Advice please

[Bonehead]

Does anyone know if:

The wiring loom on all montegos is standard? What I want to know is that I want to fit rear leccy windows and was wondering if the cables to the switches and from the switches to the windows are already present or if I have to run new cables.

Secondly I have just been to the scrappy and got a new speedo with rev counter on it. When I removed it, it only had the taco cable conected and the rest where electricasl connectors. Mine doesn't have a rev counter but if I install the new speedo will it work or is there another cable I have to run?

Thanks

Nath

[Austin-Rover]

From trying to fit a Rev counter in my Maestro - you will need extra wiring for it to work as those electrical connectors that are already there have nothing to make it work. Not sure how to get it to work, but it can be done and i am sure someone will post how to do it...

:)

[Mat_C]

I'm sure the wiring is already there for a tach. I shoved a dash unit with a rev counter from a montego into my C reg mk1 dash 1.3L maestro - worked fine!

[F690OTF(RIP)]

It appears that most Maestros have the wiring for a rev. counter even if they don't have the rev. counter itself. However, there do appear to be a few exceptions to this. The base models (Special & Clubman in latter days) appear to be missing one wire from the coil to the edge connectors where the instrument panel slots in. I think the Haynes manual tells you that this wire should be white/black or vice-versa. It you want to do it properly, then you can solder an appropriate wire onto the track behind the edge connector. On the other hand, you can simply stuff the bared end of the wire into the edge connector and it will be held there when you put the instrument panel in. I have a feeling it's the left-most contact, but don't take my word for it. I can't remember how we worked it out, but it can't have been that complicated. Then feed the wire through the bulkhead and crimp the appropriate spade connector onto the other end to mate with the vacant blade connector on the coil. Ours has been working like this for the best part of a year now.

Hope this helps,

Peter.

[Austin-Rover]

Well, that explains why it didnt work in my Maestro - with it being a Clubman...

:rolleyes:

[e692wtt]

I had to wire in a 'fly lead' on my Monty 1.6L (88MY E-reg saloon) to get the rev counter to work, even though the wiring 'appears' to be there...

Not a great difficulty to overcome, though.

[H48HPE]

normal rev counters on petrols work off the coil but obviously a diesel doesnt have a coil. i think diesels take a reading off the alternator but im not sure. did any diesel montegos come with rev counters? if not id suspect that wiring may be a bit more complicated.

andy

[e692wtt]

'Diesel rev counters' use an AC feed off the Alternator, ie from the Alternator's output before it is 'rectified' into DC. This is via a seperate Alternator connection (extra) to the standard one that petrol-engined models use, and only applies, I think, to 'diesel-specific' alternators.

[Bonehead]

Bunged in the spare dash with rev counter and it works but. It goes straight to 7000 revs and it only goes up to 8000 so if you rev it a touch it goes of the scale. Does anyone know how to cure this??

Thanks

Nath

:banghead:

[H48HPE]

What car did you take it off i.e. petrol or diesel? perhaps the two are calibrated diferently

andy

[D813YBB]

One other thing to remember is there were 2 designs of instrument pods: one type with the rectangular reset button for the tripometer and a second type with the round reset button. The rev counter should work but try to replace like with like.

Regards
Martin

[Bonehead]

It was off a petrol version, but the trip reset swith was round which is the same as mine.


Thanks

Nath

:banghead:

[H48HPE]

just my way of thinking but it might make sense, the petrol rev counter will be sensing a pulse of current every time a plug sparks. meaning one pulse to one revolution. im not sure how the alternator method works but if it was sensing each time the current alternated it would sense two pulses for every revolution if it were geared 1:1 but it isnt geared 1:1 its geared to go faster than engine speed. I dont know how faster but lets say 1:4 for sake of argument. that would mean the current alternates 8 times per revolution compared to 1 pulse of current from a coil. therefore a rev counter calibrated to read from a coil but was reading from an alternator would read 8 times higher than it should

just a possible solution

andy

[Simon]

Yes, you need a divide by 8 circuit (simple electronics) to run a rev counter from a petrol model from the diesel's "W" post on the back of the alternator. I have a circuit diagram somewhere showing how this has to be done and if i can find it I'll post it up.

[MGTurbo]

I can confirm about the pulse rate being different, as i tried a petrol rev counter on my diesel. It would idle at 6000rpm! Does also mean the wiring is there for the diesel's, but some playing around would be needed.

Gareth

[derek mclean]

Rev counter first, as it's the easiest. Most of the cars have the WB wire in the harness from the engine compartment to the instrument connectors. Far as I know all the instruments are interchangeable. You just need to find the other end of the WB wire and connect it to the coil neg. You should find there is already a WB wire on it anyway, to allow the amplifier or ECU to switch the coil. I even found the WB wire in my diesel when I fitted an M16 into it, so that bit of the job was dead easy.

Elec windows are a bit more complex, but as long as you get all the wiring from the same car as the winder mechanisms it should be straightforward enough to fit it all in. Forget about trying to integrate it into the original harness. Just run it separately. More mundane cars definitely don't have the window winder wiring built in. And it can look daunting, with big multi-plugs, but if you can get the whole harness from a car with elec windows and remove all the unnecessary wires you should be able to put it all in. Or you could change the whole harness if you want, but that could create other problems of compatibility if you are unlucky. If you are clueless about electricla systems don't bother trying it, but if you are reasonably handy with wire-cutters, solder and tape it shouldn't be too hard. Having said that, when I got mine two years ago the previous owner had tried to do this and made a hash of it, and I've never got round to sorting it out, so I have a manual window for the drive and a non-working electric one for the passenger.

Derek.

[E_T_V]

Originally posted by Simon
Yes, you need a divide by 8 circuit (simple electronics) to run a rev counter from a petrol model from the diesel's "W" post on the back of the alternator. I have a circuit diagram somewhere showing how this has to be done and if i can find it I'll post it up.

Certainly be interested as I'm trying to install a digi dash to a diesel and the revcounter will be driven by the same input I presume..

The speedo will be the interesting bit :D

[J199 HHG]

Diesels were never fitted with rev counters.

Do do this, make the following circuit:

http://www.cowdery.demon.co.uk/tacho.jpg

and you can use a petrol tacho on a diesel montego. Worked fine for me, and I flogged the electronics to Alex from Aachen (3litre) when I scrapped the car.

The only catch is that the red line is marked at 6000, and the diesel will never reach that!!!

The circuit is easy to make, and compact. You don't need a circuit board or anything, you can solder all the components directly to the bottom of the IC, and put the lot in a little poly bag.

[e692wtt]

A couple of thoughts...

1. The Diesel engine won't reach 6000 rpm, but it tells you *exactly* what the engine is doing.

2. My best mate was amazed to see Monty's Rev Counter working when he saw the '4-pack instruments' - assumed I'd fitted the '4-pack' and thought "s*d it" with regards to the rev counter... it's good to see al the Instruments in a car working properly.

3. You've lost me with the diagram, but as Monty is a 1.6 I'm not fussed. A 'magic black box'?

4. Why is a mk I Montego's Rev Counter calibrated in, roughly, increments of 167rpm??? Only a minor point, watch the needle move etc., I know...

[monty_estates]

Sorry to bring up an old thread. I'm almost an owner of a Montego TD, and want to fit a Rev counter panel.
I know some late LDV Convoys have rev counters, and the dash is still the Montego style panels, does anyone know if its got a Diesel like red line (i.e, about 4750rpm)? I guess is would work on the Monty?

Can anyone explain the diagram a bit better too, although I can solder etc, I am not very good with wiring diagrams.

[threelitre]

I've fitted Chris' electronic circuit to my father's TD and it works fine. The rev limit on his car is - according to the emissions test read out at about 5200rpm, so why not leave the 6k red line? Power trails off much earlier, so you should usually not end up on the red line...

Regards,
Alexander

[monty_estates]

so why not leave the 6k red line? Power trails off much earlier, so you should usually not end up on the red line...

Regards,
Alexander


Hi Alexander

Long time no see!!! I did pass Aachen a couple of months back, however, it was late, and I was trying to see if the speed limiter in my 330d was acurate to the speedo or true GPS so couldn't stop!!! :)

Why not leave it at 6k?? well, i'm a perfectionist!!! hehehehe

[threelitre]

Neil,

indeed - it's been some time that you have been here. And how accurate is it? I've found all speedos of modern cars (post 1980 for me) to be out more or less (Maestro/Montego -> wide off the mark, Rover 216 -> best so far), though everyone of my old things (Maxi, 1300, 1800) I've put the GPS in, I was unable to tell a difference between speedo and GPS :)

Regards,

Alexander

PS: Why be more perfectionist with the tacho then most manufacturers? Quite a few Diesels will never touch the red in real life - on the other hand, the rev-limiter of my Honda engined 216 is deep inside of the red area ;)

[monty_estates]

Alexander,

The speedo showed 163mph (262km/h) when the speed limiter stopped acceleration, GPS was 155mph (250km/h) dead on. I think it would have gone to 160mph given a bit more time, then again, it does have 231ps and 500Nm torque.... just saving for a BMW fitted chip!!! :)

My expience of redlines is a bit better than yours. My Leon TDi's red was at 4750, but it would rev reluctantly to 5800, and after being chipped, easily to 5000. Our 330d revs to 5000+ if you dont snatch 2nd gear fast enough, and the 320d is an Auto, so it is imposible to rev past 4300 (both have 4800 redline).

My 218iS revs to 7200 limiter, especially when it had the gas flowed head, now on my 216i (which also revs to 7200 easily now), both have a 6800 limit.

I may be in Koln for wine tasting in October, I will let you know if we travel at normal hours!!

[threelitre]

Just call in if you are close...

Regards,

Alexander