Had my car read for codes today I don't get it?????

audiv8quattro

audiv8quattro

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Ok so I got my car scanned today by my local garage, they used a snap on scanner, brilliant bit of kit but anyway it didn't through out any codes anywhere, brilliant I thought, so why is my car running like s**t? As I put my foot down it hesitates it's really lumpy and jumpy and then if I floor it it all of a sudden goes like the clappers like there's a blockage somewhere. It has the airbag light on for the first 3 mins of driving then goes of, it keeps telling me I've got a bulb out but they've all been changed the other day, my aircon don't work, the exhaust blows, rear diff is leaking oil and sometimes when I indicate the hazards come on, I've changed the hazard switch and indicated stalk , so the question is surely most of these things would throw some codes up, I cleaned all breather hoses and all pipes the other day so that's out of the question, please help
 
blocked cat
blocked fuel filter
one of the 2

I have the same issue with airbag light only in mornings thou... id flashed like 30-40 times for 2-3 min and then goes off...
as far as A/C check if its gassed up
locate the charging valve and use a small screw driver and push it in very gently
if gassed then its ur A/C unit
 
Hi mate new fuel filter on the car two weeks ago and both cats were replaced last month, must be a/c unit because I tried regassing it the other day and it's full. Thanks alot for reply though mate it's really baffling me as to what the problem is, the airbag light isn't bothering me at all it's the lumpy jumpy driving.
 
Must be the icm because the plugs were also changed at the same time as the fuel and oil filter thanks for that, but should it have came up on the scan today
 
Probably should have mentioned this earlier sorry but it's intermittent it happens mainly when the car hasn't been run for at least 4 hours, but if I use it then jump in an hour later it won't happen but if I go to work and leave it till I leave then it happens, not all the time but most of the time, that's what's baffling me it's not there all the time
 
I'd also have a good look over your breathers aswel make sure it's all intact and all in the right way and also have a check on the plugs for arc'ing marks, a fault may not register as it has to occur/register the fault in so many cycles of the engine to store a fault code and sometimes it may not flag a code.
 
Cheers bradderz I'll check plugs tomorrow is there a way of checking the coolant temp sensor??
 
Hi, I would say that it is unusual that there were no faults at all from a scan. In my experience there would be a few stored even if it was something like the alarm being triggered or an intermittent code.

Depending on the year of your car, Coil Pack faults and ICM may not register a fault (I know from experience on my early A4!) Coil packs tend to show themselves under load, ICM issues causes the fault to be there all the time (not even sure if there is an ICM on the v6 though). Looks like you are chasing multiple issues TBH. Your electrical gremlins remind me of a problem I had with my ignition switch which stopped my aircon from working and my indicators to play up?
 
Cheers mwarrey my cars a 1997 a4 2.6 v6 quattro, and that's exactly what I thought it should at least have a couple of codes stored but I sat there and watched them do the scan from start to finish as I know the bloke who done it he let me watch. The screen just kept coming up with no codes on the engine management ect and all the idle speed and throttle alignment was perfect rpm was good and he even ran a manual compression test but that was at the higher end of compression on every cylinder which I was told is perfect.I'm lost mate, gonna look into coolant yep sensor tomorrow to see if there is a way of testing it or if it just means trial and error and buying a new one
 
audi upgrades
You could use vagcom to see what the temp sensor is reading when cold ie when it's been left for a few hours, you could do a resistance (ohms) check on the temp sensor when cold then test it when it's hot and see if there's a difference in readings if not I'd say it's ********. But vagcom is your best bet as you can see what all the sensors are reading/doing.
 
But wouldn't that show up on the scan? I'll have the garage look at it but there is a receipt when I bought the car about 8 months ago for a new maf from Audi could be faulty though, cheers rconnn
 
Nope, mine didnt. though it showed excessive airflow. (it was showing over 250bhp worth of air, whereas my car was (at the time) only a 15bhp).

Only real way to tell is a run in second gear on a motorway or similar, from 2k up to redline and see what the MAF/AMM is reading. (though this will probably take you in excess of 70mph, just to warn you).
 
One of the ways of checking the MAF is to disconnect the plug to it and see if it runs any better. This would register a fault code that your garage should be able to see. If they can't then I would question the scan? A failing MAF will not register a code until it is really bad, you can do a measuring block test for the MAF using VAG COM. I would recommend investing in a VAG COM lead (plenty cheap on ebay) and read some of the post on here. Could save you a fortune in the long run.
 
Indefinately in theory. the ECU will default to a "backup" map, will suffer a drop in performance and MPG though :sorry:
 
Ok so I think I have found the proble,spark plug 4, middle one on right of engine doesn't tighten up properly just spins in the hole, it wasn't cross threaded when it went in and thread is fine could this be the cause and how the f**k do I fix this
 
Sounds as though the threads are shot in the head. Look for a helicoil kit or have a garage fit one, it will repair the thread again and get a gas tight seal. Alternatively... New head unfortunately
 
Thanks again rconn and thanks to everyone for helping, abit more info though firstly where is the maf, I can see the icm module with the two plugs connected on top of air box butcant see the maf, and I've just Been on a fast run down a quite road, done two runs without stopping, first run car run like s**t struggled to reach 50 in second let alone 70 when redlining and in fifth gear would only reach about 85 on a 2 mile straight road, second run it was much better it done 120 in fifth and could still do more much better when I floored it and I noticed the changed when well the only way I can explain it is like if you get a blocked straw and blow when it comes unblocked it's easy to blow through if that makes sense that what my car feels like, stupid explanation I know but that's the best way to describe it, if it was the head would the problem be there all the time. Thanks again
 
Have to say, it does sound very much like a MAF fault. One word of wArning, if you do replace, only use a proper Bosch maf, I went through 4 cheaper ones before I figured that one out...

Unfortunately I don't know where it would be on the v6 other than it should be near the airbox and will have a 4/5 pin plug on it...
 
Ok mate cheers I'll do some research as to where the maf is and I'll try that, I'm glad you understood my last post because when I read through it sounded so stupid but it's hard to explain I guess,
 
I've just answered your other thread... No the ABC engine doesn't have a maf, It has an IAT Intake Air Temp sensor. Spark plugs have been known to work themselves loose on these engines and is worth keeping an eye on. Did you check all the other plugs?
 
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If theres no MAF it must have a manifold pressure sensor instead.

I'd be checking ALL the breather/vacuum pipework, and checking the fuelling to rule out faulty lambda sensors
 
Thanks guys all breather/vacuum hoses are fine and fuelling is all good had the garage check that when they done the work
 
I'm guessing lambda or multi function temp sender. You really need to get the codes pulled properly tbh. What condition are the plug leads in?
 
Plug leads look good are they the same as the s4 because they have s4 written on them and are an s4 part number, yeah I'm gonna try find someone with vagcom near me and go from there
 
S4 leads wouldn't fit your engine. I suppose the symptom you describe could be ht related, a lead breaking down under load? Also, where is the exhaust leaking?
 
Ok mate cheers just wondered why my leads had s4 printed on them, the exhaust is leaking from just after the cat where I bought a cheap cat and it didn't fit properly
 
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