OK, now my IVA date is set, my brain is working overtime. I'm hoping that making a list of small jobs I want to do will let me sleep at night, two months of insomnia is not going to be healthy!
The first two jobs were headlight alignment and emissions. They're the two 'unknowns' left that are part of the test. The headlight alignment turned out to be relatively simple, a bit of tape on the fence and lots of tweaks with the screwdriver;
The only slight mess up I did was the centre line, I'd lined everything up then realised the car wasn't pointing in the same direction anymore! So out came the laser, I have a centre line of the car and just needed to line it up with the centre line on the fence (the top bit of tape).
From then it was a case of getting the horizontal section to be the same height as the tape, and the 'kick up' to the left to be at the correct horizontal distance. Given it was mid afternoon it was dark enough to clearly see the beam pattern and adjust to suit. At the distance measured (25 feet), I had 15 CM to play with so getting it aligned with a 2.5cm tape was pretty easy. Of course, there could still be a measurement issue at the test but I've got it as close as possible. At least the adjustment did cover the range of motion, given the bodywork position had a lot to do with it there could have been a lot more issues.
Next up was the emissions. Technically I did the emissions first, but this is just a blog. There were two parts to this, confirming the testable limits and checking the O2 sensor was behaving. If I saw a good signal from the O2 sensor, then there was a fair chance the ECU was controlling fuelling correctly.
I have a small oscilloscope that I bought as a kit, it does the job but I've never really had a purpose for it before. This time it worked perfectly. Attaching it to the O2 wire and to ground when the engine was cold gave me a 0v output which was expected. With the engine running and everything getting up to temperature, I saw the voltage rise, then after a while it started to oscillate. If I understand the process this is the ECU switching from open loop to closed loop (again, a good sign things were running well). Here is the output signal from the scope.
Of course, it appears to be ok but then I still have my doubts. The frequency seems to slow, it should be between 1hz and 5hz. Given each square is 1 second that means I have a 0.5hz oscillation which seems too slow. It's also not clean, the other graphs I've seen are more of a square wave than a sine wave like this. Finally this is me checking at the connector, It's still possible the signal isn't getting to the ECU (although it's the closed loop feedback that causes the oscillations so I think I'm ok there).
So that's all I can check on the engine side. The flip side is what emissions I am testing for. As I have mentioned before the date of the engine and on the documentation confirms a manufacture date of 21st August 1992. This puts it firmly in the BET test, which is a fast idle test of CO <=0.2% and HC <=200ppm, with a lambda of between 0.97 and 1.03.
The next step is where it gets interesting. Those limits are extremely low, basically only achievable with a full closed loop system and a cat. But the car is very early on in the date range, and it's not a UK car.
As it turns out, that's the key. It's a Eunos, not a Mazda. The letter confirms it. So if it doesn't meet that particular standard, the flow chart goes to the 'CAT 1' section. In this case, the date is still relevant, but then it says 'can you find an EXACT match in the analyser database'. As it happens, no you can't, because it's not a UK car. In which case the secondary test should be a non cat test, CO <=3.5% and HC <=1200ppm. This was the same as cars from between August 1986 and July 1992, and to be honest not far off cars manufactured before 1986, which had no emissions rules applied at all.
All this means that while the car may not have perfect emissions, it also doesn't need it. It has also been suggested that the higher emissions might work in my favour for future MOT's as well as any potential engine swap I might be considering. So I'm tempted to cross my fingers and hope for the non cat emissions.
Last job for the weekend, or so I thought... wiring. There's a few bits of wire near to the fuse box that were making me uncomfortable. Essentially unsupported wires that could move, flex and potentially chafe.
What I've done (and unfortunately forgotten to take a picture) is undo the wiring harness on the first clip of the body, and move the connector to rest on the chassis itself. I have also added a corrugated tube to the wiring as it crosses to the body, and cable tied both ends. This means that the connector is now no longer unsupported, and the unsupported wiring is running in a fixed tube. For me I'm a lot more comfortable with it, and hopefully Mr IVA man will be as well.
The top loop of wiring in the above image is also now fixed to a clip so it's not just dangling, so that was that. Of course, on the way I did see a few other things I want to sort. First is a simple one, the front wiring passes the fixing for the horns;
In practice this is probably fine, but for the sake of a bolt cover it should be pretty simple to resolve.
The next thing I want to sort is the engine fixings for the loom and radiator hose. The original fixings were planned for the loom only, but then the radiator overflow hose went the same direction so I doubled up. Problem is I doubled up by attaching the hose to the loom!
These pictures show a comparison, the first is a separated loom and radiator bracket, the second is the loom and radiator fixed by the same clamp and a single cable tie. I'm not sure why I thought this might be acceptable. However it also gives me an opportunity to resolve another issue. These mounting plates were made with thin metal, and they bend. I don't think it would need much driving for them to snap, and the very hot exhaust manifold is where the wiring and pipe would land. That wouldn't be a positive outcome. So I've 3D printed some proper clamps that provide the separation required, and I'm going to remake each of the 3 brackets out of some thicker steel. It also gives me the opportunity to move them a bit further away from the breather filter, again it would probably be 'alright' but it's not something I want to have come back and bite me.
Oh yeah, and alongside all this, the rear lights stopped working again. This was on me though. The one printed light fitting hadn't got the correct tolerances, so the bulb had basically fallen out of it's holder. As far as I can tell it had caused a short between pins, so I was getting all sorts of funky lights going on. Reprinting the holder resolved the issue. I also increased the size of the screw fixings for the lens itself, and I'm tempted to retrofit the same on the other side. As I tightened one of the screws I heard the plastic crack, the fixings just aren't big enough to cope with the self tapping screws. Ideally I'd heat up the screw before screwing it in but that can be tricky.
