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Old Jan 12 2020, 02:25 PM   #5203
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Zelandeth's Avatar
Join Date: Mar 2013
Location: Milton Keynes
Gender: M
Fan of: Dragonsdawn
Now Reading: Working my way through the whole Pern series
Default Re: What is happening

First task for today was to check the throttle balance.

The throttle actuation rods were waaaay out of whack, meaning that the throttle pulley was resting a good 1/2" off the closed throttle stop. This was due to the left one. The right one is currently seized in its bushing but has been left soaking in Plusgas so I'll give it another poke in the future. At least with my foot off the throttle the throttle position sensor will be seeing that the throttle is actually closed now.

When I checked everything at rest after that was adjusted, we had 4% CO on the left bank and 0.5% CO on the right.

After adjusting the stop screws I was able to get things stable at 1% on the right and 1.2% on the left. I was kind of hoping I could aim for 1.5% (smack in the middle of the 1-2% quoted in the handbook), but I couldn't open the driver's side up any further without opening the throttle itself because I couldn't adjust the actuating rod on that side.



It's a lot closer to correct than it was. The car smelled very obviously rich before, it doesn't now so it seems I've done something right. Idle is very obviously smoother too.

Next up was some detective work to figure out why the lighting in the stereo was refusing to go out.

Pulling it out of the dash revealed clear evidence that someone has been in here before.

Have to wonder if this was more recently when the speakers were changed or if it was back when the head unit was replaced back in 1988.

Helpfully the handbook for the head unit contains a clear wiring diagram which made the detective work a lot easier.

Didn't take more than a couple of minutes to track down that someone had connected what should be the permanent live for the memory backup to the line which should be connected to the dash lighting circuit. That will be why it was always lit up then. Goodness only knows how long it's been like that.

At first I couldn't actually find the wire for this, but after groping around blindly for several minutes I found this.

...Which when tested turned out to have 12V present on it when the headlights were turned on. That will be the illumination feed then.

Having connected this to the appropriate terminal, tested it and stuffed it back into the dash it initially didn't work. Well it did but I couldn't receive anything because the terminal for the power antenna had been pulled out. Second time round, having more carefully routed the wiring bundle we had better luck.

Headlights off:

Headlights on:

It's hard to tell from the photo, but the display is dimmed when the lights are on. Sadly the bulbs which should provide lighting to the buttons on the stereo have burned out, so I'll need to conduct some microsurgery to sort that at some point in the future. For now though it has solved the problem with it refusing to switch fully off. Do wonder how long this has been causing issues with battery drain...

The four screws which were meant to secure the cage for the head unit to the dash were also someone didn't take much care when they were in here last.

Feels like a reasonably productive afternoon.
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