Your last question is very perceptive - and as yet unanswered....

 

Lastly, as I said at the beginning, there is a spark but apparently no fuel being admitted to the injectors - I assume that is because the CPS is seeing no rotation of the engine and is shutting down the supply.

 

Best wishes

 

RB

[RW1 0]

I am slightly confused by one thing; if there is a battery voltage between pins 1 and 3 of the CPS plug, how is it that there is no connection on that plug to pin 33 on the ECU?

 

Simple, pin 33 is ECU's earth and it isn't connected to anything hence why there is no circuit to the CPS pin 3. But you get volts on CPS pin 1 & 3 cos the earth on pin 3 of CPS is connected to earth.

 

The ECU – pin 33 (Wire colour - brown with blue stripe ), CPS – pin 3 (Wire colour - brown with blue stripe) and the Intake Air temp - pin2 (Wire colour - brown with blue stripe) earths all meet in the loom. If all three of these wires are the colour stated, then they should all connect together and each should connect to the car’s chassis earth. Do this with ECU, CPS and Intake Air Temp plugs separated from the components.

 

 

Looks like this....... rough diagram, ignore the full stops. Connections represented by dash lines & vertial bars. 4 wire meet in centre of diagram. The leg from centre to ECU pin 33 is most likely broken causing open circuit from CPS pin 3 to ECU pin 33. You see voltage cos its across pins 1 & 3 and earth on CPS pin 3 IS connected to earth.

 

 

ECU pin 33 ]--------|

.............................|

.............................|

CPS pin 3 ]----------|----------[ Brown wire earth to chassis

.............................|

.............................|

Air Temp pin 2]---- |

 

 

 

.

[Roger Blassberg 0]

just to conclude this.

 

I was confused by the numbering of the pins in the ECU multiplug, and all wires were ok to there from the CPS.

 

It turned out to be a broken wire to the fuel rail.

 

Thanks to all, especially to RW1 for burning the midnight oil on my behalf.

 

Best wishes

 

RB

[h100vw 0]

Finally. 8)

 

Note to self, 'check fuel rails first'. :lol:

 

Gavin