Lumpy Boost

[1animal1]

Righty, I noticed this last night more than ever going up hill and booting it in third, the RR visit a month ago showed up a lumpy boost right up the rev range whilst on boost.

Since then i have changed the MAF, Vag'ed the car (which is showing no faults).....obviously in the process of checking the airlines (see other thread)

Can anyone think of anything else that could be worth changing? after the airlines the plan is to change the standard DV for a new one, then the N75 valve

A local mechanic mentioned taking off the boost pipe and poking the fingers in to check for 'play' in the turbo turbine.....

Any suggestions....or am i destined to become the next Themanthatcan​

 

[grathies]

Last lumpy Boost I had, I sent it back to Cadburys and they gave me a whole box of them free

 

[abdus]

I had a lumpy idle and a lumpy boost too and lacked power...car wasn't firing properly from the 3rd cylinder.

turned out to be the Ignition control module, also known as the inginition amplifier also know as the 2nd stage power output unit. changed it and it was all fine and smooth since

Costs £72 from murraysdirect via ebay.

Not sure if you have it on the S3. My car is an AGU engine yr 2000.

The unit is on the side of the airbox upper part.

BT, if you have that unit, vagcom won't show any fault code. You can test the unit to check if it faulty.

 

[1animal1]

cheers Abdus....how do you test it?

Ryan...why are you here again?

 

[Jay]

Got the same problem mate ever since the remap.... wasted a whole day at JBS a few weeks ago but they couldn't source it. Would love to get it back to how it was immediately after the remap.......now doesn't feel like its been mapped at all.

Changed the MAF which hasn't done anything. I was thinking about changing the DV to a forge but the OEM sounds fine. so it can't be that.

 

[themanthatcan]

cheers Abdus....how do you test it?

Ryan...why are you here again?

You won't have an ignition amp Tim, ours are built into the coil packs.

Think I should rename myself "Themanthatcant" cos the car still isn't working like it should and Jay's post has worried me. JBS assured me that they know what they're on about and can find any fault pretty quickly. I'm seriosuly wondering if it's worth making the trip up there at all now!

Jay - Have JBS told you what your symptoms are? JKM said mine is running dangerously lean and power is back down to standard again. It's almost like the map has just removed itself! What did JBS charge you for the day of diagnosis?

 

[abdus]

You won't have an ignition amp Tim, ours are built into the coil packs.

ah, that's what I wasn't sure about the s3...

sorry, no more help then

Good luck though and hope it gets sorted soon.

 

[grathies]

I still cant belive how many propblems people with standard cars or remaps seems to have on a regular basis!

I thrash the tits off of mine round the 'Ring and UK Tracks loads and have yet to have one single issue! (Thats ****** well done it now hasnt it!)

No chance that youve got some kinda contaminant in your fuel system? Or poor quality fuel? Do you know if your filters ever been changed? Know its a long shot but always an Idea, last thing you want is crap in your filter cauing flow problems slight starvation then a rush resulting in lumpyness.

Appart from that just sounds like an air leak tricking the engine. Either that or somehow your ECUs thrown a total wobbly and its reverting to some strangely flawed map as a result?

 

[themanthatcan]

ah, that's what I wasn't sure about the s3...

sorry, no more help then

Good luck though and hope it gets sorted soon.

You are correct in that some of the S3's do have ignition amps but it's the pre-2000 engines only I believe. The AMK and BAMs certainly don't have them.

Ryan - When I get a suitable weekend weather-wise I'm going to change my fuel filter as I'm not sure if it's ever been done. Will also run some fuel injector cleaner through the system to see if that helps. If that doesn't help then I'm gonna try swapping my throttle body out as vrbob found that his was faulty and caused similar problems.

Tim - Good luck with solving your problem matey Hopefully it'll be easier than mine!

 

[grathies]

It is something that can get overlooked, Ive had issues with them before. Thier part of the 60k diesel service due to water forming in them from the fuel, needs to be drained off but most people dont! If there are any contaminants stuck in your filter, then it could be slighly blocked or even worse passing thru bits of debris etc

Doesnt hurt to try. The Throttle Body should throw up an Error Code if it did go, can be intermittent tho and be an **** to find.

Its times like these that I go and start working on my mates Beetle engine again and think "Why did we have to get all electrical!"

 

[NHN]

I was gonna say could it be a small pipe split that only shows under pressure of course, wouldnt that be a possibility, DV I changed at same time as my map anyway for a Forge one as the oem ones are known to be crappy & never had a prob, constantly popped a pipe of though cause of boost levels, new jubilee sorted that eventually.

Have you checked the main intake pipe that is known to fold under high vacuum which is why alot of us upgraded to the silicon one that forge also do

 

[voorhees]

does 'lumpy idle' mean slight up and down on revs?

 

[themanthatcan]

does 'lumpy idle' mean slight up and down on revs?

That's what I'd class as a lumpy idle, yeah. The more I speak to people the more I hear that it's a characteristic of the 1.8T engine, but I can't believe that my "lumpy" indle could be classed as anything but a fault!

 

[NHN]

Sorry but I whole heartedly disagree it wasnt atall characteristic of the 1.8T, I had an S3 for 7 years, also recently Vagged a 1.8T standard which wasnt lumpy & mine was never lumpy unless it had an issue which was literally only a few minor ones, so no I think you are correct, you appear to have a fault.

I had an APY engine so maybe facelift was different, anyone jump in on this?

 

[alijames]

Sorry but I whole heartedly disagree it wasnt atall characteristic of the 1.8T, I had an S3 for 7 years, also recently Vagged a 1.8T standard which wasnt lumpy & mine was never lumpy unless it had an issue which was literally only a few minor ones, so no I think you are correct, you appear to have a fault.

I had an APY engine so maybe facelift was different, anyone jump in on this?

I have to agree Nigel. My AMK is absolutely rock solid at idle, with or without the aircon switched on.

My only current concern is a clatter for the 1st five seconds from cold start. I'm guessing it's the cam chain/tensioner. I hope it's not on it's way out...

Cheers,

 

[grathies]

When I worked for VAG the engines were known to pulse on idle quite a bit, Its to do with the inertia of the engine

One thing no ones mentioned... Green Coolant Temp Sender, sends signals on heat etc, and they can cause poor running, bout £13 a pop from a dealers, used to do LOADS of them!

 

[NHN]

Yeah that sender is a common one to go, on front ofset middle on pipe IIRC

 

[NHN]

I have to agree Nigel. My AMK is absolutely rock solid at idle, with or without the aircon switched on.

My only current concern is a clatter for the 1st five seconds from cold start. I'm guessing it's the cam chain/tensioner. I hope it's not on it's way out...

Cheers,

Tell me, does the clatter do it at a certain rev's as I had this after the infamouse cambelt 80k change, mine did at 1200-1500rpm then took back & was a tensioner issue

 

[1animal1]

cheers fellas, ill try to answer all in 1 post.......

i had a full service inc fuel filter in feb, new plugs etc all OEM parts so there should be no issue there.

May give the temp sender a go, changed this on my last A3 so shouldnt be a problem. Hopefully this pressure test will sort some issues like the lumpy idle (it seemed to have worked for the VW guy).......

just a thought, if the main intake pipe was collapsing.... surely this wouldnt result in up and down boost? will check it regardless when i pressure test

Ryan ive just gone back to normal unleaded from vpower, which may have amplified the issue, on the RR day though the car wa running vpower and had been for some time.... so not gonna solve my problem by moving back yet i think

Cheers Andy, Ryan.... and everyone else whos posted

 

[alijames]

Tell me, does the clatter do it at a certain rev's as I had this after the infamouse cambelt 80k change, mine did at 1200-1500rpm then took back & was a tensioner issue

Hi Nigel,

No, it's literally as the engine catches. Throttle not touched. It's similar to the old hydraulic tappet 'filling-with-oil' noise I used to get on my old mk2 fiesta, but I don't think it's that.

Cheers,

 

[Jay]

You won't have an ignition amp Tim, ours are built into the coil packs.

Think I should rename myself "Themanthatcant" cos the car still isn't working like it should and Jay's post has worried me. JBS assured me that they know what they're on about and can find any fault pretty quickly. ********!!!I'm seriosuly wondering if it's worth making the trip up there at all now!

Jay - Have JBS told you what your symptoms are? JKM said mine is running dangerously lean and power is back down to standard again. It's almost like the map has just removed itself! What did JBS charge you for the day of diagnosis?

I was there from 10am till 5pm. After an hour I was told that the cars making boost as expected but they dont want to run any more tests as the oil pressure light came on whilst it was taken for a test drive and that VAGCOM showed the pressure is dangerously low. What a ******* surprise!!! I personally think that the oil light didn't come on and the only reason they flagged this up was that I asked how much it would cost for a new oil pump over the phone when i booked it in. I was told that someone would get back to me which they didn't so I just left it and thought i'd ask when i got down there. Anyway Kevin, the guy who was running diagnostics said he couldn't feel the jerking I was on about. So after the oil pump change he asked me to show him, 3 hours later and apparently several adjustments to the map he still couldn't figure out why it was happening. It came to 5 oclock and I couldn't be ***** hanging around any more so just left. Complete waste of ******* time!!

They charged me £50 to tell me that it was making boost and that the oil pump was knackered and another £300 to repalce the oil pump. Even after all this the car feels like its reverted to its original settings.

Their customer service leaves alot to be admired. The guy who worked on the car was sound but there were a couple of other guys who wanted to argue more than help. I think it was Lee who wanted to sell me forge dump almost £30 more than what was quoted in an email I got when i first enquired about getting the map. I think he was lost for words when I told him that Mike had quoted me a different price!

£350 lighter and still got the same problem I went in with. I dont have another day to waste so I give up with JBS. Not happy at all.

Is there anything I can do myself to check whether the CC map is on there at all? Feel like I've wasted over £300 on something thats disappeared.:sign_unfair: I want that feeling back the one that I had when I first had it mapped!!!

 

[voorhees]

That's what I'd class as a lumpy idle, yeah. The more I speak to people the more I hear that it's a characteristic of the 1.8T engine, but I can't believe that my "lumpy" idle could be classed as anything but a fault!

well mine has that and my mate had an 03 TT and that had exactly the same so I think I'd agree in it being a "characteristic" (fault)

 

[NHN]

just a thought, if the main intake pipe was collapsing.... surely this wouldnt result in up and down boost? will check it regardless when i pressure test

Nothings impossible cause if you think the speed of the air in/out the pipe could collapse then expand failrly quickly again so if you think of it like this then it could cause what your saying, but as I said just an idea as one of the issues known when remaps are done on the 8L S3, but I would also be looking for any air leaks & definitely change the DV asap for say a Forge even if doesnt fix problem as they are better then OEM.

 

[NHN]

well mine has that and my mate had an 03 TT and that had exactly the same so I think I'd agree in it being a "characteristic" (fault)

I thought there was an idling sensor on the 8L S3 which would cause this aswell & the old faithful green temp sensor is very common to, even my parts guy pointed that out so must be very common.

As for characteristic I would still disagree, never had lumpiness on mine in 7 years without a known fault & I dont know any S3 fully functional that was like this unless it had one of the mentioned faults.

 

[NHN]

Hi Nigel,

No, it's literally as the engine catches. Throttle not touched. It's similar to the old hydraulic tappet 'filling-with-oil' noise I used to get on my old mk2 fiesta, but I don't think it's that.

Cheers,

Sounds like the hydraulic chain tensoiner is a bit slow to pick up the slack mate, cause if its only when starting for that split second then it cant be anything else I can think of, maybe someone else?

 

[NHN]

I was there from 10am till 5pm. After an hour I was told that the cars making boost as expected but they dont want to run any more tests as the oil pressure light came on whilst it was taken for a test drive and that VAGCOM showed the pressure is dangerously low. What a ******* surprise!!! I personally think that the oil light didn't come on and the only reason they flagged this up was that I asked how much it would cost for a new oil pump over the phone when i booked it in. I was told that someone would get back to me which they didn't so I just left it and thought i'd ask when i got down there. Anyway Kevin, the guy who was running diagnostics said he couldn't feel the jerking I was on about. So after the oil pump change he asked me to show him, 3 hours later and apparently several adjustments to the map he still couldn't figure out why it was happening. It came to 5 oclock and I couldn't be ***** hanging around any more so just left. Complete waste of ******* time!!

They charged me £50 to tell me that it was making boost and that the oil pump was knackered and another £300 to repalce the oil pump. Even after all this the car feels like its reverted to its original settings.

Their customer service leaves alot to be admired. The guy who worked on the car was sound but there were a couple of other guys who wanted to argue more than help. I think it was Lee who wanted to sell me forge dump almost £30 more than what was quoted in an email I got when i first enquired about getting the map. I think he was lost for words when I told him that Mike had quoted me a different price!

£350 lighter and still got the same problem I went in with. I dont have another day to waste so I give up with JBS. Not happy at all.

Is there anything I can do myself to check whether the CC map is on there at all? Feel like I've wasted over £300 on something thats disappeared.:sign_unfair: I want that feeling back the one that I had when I first had it mapped!!!

Take it back asap & tell them straight what you told us, leave with them if need be but you must give them the chance to resolve but at no expense cause you've already paid, tell them your thoroughly unhappy & arguing amongst themselves in front of customer is very poor overall, I've heard nothing but praise for JBS but there's always one, mine was QST, anothers was AMD, but take back for sure as I know from posts I've read they are reasonable at JBS & will resolve for you, personally I am not sure you ever needed the oil pump.

 

[1animal1]

we'll see once the pressure test is done...... definately going to change temp\sender and DV asap to seee if this resolves anything

 

[Jay]

Just a bit of an update. I decided to unplug the MAF to see if it made a difference. Seemed to pull alot better and was definately quicker than before but the jerking is still there. This is the 2nd MAF i'm on since the remap (just under 2 months). Surely it can't have gone already?

I'm gonna try and take a reading with vag com and see what it comes up with.

Also anyone know what sort of boost the 710N can handle?