Heavy Black Smoke under accelaration

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Papa TDI
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Heavy Black Smoke under accelaration

Post by Papa TDI »

Hi All

I have'nt been acive for almost a year now however i've been keeping up with posts etc.

Sorry for the repost as i've posted this before however my non-participation has dearly costed me.

My MK4 TDI smokes a lot with black smoke under accelaration even at normal accelaration when i pull off from a stop sign or robot etc though once i'm on fifth gear and cruising the black smoke goes away unless if i have to overtake or increase my speed,He's got 378k on the clock so to remedy this changed from Shell VPower Nitro 50pp to Sasol 10pp for a cleaner diesel which i must say there was no diffrenece so after reading on this forum about these babies running better on 50pp i switched back to Shell VPower Nitro 50pp still the problem persists.

I had the full cambelt service done,water pump,tensioners etc about a month ago with genuine parts however still no luck.Also he blows blue or white smoke at warm up in the morning but with 378k under his belt guess that is normal corect?Forgot to mention there's a slight consumption of oil, i had a small leak on my sump which was fixed with a new sump from Goldwagen Kensington a while back so thought that was gonna solve the problem however it's still there though on a minimul scale as a result i top him up fornightly or so with Castrol Magnatec Professional 5w 40 courtesy of VW Benoni Citi.This morning before starting he coughed up a great deal of soot which he does sometimes after i crank him and he gets a rough start then he would cough up soot before starting to warm up, i don't rough him up at take off or pull my gear change to max or any other times and i follow all rules of a diesel turbo engine e.g corect service intervals etc thus fur.

I've also come acoss that there might a boost issue also in the process coz accoding to me he responds late especially on uphill slopes,i commute daily from Parktown to home and i use Munro Drive to beat traffic in Houghton so if anyone here is familiar with the area esp Munro Drive you'll know its one hell of an uphill slope especially towards the curve at he top and if there's a car in front of me i can't put 3rd gear as i have to gain enough speed to do so therefore i have to stay on 2nd gear and my revs up high all the way which i would'nt want to do as it puts the turbo under strain so i believe?

Sorry for the long Titanic novel as i don't wanna sound like nagging wife,however these are the underlying issues with my beloved diesel burner not sure if they're inter related or they can be assimilated accordingly?Well i'll leave that to the member's expectice on this Club.Besides the above in the five years we've been together, he's a well behaved and trusted fellow and planning to keep him longer.

Thanx & Regards
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VAG Fan
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Re: Heavy Black Smoke under accelaration

Post by VAG Fan »

Regarding the soot and rough start:
1) If the cambelt was recently changed, then I would start by re-checking the injection pump timing. I have read quite often that the pump timing can go out some time after work was done on the cambelt. The pump timing can only be set properly with VCDS.
2) Are the injectors still original? My understanding is that they wear with time, which leads to a bad spray pattern, causing problems like bad start or soot. Apparently Bosch can recondition them, but I must still investigate this.

Regarding the loss of power:
1) Is the turbo still original, or has it run more than 100k km? If so, the VNT mechanism may well be stuck, leading to underboost or (more probably) overboost which can cause the ECM to switch into limp mode, to protect the turbo. If you know where to look, you can see the actuator lever. When you start the engine, it should move down (vanes closed) when you start the engine, and back up (vanes open) when you stop the engine. The travel of the lever is about 15 mm. If it's much less than that, then your VNT is stuck. You can typically get out of limp mode by quickly switching the ignition off and back on.
2) You can check your inlet manifold for fouling by removing the boost pipe and looking inside the manifold.
3) If your car still has its catalytic converter in the exhaust, this may be blocked. This would rob the engine of power, especially at high loads and revs.
Mark R.
- - - - - - - - - -
2004 VW Golf TDI, type 1J, AHF, 317k (2016-current) --- daily
1990 VW Fox, type 16, HM, 304k (2005-current) --- spare runaround
Previous:
1992 Audi 500 SE, type C4, AAR (2001-2020) --- nice while it lasted
1983 VW Golf GTS, type 17, FR (1992-2005) --- most fun car I've ever had
1978 Audi 100 GLS 5E, type 43, WC (1991-92) --- died in the side of a Rekord who cut me off
- - - - - - - - - -
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panic-mechanic
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Re: Heavy Black Smoke under accelaration

Post by panic-mechanic »

If it smokes it could be a lack of boost or a faulty MAF or an injector problem. BUT usually injector issues are followed with white or blue smoke.
Yes injectors can be redone - go to northern diesel in pretoria.
but start with checking how much boost it makes and if the MAF is working right. Yes use VCDS to check the fuel timing. Needs setting after a canbelt change.
Stephan van Tonder - Jhb - Putfontein Benoni
'05 Audi A6 3.0L TDI Avant
'09 Touareg 3l TDI
'13 VW CC 2l tdi (repair project)
'05 Touareg v10

Perfect Power dealer. I do dyno tuning.
Rudi46
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Re: Heavy Black Smoke under accelaration

Post by Rudi46 »

To see if Maf is dead, hook up VCDS and Check the requested and Actual Maf readings. If the differ alot on a drive that can be your problem.
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VAG Fan
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Re: Heavy Black Smoke under accelaration

Post by VAG Fan »

How can a sensor reading like MAF be a "requested" quantity if it only measures flow?
Does the ECM actually calculate an expected air flow from revs and boost pressure?
Mark R.
- - - - - - - - - -
2004 VW Golf TDI, type 1J, AHF, 317k (2016-current) --- daily
1990 VW Fox, type 16, HM, 304k (2005-current) --- spare runaround
Previous:
1992 Audi 500 SE, type C4, AAR (2001-2020) --- nice while it lasted
1983 VW Golf GTS, type 17, FR (1992-2005) --- most fun car I've ever had
1978 Audi 100 GLS 5E, type 43, WC (1991-92) --- died in the side of a Rekord who cut me off
- - - - - - - - - -
Ashveer03
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Re: Heavy Black Smoke under accelaration

Post by Ashveer03 »

VAG Fan wrote:How can a sensor reading like MAF be a "requested" quantity if it only measures flow?
Does the ECM actually calculate an expected air flow from revs and boost pressure?
Lol it does have a requested maf value, group 009 if im not mistaken. I dont know what values are used to calculate it though, probably engine rpm + n75 duty cycle maybe even linked to the fueling maps. A tuner should know better..

Personally i rather get it deleted. Thats 1 less electronic kak part not to ever bother about again.

Sent from my SM-J500F using Tapatalk

When a car tailgates me, i slow down - then floor it and give them a cloud of diesel smoke to choke on :driving:
Papa TDI
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Re: Heavy Black Smoke under accelaration

Post by Papa TDI »

panic-mechanic wrote: Thu Jun 21, 2018 1:04 pm If it smokes it could be a lack of boost or a faulty MAF or an injector problem. BUT usually injector issues are followed with white or blue smoke.
Yes injectors can be redone - go to northern diesel in pretoria.
but start with checking how much boost it makes and if the MAF is working right. Yes use VCDS to check the fuel timing. Needs setting after a canbelt change.
Thanx Panic, i think it would be cost effective for me to start from checking the boost & MAF sensor last resort as injectors coz i know they don't come cheap to fix let alone recondition.My cousin Bro is clued up with VW & Audi so ill let him assist with VCDS and will update as soon as hes done.
Papa TDI
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Registered for: 6 years 8 months

Re: Heavy Black Smoke under accelaration

Post by Papa TDI »

VAG Fan wrote: Thu Jun 21, 2018 10:58 am Regarding the soot and rough start:
1) If the cambelt was recently changed, then I would start by re-checking the injection pump timing. I have read quite often that the pump timing can go out some time after work was done on the cambelt. The pump timing can only be set properly with VCDS.
2) Are the injectors still original? My understanding is that they wear with time, which leads to a bad spray pattern, causing problems like bad start or soot. Apparently Bosch can recondition them, but I must still investigate this.

Regarding the loss of power:
1) Is the turbo still original, or has it run more than 100k km? If so, the VNT mechanism may well be stuck, leading to underboost or (more probably) overboost which can cause the ECM to switch into limp mode, to protect the turbo. If you know where to look, you can see the actuator lever. When you start the engine, it should move down (vanes closed) when you start the engine, and back up (vanes open) when you stop the engine. The travel of the lever is about 15 mm. If it's much less than that, then your VNT is stuck. You can typically get out of limp mode by quickly switching the ignition off and back on.
2) You can check your inlet manifold for fouling by removing the boost pipe and looking inside the manifold.
3) If your car still has its catalytic converter in the exhaust, this may be blocked. This would rob the engine of power, especially at high loads and revs.
Thanx VAG Fan

Regarding the soot and rough start

I'll speak to my cousin Bro who's very clued with VW & Audi to check the pump timing with VCDS

As for my injectors not sure whethe they're original or not as i got the car @ 201k five years ago it's now siing @ 378k

Regarding the loss of power

My Turbo was reconditioned some time last year let's say about +- 15k ago so i will diect him towards VNT mechanism and other related issues regarding the cartalytic conveter i'm not sure my car still has or not.

Will report back with developments afterwards.
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