Unusual Lag and cutting out

[S2central.net]

All good info except the 3B Ecu doesn't get VSS input.

[20Vcqdriver]

I cant find my pin out for the ECU but on the AAN im pretty sure its pin 50. On the five speed box it receives the signal from the centre pin on the hall effect unit which screws in to the side of the gearbox. With the other two connections being a 12v+ and an earth.

I cant remember the wiring configuration on the 2 pin sensor for the six speed but its similar to the above. When you have it connect to Vag Com you should see the speed rise when driven. As i understand it this then applied the appropriate map for over run until the car becomes stationary..

It certainly seem to make a difference to my car, but my car probably exaggerated the problem due to the light bottom end.

Unfortunately due to me using the mechanical speedo in mine, the hall sensor in gearbox doesn't exist.

[20Vcqdriver]

All good info except the 3B Ecu doesn't get VSS input.

Ah that's that sorted then

[20Vcqdriver]

OK, bit more info. The timing is fine. However I have the rev counter attached to the coil on mine as its the type 85 with analogue instruments and have noticed today that the rev counter drops to zero momentarily and jumps up again, if it happens at a junction the engine cuts out but will start straight away and when this happens the car runs badly for a while afterwards but will sort itself out and perform better afterwards but with slower responses. Getting codes read saturday but suspecting the Hall sender starting to fail or some other sensor that cuts coil pulses to zero. Any other ideas areas prior to Saturday.

[prj]

ECU is resetting.
Check all grounds and supply to ECU.
Pull codes and make sure you don't have any errors on the trigger sensors.
Bad grounds or bad triggers will cause it to reset like that.

As for your other issues - bad maf or big boost leak. Pressurize your intake.

[20Vcqdriver]

ECU is resetting.
Check all grounds and supply to ECU.
Pull codes and make sure you don't have any errors on the trigger sensors.
Bad grounds or bad triggers will cause it to reset like that.

As for your other issues - bad maf or big boost leak. Pressurize your intake.

Cheers! That got me thinking last night .... I have for some time been using these resettable Auto fuses and so swapped all the ones used for the Engine last night for normal spade fuses, drove to work this morning and no problem. Could have just disturbed something so will keep monitoring but had one fail on me last year (Have one across the battery disconnect switch to keep clock etc going). Left the battery completely disconnected once at work to let ECU reset for an hour or so and see if everything returns to normal. Fingers crossed

[20Vcqdriver]

Well it's getting worse, Going tonight to get codes read but car cut out on me altogether this morning and wouldn't restart for 2 mins then fired up and managed to drive back home without any sign of a problem. One thing that seems to be common to this issue is that it only happens on cold damp mornings....

[prj]

Probably an electric wiring problem somewhere.
Or it could be the Hall Sensor.

But yeah, pull the codes first, so you know what the problem is before swapping out parts.

[20Vcqdriver]

OK I had codes read yesterday and several codes were stored. Inc G40 Interrmittent short to ground, G4, G28- no signal, G50 Idle switch. The common thing to these is the earth, so hope to get time to look at this today. Might just add an earth to the Diagnostic earth wire that is common to these too and see if it makes a difference.

[prj]

OK I had codes read yesterday and several codes were stored. Inc G40 Interrmittent short to ground, G4, G28- no signal, G50 Idle switch. The common thing to these is the earth, so hope to get time to look at this today. Might just add an earth to the Diagnostic earth wire that is common to these too and see if it makes a difference.

Bodge alarm!

[20Vcqdriver]

Bodge alarm!

temporary trial fix... honest. The earths for these are all wrapped up together in the loom and it's a mammoth task to get to the junctions.
If this does fix it I'll have to unravel the whole loom until I find the offending junction and redo it.... Argh!

[20Vcqdriver]

OK cut out again but this time only codes for G4 and G28 came up. Also noticed that it only cuts out when at tickover, though you can 'feel' its not running smoothly at part throttle/steady speed, as if timing or fuelling is wrong or that its occasionally missing a spark on a cylinder. Slowly applying throttle in say 3rd has it hold back for a second and can feel additional vibration until you open the throttle a bit more and it then accelerates away ok. WOT is not an issue either.... weird

[20Vcqdriver]

Spent few hours yesterday and again today taking off every connection under the bonnet, cleaning contacts and refitting. Removed and cleaned up engine earths and re-made this time soldering them as well as crimping, Removed glovebox and checked all the wiring to the fusebox, pulled all plugs and refitted checking for any signs of loose wires or corroded / overheating connections. Drove the car afterwards and it at least drove smoothly again, though on way down road whilst coasting and it cut out again. HAve changed G28 and MAF that have made no difference and strange thing is that according to what I have read if you lose any of the G40, G69, G28 whilst engine is running it should stay running but will not start again afterwards. Beggining to wonder if an issue with the ECU itself or plug connections (Only thing left to look at)

[driftin jo]

I know exactly what is wrong with this car !
It doesn't work properly

[prj]

If you lose G4 or G28 during operation your car will instantly die.