S3 running lean on idle and load

DanA3S3

DanA3S3

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Hi, new to the forum and cant seem to find any kind of similair issue posted....

I recently got a 2007/57 S3 quattro. Knowing from previously owning an Edt 30, i changed the cam follower, RS4 fuel pressure valve and fitted Rev G diverter strait away. Over the past few weeks i have noticed the car becoming more and more hesitant so decided to check on VCDS and Torque pro if there was any codes stored etc and found a system lean code which cleared ok. Few days later i started the car and noticed it idling lumpy, so checked torque pro and the AFR was lean (15 to 16 on idle) and when driving was going to 18/19 and spluttering. But when checking on VCDS there was no codes.

Any one had this? Cars now parked up and id rather ask before spending money on non required sensors etc
 
Vacuum leak? Possibly change your PCV valve as a process of elimination.
 
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Hi, the car has a REVO PCV delete kit fitted?

The issue was there prior to the RS4 valve being done, that was only fitted to see if the OE was nackered.
 
Is it remapped?
List all the mods that you know of, someone might recognise an issue from doing one of them and help you pinpoint an area to check.
 
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Daveyonthemove said:
Is it remapped?
List all the mods that you know of, someone might recognise an issue from doing one of them and help you pinpoint an area to check.
Click to expand...

Hi, had the map checked and its not got a map on no.

It has the following things that im aware of:
Milltek turbo back sports catted
REVO PCV blank (1 outlet)
Turbo inlet pipe with induction kit

Iv also changed the following since getting it:
Rev G Diverter
Cam follower
Fuel filter

The issues only started a few weeks ago, nothing specific to changing any part just seemed to start spluttering a bit when driving then lumpy idle so i checked on VCDS and it was lean as hell so parked it up
 
Check the wiring to your MAF - they are notorious for breaking down. Also clean the MAF sensor with some isophoric alcohol and check the intake for leaks after the MAF. Seems odd that you've got all that kit fitted but no map? Do you have the orig PCV as the delete kits can often cause issues with lumpy running?
 
Just a couple of thoughts.
Although you say the fault was there before you fitted the RS4 valve this is only needed if you are at stage 2+ mapping.
Thinking about the exhaust, are you really sure it hasn’t got a map loaded on as the exhaust should be putting a light on the dash that is coded out with a stage 2 map.
You would expect to find a map with that other hardware on too.
Was the fuel filter a genuine 6.6bar item?
I’d be putting the latest PCV back on. These deletes can cause more problems
If the fuel pump has been disconnected from the little flexible pipe underneath at any time eg changing the cam follower it is possible for tiny pieces of rubber to block the inlet to the fuel pump causing your symptoms. AKS sell replacement pipes and clips. Take care you don’t loose the little washer if you undo the fitting to check. It may have had the 5mm drill mod and swarf is partially blocking the inlet if the person was not careful.
 
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prt57 said:
Just a couple of thoughts.
Although you say the fault was there before you fitted the RS4 valve this is only needed if you are at stage 2+ mapping.
Thinking about the exhaust, are you really sure it hasn’t got a map loaded on as the exhaust should be putting a light on the dash that is coded out with a stage 2 map.
You would expect to find a map with that other hardware on too.
Was the fuel filter a genuine 6.6bar item?
I’d be putting the latest PCV back on. These deletes can cause more problems
If the fuel pump has been disconnected from the little flexible pipe underneath at any time eg changing the cam follower it is possible for tiny pieces of rubber to block the inlet to the fuel pump causing your symptoms.
Click to expand...

Hi, definatley no map as it has been read with KESS and is stock file.

RS4 valve was fitted as planning to do mods once resolving issue.

Fuel filter is a 6.6 bar OE yes.

Fuel pump has metal lines not the rubber outlet.

May look at restoring the PCV system.....
 
I agree with the above comments, that's a lot of hardware without a map installed, usually a stage 1 map is the first thing people do as it offers the biggest 'bang-for-buck' and then start adding hardware to get more from it and advance to stage 2 or above.
I hope you can pinpoint the issue and get it sorted.
 
DanA3S3 said:
Hi, definatley no map as it has been read with KESS and is stock file.

RS4 valve was fitted as planning to do mods once resolving issue.

Fuel filter is a 6.6 bar OE yes.

Fuel pump has metal lines not the rubber outlet.

May look at restoring the PCV system.....
Click to expand...

The fuel inlet pipe on your car is normally the flexible rubber type on an S3 of that age. It should have the BHZ engine. As far as I am aware the hard pipes are fitted to the earlier AXX engine.
Do you have a photo of this?
 
I had intake and full BCS at stock - you’ll be fine. As you have a cat then you may not get the engine check light - some do, some don’t.

The RS4 FPRV is fine to run - basically is relieves pressure on the fuel pump in tuned vehicles. The stock fprv cracks at 130’ish bar - a STG2+ tune can request up to 140 (supply the additional fuel requested) hence why you need to upgrade.

Check that your intake is fitted and sealing properly where it connects to the turbo - losing metered aid can cause issues (metered as it’s after the MAF)

MAF is a good call - in plug it and take the car for a run, see how it goes. I’m still thinking the PCV but I’m not a mechanic.

Out of interest, what is the error code you’re getting on VCDS?
 
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@prt57 - Not to hand but its definatley metal lines as it was a pig to do the RS4 valve

Engine code stamped on head i think says BWA? Just infront of oil filler cap.

@samuelh_888 - i will check the intake to turbo and MAF sealing also later. I removed and cleaned the MAF before fitting the RS4 valve but didnt check the pipe on the turbo.
 
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It should be a BHZ for pre facelift and CDL for facelift. BWA is from the Golf GTI but still from the EA118 family of engines. Don’t think there is much of a difference, main difference is in the crank, rods, pistons and cams.
 
check when putting orginal pcv back in that it seals correctly there should be an O" Ring there and if not then air will easily pass through
 
samuelh_888 said:
It should be a BHZ for pre facelift and CDL for facelift. BWA is from the Golf GTI but still from the EA118 family of engines. Don’t think there is much of a difference, main difference is in the crank, rods, pistons and cams.
Click to expand...

Not sure I'd want to map it beyond 300hp if it's the GTI engine - it is nowhere near as strong as the S3 engine.

This is a good post for looking at common issues ...
http://www.gt-innovation.de/wordpre...posts/2-0l-tfsi-ea113-common-engine-problems/

Can you log rail fuel pressure on block 230 using vcds?
 
So it looks like your car has had an engine swop.
Still intrigued about that hard pipe running to the fuel pump. We have a BWA engine in a TT. They normally run a K03 turbo as standard. As mentioned, if it is running K04 now a stage 1 map would take it near the top end of reliability for that engine.
I wonder which injectors it is running? Any chance of asking the previous owner about all this?
 
prt57 said:
So it looks like your car has had an engine swop.
Still intrigued about that hard pipe running to the fuel pump. We have a BWA engine in a TT. They normally run a K03 turbo as standard. As mentioned, if it is running K04 now a stage 1 map would take it near the top end of reliability for that engine.
I wonder which injectors it is running? Any chance of asking the previous owner about all this?
Click to expand...

I dont have any contact with the previous owner or i would be asking already :(
 
That could go a long way to explain the issues. If the Golf engine is paired to a S3 ECU then the engine might not be able to keep up with the expected inputs, and is causing running issues.
The hardware may also be causing additional issues if the lower powered engine has mods designed for a higher powered engine.
 
We don’t know if it’s an engine swap or just a replacement block - let’s not rush in to assumptions... A good tuner (RTech) would be able to tell you more from a health check than we can.
 
I know it has a K04 turbo on for definate as i checked the tag on it. Injectors im unsure. Im thinking its possible that the tall engine was swapped out and all the bolt ons changed over from the original engine.

Iv had the car a few months and it was running fine, then just seemed to start doing this hence checking the AFR via Torque Pro.

I did try to speak to R Tech as i know there good as they did my Edt30 about 7/8 year ago, but havent had a reply for a while.

Was hoping the log i pulled may be helpful and someone may be able to see from that a possible problem....

As for the engine being BWA, arent these still good for upto 350bhp as long as the torques toned down?
 
Your car seems to be mapped, albeit only a mild tune, as it's peaking at 1.4Bar (stock is 1.1-1.2Bar). Your fuel pressure is low - it doesn't seem to get much above 80Bar, whereas a stock car will run approx 110Bar. Also, if you are reading AFR via an app then you have to question how accurate it is??
 
nluk100 said:
Your car seems to be mapped, albeit only a mild tune, as it's peaking at 1.4Bar (stock is 1.1-1.2Bar). Your fuel pressure is low - it doesn't seem to get much above 80Bar, whereas a stock car will run approx 110Bar. Also, if you are reading AFR via an app then you have to question how accurate it is??
Click to expand...

That log is just before the RS4 FPRV and OE 6.6bar filter was fitted, iv only driven it once since and it was spluttering like mad and AFR via torque pro was 17-19 just driving like miss daisy, and aroun 15.5 on idle.

Map wise, i have sent the file off the car to a guy who does mapping and hes overlayed it with a stock file in winols and there idecticle.

Gonna check all fittings and maf at weekend. Whats bafgling me is that the car ran perfect then all of a sudden this started :(
 
Did you log requested boost and actual boost, as the ecu will request more boost if there is a leak and you can usually see this clearly in a graph?
 
See how it runs with the MAF unplugged.
 
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nluk100 said:
Did you log requested boost and actual boost, as the ecu will request more boost if there is a leak and you can usually see this clearly in a graph?
Click to expand...

I just logged what was on the graph i attached. Read on another poat about logging 003, 118 & 230 blocks.

Even running like a dog, im getting no codes on VCDS :/
 
So after getting my bumper back on from paint i reseated MAF and ran with and without it plugged in... AFR seems to be better but still seeing slightly lean numbers on load but seems better unplugged so gonna smoke test the pipework see if its leaking air in.

Can anyone advise what rail pressure should via vcds when under load?
 
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