The Continuing Saga Of The Metro That Drinks Petrol

Thanks for all the advice on the Metro so far. Here's where I'm at with it :-

Timing: well the tacho bit of the tachostrobe just ain't working so all I have been able to do is check the BTDC angle at what I guess to be about

1500rpm (sort of just-changed-up-into-a-higher-gear kind of revs?) and there's no particular indication that the timing is off. Timing is advancing as you would expect at higher revs. I'd check the camshaft timing too if I knew how but to be honest the timing never seemed that likely a culprit for low MPG with no other adverse effects evident, it was just something easy to check (or would have been easy with a tacho that worked...).

Vacuum advance: I think worrying about this was a red herring. At idle there is no vacuum being supplied to the vacuum advance and no timing advance. At increasing revs there is vacuum coming through, it seems a bit weak but there are no vacuum leaks that I can find anywhere in the vacuum system, and plugging up the other branch of the vacuum system (to the hot/cold changeover flap in the air intake) makes no difference. And what's being fed through is definitely causing a bit of retardation at higher revs (you can see a couple of degrees variation in the timing between the vacuum being connected and not connected at moderately high revs), and a not-leaking-but-partially-blocked vacuum seems unlikely, so I can only conclude that the vacuum advance is working as it should.

Carb adjustment: the various idling checks/adjustments in the HBOL don't seem relevant because the idling is fine. And I can't adjust anything else without a tachometer, CO meter, exhaust analyser etc. so this would appear to be a garage job, which may be the way to go with it - can't see a tune-up being that expensive. However there is a Metro of the same year with the same engine (including the mystery black cylinder which I think is a charcoal canister) sitting temptingly in my local scrappy. Looks like an accident job but didn't check. It's quite tempting to whip the carb off that and do a quick carb swap and see what happens - good idea, bloody stupid idea, or somewhere in between?

Now I probably should have mentioned earlier but the temperature gauge is reading a *little* low - about three-eights of the scale rather than halfway. Nothing I would normally have worried about which is why I hadn't mentioned it. But given the low MPG problem I was going to change the thermostat on general principles - but looking in the HBOL it looks to be a fair job of work, inlet manifold needs to come off. Doable, but is it worth it given the fairly slight low reading, i.e. about an eighth of the scale? (and obviously the temperature measurement system probably doesn't exactly conform to NASA levels of accuracy anyway). How likely is this to be the culprit?

A million thank-yous to anyone who can be bothered to read all this and give any help they can.

Reply to
Vim Fuego
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The obvious things to cause high consumption would mostly be carb related. I'm assuming it has some kind of HIF SU although my experience of these motors is well before the days of catalytic converters. Badly worn jet or needle, wrongly adjusted float level, faulty temperature compensation doohicky which later SU's had inside them, sticking piston, faulty choke mechanism.

Obviously you also check all basic service items and do a compression test before ripping apart things which may be perfectly ok.

I ran a 1.3 A+ Metro for over 20k miles many years ago. I only managed to keep it standard for 1 month before modifying the engine (almost a record for me) but as standard it easily gave 50 mpg on a run and over 40 mpg overall. Even with a big valve head, 1380cc bottom end, hairy cam and well over 100 bhp it averaged 35 mpg for the next 20,000 miles with several tanks in the low 40s on the rare occasions I took things easy.

A 1.1 ought to at least match those standard figures. If it can't even match the modified ones then something is seriously wrong.

-- Dave Baker Puma Race Engines

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Reply to
Dave Baker

KIF38 SU, MAC 10050.

Yep, done that.

Other things the Haynes says to check before attacking the carb are idle bypass system (you can hear the bypass solenoid clicking in/out and I have no idle problems apart from I can't get out of bed in the morning, baboom-tsch, so I assume this is irrelevant) and that the crankcase breather hose(s), float chamber vent hose and full load air bleeder hose are clear. Especially the latter if an over-rich mixture is the problem. Guidance on finding these would be much appreciated (like telling me about how big they'll be and they go between what and what) as the Haynes isn't being too helpful.

Useless though I am, I can probably find the crankcase breathers...

Reply to
Vim Fuego

=============================== A 'Colourtune' (google for 'colourtune' if you don't know what they are) would show the state of the mixture and would also help to set it correctly. There should be plenty of these lying around in older toolboxes as they're used less than they used to be.

I haven't followed every detail of your threads but I think you may not have checked the free movement of the carb piston. The test for this is to use one finger through the carb (air filter removed) to lift the piston and listen to the sound as it drops. It should give a solid 'clunk' sound. It's not unusual to have this piston get stuck by having the dashpot slightly out of alignment. If it appears to be stuck free it off by adjusting the dashpot.

Cic.

Reply to
Cicero

Correct, I haven't, I'll give it a go, thanks.

I think I could safely offer four pints (at Vim's apparently dubious going rate of £1.80 a pint :-) to whoever pinpoints the cause of my MPG woes!

Reply to
Vim Fuego

Yeah, I've heard of them. I'm reluctant to lay out on petrol-specific tools like this for this job as normally I'm a diesel man, I'm only running the Metro (or hoping to) because it's such a little gem and was such a bargain.

Reply to
Vim Fuego

God, how depressing.

Entries on ebay.co.uk for ColourTune or "Colour Tune": two.

Entries on ebay.co.uk for ColorTune or "Color Tune": eight.

Good evening to all my fellow Burger Eating Invasion Monkeys from Airstrip One and the Fifty-First State of the US of A. :-)

Reply to
Vim Fuego

Got mine off Fleabay for about a fiver. The bendy connector was bust the and the end of the insulator is cracked, but it still works and was well worth the money :)

Reply to
Stuffed

Wassup wid ya? Haven't you learned to blink quick?

Wouldn't do any harm. What do your exhaust emmissions smell like? Like a a back draughting coal fire or like a tingly nose form fizz bombs and sherbet? You wnat it somewhere in between. I always found the little mixture screw ghave me hours of pleasure on the Metro, give it a tweak until it runs quietest; you can set it up for stinky tail pipe and high speed or nice cherry blossom and max efficiency.

Temperature sender gauge could be faulty, thermostat wouldn't affect readings I don't think. But new thermostats are a useful safeguard on the old bins aren't they? IIRC the thermostat on the Meteors isn't a hard job, but I wouldn't suspect it for a low temp gauge reading.

Reply to
Billy H

Just out of interest, how did you come by it?

Was the previous owner (any of) boy racer types, or waas it a sunday driving old dear who would lose her blue rinse if she hit 35mph?

Reply to
Billy H

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