Club 80-90 Forums

Tony
Digifant and Digijet ECUs are not compatible, different pin outs and controls
there is a label on the ecu with part number and they say Digijet or Digifant on them, post part numbers up to check
don't swap them if not the same part number
2wd auto is different ecu as well

Thanks Aiden,

The numbers on the ECU

025 906 021F

Digijet

5WP6 001

Are like for like units hot swappable?

Cheers,

Tony

syncrosimon wrote:I would pull one side of the fuel injectors and see if you have fuel there. Could be an ecu fault. I dont know what fuel regulators do when they fail but might be worth checking fuel pressure.

Thanks Simon,

Checked that and has fuel when working properly but when the fault kicks in there's nothing. My Nephew lent me his fuel regulator and same symptoms so I don't think it that either.

Still having the intermittent problem re petrol pump (new) sometimes doing what it should when ignition switched on and other times not. Relays good. Not too sure about the ignition amplifier/hall control box. Did some tests re Bently and readings good but one reading on T7 not too sure about cos Bently did not specify reading for Bosch unit.

Tony

Have you checked the ignition switch. Faults here can cause low voltage to the ECu which may cause your problems. See if you can measure the voltage at the ecu when it is not working.

Double check the wiring and try and source a spare ECU.

I will read through the pro training manual and see if there is a fault that switches off the injectors.

Hi, maybe I have similiar problem,
https://club8090.co.uk/forum/viewtopic.php?f=2&t=76363

its in garage now, getting checked out. The pump WAS doing its job when turning to they key, before starting. But nothing was happening besides that. Then suddenly (coinciding with having headlights on) it did try to start, starter motor turning over but then realise the pump was NOT doing its job when turning the key and the engine wont start.

Maybe my ECU is broke then, giving symptoms above

or can someone tell me for sure that the sound u hear from somewhere( could be engine bay or could be from under the floor) when turning the key, is definitely the pump initialising itself?

E D I T: WAS IGNITION COIL

Hi Simon,

Dissed battery to take block connector off ECU do do a Voltage test across terminals 1 and 7 of connector and reconnected battery.Should be just under batt voltage according to Bently but I only got 0.11V which doesn't sound right. Does this point to anything?

Hi Epi

I posted some of this stuff to your thread yesterday (but obviously didn't!!) I'll see if I saved it.

Tony

Hey, Ive got my bus back, it was a dead ignition coil. Simply replaced and is now starting up again. See my thread for the details

Good for you.

My coil is ok. If only it had been that.

Tony

Demon tweeks do a great little oil filled fuel pressure gauge, these are indispensable for trouble shooting. This one needs an in line adapter to screw it into.

http://www.demon-tweeks.co.uk/Motorspor ... /1539/2448" onclick="window.open(this.href);return false;

I have a cheaper E-bay version which I can screw into an adapter fitted in the fuel line. This is very helpful for trouble shooting, as will show up leaky injectors, pump problems, and fuel regulator problems. All for 15 quid.

Tony, do a resistance check on your earthing for the ecu. This has to be spot on.

just digging out the pro training manual, it wasnt where I thought it was, and i have lost the on line link for it.

There is a way of measuring the voltage in the injector wiring to see if you have an ecu output when cranking, think it is in bently.

If the injectors are not firing, but you are getting spark that must be a fault in the ecu or the injector wiring.

Found the manual.

VW says for no start hot or cold but with spark test the following.

1. fuel system (pressure test, volume test, and fuel pump electrical operation)
2. Injector system ( Leak down test, component test ie individual injector ohm test, and wiring test between the injector and ecu plug.)
3. Air flow sensor test (http://www.youtube.com/user/syncrosimon ... Tn8dyzn9a4" onclick="window.open(this.href);return false;) you can do this with the engine not running but ignition on

You can feel that the injectors are operating by holding one when cranking and feeling for the clicking.

Hi Simon,

On point 1: only the pressure test hasn't been done but I swapped out the regulator and same prob. Fuel pump is brand new and delivering as spec.

On point 2: All wiring between injector and ECU connector good and injector spray patterns good. Is leak down test the one where no more than 2 drops per minute? If yes then this is ok too.

On point 3: This was one of the first things and ok.

Do you know what the voltage between Ter1 and 7 of ECU connector should be with ignition switched on? I am reading less than 1V and according to Bently should be just under 12V.

ECU earth perfect. Tested it from its heatsink and the alternator body. Zero ohms

When testing for power at injectors using lamp we couldn't get it to light but we got a changing voltage when cranking using a meter!

Where I'm lost is that it's all good when functioning

Thanks for all the help,

Tony

If all the above ok, the VW says replace ECU!!!!

Nice and helpful.

The units get cracks in them apparently which show up under change in temp conditions as intermittent problems. Sounds like that could be it. All the other things you have checked either work or dont, but the ECU can be temperamental so that must be it.

Simon.

You can swap them out real easy. Best to remove the rear left tail lamp assembly to help with access to the screws, only 2!!

This is it.



As Aidan say's most are interchangeable.