Because the 4x4 ecu doesn't like seeing 4000rpm and no PAS pressure.
Of course there is a third cheap option. Fit a 4x4 reset switch as described on cavweb
M5 junction 3..........................yes but there is an easier way!
Does that mean you are willing to take on the job!
Andy K your inbox is full
Hopefully this should be sorted soon as I have just read in a thread that Andy K is going to give me a call to arrange a time to meet up so he can have a look at my car
good luck you 2...
i'm sure andy k will find the fault
New to this one, been busy - sticky to say the least.
Taking a simplistic approach. You have not indicated which model of car you have. Has it got twin airbags?
Both versions of the 4x4 ECU require an input from the engine management ECU. If the rev counter is not working it would tend to suggest the 4x4 symptom is a result of the original fault rather than a cause.
My guess is if you can find out why the rev counter is not working the 4x4 ECU will sort itself out.
One puzzling thing is that you say you get a 'clunk' driving it out of the garage, after starting.
If you started the car and the 4x4 light was on before you moved off, the 4x4 is not engaged - so what is the 'clunk'? - or did the light come on at the same time while you were moving out.
According to the GM Fault Code listings, if the 4x4 ECU is without the engine running input it should produce a FC 31 for the 4x4 ECU. In both variant cases the rpm signal is seen as being outside the 8k range.
In the pre-twin A/Bs variant, with the engine running and the 4x4 plug off the ECU you should see 12V at Termianl 2.
In the Twin A/B model you should see 12V at terminal 10 with the engine running and plug off the 4x4 ECU.
Please say if the 4x4 has any fault codes stored.
Thanks for the reply Richard, my car is a 93 (K) Calibra 4x4 turbo.
There are no fault codes stored and yes there is around 12 volts (cannot remember exactley) at terminal 2.(Green wire)
Also if I leave fuse 19 in I can hear the accumalator(black ball with a white ring) whoosh & click if I press the brake pedal, then as soon as I turn out of my garage I hear/feel the clunk.
And if I have fuse 19 removed I do not get the whoosh/click when I press the brake pedal or the clunk as I drive out of my garage.
What do you think??
What do you think?
well its fecked init lmaoOriginally posted by Damian666
What do you think?
Sir, please step away from the car
Originally posted by Damian666
I hope not
Only joking mate! can't be major whatever it is
Sir, please step away from the car
PHEW!.....................................was panicing for a bit thenlmao
What you guys have to realise is that I cannot even service my own car yet the closest I get to cars is when I sit in the drivers seat, anything under the bonnet is a mystery to me.
Put it like this, if one of your headlights went you guys would get out the toolbox and sort it but me on the other hand I would just book it into my local garage (see what I mean now) and just to prove how ***** my local garages are when I found out how to check the fault codes they were calling me Mr. Vauxhall.
Since then they phone me for the fault code lists (cowboys) that is why this problem is so BIG to me but to you guys it is just a small wiring fault
Going to LETlmao Andy K have a look at the weekend
Yes my brake lights work fine!
Astra Dan, what has my brakes got to do with it
damian, just seen you post on cavweb, you say your green wire at the coil isnt connected, mabye this is the cause as this supplys the feed for the dash, seeing yours is a K '93, your speedo should be working of a cable, soooo, your rev counter will be working of the green wire from the coil.
mabye this is the problem, maybe not but it worth a go
It could be but if I shine a light on the coil there does not seem to be a connection for it!
Thanks for the ideas lads I will do some more checking at lunch time
Well I had a look at Damian's car today.
Had a look in the footwell at the green rev signal.
Was stuck at 13v. Not working correctly when the engine running.
13v was not coming from the motronic ecu.
Disconnected the dash. Still 13v.
Disconnected the 4x4 ecu. 13v went away. So I blamed the 4x4 ecu for causing the problem. (but I found out later I was wrong)
Anyway still no output from the motronic ecu. So ran a new wire from the coil and got the revcounter working.
Because I thought Damian's 4x4 ecu was faulty I fitted a spare one of mine. It was faulty. Fitted a 2nd spare one of mine. All working fine when the car stationary.
Damian took the car out and the 4x4 light comes on when you get to about 4000 RPM Bugger !
Fault Code 31 RPM stored !
The diag plug wasn't in it's holder so prayed that was the problem but it wasn't.
So in desperation I put Damian's 4x4 ecu back in. Took the car out and the same thing. 4K 4x4 trips.
The speed MPH signal was working on the fuel comp.
So I checked the MPH signal at the 4x4 ecu while rolling the car. Fine. (because that can cause 31)
Checked RPM signal at 4x4 ecu fine.
While I was there I did a check of all the 4x4 wires. Fine.
brake switch fine, pressure switch fine, solonoid fine.
So it's got me !
All I can think is that the 4x4 ecu doesn't like using the RPM signal from the coil ? Has anyone done my "green wire mod" and the 4x4 has worked ok ?
Humm if that is the case RDS won't be very happy! LOL Although he does have a different type 4x4 ECU.
So I suggust Damian get his Motronic ECU sorted in hope and try the 4x4 ecu with that.
In the mean time I unplugged the 4x4 ECU and bypassed it.
I connected black/green to white/black (using black link wire) so that the 4x4 would work until you brake. (rather than ecu controlled only above 16mph)
and connected brown/green to brown/black (using brown link wire) so that the 4x4 light indicates you are in 2WD. (ie when you brake or if something fails).
Fuse still disables 4x4.
So Damian has his revcounter and 4x4 working for now so is a little .
he then took me for a blast.
So Richard as the 4x4 is disabled everytime you press the brake that will slightly reduce life. Damian only uses it as a weekend car so should be too bad. What bits are likely to wear more ?
Andy, I can't see that was going to be sorted over the internet, so well done for that.
Although I have have no Haynes in front of me I cannot see there is anything to wear.
If anything, you are disconnecting the txb more often than not. All you have done is made the txb disconnect below 16 mph which it would not do on a standard system - hardly cause for concern methinks.
Looks like the only downside is a dash alarm everytime to put your foot on the brakes!
i had this once one of the earth wires on the fuel rail had broke but it didn't look like it " the copper wire had broke but the insulation was complete "so i didn't find it till i pulled on it then the insulation broke cus thats only softish rubber/plastic
Thanks Andy K
I was wondering, will my 4x4 still disengage if other problems occur like TX box overheating???
What I am trying to find out is will my car still be able to store fault codes and still disengage if there are problems???
Did a quick search on Mig/Cavweb & Club Calibra and it looks like the green wire mod is a big NO NO
It seems like the ignition module will give a signal to the rev-counter but instead of the voltage rising when the car is driving it is dropping to the point that at 4000rpm the voltage is that low that the 4x4ecu will disengage the 4WD.
I have been in contact with EDS(Arno) about this and he states that I should not connect it to the ignition module, he said I should connect it direct to the coil
Will this work Andy????