Rovergauge - speedo input
Discussion
So I have been having problems with the idle occaisionally dying as I approach junctions for a while and finally got round to running Rovergauge on it to see what is going on.
The log is showing not showing any input from the speedo sensor so I thought OK - put in a replacement. I bought a refurbised replacement and put that in but still not getting any speedo indication.
So my next thought is some sort of cabling issue, does any one know how I can check the cabling from the speedo control unit down to the ECU?
Is it possible to bench test the speedo control unit?
Any other ideas why I might not be seeing a speedo signal?
The log is showing not showing any input from the speedo sensor so I thought OK - put in a replacement. I bought a refurbised replacement and put that in but still not getting any speedo indication.
So my next thought is some sort of cabling issue, does any one know how I can check the cabling from the speedo control unit down to the ECU?
Is it possible to bench test the speedo control unit?
Any other ideas why I might not be seeing a speedo signal?
Not sure if these are the same but 97 Chim has signal from sender to module. I believe that signal passes straight through the module to the speedo.
You don't mention the speedo not working so I've assumed it is.
To produce a suitable signal for the ECU the module needs a supply and earth so I would be checking those first. The Chim is supplied from the same fuse as all the instruments so that fuse must be good or you would be complaining none of your instruments work.
The signal goes into ECU pin 6.
Steve
You don't mention the speedo not working so I've assumed it is.
To produce a suitable signal for the ECU the module needs a supply and earth so I would be checking those first. The Chim is supplied from the same fuse as all the instruments so that fuse must be good or you would be complaining none of your instruments work.
The signal goes into ECU pin 6.
Steve
Yes - Speedo is working fine
Any idea which are the eart and supply wires to the module?
Hopefully it will be obvious when I take the dash out (again)
hopefully it is something as simple as supply or earth.
Another question - I have the Steve Smith speedo transducer fitted which connects to the speedo through another box that has a test switch on it. When I switch to test mode it auto generates a speedo signal so the speedo shows about 50mph. I assume if I switch this on then it should also feed the speedo control box and hence the ECU which would be easier for testing than taking the car out for a drive.
Any idea which are the eart and supply wires to the module?
Hopefully it will be obvious when I take the dash out (again)
hopefully it is something as simple as supply or earth.
Another question - I have the Steve Smith speedo transducer fitted which connects to the speedo through another box that has a test switch on it. When I switch to test mode it auto generates a speedo signal so the speedo shows about 50mph. I assume if I switch this on then it should also feed the speedo control box and hence the ECU which would be easier for testing than taking the car out for a drive.
Only 4 connections- 12 v, ground, input and output. The input is the tiny signal from the transducer that it then converts into a fixed output of between 30 and 50 mph when the input is about 3 mph. I was going to say check the transducer air gap as this affects the output voltage the unit sees, but if it was the gap Id expect the unit to burst into life at speed as the transducer voltage rises. Not a unit thats easy to bench test.
Seems like the replacement speedo unit is faulty too. 
I was able to check the continuity from the plug down to the ECU and that was good too. The Speedo box must be receiving an input signal because my speedo is working and there is 12v and earth connectivity.
Annoyingly I also seem to have picked up some other issues. I'm now getting a fault on one of the lambdas and also a low fuel pressure warning, the long term and short term also seem to be at -100% so it seems to be overfueling.
I was able to check the continuity from the plug down to the ECU and that was good too. The Speedo box must be receiving an input signal because my speedo is working and there is 12v and earth connectivity.
Annoyingly I also seem to have picked up some other issues. I'm now getting a fault on one of the lambdas and also a low fuel pressure warning, the long term and short term also seem to be at -100% so it seems to be overfueling.
Hmmm now I don't know what to think.
After the ECU reset when I was checking the continuity on the speedo feed the long term trim started at 0 then both sides long term trim went to -100
Went back again as I wanted to look again at the fault codes and trim levels. Let it idle for a few minutes and then the long term trim on one side wen to -94 with the other at -90, but left it a bit longer still at idle with some prods on the accelerator because I was bored. Now the long term on one side has moved from to +74 and the other is now at +18.
I assume there is some sensor that is reading erratically to cause these large swings.
I cleared the errors and none of them have returned.
After the ECU reset when I was checking the continuity on the speedo feed the long term trim started at 0 then both sides long term trim went to -100
Went back again as I wanted to look again at the fault codes and trim levels. Let it idle for a few minutes and then the long term trim on one side wen to -94 with the other at -90, but left it a bit longer still at idle with some prods on the accelerator because I was bored. Now the long term on one side has moved from to +74 and the other is now at +18.
I assume there is some sensor that is reading erratically to cause these large swings.
I cleared the errors and none of them have returned.
So a bit of follow up on this.
The replacement speedo box appeared not to show any speedo signal in rovergauge. Steve kindly lent me his known good one and with that plugged in and using the android version of rovergauge on my phone I was getting a speedo signal.
So swapped back to the replacement unit this evening and that is also now giving me a signal using the android app. I will try again with my laptop version of rovergauge sometime and see if possibly I have a problem with that. It's a linux build of rovergauge that I compiled myself and there may be a problem with that otherwise it would point to an intermittent type issue
The replacement speedo box appeared not to show any speedo signal in rovergauge. Steve kindly lent me his known good one and with that plugged in and using the android version of rovergauge on my phone I was getting a speedo signal.
So swapped back to the replacement unit this evening and that is also now giving me a signal using the android app. I will try again with my laptop version of rovergauge sometime and see if possibly I have a problem with that. It's a linux build of rovergauge that I compiled myself and there may be a problem with that otherwise it would point to an intermittent type issue
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