Club 80-90 Forums

Hi to all.
 I'm struggling to figure out what the cause of a severe overfuelling problem is on my previously good running  2.1 DJ engine.
A few months back, the fuel pressure regulator failed (petrol in the vacuum side of the regulator) and loads of fuel was going in to the cylinders and getting into the oil in the sump, I guess by going past the rings.  replaced with a 2nd hand one which cured the prob for a while, but then the over fuelling problem returned. fitted a brand new one thinking this will definitely cure it, but no, the cylinders are drowning in fuel, it's dripping from the exhaust and also diluting the engine oil again. I don't think there was anything wrong with the 2nd hand one, it holds vacuum when tested.
I have replaced all the vacuum tubing, checked that the throttle position switch is working, the idle speed valve is getting power and buzzing, 2 relays in the box above coil are clicking when ign. turned on and the fuel pump relay clicks off after a few seconds as normal, tested all injectors for drips when pressured up and they're fine, I just renewed the temp 2 sensor and noticed the connector has a bit of corrosion on one terminal so will replace it with one from a scrap but good loom I have. have checked as many ECU plug tests as I can find and all seem ok apart from pins 1 + 7 with ign on should produce battery voltage, mine is showing 0.5V
Should this battery voltage be there with just the ign on, or when cranking the engine does anyone know?
The van has power steering and there is a switch on the pump which I think affects either timing or fuelling when under load, could this be a suspect? Could the ECU be the problem?
I'm getting nowhere with this problem and don't know if it's an electrical problem or vacuum related, though applying vacuum to the regulator using a brake bleed pump rather than the line from the plenum doesn't reduce the overfuelling either. If I remove the fuel pump relay, the engine will briefly run on the fuel in the cylinders, but when the relay is replaced it throws in way too much fuel.
Any ideas as to possible causes and what to check would be great, I'm tearing out what little hair I have over this ongoing problem
Many thanks.

give me a bell 01691648011

1 & 7 is Hall control unit AEG type (there's a Fairchild version, too, with a different test).
Voltage with ignition on should show battery voltage or slightly less to 1.5 volts. Check 7 & 25 for ground connection on OHMS. Should read zero.

I have had one DJ ecu here that has failed and now just locks the injectors open and floods the cylinders.
They do go wrong.

So do l. Sitting in my garage. One faulty ECU..
Messing around with the Digijet system on my camper trying to sort out minor pressure loss (injector leak) recently. Just to see, l connected my old faulty ECU and got same issue. Flooding cylinders with fuel.
Is it the four injectors batch fire with constant power and the delivery is interrupted by earth?

Many thanks for the replies,
Cheers Aidan, will message you about what time will be best to give you a call.
Numpty question, but how do I tell which type hall sensor system is fitted to know if the pin 1 + 7 test is relevant?
Can the ECU's be tested, apart from swapping for a known good one if all other checks are ok?

Worth mentioning, if at some point you need to replace your ECU manual and autos have different ECUs.
Auto part No 025 906 021 E   Manual part No 025 906 021 F

silverbullet wrote: ↑07 Feb 2022, 14:17 I have had one DJ ecu here that has failed and now just locks the injectors open and floods the cylinders.
They do go wrong.

I should be able to repair this for you if you need it. It'll likely be some corrosion inside, rotted through the gate resistor on the injector mosfet and allowed it to go "half on" til it cooks itself.

Just to recap, on switching ignition, fuel pump primes for about one second then switches off?
Assume you have AEG version. Check ECU earth (7) to left cylinder head for clean connection. Next check ECU multi connectors 1 & 7 with ignition on. Approx. battery voltage minus 1.5 volts.
Thick earth lead between wall and left cylinder in good condition too
Lastly.
Ignition off.
Injector check through ECU multi pin connector
11 & 7
12 & 7
23 & 7
24 & 7
Approx 16 OHMS

PAS will not impact upon this issue. The two PAS connectors simply increase revs a bit to compensate for additional load on engine when turning steering wheel.

Thanks a lot for the replies,many thanks to Aidan for sharing his knowledge of the system on the phone. I will do a few more tests at the weekend, and if I have no luck, look at getting the ECU looked at and repaired.

Any news?