a3 hunting

D

delboy68

Full member
Points
16
Location
hereford
Car
a3 sport
hi all, i have recently bought a 1.6 a3 from an auction, problem is that its hunting, its ok when first started up but as soon as you rev it it starts hunting between 1000 and 1300 rpm, i looked under the bonnet and found 2 air pipes had been removed, by someone in the auction i expect to try to get it cheaper, i put these back on but its still hunting, could it be a air leak , lamda sensor etc.
 
Plugs leads and coil packs would be my best bet. This may have killed the cat but it is a good starting point. Then i'd get the cat checked. If the cat is dead and you replace it without addressing the fault it will only happen again.
 
VAG cars seem very prone to dirty MAFs and throttle bodies. I've never had either fail in any car of mine but then again I've always stock standard air filters.
 
update on this, ive been under the weather the last week or so , so i havnt realy looked at the car, i did take the air flow meter out and to me it looked brand new, all the screws were new also , anyway i tried it on another a3 and it worked fine , so that leads me to belive the maf is fine, so im back to square one, would the plugs and leads cause it to hunt, the car drives fine otherwise, there is a little hesitation but no noticable misfire like a plug or lead going down, ??
 
did you check the throttle body ?
alot of work to get to on the 1.6 as the whole airbox has to come off

also has the battery been disconnected any time recently ? last 100 miles or so

the maf looking new doesnt really mean anything, mine still looks brand new if looking through it and its 8 year old

theres no leads as the coils does the work. doubt it would cause it to hunt but if they were failing youd notice it when driving
 
i dont honestly know when it was last serviced as i bought it from an auction, ive tried the maf on another car and it worked fine so i think that counts that out, ill take a look at the throttle body tommorrow., is it easy to access ??. also it dosnt start hunting until the car is revved,
 
Looking around on the net, apparently a common problem on these is the idle control valves fail and need replacement, also a throttle body clean is in order and injector cleaner, buy your self a can of carb cleaner for the throttle body and chuck some injector cleaner in your petrol tank
 
BCB engine code - remove the airbox, bout half a dozen screws, then 4 cap bolts (allen key type) on the throttle body itself

other 1.6 engine codes i cant help you with as not done but they cant be that different
 
well i dont know what the hells happened now but i put the maf meter back on the car and sprayed a bit of carb and throttle body cleaner fluid down the air pipe and now it sounds like a 3 cylinder corsa, im beggining to wish id never set eys on this car lol, any suggestions as to whats happened now :(
 
delboy68 said:
well i dont know what the hells happened now but i put the maf meter back on the car and sprayed a bit of carb and throttle body cleaner fluid down the air pipe and now it sounds like a 3 cylinder corsa, im beggining to wish id never set eys on this car lol, any suggestions as to whats happened now :(
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Well I cannot say for certain, but it sounds like a similar occurrence that I had on my own little chariot! I had a new performance panel filter that was fitted to the car and it was pre-sprayed with oil to catch dust particles better.
The oil droplets went onto the MAF sensor needle thingy and started to lie to the ECU. Brought up the engine check light and the car ran like a stabbed pig (all over the place) the MAF was stripped down by the garage who diagnosed the problem, cleaned it up and refitted it and I was off up the road like a Greyhound on acid :lol:

Might be worth a look!
 
it was running fine before, apart from the hunting problem but since i put the carb cleaner down the air pipe its running on about 2 n half cylinders, well thats what it sounds like, i revved it for a couple of minutes thinking that the carb cleaner had to work its way out but it sounds and runs terrible.
 
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you didn't spray it in front of the MAF sensor did you?

Also you are supposed to use the carb cleaner on the throttle body and then wipe it off rather than leaving it there, you might have buggered something up in an effort to cure your running problems,

Best thing new is to remove your spark plugs and check there conditionbefore doign anything else.
 
jarrus said:
you didn't spray it in front of the MAF sensor did you?

Also you are supposed to use the carb cleaner on the throttle body and then wipe it off rather than leaving it there, you might have buggered something up in an effort to cure your running problems,

Best thing new is to remove your spark plugs and check there conditionbefore doign anything else.
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x2

Never, ever spray anything with parts still attached to the car. Take it apart then do it. Make sure everything it cleaned off as well as you'll cause the engine to suck it in.

I took my ICV out to clean it last week. This involved taking the MAF, the throttle body, the top half of the inlet manifold and a bunch of pipes off. It requires a lot of patience (something I don't have) but it was worth it.

At the very least you've learnt a lesson here.
 
VAG motors seem very susceptible to filthy MAFs and reduce systems. I've never had either fall short in any car of acquire but then again I've always supply common air filter systems.
 
just a quick update on this, the guy i wanted to look at it is on holiday, typical, but a friend who knows a little about cars and he took a couple of the plugs out and they were covered in petrol so he thinks theres something wrong with the ignition side of it, he said theres fuel getting into the engine but its not igniting, its going straight out the exhaust, it really is running that rough, the engine is shaking like its cold the flu its missing that much. so im stumped again.
 
get it on a diagnostic machine mate and see whats its showing up other than the missfires.

you dont need to wipe off the carb cleaner as said but it should have been done off the car and left to dry
 
i have dropped it off at a garage just now m8, he seems to think the way its running its almost certainly coil pack, so fingers crossed hell look at it this afternoon, plug it in and get it sorted. will keep you updated.
 
had a phone call tonight and he says its the coil pack, and its not the one thats on a recall, o well at least i know whats wrong, so a trip to the motor factors in the morning :D
 
£45 for the coil pack, its the block one, had a call to say the car is running fine now, just smoking still a bit, but im sure thats prob just excess fuel and the carb cleaner, a quick blast up the road should sort that out
 
well would you adam n eve it the damn thing is still hunting, its doing my swede in now lol, its running ok due to the coil pack replacement but its still hunting.
 
Try cleaning the plugs, they have probably got really dirty with all the misfiring. Is the hunting any better than it was?
 
nope, its just as bad, also the engine light has come back on and theres another light on aswell, and exclamation mark in a triangle with a circle like round it ????
 
Well Delboy, I have just had my engine check light come on a few days ago due to some hunting issues. The fault was found to be an air leak around the new monster fuel injectors seal inside the manifold. A new set of seals with an oval design rubber cured this problem as off 5pm this afternoon! Worth checking out on your car buddy ;)
 
funny you should say that m8 cause i think i can hear a little air leak round the back somewhere, i might strip the throttle body off aswell and give that a clean while im at it, this car is not gonna beat me :p
 
delboy68 said:
funny you should say that m8 cause i think i can hear a little air leak round the back somewhere, i might strip the throttle body off aswell and give that a clean while im at it, this car is not gonna beat me :p
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Marvellous and good to hear, I wish you the very best of luck ;)
 
delboy68 said:
funny you should say that m8 cause i think i can hear a little air leak round the back somewhere, i might strip the throttle body off aswell and give that a clean while im at it, this car is not gonna beat me :p
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Just remember to take them off the car, clean, let them dry, put back on. Check ALL air hoses as well.

Camshaft sensor also comes to mind, as does the lambda sensor.
 
yet another update on this car , i guy has said now he thinks that the inlet manifold gaskets need replacing or the manifold itself is cracked, how easy is this to remove as i might have a go at it myself to save labour costs, does anyone have a link to a picture or instructions of how to remove the inlet manifold, thanks
 
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