boost problem- audi a3 1.8t with twin intercoolers and k04 turbo

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simon_lenard

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hi all
I have a problem with my audi a3. I have a 8l model 1,8t with few mods like twin intercoolers and k04 turbo and it developed a problem basically when accelerating i have a boost for about 5 seconds then it drops to 0 (no boost at all) then second later it is back up again and then its gone again. when i start engine vac is on 18 and max boost i am achieving is about 15 psi what could be the problem why the boost fluctuates? thank you in advance for any info. regards simon
 
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Dumping boost as the ECU is detecting a problem (typically overboost)

Year/engine code will help as would any other mods like ECU (standalone, OE etc), boost controller etc... as your car is clearly not std we cannot use the normal diagnosis thought process without knowing a bit more about the build...

Scan for fault codes and post these up too..

<tuffty/>
 
hi thanks for your reply. my car is 2001 with aum engine. All mods done by previous owner but from what i was told it has standard remapped ecu. there is no boost controller. i dont have diagnostic tool but i will pop in to my mate mechanic to scan it. regards
 
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Humm... standard mapped ECU?? doesn't sound hopeful... K04 conversions on A3's require S3 MAF tubes and larger injectors (S3 ones for a std K04) and the mapping will need to be custom to the setup as it will need to be rescaled for the new setup...

Got any idea on what else was changed? invoices for mapping? dyno print outs?

Prob worth investing in VCDS seeing as you have a modified car... will save you loads in the long run

<tuffty/>
 
on the picture we have my engine bay from what i can figure it out maf has been changed boost controller is manual. I dont think injectors were changed. I havent got any info about mapping! Rsz img 0941
 
so i guess my best bet is just to read the fault codes first? probably start sorting injectors? and start thinking about custom map?


but thats the plan for the future at the moment i need car which wont loose boost half way through overtaking.
i cant spend to much on this car as my volvo c30 is getting a remap and dpf deletion this week which isnt cheap lol
 
Dont floor it and overtake then.
You havent a jar of glue whats going on engine or ecu wise, something bad could happen. And the fact youre boosting to 15 and hitting limp repeatedly suggests the ecu doesnt like one bit whats happening


Some measures to take:
Unplug the n75 sensor electronically, this is the factory boost solenoid, with it unplugged you will only boost to actuator pressure, which should be 5 or 6psi. Unplug it, see what you boost. This could be safe way of running the car until you find out whats done/isnt done.

pull your injectors for a part number, measure your maf sensor tube internal diameter, and maybe once things are clarified can you take it to a respectable tuner who will map it specifically for the hardware it has.
 
...and research whats actually been done mate by the looks... previously you said you have no boost controller but there is clearly a manual boost controller in your picture...

Personally I would consider taking it to someone with experience of this setup (Badger 5 or R-Tech) for example and get them to give it a once over as there are far to many unknowns here by the looks and who the hell knows whats going on...

Had a Mk4 Golf come in a while back with a similar conversion and similar issues... turned out to be the chinese K04 that the previous owner had fitted as chinese hotsides have a habit of having very small wastegate holes and it was suffering from huge boost creep...

<tuffty/>
 
i just sent an email to previous owner which had it for 9 years (he told me he is a mechanic so theoretically he should know what was changed) for some clarification? in mean time if i would adjust that manual boost controller to decrees boost would that help?
 
simon_lenard said:
in mean time if i would adjust that manual boost controller to decrees boost would that help?
Click to expand...
you need to make sure the N75 valve is in there. I cant see it from the picture.
Fit that. I suppose if you can then get the boost down to 5ish psi using the boost controller.

Most important thing you need is fault codes though.
 
Looks like the MBC is all thats plumbed in Karl... ECU will be using throttle plate to cut boost or maybe N259 if still connected as it currently has no way to control boost...

I would suggest turning boost down via the MBC... if this doesn't cure the issue then join the pipe coming from the top charge pipe with the pipe going to the actuator (bypasses the MBC essentially) and this will give you actuator pressure only of around 0.5bar (assuming alls well with the turbo)

Do you have a boost gauge fitted?

<tuffty/>
 
Hi guys just a quick update i went to my mate to read the codes and there was like 15 of them so to be sure what it might be we deleted them all and i going to him again today to check which ones will stay on. Can anyone recommend good garage in west-midland area. I need to sort this out as it is getting on my nerves now.
 
Would have to be a specialist that has experience of this type of build... I don't know about your particular area but Badger 5 is just off J13 of the M5 and worth a visit

<tuffty/>
 
Just received info from previous owner turbo is original s3 one not some Chinese knock off, injectors are standard 1.8t 150 ones as previous owner had fault codes saying mixture too rich with s3 injectors, also n75 baypassed with manual pressure regulator and map is custom done by a guy in Bridligton. Boost doesn't exceeds 15 psi so its reasonable, on second gear boost is dropped almost every time on 3rd and above most of the time i can maintain it but its not good enough for me.
 
Oh dear god.....

Injectors will most likely be maxed out as they are too small for a decent K04 map... chances are the 'map' is not going to be suitable for the setup you have... unknown map may not be scaled for the S3 maf tube (assuming thats what you have)... still too many unknowns dude... proper K04 conversions on K03 turbo'd cars require S3 MAF tube, S3 injectors and the map scaled accordingly... no mention as to what year your car is so don't know if its wideband or narrow band, I assume its a facelift and runs a DBW throttle rather than AGU cable throttle..

In the pic above I notice there is a section of the hard servo vac pipe that has seen heat and has collapsed... these generally split and become a vac/boost leak

Splitpipe

Too many unknowns to be able to diagnose over a forum dude... I assume you haven't scanned for fault codes yet?...

<tuffty/>
 
it has upgraded throttle body from s3 as well. car is 2001 so face lifted model. i am going for code reading tomorrow
 
S3 throttle body is the same as the A3 dude... all 1.8t DBW share the same throttle body...

Your car was an AUM (assuming its FWD and not a quattro)... Was it just the turbo etc that was fitted or the complete engine? can you check what the engine code is?

<tuffty/>
 
don't get me wrong i am not even trying to get it diagnosed over internet as its impossible as you stated to many unknowns, i am simply trying to figure it out what should be my next step, should i start looking at buying s3 injectors iam clueless .Contacted Badger via email and his prices are affordable but due to health issues i would rather use somebody local.

the engine is original one he just added bits to it. its fwd unfortunately.
 
Appreciate your reasons dude and sorry to hear about your health issues... only thing I'll say is Bill has more experience of these cars and engines (especially from the hardware side of things) than most tuners in the UK... an hour of Bill's time would most likely answer everything you need to know and you can go away and fix it yourself or advise someone more local to you of the issues... not saying this because I am biased but there aren't that many out there that could diagnose the setup you have properly and completely...

<tuffty/>
 
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<tuffty/> said:
Appreciate your reasons dude and sorry to hear about your health issues... only thing I'll say is Bill has more experience of these cars and engines (especially from the hardware side of things) than most tuners in the UK... an hour of Bill's time would most likely answer everything you need to know and you can go away and fix it yourself or advise someone more local to you of the issues... not saying this because I am biased but there aren't that many out there that could diagnose the setup you have properly and completely...

<tuffty/>
Click to expand...
Hey tufty sorry to bother you similar to this post just wanna know if s3 twin intercoolers will fit an Audi A3 Quattro 1999? Any info would be great cheers
 
Zman6000 said:
Hey tufty sorry to bother you similar to this post just wanna know if s3 twin intercoolers will fit an Audi A3 Quattro 1999? Any info would be great cheers
Click to expand...

Not directly no... pipework is different so its not a straightforward fit... you would need to have most if not all the S3 pipework and then have to mod things... A3 inlet is the opposite way around, MAP sensor is in the SMIC on an A3, the S3 uses a tube for this...

While its doable the effort required is not worth it IMO... you would be better off using one of the FMIC setups already available for the A3

<tuffty/>
 
<tuffty/> said:
Not directly no... pipework is different so its not a straightforward fit... you would need to have most if not all the S3 pipework and then have to mod things... A3 inlet is the opposite way around, MAP sensor is in the SMIC on an A3, the S3 uses a tube for this...

While its doable the effort required is not worth it IMO... you would be better off using one of the FMIC setups already available for the A3

<tuffty/>
Click to expand...
Thanks you the man :) any links to any intercoolers that won't take too much modification?
 
Its going to be worth taking this car to Badger 5, have a chat, and I guarante within an hour he gives you a list you can progressivley work on to get your car running right.

Its sounds like an utter plonker has done the conversion

"It was running too rich so the 150 injectors went back in". Massive alarm bells.

Save yourself money by biting the bullet and paying for some proper diagnosis up front, and soon enough your car will be sweet as a nut with guided information from the best.
 
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