137 replies to this topic

[doctorfrag]

if youve not checked, the earthing on the ECU and chassis?

[Goldfinger]

You raise an interesting point, there is the eye connector which fastens to the ECU mounting bolt, I have checked the ECU and when this is connected the ECU is earthed. Once the ECU is earthed then this should be correct?

 

Thanks

[doctorfrag]

Thats correct, that would earth the ECU to the chassis, however for the circuit to complete, the chassis needs to be earthed back to the battery.

 

There are two chassis earthing points front and back. The front one is underneath the n/s chassis member beside the battery. You have to have the battery out to access it.

 

Also do check the earthing cable to the battery, after a recent exhaustive check for starting problems and flickering display, I found out the two little screws (not blots) on the earth side of the battery had worked loose!

 

Joe

[Goldfinger]

Hi thanks for that you mention the other Back earthing to the chassis, where is that so that I have done a complete check

 

Thanks

[doctorfrag]

Earthing points 

 

I hope this helps 

[Goldfinger]

Thank you.

 

So I have now realised that I have wasted £180 on a rebuilt ECU as there is still no throttle response and I dont have my Op Com device as I sent it back due to being rubbish.

 

As things stand the ECU replacement has done nothing to correct the Pedal position sensor. So if I have continunity from the pedal to the ECU pins and also to the TB what else do I need to do ?????

 

I am now approaching thoughts of breaking it for spares as I think it would be more valuable

[doctorfrag]

There's a vx220 wiring loom on ebay at the moment?

 

please check earthing at the engine also

 

Joe

[speedster]

Thank you.   So I have now realised that I have wasted £180 on a rebuilt ECU as there is still no throttle response and I dont have my Op Com device as I sent it back due to being rubbish.   As things stand the ECU replacement has done nothing to correct the Pedal position sensor. So if I have continunity from the pedal to the ECU pins and also to the TB what else do I need to do ?????   I am now approaching thoughts of breaking it for spares as I think it would be more valuable

Who rebuilt the ECU? If it had water ingress I am surprised it could be salvaged.

[Goldfinger]

Bluehawk Electronics.

[siztenboots]

I wonder if a fault could have just damaged the new ecu in the same manner as the previous one, ie. output driver

[Goldfinger]

I hope not !!!!!!!!!!!!!!

[4cTech]

A couple of thoughts , when you say continuity are you ohms checking or beep testing . Are the pedal and throttle feeds shared with other sensors that maybe consuming the voltage maybe disconnect them. Are there any wiring diagrams on the net I'm sure to go through this pain when I try and start mine in say 2025

[TheHood]

HERE is the circuit digram (1041 to 1046) 

 

Throttle pedal circuit is intendant of any other sensors.

[4cTech]

I see , think I would try running shielded cable before a loom , so throttle sensor 1 has a resistor to drop it I guess to half the other one ?

[FLD]

Thank you.

 

So I have now realised that I have wasted £180 on a rebuilt ECU as there is still no throttle response and I dont have my Op Com device as I sent it back due to being rubbish.

 

As things stand the ECU replacement has done nothing to correct the Pedal position sensor. So if I have continunity from the pedal to the ECU pins and also to the TB what else do I need to do ?????

 

I am now approaching thoughts of breaking it for spares as I think it would be more valuable

 

Why was your op-com rubbish?  They are cheap and the software is a bit of a pain to install but they generally work OK.  You will find it invaluable for problems like this.

[Goldfinger]

Hi The Op Com was reading the faults but not telling me what the fault code is. Chap who lent me his OP Com for half an hour showed throttle pedal sensor position and variable voltage from the pedal. I could not get that with mine. So I have ordered a new one

I have performed a beep test from the pedal to the ECU and also from the ECU to the Throttle body, I have checked the pedal voltage and I am getting two 5 volt readings these alter as you depress the accelerator

 

Unfortunately this is the limit of my circuit testing ability, I never did pay that much attention in the physics lessons.

 

 

 

 

[speedster]

If the circuit (no shorts), connectors and sensors are good the only thing left really is the ECU hardware and software. Maybe get somebody to reflash the ECU or did they do that already after repair. If the ECU is wonky anything plug into it is going to operate or read wonky.

[4cTech]

Doing an ohms test is better as it may pick up a corroded wire better , also did you check the wires to earth and battery ie shorted to another wire . Did you put the probe in the connector this can open a terminal up and add problems you didn't have . I find taking each individual terminal out of the plug and trying it on the male part to see if it grips ok the only way to tell for sure but you do have to have a decent set of terminal removal tools I Get to do it lots on alfas :-)

[TheHood]

It's almost a cliché to sat it, "must be a bad earth mate" seems to apply providing the people that fiddled with you ECU knew what they were doing. http://www.onallcyli...-ground-issues/ Seems to cover how to trace this.

Edited by TheHood, 30 November 2014 - 05:01 PM.

[CHILL Gone DUTCH]

How old is your battery ?? Have you checked voltages Engine sitting Engine started Also starter motor and alternator can do strange things

Edited by CHILL Gone DUTCH, 30 November 2014 - 05:07 PM.