hi can anyone help me with the following problem or point me in the right direction?
I have a audi a4 1997 1.8 adr engine with a misfire .I cannot run the car on the road so i dont know what the misfire is like when being driven,but when left to idle until warm the misfire apears when the engine is revved. Any ideas what this problem could be?
rmhomr smf urst fryso;d omdryrf om yjr dinkrvy ;omr
Edited by Pugugly on 31/03/2008 at 23:23
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What sort of misfire is it - idle, single cylinder etc.? When did the car last drive and was it OK then?
How old is the fuel?
[PU Is that text a direct transcript from the Max Mosely tape.....?]
Edited by Screwloose on 31/03/2008 at 23:29
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SL,
Just get so bored of typing the engine/year stuff that I felt I needed a change, it can be de-coded. I have SWMBO working on a Welsh language version for the next transgressor !
What you said made me laugh out loud though so it was worth it !
Edited by Pugugly on 31/03/2008 at 23:33
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i have never driven the car it came from a salvage yard six weeks ago so the fuel could be fairly old ,there is no missfire at idle only when car is revved ?
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A salvage yard.....?
OK; let's have the rest of the story.
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The car is a cat c damaged repairable and was delivered on a recovery truck , so until it has a vic check i cant run it on the road only in the garage . Hence i cant take it to anyone to do a diagnostic !
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Is the engine management light on? Where was it damaged? Could the cat have shattered and blocked?
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no engine management light on ,it was scraped along side only cosmetic really so i doubt the cat took a knock .
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So is it a single cyl miss, or does it fail to rev? Not much to go on so far.
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It revs fine so i think its a single cyl miss ? When its revved hard it sometimes backfires .
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Backfires through the inlet or the exhaust?
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It sounds like the exhaust to me .
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Backfiring through the exhaust would suggest an ignition problem; check coil; leads and plugs.
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As screwloose said sounds like a ignition fault. Cant remember if this is a ADR is a turbo or not but if it is check basics ie fuel plugs coil packs failing that air mass meter and ignition output stage module can cause this to happen.
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Theres no turbo on the car but i managed to get hold of a fault code reader ,i dont know if the codes are old ones or new .
18010 01/05 power supply (b+) terminal 30 low voltage
17967 02/05
0561 03/05 mixture adjustment control
17967 04/05
01247 05/05 evap canisterpurge regulator valve
0532 01/01 supply voltage (b+)
i dont know what code 17967 reads as?
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Probably a load of accumulated codes; clear and re-read what comes back.
18010 Low voltage at ECU - flat battery at some time?
17967 Throttle control setting procedue failed. Throttle setting has been lost.
01247 EVAP valve circuit fault. Not vital.
0532 ECU supply voltage fault. See above
0561 Mixture control error. Could be historic.
Edited by Screwloose on 03/04/2008 at 23:37
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I cleared codes nothing came back ! I did fit a second hand charcoal canister when i found a crack in the original , the replacement came off a diesel would this make a difference ?
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Not sure if the diesel one is compatible or not; fairly unimportant anyway.
Keep an eye for any codes returning - particularly any low voltage ECU feeds.
Edited by Screwloose on 04/04/2008 at 00:50
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Hello again !I ran the engine today after clearing the fault codes yesterday . The engine was ran at idle and revved hard when warmed up it ,it backfired and popped quite a bit and the purge valve was clicking .The following fault codes appeared -
01247 01/01 evap canister purge regulator valver -n80
0532 01/01 ?
also when it backfired i felt it from the exhaust manifold side ?
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I'm beginning to wonder about the feed voltage to the ECU. Check the voltage coming to the black wire on the coil as it revs; as that ignition feed is shared with the ECU.
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hello again i put meter on the coil and i got the following results
14.28v at idle when cold
14.28v with engine revving when cold
as the car was warming the voltage dropped slightly .
14.09v at idle when warmed up
14.5v with engine revving when warmed up.
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Nothing wrong with those figures - bit high if anything. It would need to be below 10 volts to give a problem.
Checking the permanent feed to the ECU is a bit trickier - live-data is the normal way.
As this is a Motronic 3.8.2; I always suspect MAF sensors if they are doing something silly. The ECU seems unable to cope with a fluctuating MAF or oxy sensor signal - yet won't set a code.
What's the voltage on pin 1 of the MAF [the green wire] idle and revved?
What month of '97 was this reg'd?
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Hello again sl. I put the meter on maf sensor green wire and got the following
idle cold 1.4v
idle warm 1.14v-1.19v
rev cold 2.9v max
rev warm 3.16v max
the maf sensor is a hitatchi 058 133 471 afh 80-10b the date on the side is 1/09/97.
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Now that's odd. The system changes at the end of July '97 and the later ones should have a Bosch or Pierburg MAF that peaks at 4 volts.
Earlier systems should have the Hitachi MAF - for which those readings are spot on - but it's dated Sept...?
No obvious fault with it; so unless it's come from another car, it's not that.
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I dont have the log book so dont know the exact reg month !The plugs are new ! im at a loss .
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The service book says the car was registered on 22/05/97.
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Interesting; looks as though that isn't the original MAF then - still, it's type fits with the early build date and it gives the right readings so......
If it's telling the truth; then the system airflow is correct, so it must be fuel, ignition, or mechanical.
This is going to need plugging-in to a proper scanner to go much further; there are so many odd things that could have happened while it was salvage, that examining the readings for a clue is all I can think of.
Is that "ECU low voltage" code still coming back? If so; check the earth point on the N/S chassis leg.
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Hi again the only code i got from the car is
01247 01/01
i had cleared the codes last time and i havent run the car since ,just thought i would check for codes?
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Yes; you've clearly got an EVAP valve problem that want's fixing, so check it's resistance [or get another one;] but I can't see a little air leak stopping it revving cleanly.
It's going to need a proper scanner like VAG-Com.
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hi ,i have the following fault codes showing on my scanner could anyone point me in the right direction thanks
18010 01/03
17967 02/03
17967 03/03
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The definitions are above. Have you tried to set the basic idle setting? Have you checked the ECU's plug for corrosion?
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hello again ! I had the car into an vw specialist and he reset the basic settings and got the car through the mot i drove it home it was fine but for slight hesitation pullig away ,but the misfire has returned at about 2500 revs and the fault code that came up is 16486 on my scanner im lost !
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A diesel would not require and would not be normally fitted with a charcoal canister;there is no Evap emission requirement on a diesel.
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hi there the charcoal canister came from a breakers it said a4 tdi on the side so i dont know what car its off the part numbers matched mines an a4 1.8 petrol.
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