I am imposing on those knowledgeable about long-in-the-tooth modern Fords because mine is still good. But lately I have noticed in both town and country an occasional tremor on light throttle, short of shunting but the same sort of thing.
That apart, for some time past, every now and then, the car has been reluctant to accelerate in third gear on a light partial throttle opening, requiring a good stab at the pedal to get any action. Then it reacts like a roughly-tuned car with a twin-choke Weber carburettor, suddenly turning on a lot more power, noise and no doubt thirst. Yesterday on mimser-infested A roads it did this a few times. At higher speeds or with a heavier foot it goes as usual, pretty well considering, but I'm afraid even that won't last without some attention.
When young I wouldn't have noticed because my foot tended to be too far down anyway. Now I recognise it as a fault which seems to be getting worse. It's a 93/94 German-built 90hp 16v Zetec or semi Zetec by the way.
Sorry to bother people, but does anything obvious suggest itself to experts?
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Lud
Light-throttle tetchiness tends to mean running lean. Slight air leaks; manifold gaskets, PCV valve stuck, split breather hoses, etc. would be my first thought. Won't necessarily show up as a bad idle as it's electronically speed-controlled.
Checking the oxygen sensor signal voltage readings at idle and fast idle might show something useful.
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Thanks Screwloose. I will have a look. There are quite a lot of little breather hoses going hither and yon and I have never cleaned them out, the car now having done I think around 150,000 miles. I wonder whether that might be a good idea, although I can't say I fancy doing it.
I don't know what the PCV valve is or how to get at it though. There is something that looks like a valve of some sort with a breather hose going into the top of it at the right hand side of the manifold looking at the engine from the front, easier to get at than the idle control valve.
By the way, these symptoms only appear when the engine is thoroughly warm, which tends to support your suggestion of a mixture problem as it doesn't happen when the engine is running enriched during the warm-up period.
I suppose a good independent garage will have the kit for measuring those voltages and be able to interpret the results?
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Lud
The, push-in, PCV valve is on the end of the breather hose that runs under the coilpack to the front of the engine. Service item; should be regularly changed - never is. Check every inch of it's hose too - they split and collapse inwards.
A simple voltmeter will give you the oxy sensor voltage - on the black wire of the four.
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Thanks again. Dirty paws time, yuck... :o}
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Not any more; wear some disposable rubber gloves like 95% of the trade. Around £5 for 100 at any factors. Most workshops get through <100 a day.
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Just looked it up in Haynes Screwloose. I know the thing and the place, it's inside the air filter housing, in its oiliest corner. The one that was originally there disintegrated and I think what's there now is a bit of rag or something... not good, clearly. Heigh-ho. Will inspect the breather pipe too.
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Lud
Last time I looked; it was pushed into a rubber mounting low on the front N/S of the block right next to the clutch housing.
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Yes, as SL says, it's hidden away, under the exhaust manifold near the bellhousing at the front of the engine. It's a small metal valve, about 11/16" diameter, and about an inch long, with a rubber pipe connecting to it, and the other end pushed into a rubber grommet.
I suspect Lud is referring to the sponge pad in the air filter housing which soon clogs with oil and gunk - although you get a new one with a proper Ford air filter - have you been fitting spurious parts at service time Lud?
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I was indeed thinking of that sponge filter. Since then I have looked again and Haynes has told me where the valve is, although it hints (by covering all the different engines in one) that I may have to take the exhaust manifold off to get at it. I'm not going to do that in the street at my age. I will take a look tomorrow. Yes, last air filter was from Halfords. There used to be Ford dealers on every main street but the nearest main one to here now is at Highbury Corner and no joke to get in and out of at busy times.
Thanks very much for the inputs.
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Yes, it looks a bit like a manifold-off-to-let-the-dog-see-the-rabbit job. Damn. I will ask my man down the road however. He knows a lot of tricks.
How can a rubber grommet survive under there?
Edited by Lud on 10/06/2008 at 18:45
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One could, if so disposed, drive a mile or two from home, call the AA and act fearful of further progress. Await diagnosis and even possible repair........if that were not dishonest of course.........
Edited by Shoespy on 10/06/2008 at 19:20
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Lud
No need for manifold removal; follow that rubber breather hose to it's end and pull.
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OK, will try.
Car behaved impeccably in town this evening by the way. But it usually does.
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