The ecu on the Mk3 Fiestas doesn't have an engine warning light.
I suspect the garage in question hasn't used a fault code reader as they've
changed more than one part already.
My 2 Mondeos used to fail emissions every year with no fault codes.
For some time i just swapped the air flow meter, cat and and lambda sensor
between the 2 cars for each MOT and it would pass.
Eventually one year it still didn't pass and in the end a good thrash down
the road with the emissions test straight after got it through.
That really needs co-operation of the tester though.
Since changing MOT garages though it's passed the last 2 years with no
messing about.
I have found the air flow meter is a common cause of poor running on the
Zetecs, take it off and check that there no dust or dead flys (BTDT) stuck
to the 2 tiny sensors inside it.
You can clean them but use a really soft paint brush or you will damage
them.
Jim
--------------------------------------------------
From: "barnacle" <[email protected]>
Sent: Wednesday, April 20, 2011 2:33 PM
To: "Quantum Owners Group" <[email protected]>
Subject: [Quantum Owners] Re: H4 Electrical fault ?
I'm not an expert on Ford ECUs (except the Cosworth, which uses the
same Weber as my Fiat) but in general, ECUs just don't fail - if they
do, things stop, and that's about it. So this is a bit generic...
ECUs calculate the petrol and timing based on (a) air mass flow or (b)
manifold pressure, modified by throttle position, intake air
temperature, and engine revs. If any of those sensors is unhappy, the
ECU will usually throw an error - red light on the dash, as a rule.
You can usually talk to an ECU and it will tell you what any problems
are, given the right tool.
For an ECU running rich, I'd be mostly concerned about leaks around
the fuel pressure regulation, or a faulty pressure regulator, or an
incorrect index for the timing (I don't think Fords can do that,
though). Also, it's important to make sure the cat is up to
temperature - an 'Italian Tune' just before the test can improve
things no end. It can also be a problem with the thermostat failing
open; the engine never gets to temperature and remains in 'cold start'
mode - i,e, rich. But I'll be surprised if there's an electrical
problem, with no error messages from the ECU.
Neil
On Apr 20, 11:30 am, bilje55 <[email protected]> wrote:
I took my H4 to my local garage for the annual MOT following a new cam
belt, plugs, filters and oil. It shouldn't have failed..but it
did.....on emissions. And this is where modern mechanics enters (for
me) the realms of voodoo or witchcraft. It's a fuel injected 16v zetec
with about 40k on the clock only...with new oil and filters and a
satisfactory exhaust...but it fails on emissions? Two new sensors are
fitted...something to the block..temperature? and a Lambda sensor? The
situation improves but not enough...so a new catalytic converter is
acquired...and fitted...but the situation has still not improved
enough....so my garage man wants to call in a specialist auto
electrician, as he believes that there is some kind of electrical
fault...either wiring or (Please no) within the ECU. He (my garage
man) freely offers that he is really out of his depth...so I've agreed
to the specialist guy having a look...but he ( a travelling man who
undertakes specialist work for various small garage businesses in my
area) probably can't do the business until next Tuesday..and that's
just for diagnosis!
Friends...I need information: what is likely to be the problem here?
Should I be preparing for further expenditure on replacement parts?
Where should I start?
with thanks in anticipation....
Bill
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