Downpipe Issues

[pog]

Hi guys,

Recently installed a custom 3" downpipe with a 200 cell HFC (Magnaflow).

Long story short, the CEL comes on. Turns out the defowler (o2 spacer) is facing to the rear of the car. Apparently this is wrong and it should face front to the car.

So we change it around and have it facing the front, clear the codes and off we go. All seems fine until 80kms later, the CEL comes on again.

Now I'm stumped.

Can anyone chime in and help? I'm heading to Exoticars next week to have this looked at but in the meantime, I need to know there is light at the end of the tunnel.

---------- Post added at 11:19 AM ---------- Previous post was at 11:06 AM ----------

Just spoke with Derek from European Automotive and apparently APR (from what he has been told) has software that eliminates the CEL for their APR Exhausts but also tunes the car to the newly installed APR exhaust.

Mine is a non-APR exhaust as mentioned above, so therefore it's going to cost $250.00 for the CEL eliminate and tune. According to the website it says it's a free upgrade to all existing APR Software customers. Not sure if it's referring to when you purchase their exhaust or regardless.

I didn't know APR write a tune for an exhaust stage other than what's offered for Stage 1. I'm saying this because I spoke with Guy and I think he mentioned APR don't do this for the Polo's.

Can anyone chime in here as well?

[VWindahouse]

I think Derek is trying you on sorry mate. My understanding is exactly what Guy told you. There is no APR exhaust tune, all the flash will do is eliminate the CEL caused by losing your rear o2 sensor when you upgrade your DP. Give Guy a call mate, I'm sure he has another dealer in your area that won't try to screw you out of 250 clams.

[pog]

Yeah when I asked 'Does it tune it for you as well as eliminate the CEL' he responded "That's right, well.. thats what we've been told by APR". The tune will probably do nothing for me as I do have a 3" downpipe versus APR's 2.5".

I'm not trying to bad mouth him here, but I thought $250 to remove a CEL from an existing APR customer was a bit on the high side. I generally prefer to deal with Guy, mainly cause he's on here, but everytime I've called him he has always been helpful to me even though I'm in Sydney.

There really is only one other person, and that is Muller and Muller.

Thanks Windahouse, I'll speak with Guy soon and see what goes.

[Bflat]

Just to clarify, you've got an aftermarket o2 spacer (like a 42DD design one???) that you've plugged into the o2 sensor socket and it's still not eliminating the CEL?

My CEL appeared a few days after I installed my APR DP and the o2 spacer got rid of it straight away.

You may find they fould on the exhaust tunnel somewhat (mostly the cable just being stubborn) but it should be too hard to make it face the right way (towards the driver, IIRC).

[pog]

Just to clarify, you've got an aftermarket o2 spacer (like a 42DD design one???) that you've plugged into the o2 sensor socket and it's still not eliminating the CEL?

My CEL appeared a few days after I installed my APR DP and the o2 spacer got rid of it straight away.

You may find they fould on the exhaust tunnel somewhat (mostly the cable just being stubborn) but it should be too hard to make it face the right way (towards the driver, IIRC).

Yeah I have an aftermarket o2 spacer (like the 42DD design) that I've plugged into the o2 sensor socket and it eliminates it for 60-80 kms then it appears again.

I'll get underneath the car again, check the sensor, make sure it's facing front, check the wiring and for goodness sakes, check those bolts, especially the turbo bolts especially after driving around for about 2 weeks. I believe they tend to become slightly loose after an exhaust install.

---------- Post added at 12:31 PM ---------- Previous post was at 12:28 PM ----------

I'm getting the same symptons as this guy:

CEL and whistle after APR Downpipe/Carbonio Intake install - AudiWorld Forums

On very low throttle I have a whistle. It could be that of the HFC, and 3" downpipe but it's quite noticable. Anyone have a similar experience?

Engine mods:

•APR Tune
•SEAT Intake
•3" Downpipe with 200 CELL HFC

Before anyone says anything, yes it's going to be diagnosed next week, but I just want to gather information prior to heading there. Cheers

[clicht]

Just a quick check...is aprs downpipe not a 3".
You mentioned 2.5"...

Yeah when I asked 'Does it tune it for you as well as eliminate the CEL' he responded "That's right, well.. thats what we've been told by APR". The tune will probably do nothing for me as I do have a 3" downpipe versus APR's 2.5".

I'm not trying to bad mouth him here, but I thought $250 to remove a CEL from an existing APR customer was a bit on the high side. I generally prefer to deal with Guy, mainly cause he's on here, but everytime I've called him he has always been helpful to me even though I'm in Sydney.

There really is only one other person, and that is Muller and Muller.

Thanks Windahouse, I'll speak with Guy soon and see what goes.

[pog]

Just a quick check...is aprs downpipe not a 3".
You mentioned 2.5"...

APR - High Performance Development for Audi, VW and Porsche Vehicles.

"APR Australia is proud to introduce the new exhaust system for the 9N Polo GTI. This new system is 2.5" in diameter throughout, and constructed in high-quality stainless steel."

[jasonc23]

I have a 3inch downpipe with a high flow cat (100 cell or less) - never had an engine light with my o2 spacer. Also had one on a decat pipe without any issues...maybe try a different spacer?

[pog]

I have a 3inch downpipe with a high flow cat (100 cell or less) - never had an engine light with my o2 spacer. Also had one on a decat pipe without any issues...maybe try a different spacer?

Hmm, might need to try the 42DD spacer then. But I want to be sure before having to buy another. What one do you have Jason?

I will say this though - when I got it scanned for errors, the o2 sensor was the problem. I'll take a look underneath the car tonight, and if everything (exhaust bolts and sensor), look fine, I'll try a new spacer.

As a process of elimination, does it matter what HFC you have?

[Greg Roles]

It should not matter which way an angled spacer is orientated, well not with 42DD that I know of. The whole idea is to remove the sensor from the direct flow, and as it is now on an angle it will only sniff a small fraction of the exhaust and be happy. All I can assume is the one you have allows simply too much gas through to the probe, and any sort of physical obstruction you can tack weld or bolt in place will assist such as a mesh between the flow and the probe. I have had a mad run on angled spacers this month, and am totally out, plus have pre sold the ones arriving shortly so it will be weeks before I have more I am afraid.

[bfeboi]

Did you go to Hax at Performance Exhaust centre? he called me saying one of his customers had the exact same thing you were talking about.

[pog]

Did you go to Hax at Performance Exhaust centre? he called me saying one of his customers had the exact same thing you were talking about.

Yeah I did goto Haks. I called him in the morning and he told me he was going to follow up. God I love the guy, man of his word!

I'm assuming you got the test pipe file from APR with your downpipe.

[bfeboi]

i did the downpipe and apr tune in one go so i don't have any issues that you were referring to

[pog]

i did the downpipe and apr tune in one go so i don't have any issues that you were referring to

No problem. Will be diagnosed tomorrow. Did Haks do you custom catback?

[bfeboi]

yeah. he did my cat back with 2 resonators and magnaflow back box. I love the sound of it