Fried my Motronic! Experts (e.g. Roger04RT, Ian J Hartley) input welcome!

Are you sure you are on DC scale ??

And have you tried adjusting it down to 0.38 ~ 0.4 volt??

I think that it may be user error rather than system error because It would likely not run at that value

I haven't tried to adjust the TPS, as it's almost certainly set correctly and the crazy readings (which I'm sure of by the way, I know my way round electrics and meters, though your point is well made and I would probably have said the same to someone else:) )
 
Try removing fuse 5 for a while and allow the Motronic to reset.

Not saying it will have any affect, but it will do no harm.

Then check your TPS voltages again. 5v across pins 1 and 4 is the TPS at maximum range which you would see with an open throttle.

Yes, I didn't remember to put in my first post, but resetting the Motronic made no difference.

TPS voltage readings don't vary significantly with throttle opening and are close to zero (20mV-ish) between pins 1 & 4, but close to 5v (4.7-4.9-ish) between pin 1 and battery -ve.
 
Unplug the TPS and see if the bike will start and run. It should do using the motronic in built fixed values.

:nenau

Never thought of that, but it does start and run with the TPS connected. I'll ghive it a go, but I'm pretty certain the TPS is OK (resistance readings between pins 1 or 3 and pin 4 vary with throttle openings and are in the region of 900-1800 ohms)
 
My thinking is that pin 22 on the Motronic should be 'earthy': i.e. internally connected to earth via a diode or resistor or something, but it's acting as if it's floating - no connection to anything. I've checked resistance from pin 22 to Motronic earth and it's open circuit.
 
Try disconnecting the Air temp sensor. That gets a 5v feed from the motronic on the brown/blue wire and if it’s shorting inside, it will feed that same voltage across to the TPS pin 4.
 
Try disconnecting the Air temp sensor. That gets a 5v feed from the motronic on the brown/blue wire and if it’s shorting inside, it will feed that same voltage across to the TPS pin 4.

I'll check that out, good call. I'll do the same with the oil temp. sensor, which shares the return pin 22 with the TPS & air temp sensor.
 
Try disconnecting the Air temp sensor. That gets a 5v feed from the motronic on the brown/blue wire and if it’s shorting inside, it will feed that same voltage across to the TPS pin 4.

Tried that, no dice. The 5v on pin 4 of the TPS seems to be just coming through the TPS from the live pin 2 - in fact, relative to battery -ve, all 4 pins are around 5v

I've ordered a used Motronic from Motorworks, on a sale or return basis. We'll see in a few days.

Thanks for all the input, some of you (and perhaps me) will expect my next post to be asking where to buy a Hall sensor :D
 
Have you tried running it with the PCIII bypassed? I had a power commander fail many years ago which caused a huge amount of head scratching and resulted in similar issues.

Hope you get it sorted:thumby:
 
Have you tried running it with the PCIII bypassed? I had a power commander fail many years ago which caused a huge amount of head scratching and resulted in similar issues.

Hope you get it sorted:thumby:

That was my first thought, but I can't get the wideband lambda sensor out of the exhaust without likely damaging it :blast

I did speak to Dynojet about the problem and I confirmed that the PCIII is merely 'piggybacking' the TPS signal and it can't alter it in any way, so I don't think it's the PC. It's 3rd on the list though, after the Motronic and Hall sensor :rolleyes:
 
That was my first thought, but I can't get the wideband lambda sensor out of the exhaust without likely damaging it :blast

I did speak to Dynojet about the problem and I confirmed that the PCIII is merely 'piggybacking' the TPS signal and it can't alter it in any way, so I don't think it's the PC. It's 3rd on the list though, after the Motronic and Hall sensor :rolleyes:

Don't worry about the exhaust lamda - just disconnect the PCIII piggy back wires at the throttle bodies and see if it runs. It'll take about 20 seconds to find out:) :thumb
 
Don't worry about the exhaust lamda - just disconnect the PCIII piggy back wires at the throttle bodies and see if it runs. It'll take about 20 seconds to find out:) :thumb

Tank's off and wiring's hanging out all over the place ATM. I'll try that when I get it back together, but won't it run sick without a lambda connected?
 
Tank's off and wiring's hanging out all over the place ATM. I'll try that when I get it back together, but won't it run sick without a lambda connected?

For the purpose of diagnosing your issue it'll run fine with no exhaust lamda connected - if it is the PCIII that's the issue. Let us know, and good luck.
 
Tank's off and wiring's hanging out all over the place ATM. I'll try that when I get it back together, but won't it run sick without a lambda connected?

It'll run perfectly normal..... about 10-12 years ago it was the flavour of the month to run the bike with the lambda unplugged....

Don't ask me why, I have no idea why owners want to feck around so much with their bikes with no discernible benefits.
 
It'll run perfectly normal..... about 10-12 years ago it was the flavour of the month to run the bike with the lambda unplugged....

Don't ask me why, I have no idea why owners want to feck around so much with their bikes with no discernible benefits.

Cheers Mr S, I'll give it a go if the replacement Motronic doesn't do the trick. TBH, the PC was the first thing I suspected, so I called them to ask if the PC could possibly change the TPS voltage.
 
Cheers Mr S, I'll give it a go if the replacement Motronic doesn't do the trick. TBH, the PC was the first thing I suspected, so I called them to ask if the PC could possibly change the TPS voltage.

I see you're still barking up the wrong tree .. :D Formulating a diagnoses based on a wrong diagnoses.
You've got yourself in a diagnoses chain. Not good. :D
 
I see you're still barking up the wrong tree .. :D Formulating a diagnoses based on a wrong diagnoses.
You've got yourself in a diagnoses chain. Not good. :D

Woof! So explain to me why the TPS voltage is so far out? My first thought was Hall sensor, then I read on here that a dodgy TPS could cause exactly the symptoms I am seeing, then measuring the TPS voltage is indicating something up with the Motronic. What else could cause that? :nenau
 
Woof! So explain to me why the TPS voltage is so far out? My first thought was Hall sensor, then I read on here that a dodgy TPS could cause exactly the symptoms I am seeing, then measuring the TPS voltage is indicating something up with the Motronic. What else could cause that? :nenau

Why would a dodgy TPS affect the rev counter..

TPS units send out many and varied signals under testing using a meter, and usually different on each bike.
And mostly completely different when reading voltage on a meter compared to the percentage readings on a GS-911. Strange old things.

Why i gave up using a volt meter testing a TPS.....

That's not to say your TPS isn't fannying around. :D
 
Why would a dodgy TPS affect the rev counter..
It wouldn't, of course - that only happened once, during the first start, which was what buggered up whatever it is

TPS units send out many and varied signals under testing using a meter, and usually different on each bike.
And mostly completely different when reading voltage on a meter compared to the percentage readings on a GS-911. Strange old things.
Yes, I got that by reading around. The 'recommended settings' vary wildly and the best advice I have seen was from Roger04RS, which essentially says no need to adjust it as long as it's in the 'sensible' range of about 0.3 to 0.5 volts, the Motronic will deal with it. I haven't adjusted the TPS and I don't intend to, but no way should it be reading nearly 5 volts on all 4 pins...

Why i gave up using a volt meter testing a TPS.....

That's not to say your TPS isn't fannying around. :D

I think the TPS is fine, but pin 22 on the Motronic has gone open circuit. It may well be that the Hall sensor's fucked as well, but that wouldn't explain the TPS voltage I'm seeing.

Also, the Motronic's coming on sale or return, which I'm sure I couldn't manage with a Hall sensor. :)
 
The Motronic arrived today and I have just fitted it. There's some tidying up of wiring to do and I need a new O-ring for the inlet tube which I removed from the throttle body to get at the wiring behind it, then I need to refit the tank etc. before I can take it for a test-ride.

However, I checked the TPS voltage and it's now at the expected 370mV. I believe this proves my thread title, but I may yet need a Hall sensor as well.

The source of the initial problem seems to have been a loose connector on the battery negative :blast

I'll get it reassembled and ridden tomorrow probably, so we'll see. I'm hoping it's sorted.
 
Sorry for the belated finale, I got distracted and the O-rings were on back-order, so I only got around to finishing the job today.

The bike's now running fine, the only small glitch is it's ticking over a little fast, probably due to me balancing the throttles whilst the Motronic was sick.

I'm glad I didn't jump to conclusions re Hall sensors and it has occurred to me that, in order to bollix the Hall sensors, surge/spike voltage must pass through the Motronic first... :nenau

I'm going to look into fitting some kind of spike/surge/back-EMF suppressor to prevent a recurrence. I'll post here if/when I figure this out.

Anyone want a buggered Motronic to play with? :rolleyes:
 


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