snowy2
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| posted on 19/2/17 at 08:54 PM |
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miss fire
when i snap open my throttle the car dies and cuts out.....but if i open the throttle slowly it is fine
so air leak?
fuel starvation?
or sensors at fault. the OBD socket only tells me what i know, no evap purge and no second O2 sensor.
however it does say that the O2 sensor i have isnt getting preheat voltage (i will look later)
so.....O2 sensor at fault?
or something else, i am thinking AFS.
oh its a 1.8 zetec on stock ecu.
sometimes you are the pigeon, most of the time the statue.
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pmc_3
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| posted on 19/2/17 at 09:46 PM |
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Quickest test of the MAF sensor is normally to unplug it, if it runs better with it disconnected sensor is faulty.
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r1_pete
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| posted on 19/2/17 at 10:19 PM |
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Sounds like the tps could be at fault, it sees when you snap the throttle open and richens the mixture.
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britishtrident
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| posted on 19/2/17 at 10:20 PM |
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Ford MAF sensors can usually be cleaned but it is better to have a look at live data from the MAF and fuel trims and TPS preferably in graph form
before doing anything.
https://www.youtube.com/watch?v=CEKjjXNLTjk
[Edited on 19/2/17 by britishtrident]
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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snowy2
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| posted on 20/2/17 at 08:08 AM |
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Interesting video there......
I like his scanner tool....bet that is some wedge.
sometimes you are the pigeon, most of the time the statue.
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snowy2
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| posted on 5/3/17 at 07:24 AM |
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MAF replaced.......no effect.
TPS also seems OK
fuel pressure is 2.9 to 3 bar when running.....but only 1 bar on prime (when i turn on the key)
STFT (short term fuel trim) 0+/-1 at tick over
LTFT over 25%! but it will drop to about 8% when revved hard.....odd that the ECU hasn't given me a fault code for this..
the ecu gives me a fault code for the O2 sensor (heater inop).....but when warm it goes into closed loop ?
so.......fuel pump seems OK, might be an air leak to inlet manifold but i would have thought that the STFT would be all wrong at tick over if i have
an air leak
i do have a 4-1 and weed burner exhaust fitted (41mm primaries and 50mm tail) and an inlet plenum with short equal length inlet runners.......could
the engine be delivering more power from standard? therefore needing uprated injectors? i would expect the STFT to be low at tickover and the LTFT to
be high if this were the case but do i have that right?
sometimes you are the pigeon, most of the time the statue.
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turnipfarmer
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| posted on 5/3/17 at 06:23 PM |
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If it's not injectors or an air leak, the LTFT readings you're getting might be suggesting a faulty O2 sensor. If it is, you'll get
all sorts of weird fuelling problems, and you may not get an error if it's 'false fuelling'.
Take a look at this article...
https://www.obd-codes.com/faq/fuel-trims.php
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