Mixng dash clock manufacturers and other electrical issues

[tony_ack]

Hi there

I've just taken the plunge and got myself a 1992 8v mk2 runout. It runs sweet for it's age/mileage, and the body is very good, but it suffers from a few niggling electrical problems, one of being the dreaded MFA/rev counter problem. Most of the MFA functions work, except for the MPG (reads 99.9) and the Oil temp (suspect this may be a dodgy sensor, as most other people with MFA problems don't have this - I'll change it next time I drop the oil and filter). I've tried most of the 'quick fix' tricks, none of which have worked for me (removing fuse 21 with the engine running and replace, removing 21 and 16 for several minutes while switched off, etc.), so it looks like I may need to invest in some new clocks to get the rev counter working. The MPG is nice to have, but the rev counter is pretty important to me.

I would prefer to keep the original speedo, showing the original mileage, and it should be pretty easy to swap the speedo into a new set of clocks. However the current clocks are Motometer, and the only single pin ones I can find at the moment are VDO.

Is it possible to mix and match the clocks - using a VDO instrument panel with a Motormeter Speedo?

Then again, there is a rattle/whirring coming from behind the clocks at speeds above 60/70 (definitely behind the clocks, as tapping the side of the clocks cures it momentarily) - could the MFA actually be okay, and the issue be a loose plug from the rev counter rubbing against something? Perhaps the MPG problem is caused by something else?

One of the previous owners has done quite a lot of work on the electrics it seems - and as a result a lot of small stuff isn't working:
-Dash lights - I think this is a loose/poor connection in the lights switch/slider, as tapping it seems to re-light the dash.
-Handrake/brake warning light - this wasn't working - I took off the lamp, and it's not even connected. If I read my wiring diagrams correctly, I should be looking for grey/black wires into a connector plug - can anyone confirm?
-Glovebox light not working - haven't had time to investigate this yet
-Boot light not working - again, not even connected, and I haven't had time to look at which wire to look for - does anyone know what colour it is? The interior light works okay, though even that is intermittent
-Front fog lights not working - haven't even begun to investigate this. I'm going to wait to get it up on a ramp so I can see what's plugged in to the lights themselves (if anything)

There are quite a few electrical mods - it appears to have Xenon headlights, which are pretty good actually, even if they aren't original. There's also some electrical circuitry fastened to the bottom of the door pockets, which I suspect is something to do with the speakers. It wouldn't surprise me if the rear speakers have been replaced too, though thankfully they're not attached to the nice original parcel shelf! I'm just hoping that the guy who fitted the mods hasn't 'borrowed' from other parts of the loom...

One last thing - the car seems to be running a bit cold (about 1/4 the way up the gauge - it's never been past halfway, even in traffic). What's more, there is cardboard under the bonnet vents and behind the front grill to stop heat escaping. I suspect a dodgy thermostat - is there anything else that could cause this? We're changing the cambelt in a couple of weeks anyway, it may be worth doing the thermostat at the same time.

Thanks for your time

[nealey]

You can mix the dash clock manufacturers, if you were really patient you could even completely strip down the dash clocks and change the faces over on the rev counter so although the actual units will be vdo the clock faces will have motometers on them (the vdo clocks are also supposidly more reliable)

As for the mpg reading, make sure the vacuum hose is connected on the back of the clocks and check its connected in the engine bay, also make sure it has no splits etc

[JimR]

Yes, mixing clocks is no problem, my 90 spec 8v came with  140mph motometer clocks with knackered rpm and mfa, bought a set of 140mph VDO clocks and swapped the speedo to show my original mileage (72k  ) and have had no problems.
My oil temp sender was knackered too, cost about £15 from VAG, pound per part must be the most expensive thing on the golf! I'll dig out the part number for you if ya like.

Mine also runs cool like yours, 1/4 way on gauge for normal, between 1/3 and 1/2 for traffic, have had no ill effects so far so wouldn't worry too much about it.

[nealey]

Under normal driving my temp gauge used to always be around half way, after replacing a leaking radiator and the 2 coolant unions on the head as well as a coolant flush and new expansion tank it never moved from the first block as something managed to jam my thermostat open, after replacing that, the housing and the seal as well as new coolant again the temp gauge only gets to half way in traffic and normally sits around a quarter on the gauge so as said dont worry about it

[tony_ack]

Thanks for the advice everyone!

The clocks I've found are 120mph ones, as opposed to the 140mph ones currently in the car. I guess since I'm going to swap for my own speedo anyway, and the speedos look like they're cable driven, this shouldn't be a problem. I'll investigate the vacuum hose when replacing the clocks too, though hopefully this will be cured with the new (and working!) MFA. I'll also take chance to look for loose cables behind the dash to see why various things aren't connected.

I'm picking up an oil temp sensor tomorrow - this will go on when I do the oil/filter change in a couple of weeks.

I'm not too worried about the engine running cool - it does operate above cold at least - it would just be nice to have a warmer heater! I did consider that there may be a problem with the heater matrix too, but I'm not getting any of the usual tell-tale signs like steamed up windows, wet carpets and the smell. I'll just give the thermostat a go and see what happens - I'm not going to waste too much time investigating the problem beyond that.

I'm just looking forward to getting stuck in to the repairs and servicing now!

[mattkh]

- it would just be nice to have a warmer heater!

Hi
Get rid of the bypass valve or clean/replace.

[tony_ack]

Thanks - I've done a bit of research into the cold heater problem, and saw that the bypass valve can cause problems. Another job added to the list!

The heater isn't completely cold, it just isn't very warm - I've never needed to turn it down from the maximum heat setting. I guess that the valve may not be completely gone - it just may need a good clean. Also, the fact that the car runs a bit cool anyway probably doesn't help. I'm saving up all the cooling system jobs for when we do the cambelt change - hopefully this will give us better access to the thermostat, and there's no point draining the system more than we need to!

I'm still tearing my hair out a little over the electrics. I've started to investigate some of the little niggles now..
The glovebox light has no bulb, so hopefully a new bulb will sort it out. Does anyone know what type it is? I noticed that the wiring diagrams show that there should be a red and black wire going into the bulb holder, but there's only a black one and brown one.

I've found what I think are the wires for the boot light. They've been taped up, and the brown/white wire looks like it's broken. I only had a quick look, so I haven't worked out where it's broken and why it was taped up.

I haven't had chance to look at the front fog lights, but I noticed that they should have a 10A fuse. I've checked and a 15A fuse is plugged into the fusebox for the fogs. I guess the guy could have just run out of fuses, or is a 10A fuse prone to overloading?

I think I'm going to look at the rear speakers and the HID lights that are installed, to see if they're 'borrowing' wires that should belong to the things that aren't working!

For all the frustration in trying to fix these niggles, they're soon forgotten when I start her up and go for a drive :-)

[tony_ack]

Starting to come together now.

I did the ole' bottom rad pipe test to see whether the thermostat was working - it was warm even though the temp hadn't got anywhere near half way, so looks like a new thermostat may solve that! Also going to clean the heater matrix bypass valve at the same time, and give the system a good flush.

Picking up a new set of clocks tomorrow - not really looking forward to that job, but I keep telling myself it's worth it for a working rev counter. The boot light circuit still works, I just need to reconnect the switch - I'm guessing someone got careless, and ripped the wires out by accident when putting something in the boot. Glovebox bulbs are ordered - I didn't realise they were so rare. For reference it's a 257 festoon bulb - 12v, 3w.

I noticed a groaning/slipping on the power steering - only when stationary, and only when I turn the wheel relatively slowly. At first I was worried it may have been the PAS pump/rack but then I realised it's probably just the belt. The fluid level is still normal.

I have one more question regarding HIDs - I realise that they have already been discussed at great length on here! The headlamps on the car seem original, but there are definitely xenon bulbs in there. However, I don't seem to be getting the scattering that most people report with half-assed conversions. I'm slightly worried that if I replace with normal bulbs, the lamps may have been somehow optimised for the xenon bulbs, and the beam won't be right. Are there any tell-tale signs in the lamps (other than the bulbs themselves!) which will tell me that extra work has been done to make them work properly?

Many Thanks