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        General >> Problems >> Rev counter not working.
        
(Message started by: Bikerdon on Jun 23^rd, 2012, 8:01pm)

Title: Rev counter not working.
Post by Bikerdon on Jun 23^rd, 2012, 8:01pm

Hi all, the rev counter on my 2.0l 16v scorpio has stopped working, although when I disconnect the battery and then reconnect it the needle swings round as it should, so where does it take its signal pulse from and are there any diagrams here that I can use to trace the fault? Also not sure which fuse takes care of that circuit. Also having a problem with the battery discharging completely overnight sometimes, battery has been tested and is good, also fuseboxes have been stripped and rebuilt so no issues with moisture in them. Thanks.

Title: Re: Rev counter not working.
Post by leewar on Jun 24^th, 2012, 12:11am

Is the light permanently on in the glovebox. Been a common cause

Title: Re: Rev counter not working.
Post by Jonnycab on Jun 24^th, 2012, 2:32am

Rev counter (as far as I remember) takes it's reading from the alternator....this could also be the reason the battery is losing charge overnight.....well not necessarily overnight, but insufficient charge from the alternator to the battery when the car is used would cause the battery to lose it quite quickly over the space of a few hours when the car isn't being used :)

Have you checked the battery terminal voltage with a multimeter when the engine is running ?....should be between 13.8-14.2 volts. Anything less, then the alternator is probably faulty ;)

Title: Re: Rev counter not working.
Post by Simmo on Jun 24^th, 2012, 7:42am

If you look at Fault finder (http://www.fordscorpio.co.uk/faultfinds.htm) and scroll down to 'electrical' you may get the answer. Select 'voltage' which will take you to the detail of how to check the voltage from the instrument panel. :)
You may also find This (http://www.fordscorpio.co.uk/electsystemtest.htm) useful.

The wiring diagram Here (http://www.drich2422.ukfsn.org/SCORPIO_WIRING%20DIAGRAMS/ELECTRICAL_SYSTEMS/CHARGING_SYSTEMS.pdf) clearly shows that the alternator IS the source for the rev counter as Jon says. :)

Title: Re: Rev counter not working.
Post by Bikerdon on Jun 24^th, 2012, 10:58am

Hi again all, I have had the charging system checked out by my local motor factor guy who did the full range of checks on the battery and charging system, it is all working correctly and the battery itself is in tip top condition, I'm beginning to think that when I refitted the rebuilt main fusebox to the car that I might have disturbed the loom going to the instrument panel when I was reconnecting all the leads under the dashboard. I guess that is my next job to check out but any other suggestions will still be appreciated.

Title: Re: Rev counter not working.
Post by gozz on Jun 24^th, 2012, 12:23pm

My V6 cars received the tacho signal from the alternator,but I was under the impression that the 16v engines received it via the ignition,possibly the EDIS.

Title: Re: Rev counter not working.
Post by Tompion on Jun 24^th, 2012, 12:27pm

Beat me to it :)
In fact I think it was you who proved it by running the engine without a belt.

Only from the alternator on the 12v & diesel.
See here in the table for 3 pulses at the bottom of the page:
http://www.fordscorpio.co.uk/instreset.htm

“Shows the input frequency of the engine speed sensor, updated every second. This check allows the engine speed signal coming from the alternator, (12V V6, 2.5 TDi) or the EDIS (all others)”.

Title: Re: Rev counter not working.
Post by Tompion on Jun 24^th, 2012, 12:49pm

on 06/24/12 at 07:42:53, Simmo wrote:

The wiring diagram Here (http://www.drich2422.ukfsn.org/SCORPIO_WIRING%20DIAGRAMS/ELECTRICAL_SYSTEMS/CHARGING_SYSTEMS.pdf)

Glad you posted that Mike as I was looking for Snoopy's other diagrams, there are ones here that don’t appear to be on the link in the how to do things section.
I have a copy of the breakdown of the diagrams on my computer but didn’t know the link to post for others.
Anyone wanting to understand the diagrams better see the symbols PDF here:
http://www.drich2422.ukfsn.org/SCORPIO_WIRING%20DIAGRAMS/

Title: Re: Rev counter not working.
Post by Bikerdon on Jun 24^th, 2012, 6:23pm

Well folks, I still have no rev counter, but along the way I now have no more flickering airbag light problems after soldering up the faulty pins on the instrument cluster, and also a problem I had with the o/s dipped beam not working is solved too, it was a dodgy dim dip relay that was causing that so at least some good news. Another thing I have noticed today when working under the bonnet is that one of the cooling fans seems to have a mind of its own even with the heater blowers switched off and the engine temp low, Should it do this or not? I do know that the fans are controlled by the large green relay behind the o/s headlight as disconnecting it stops the fans.

Title: Re: Rev counter not working.
Post by Simmo on Jun 24^th, 2012, 6:44pm

on 06/24/12 at 18:23:14, Bikerdon wrote:

Another thing I have noticed today when working under the bonnet is that one of the cooling fans seems to have a mind of its own even with the heater blowers switched off and the engine temp low, Should it do this or not? I do know that the fans are controlled by the large green relay behind the o/s headlight as disconnecting it stops the fans.

According to This (http://www.fordscorpio.co.uk/coolfans.htm) both should work together. :)

Title: Re: Rev counter not working.
Post by Bikerdon on Jun 24^th, 2012, 7:04pm

Thanks Simmo, will check the fans out, I was just unsure if any should be running with the A/C switched off and the engine cold, seems they should not so obviously another issue to look at. Ho-hum!
Ok, have checked the fans out and they are both running ok now, I still think they are running when they shouldn't be though.

Title: Re: Rev counter not working.
Post by Bikerdon on Jun 24^th, 2012, 8:20pm

Ok, next issue I have noticed is that when reconnecting the battery even with the ignition off, keys out etc, and nothing switched on at all it seems like the injectors are energising as I can hear them click open and a short hiss of fuel go through them, I'm sure that cant be correct!

Title: Re: Rev counter not working.
Post by Mike H on Jun 25^th, 2012, 11:25am

This is starting to sound like a rotten wiring loom problem

Title: Re: Rev counter not working.
Post by Bikerdon on Jun 25^th, 2012, 5:25pm

Hi all, well I have some further developments in the saga, I replaced the ignition lock relay this morning and this has cured the injectors energising when reconnecting the battery, the cooling fan issue was an intermittent connection at the green relay due to the connector not locking in properly, I now also have fully functioning reversing lights, passenger dipping mirror and the auto dim interior mirror is working properly too, so at least I have resolved a lot of other problems along the way. I still have no rev counter as yet although it did decide to work for a while this morning on the way to the shops so it seems it is just a dodgy connection somewhere, I will check all the contacts at the EDIS module and the ignition switch next. In the meantime if anyone has any other ideas they will be greatly appreciated. Thanks.

Title: Re: Rev counter not working.
Post by Simmo on Jun 26^th, 2012, 6:28am

I take it that the relay you refer to is No:21 in the Auxillary fusebox?. Interesting to note the 'connection' to the reversing lights, passenger and interior mirror. ;) Are the reversing lights standard or an aftermarket unit?.

Title: Re: Rev counter not working.
Post by Bikerdon on Jun 27^th, 2012, 1:15pm

Hi again, I have some more developments in the battery discharge saga. Today I connected my multimeter through the battery positive lead as described in the fault finding section, immediately finding a current drain of almost 1.8 amps. So I started pulling fuses one at a time to see when it would stop, removing the 30 amp fuse, no: 44 in the auxiliary fusebox, (cooling fans) stops the current drain. Anyway to play safe I then disconnected the fan relay and also the fans themselves and then replaced the fuse, surprisingly the current drain is still there at almost 1.8 amps, so my question now is what other circuits if any does fuse 44 supply. This was done with the ignition switched off and key out, all doors closed, so no other things draining power.

Title: Re: Rev counter not working.
Post by Simmo on Jun 27^th, 2012, 5:06pm

According to This (http://www.drich2422.ukfsn.org/SCORPIO_WIRING%20DIAGRAMS/FUSES_and_RELAYS.pdf) from Snoopy's wiring details it seems to be the main engine control!. ;)

A further look produces This diagram (http://www.drich2422.ukfsn.org/SCORPIO_WIRING%20DIAGRAMS/ENGINE/23%20DHOC%20AUTO%20IGN%20SYSTEMS.pdf) which appears to relate to the cooling fans!. Scroll to page 28. ;)

Title: Re: Rev counter not working.
Post by Bikerdon on Jun 29^th, 2012, 9:12am

Hi again, and thanks for the extra info Simmo, well I decided to play safe and rebuild the battery side fusebox, no problems with that as it is all clean and dry. What I did do as I was reconnecting it was to keep my multimeter connected as suggested before to see which of the connectors underneath relates to the current drain, it seems to relate to whatever is connected by connectors C421 (white) and C321 (green), any suggestions folks!

Title: Re: Rev counter not working.
Post by Simmo on Jun 29^th, 2012, 11:07am

Can you not relate these connectors to the appropriate fuses/relays?. Ive tried to work it out from the site without success!. ::)

Title: Re: Rev counter not working.
Post by Mike H on Jun 29^th, 2012, 1:34pm

If it's 2.0L 16V then it's this diagram, page 24:

ENGINE CONTROL 2-0L 16V (https://skydrive.live.com/?cid=eb36f845ea9b8fb6&id=EB36F845EA9B8FB6%21146#cid=EB36F845EA9B8FB6&id=EB36F845EA9B8FB6%21176)

1.8A suggests a resistance to ground of about 6.5 Ohms.

If you've been messing with the fusebox which fuse F44 is in there could still be something wrong with it causing the short. Perversely, of course, it's not enough to blow the fuse.

E.g. in the fusebox, what is P1, "busbar" ?

Or, a pair of shorted wires could do that as well. E.g. wiring to the fan relay.

Title: Re: Rev counter not working.
Post by Bikerdon on Jul 3^rd, 2012, 1:04pm

Hi again folks, I have another development in the overnight discharging battery saga, there are two large bolt together connectors in the engine compartment drivers side, I believe the rear one relates to the fuel shut off loom but dont know what the front one relates to, anyway disconnecting the front one of the two results in the current drain problem dissappearing completely so the issue seems to be with this part of the wiring, does anyone know which components are related to this connector as I am struggling to decipher the scorps wiring diagrams. Thanks.

Title: Re: Rev counter not working.
Post by Simmo on Jul 3^rd, 2012, 1:37pm

Where are these connectors?. Do you mean the ones on the inner wing either side of the power steering reservoir?. ;)

This diagram and chart (http://www.fordscorpio.co.uk/23loomsauto.htm) may help. C110/C112 ;) There is also the large connector to the ABS controller?. ;)

Looking back to page 1 you mention the injectors and if you look at the diagram which Mike H suggested C110 features in that circuit?.

A further thought.Is there any sign of power steering fluid leaking on to the connectors?. If so separating the connector and giving them/it a good clean may sort the problem ;)

Title: Re: Rev counter not working.
Post by Bikerdon on Jul 3^rd, 2012, 7:24pm

Ok folks, made some progress today, rev counter issue has been tracked down to a general earthing problem and resolved, I am fairly sure I have cured the battery discharging issue as well by methodically replacing relays and cleaning connections and fuseboxes, (will wait till tomorrow morning to find out for sure), but using my multimeter as before, the current drain from the battery with everything shut down is now only about 70mA.

Title: Re: Rev counter not working.
Post by Bikerdon on Jul 4^th, 2012, 9:44am

Oh well! how WRONG was I! Battery discharging issue is still here, Aaaargh! It is the fuel pump relay circuit that seems to be the cause this time, pulling it out stops the current drain immediately, I can hear it click off as I remove it from the circuit. This with the ignition off, keys out and everything else shut down,

Title: Re: Rev counter not working.
Post by Mike H on Jul 4^th, 2012, 1:32pm

Still appears to keep coming back to damp in the fusebox(es) causing shorts and tracking. And possibly wiring elsewhere ~ 70mA is still not low enough IMO; well a relay coil could account for much of that, yes.

Title: Re: Rev counter not working.
Post by Mike H on Jul 4^th, 2012, 1:34pm

PS: all this rain and damp we've been having lately won't help at all so I wouldn't be too overly surprised TBH

Title: Re: Rev counter not working.
Post by Bikerdon on Jul 4^th, 2012, 3:04pm

I'm starting to think it is an earthing issue after looking at the grounding diagrams pdf's as the faults all seem to be related to a particular grounding point, the main repeating issue seems to be the green fan relay behind the headlight as it has started to click frantically when the battery is reconnected, unplugging it solves this and seems to prevent any other relays associated with the fault such as the fuel pump relay from actuating as well, also it stops the current drain too. And as I discovered the rev counter fault was ground based, (solved by cleaning the two earth wires that bolt to the bodywork behind the n/s headlight) I think my next checks should be the various earthing points under the bonnet, I may try to strip the fan relay too.

Title: Re: Rev counter not working.
Post by Mike H on Jul 5^th, 2012, 12:01pm

Could be!

Title: Re: Rev counter not working.
Post by Bikerdon on Jul 5^th, 2012, 11:42pm

Well folks, the battery discharge problem is solved, it was related to the cooling fan circuit and the green relay behind the headlight, I still have not resolved why this is causing the problem yet but after checking and cleaning all the accessible earthing pionts on the car and completely removing the relay from circuiit all is well again. The mystery I have to solve is that when the relay is reconnected it triggers the fuel pump relay and causes the cooling fans to run very slowly as well, this is with the ignition off or on, dismantling the relay shows nothing obviously wrong with it though. I should have suspected something when I first noticed the relay connector was not locked in but just sitting partly in its recess in the relay, (perhaps an issue for the previous owner?) anyway it was after I had fitted the connector properly that the problems began showing up. I will find the full solution eventually as I now know which circuit and wiring colours to work through and will let everyone know the outcome. The car seems to run quite happily without the fans and with no signs of overheating in any driving conditions. Thanks for all the help and advice so far.

Title: Re: Rev counter not working.
Post by Simmo on Jul 6^th, 2012, 8:54am

The only thing that I can think of which may help is the route of the wiring. IIRC from many moons ago there can be 'issue' with the wiring which runs across the car from offside to nearside near the radiator etc. If the wiring to the relay seems to come from that area I'd have a look in that vicinity. :)

Title: Re: Rev counter not working.
Post by Mike H on Jul 7^th, 2012, 1:10pm

I concur, still sounds like funny wiring

Title: Re: Rev counter not working.
Post by Bikerdon on Jul 15^th, 2012, 12:38pm

Well Mike, it seems you were right about the funny wiring, my scorp started acting wierd again on wednesday night, then wierder on thursday and finally became undriveable on friday, (misfiring, cutting out, smoking exhaust etc) so I decided to investigate the loom along the front of the engine and along the n/s wing. Along the front was all good but along the n/s wing! WHAT A MESS!! insulation broken away on all the signal leads and many others, one main power feed wire completely broken and some others just hanging by a thread, also looks like water-antifreeze mix had got in at some point from the heater hose, (not while I've owned her though) so that explains the discharge problem I've been having. Anyway after a 12 hour loom rewiring and repair marathon yesterday, lots of new cable, soldering and heat shrink tube, grazed knuckles and an aching back, she is now running properly again, fans and rev counter working as they should, and no battery discharging either. I just hope thats the end of this saga at long last.

Title: Re: Rev counter not working.
Post by Mike H on Jul 15^th, 2012, 2:34pm

Well there ya go! Congratulations ;D

Just goes to show tho don't it.

Nasty stuff for wiring, that coolant.

Title: Re: Rev counter not working.
Post by Simmo on Jul 15^th, 2012, 4:00pm

Good to know you're sorted. Congratulations :)

Title: Re: Rev counter not working.
Post by Bikerdon on Jul 31^st, 2012, 10:47pm

Hi again all, thought I would just let everyone know that since my marathon rewiring session on the main loom my scorp is still behaving itself perfectly, it hasn't missed a beat, all electrical systems are working better than ever since I've owned her, (I bought her on ebay for the princely sum of £56 six years ago :)), so it seems like the loom damage had also been part of the various electrical gremlins that have come and gone over that time. Economy has improved dramatically as well about town, and she is much smoother and also very much perkier in the acceleration department too. I really dont think I would have persevered with this problem without the help and advice of all you great people on this site, so a very big thank you to you all from me. Also many thanks to Leewar for posting a fuel shut off loom out to me even before I had paid him for it.

Title: Re: Rev counter not working.
Post by leewar on Jul 31^st, 2012, 11:19pm

Glad to be of service ;)

Title: Re: Rev counter not working.
Post by Mike H on Aug 1^st, 2012, 12:36pm

Wunderful. ;D Good deal for £56 then.