Crisco on the Carburettor - A Sequel to Fuel On The Roof

So, having (probably) eliminated the fuel supply as a source of the kangaroo-ing,(see Fuel On The Roof topic) a vacuum leak is probably favorite

I can’t find a vacuum leak by blowing butane over the pipework and inlet manifold. Most of the complex system of vacuum hoses (which I don’t understand) was disconnected and blanked off as a response to running problems a couple of years ago.

Over the past couple of months I’ve painted sunflower oil over the carburettor and inlet manifold in the hope it’d seal off any leaks. My main concern was that this would cause the throttle to stick, but short test drives have been OK

Time to go for inspection. since I’ve already got a late fine and more penalties loom (Told myself its only 20 quid but these days its 27. Brexit is costing me money)

What could possibly go wrong?

Car performed impeccably on the 20k ish drive into the city centre testing station (well, there’s a rythmic pulsing through the steering that wasn’t there before but the engine response was fine.)

Looking like that sunflower oil soaking might have done the trick.

The “What could possibly go wrong” question was answered by a big cloud of steam in the testing bay. Apparently the fan wasn’t working and the static revving for the emissions test popped the cork.

Still passed (Huzzah!), in fact they might have skipped a bit to get rid of it, but limping it back home, stopping to dribble ditch water over the radiator a few times, was a bit fraught and tedious.

(No free parking in the city any more AFAIK. Taiwan’s anarchic charm is fading fast and soon it’ll be a bigger PITA than…well…The Yook)

Can you guess yet?

Try stocking up on Guinness!

Uh-huh. No guesses then…

When I wrote “Can you guess yet” I was convinced A RAT had chewed on the wire from the temperature sensor, which in hindsight seemed a predictable downside of soaking it in sunflower oil, though I hadn’t predicted it, even though rats had attempted to establish a nest in the spare wheel well while I was away for a couple of days. Think the heavy rain is pushing them to seek dry hideouts.

(CORATERAL damage? works with a cod Japanese accent. )

Now I’ve had a better look I’m not so sure. Some insulation is missing but the wire seems intact. Shorting it to earth (which I THINK should activate the fan), doesn’t

Fan is OK from jumpering it direct to the battery with half an old power cord, though I got my feet quite badly bitten by aggressive little red ants (probably Fire Ants) getting some field sand to rub the contacts with. Still hurts.

The fan relay seems to work when 12V is applied to the low resistance (about 100 ohms) contacts, and jumpering the ports in the connector block corresponding to the switched contacts together with a bit of wire makes the fan run.

This SEEMS to indicate a break between the temp sensor and the relay, inside the wiring loom, which would be a pain to trace. I could maybe bypass it with an extra wire though.

I used sunflower oil because I thought its special characteristics gave it a chance of working, and maybe it did. Hard to tell with an intermittant fault but that’s the longest roo-free run I’ve had since this started.

Took the temperature sensor off to hopefully bench test it (not that I have a bench)

Seems to have PTFE thread tape on it/

Normally I like to see that, and use it a lot myself in places for which it is not intended. like the caliper pins

BUT here doesnt it have to make ectrical connection through the threads in order to work?

Unlikely to be the cause of the current problem, though, so I suppose I.ll put some more on when I re-install it

Well, that was F for FIDDLY.

Trying to get consistent multimeter probe contact with a wee cylindrical metal thing in near boiling water, I said MANY words not allowed on most US-based websites, and a few that they probably wouldn’t know.

But seems the thing works.

Painfully hot water, about 80 ohms

Cold water: INFINITE

I don’t have the specs, but that seems to be doing the right thing in qualitative terms at least.

If it had been broken I might have just rigged the fan always-on, which is still an option, but nice to avoid if possible.

Now I just have to wire it up somehow.

A direct wire from the sensor terminal to the back of the negative coil port in the relay connector restores apparently normal fan operation.

The wire is attached by a ball-point pen spring (slightly unwound) and is just twisted and pushed in at the connector block, so it could be more secure.

I was going to use more pen-bits (plastic sleeve for sensor connecton, and nib as bullet connector, but I parked them in the roof gutter and they blew away. Probably have somethiing else suitable though.

Temperature guage (which uses a different sensor) isn’t working either but access to the guage back is likely to be a pain and I may not bother.