deNs' 1993 940 GL Wagon - "Odin"

Amongst other things that were going on at the time, I occasionally took a break to work on some electrical things, like the Wasted Spark install.

I'd already installed a chip in the EZK unit but I'd bought a Buchka wasted spark board from cflomoto last year, and was waiting for the opportunity to install it.

I took a night off from wrenching and did some soldering instead, wiring in the WS board into the EZK. Potted the joins on the EZK and WS board with hot glue to stop damage from vibrations/movement.

I used a 4-pin microphone connector for the two-channel ignition output and also for the arm/set features of the launch control, if I feel like implementing that down the line. Note, if you're going to use a microphone connector in this location, get a right-angle female connector as space is tight where the EZK mounts.

I'd also purchased a 2x2 coil for $3 on closeout at RockAuto, and got a 960 ignitor module at the same time. The ignitor is a Huco item, and the coil is... unknown. So unknown that when I found a genuine new Bosch motorsport 407 coil for $69 I smashed the Buy It Now button on it so I wasn't worrying so much if I'd end up stranded somewhere because of being a tightarse. The other coil will be a spare.

With the parts all ready, I started to plan it out. I picked up a heatsink and started fabbing up a plate to mount to the drivers side strut tower support where the ignitor and relay for tacho drive would live. Here's what it looked like installed, later:

I then started measuring, designing and then 3dprinting a coil mount for the rocker cover. Remember: measure 3 times, print 4 times, then change your mind about where you want to mount it.

I decided after the first couple of mockups that I'd mount the coil on the rear most valve cover holes. I'm keeping the dizzy in place because it doesn't hurt to have it there while I source the head plug and make a bracket to hold it in. Also, I could easily revert back to coil and dizzy should this fail and leave us stranded at the side of the road.

I hadn't found many details online about how to modify a relay for the tacho drive. Because I was planning on keeping the original ignition stage in place, I'd just need to figure out how to remove the contactor in a relay I had spare, and we should be in business. So I cracked one open, found the part of the relay that goes 'click' and started hacking it out. Removing the above seems to have worked. Hooray for saving all those relays from someone's old car alarm install..

I used some 4-core wire with a sufficient heat rating to hook up the coil and the new ignition module, and hooked up the relay to the old coil wiring.

I was chuffed that it worked first crank, and even the tacho worked. It's so nice when things work out like you hope.

The verdict? Immediately noticed that it seems more eager, and revs cleaner, as hard as that is to convey in writing. Hooray.

nugget_940

Awesome. How good are those Bunnings standoffs!

I reported the same results when doing the wasted spark conversion on mine. Much smoother and revs cleaner.

However for simplicity I used an NA6 MX5 J702T ignition module as it drove the tacho directly!

I also wired up the launch control on mine, worked great!

Wait what, bunnings have standoffs you can buy in store? That would've saved me some time. I ended up buying them from here because that appeared to be the easiest source at the time. Oh well!

What did you use for a switch for the clutch, if that's what you did? or did you just set it up to a couple of momentary switches on the dash perhaps?

Dunno if we're talking about the same thing @Major Ledfoot though I do still intend on getting one of @asiandriver's silicon replacement bellows if he's still got some, but that'll be another day. If the vacuum motor is a thing that goes as well, then.. well it's an old Volvo so I knew what I was in for. ? Getting the central parts of the dash off isn't much of a chore for me these days, as I've had it out enough that it's just a matter of just putting the time aside to do it :) I'm more worried about having to do heatercore and A/C evap on our 850..

Pretty sure the belt configuration is standard 940 fare, and yeah I do agree it's a good setup - having some isolation from each accessory is nice. For the most recent roadtrip after all these changes I had just about every spare part packed into every nook and cranny that you could find, including an additional one of each accessory belt in case one let go. I'm not hugely used to V-belts so it was hard to gauge if I was over-tensioning them or not. I've had a alternator belt let go in our 940 in the middle of nowhere in the Czech Republic so I'd rather be prepared in case it happened again!

Thank you once again for the kind words.

That pin on the control unit circuit board - is that the one under the little black relay? 

Yes, that's the one - seems it's simply a fact of life for these control units. I'm glad to have some on standby in case of failure. If I had another fail, I might swap out the relay entirely with a new one to see if that makes any difference.

These boards are aging and I can't remember where I read it but I think there's a decent amount of current going through that pin with the A/C on (4A springs to mind?) presumably to power the clutch on the compressor, so perhaps something to consider in the future is using that pin as a trigger for a separate, external relay so there isn't so much current being drawn through that PCB, if that's in fact part of the issue.

Good to hear the 13mm belt is okay at least :)

I wanted to make up some heat shields, one for the brake master and one for the oil pressure sender and its wiring that both live close to the exhaust manifold, so I broke out the cardboard and made some up quickly with some sheet metal I had lying around.

Then the one for the oil pressure sender:

It didn't take long and I didn't bother painting them, but I might do so one day. Function over aesthetics when you're prepping a car for a roadtrip!

Since purchasing the car the antenna mast has always been at half... mast.. eyy!

I purchased a replacement mast from Skandix with one of my orders a couple of years back and it was 14 EUR or thereabouts.

I pulled the old one out, and there was no fixing it - in the bin it went!

The new one took quite a bit of wrangling to get it to go into the motor. I pulled the entire thing apart, thinking it was busted or had a broken motor or possibly had some old gear in it, only to realise I wasn't quite understanding how it worked. The mystical black box attached to the antenna motor had 3 wires, one of which was 12v battery constant, one was ground and the third was 12v to control up/down on the antenna. When 12v is supplied, antenna go up. When power was removed, after a couple of seconds the antenna would go down again.

Right now I cannot figure out why the dash switch or my head unit doesn't make the antenna go up, but realistically that's not the most important thing, as long as we still (kinda) have radio, and now the antenna fully retracts into the car! I will get the antenna switch sorted as it's pretty useful when you're outside of big cities and want some radio.

Brad

Those power antennas can be a PITA to install and get working right. Took me hours to get the one on mum's 740 sedan working properly when I replaced it.

I had a problem with my 940's antenna years ago where it would extend up fine but often would not retract after switching off the radio or using the switch (basically the opposite problem you have). If I fiddled with both for long enough eventually the antenna would retract. Turned out to be a problem with the circuit board in the little black box mounted beside the antenna. I can't recall what the problem was but I replaced it with a spare I had on the shelf and it's been fine ever since.

Good to know - in my limited searching it seemed like that black box attached to the antenna motor wasn't really documented in terms of what was inside it or how it functioned, presumably as it would just be a 'replace if not working' kinda situation. Because I was able to essentially bench test it like in the video, I'm confident it's working as expected, but much like some of the other parts of the dash wiring, there's probably a missing link somewhere I haven't yet found.

Major Ledfoot

interesting - your 945 doesn't have the radio antenna built into the LH rear cargo glass window....

My 93 945T has one, and IIRC my former 945 NA (which is for sale again on Gumtree by one of its new owners...) also had the cargo window aerial. They also use an RF amp signal booster.

Both of the 945s have the provision for an antenna in that spot, but that location was used in the both the 745s I've owned.

Nice work on the heat shields - they don't have to look pretty to work.

Didn't realise they had them fitted to the glass so early - I'd prefer the glass antenna but now I've had tinting, I'm definitely not gonna change it from this. Perhaps it was an option to have the glass antenna or for the fancier models or a matter of what the factory had available that week.

There was a couple of things left I really wanted to fix before going on the trip, so I decided to tackle them before we left. 

These are normally a warning light on the dash, however it requires your cluster to have the diode installed at the position that the lamp is going to be wired into. Not really wanting to pull the dash cluster out right now, I decided I'd grab a couple of LEDs, design print myself a basic housing for them and at the same time, cover up a hole in the dash from the previous owner.

I made it to accomodate 2 LEDs in case I found another use for the other one. It's got a couple of 510 ohm resistors in-line to drop it down to the correct forward voltage from 12v in, then switched by the float switch in the coolant tank then to ground from there.

I tested it out when I was swapping out the coolant as part of the pre-roadtrip maintenance (though the coolant looked perfect, and really probably wasn't necessary..). At least I got to test the light worked, so that gives me some confidence. It's absolutely a feature worth having so you don't pop a headgasket over something that could easily be fixed.

It's a silly modern convenience but one that definitely comes in handy. I believe I saw someone on instagram fit one of these to a 940 in the same location literally a month or two after buying the car in 2018 so I cannot take the credit here. It's screwed to the panel and I have spares in case I want to remove it and have no holes, but I feel like it's a small sacrifice to have a cup holder.

That said, it's not the best at actually *being* a cupholder except for perhaps takeaway coffee cups, which I suppose what we'll mainly use it for. It holds pringles cans well though!

eyy.

This was done because after a hot day (37C+), I got home, parked the car, then a few mins later opened the garage to put it inside and tried cranking but got nothing. Turns out a few people on tbricks had similar issues in hot weather with the solenoid on the starter getting heat soaked and that's where the idea to put a starter relay in came from. Essentially it's using the old starter wire as a trigger, and then using the battery lead to the starter as the source for current, so there should be no more issues with a lack of current. I'm keeping spare relays in case it doesn't like being in the engine bay there.

Jumping ahead, but I believe this saved my butt when I accidentally stalled at a set of lights on a hot day in heavy traffic and needed to quickly restart.