How bad is the smell after DPF delete?

T1MMBOJONES

Veteran Member
Joined
Nov 10, 2020
Location
Milwaukee
TDI
2013 CJAA JSW/DSG
There were standards set long before 1991, LOL... man, you guys need some EPA history lessons. There was this US President, Richard Nixon, who signed things into law.
this still has no direct correlation to the standards becoming more strict post 07 like ive emphasised several times now. although it humors me you referenced nixon given the nickname "dieselgate" pays homage to his watergate scandal. either way this is merely my opinion based on patterns ive seen in my 15+ years of diesel ownership. and you know what they say about opinions they are like *******s who roll coal, or ummm, we all have one....
 

SkiBumJH

Well-known member
Joined
May 27, 2016
Location
Jackson, Wyoming
TDI
2009 JSW, sold back 11/17, 2012 Jetta Sportwagen
Hey OilHammer, I've got a diesel smell question for ye: I had my dmf replaced last fall. Prior to that I couldn't smell squat from my car, even after idling in a closed garage for a few minutes.

Now I sense a faint smell occasionally.
At least I think I do. It's that vague.

During the dmf R&R, is it possible that something didn't get reconnected properly and that is producing a slight odor?
I'm fixing to get under in a week and would appreciate knowing what/where to look for anything that could be producing this.

Grazie
 

supramonsta

Member
Joined
Jul 6, 2024
Location
NZ
TDI
2008 MKV Golf GT Sport 2.0
I did a full delete and added a high flow cat, which does nothing, and it smells ridiculous. Comes right in through the hatch, can't drive slow with the windows down, it's awful. Everyone here who says otherwise is lying. "Smells like a candle, only at idle", and other such nonsense. Might sell mine on here soon after I pay it off. Drives great...
I have to agree.

I have unfortunately just purchased a 2008 MKV Golf with DPF and EGR delete. I have to agree with you. Mine is rancid. The smell is impregnated in everything and is unbearable after 2-3 hours driving. Im gutted. I smelt it as soon as I got in the car when I brought it off the guy, but didn't know what it was. I have tried airing it out, driving with windows up, no air con on, recirc on, windows down, one window down a bit, nothing solves it. It has a mild tune and drives wonderfully..... but I've brought a lemon as its unbearable and got it for my son. Can't let him drive it as its carcinogenic as hell isn't it? I wiped the plastics down and the cloth was black....my clothes stink? If the cars been parked in the sun for a few hours and you open it up it hits you....its gross.
 

Nuje

Top Post Dawg
Joined
Feb 11, 2005
Location
Island near Vancouver
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2002 Golf 6MT; 2015 Sportwagen 6MT; 2016 A3 e-tron 6DSG
If it's that bad, I'd be taking a look at the exhaust joins and looking for any soot (telltale sign of leak on a diesel). A deleted car definitely has a smell compared to pre-delete, but it shouldn't be THAT bad.
 

jesus_man

Veteran Member
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Nov 9, 2005
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PNW
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2005 Jetta (gone), 2002 Passat (gone), 2009 JSW (VW bought), 2010 JSW
Something isn't right there @supramonsta. I certainly do smell mine, more so when it's cold than any other time. But it doesn't make me or the interior of my car smell bad as long as I am not standing at the tailpipe. If I am moving, I can even have the windows down with no smell.
 

supramonsta

Member
Joined
Jul 6, 2024
Location
NZ
TDI
2008 MKV Golf GT Sport 2.0
Something isn't right there @supramonsta. I certainly do smell mine, more so when it's cold than any other time. But it doesn't make me or the interior of my car smell bad as long as I am not standing at the tailpipe. If I am moving, I can even have the windows down with no smell.
OK thanks jesus_man and Nuje . I will start looking harder! Gives me hope its not a total lemon
 

Nuje

Top Post Dawg
Joined
Feb 11, 2005
Location
Island near Vancouver
TDI
2002 Golf 6MT; 2015 Sportwagen 6MT; 2016 A3 e-tron 6DSG
Not sure what engine you have on your NZ car, but there's an exhaust joint in the engine compartment coming off the turbo to the exhaust system; another one there that recirculates exhaust gas to be burned again (EGR). The EGR pipe in particular on the Mk5 cars we got here (NAR) were susceptible to the EGR pipes cracking and breaking - didn't look like it because they were still held together, but you could easily feel air escaping from them with the engine even just idling (not to mention the diesel smell).

If you're getting overpowering smell in the passenger compartment, my guess would be something in the engine area - with the EGR being the first place I'd be looking.
 

dbhyslop

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Joined
Mar 9, 2008
Location
Warwick, RI
TDI
2002 Jetta TDI
There’s three specific parts people delete: the EGR, cat and DPF. Which of these components are most responsible for the smell? I would expect it to be the cat, but some in the thread report having the smell with a high-flow cat (maybe high-flow is less effective than stock?).
 

Wilkins

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Joined
Aug 19, 2005
Location
British Columbia
TDI
05 Jetta Wagon 5sp, 10 Sportwagen 6MT
I think part of the problem with aftermarket cats could be they don’t get hot enough. The stock cat is right on the turbo outlet for a reason. They may also be poor quality. That said the only reason there should be a smell in the cabin is an exhaust leak. Hard to say where without knowing what sort of downpipe is installed. As far as I know some don’t have the EGR connection while others do. If your EGR is deleted that’s the first place I’d look. On a CJAA it’s pretty close to the bottom bend, not too hard to get at under the car. If the EGR pipe is still connected the logical place for the delete is at the EGR cooler. Another possibility for a leak is the turbo to downpipe connection and the third is if it has an O2 sensor connection . I can’t think where else it could leak.
 

supramonsta

Member
Joined
Jul 6, 2024
Location
NZ
TDI
2008 MKV Golf GT Sport 2.0
Hey thanks to all for your help. I really appreciate it. I know its time out of your lives to help an unknown :)

Its a BMM engine

The EGR has a blanking plate on the engine. O2 Sensor connection looks fine. Im having trouble seeing down back of engine as its so packed in behind the turbo. I cant see any immediate soot around the turbo area BUT on the rear lip underneath the bonnent (just on the enginge side of the rubber seal).... shes pretty black along there. A starting point!

Looking down at what I imagine is the flexible exhaust joint [stainless honeycomb looking exterior] there seems to be some black externally on that. Not sure how that would be getting in the car windows when at speed?

I will have to try and get my fat ass underneath it or find a hoist to put it on.
 

dieseldonato

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Mar 10, 2023
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Us
TDI
2001 jetta
Flex joints do crack and wear out over time, even higher quality ones. Soot on the weave is a good indication of it being cracked/broken. Usually the cabin outside air intake is somewhere around the cowl area. Depending on airflow and turbulence under hood it can easily make its way into the cabin.
 

supramonsta

Member
Joined
Jul 6, 2024
Location
NZ
TDI
2008 MKV Golf GT Sport 2.0
Pretty sure I have found what it is, and feel like a di*k as I don't think its exhaust gasses.

I may be wrong, but the inner CV has thrown grease directly over [everything] but especially the exhaust flexi joint. Now I did remember when I was moaning to the guy about the smell on my 1500 km trip home, one of the things he told me was that the boot was loose and had thrown some grease on the engine. I did not realize the location of the CV and the extent of the grease thrown around.

Much research tells me its a distinctive horrid smell [burning CV grease], and the noticeable tell-tale issue is that it wouldn't smell until and hour or 2 of driving when the weather was near freezing. Then it would progressively get worse. The grease is stuck in all the holes in the outer mesh of the flexi-joint, so takes a while to heat properly. It explains why the odd time I got out of the car and it stunk externally while parked outdoors.

Dumb thing is, I swore the smell in the car was the same smell as when I hopped out of my Mitsi Pajero after just turning the engine off....maybe I was dreaming, but geez it smelt the same. In my head maybe?

So now off to get some brake cleaner and try and clean it off. I have read though that it could be a couple of months before it will come right?

I will report back in due course. Thank you to all who pitched in, really appreciate it.....
 

supramonsta

Member
Joined
Jul 6, 2024
Location
NZ
TDI
2008 MKV Golf GT Sport 2.0
Maybe hit it with a pressure washer.
Yeah its a bugger to get to. Im going to have to lie under the car to hit it with brake cleaner.....while trying not to get drenched in the nasty stuff. Then the plan is to lie under there with the pressure washer. Thats going to be fun :) Needs to be done though
 

jesus_man

Veteran Member
Joined
Nov 9, 2005
Location
PNW
TDI
2005 Jetta (gone), 2002 Passat (gone), 2009 JSW (VW bought), 2010 JSW
Maybe a degreaser of sorts? Simple Green concentrate for instance. Let is soak a while, then pressure wash. The issue is now it's cooked on.

Oh, and remedy that CV.
But sounds like it's good news to me!
 
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