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Discussion Starter #1
Guys,

This is my first foray into diesel ownership and the car I have has a history of DPF problems. It is pretty sluggish under 2k revs then the turbo kicks in with a rush. On the way home ( 275 miles on motorway ) it dropped into LHM a couple of times. I cancelled the codes on the move so really didn't get a chance to note them. The previous owner has done this too. Now, though the car starts well, it won't rev and just feels 'chocked'. I suspect that the DPF is completely blocked.

Any suggestions on the best way to tackle this ?

Paul @ Kippen
 

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Guys,

This is my first foray into diesel ownership and the car I have has a history of DPF problems. It is pretty sluggish under 2k revs then the turbo kicks in with a rush. On the way home ( 275 miles on motorway ) it dropped into LHM a couple of times. I cancelled the codes on the move so really didn't get a chance to note them. The previous owner has done this too. Now, though the car starts well, it won't rev and just feels 'chocked'. I suspect that the DPF is completely blocked.

Any suggestions on the best way to tackle this ?

Paul @ Kippen
Buy my brand new DPF advertised on this forum!!

:)
 

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Best bet first is to get the codes read first , and take it from there
Did it display limited performance, or did the engine check light just come on ?
I would check the normal things like inlet manifold for carbon fouling
EGR remove and clean
MAP and MAF remove and clean ( I knew KEZ put a " how to " on here based on the TTID but same applies to the TID )
Check oil level and smell
What power output is it? 120 or 150 ?
How many miles ?
And as SSpeed has one of those DPF up for grabs might as well , grab it !
 

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Havent had the pleasure of removing the DPF and cleaning it as yet(touch wood) however when I do its highly likley I would do something similar to the guy in the video below.
https://www.youtube.com/watch?v=bBH8kuBav6Y
I think the most important part is reverse flushing to make sure the involatile ash is blown out first and whatever chemicals used (Mr Muscle/dgreaser etc) is thoroughly rinsed out and then
the DPF dried out effectively before it goes back on the car.
If I had access to a hot water pressure washer I would use it and even steam if it was available....whatever your weapon of choice.
These things run at around 600 degrees so you are unlikley to do any real damage.
You may wish to try a forced regen first using Tech2 or you can do it cheaply and easily with Opcom.
After the forced regen you can reset the counter again with either TEch2 or Opcom which sets a new baseline for the DPF.
You will also see the pressure drop across the DPF...this will tell you if it is still blocked up or not.(or possibly a sensor problem for example)
After that use the android "DPF info" app with a 1.4 OBD2 dongle and you should get anywhere from 400-1000M between generation cycles depending on the starting inherent back pressure.

In my own experience the most effective thing you can do is avoid repeated failed regens as the car will just keep trying and then failing rinse/repeat until completely blocked.
Unfortunately without the read backs on status (ie DPF info etc) you have no real way of knowing what the car is doing and even the thrash it up the motorway at 3000 rpm for 30mins
isnt exactly scientific and is hit and miss.

After that you may wish to consider a cheap and simple remap.(user Teapots on uksaabs for example)
Both our TID's have the EGR valve software closed and the swirl flaps software open which is equivalent to the hardware mods you will see available.
The hesitation you describe below 2000rpm is another inherent design fault although some cars are worse than others...this again can be compensated for via remap.
Its also possible you have a partially blocked control valve or vac pipe(centre top just behind radiator) or a slightly sticky VNT mechanism in the turbo...the only real way to fix that is to strip the turbo down and clean it a la Mr Muscle.
 

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Discussion Starter #5
Guys,

Thanks for the info. I've watched a few of these videos and have sent for a can of Forte DPF foam cleaner ( perhaps should have bought 2 ) and will start stripping down once it arrives. Car is currently parked up and I can't do much 'cause of the snow ( AGAIN ) but will see what codes it has lurking. It did go into limp home ( twice ) on the way home, not just the CEL. There was one code and one pending. Mrs P @ K was pressing the buttons while I drove and didn't take a note of the numbers.

EGR valve seems to get mentioned in the same breath as blocked DPF to might look at that as well. Swirl flaps and VNT mechanism are terra incognito to me at present !

One video I watched seemed to suggest that blocked DPF should be regarded as a symptom, not a disease and to look for what is the root cause. Certainly this car spend its previous life tootling around the Peak District with very little chance of getting a good blast. With some luck this should be its underlying cause. Oh yes, it has done 152k miles.

Paul @ Kippen
 

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Sounds like you watched the same video as me ( Austrlian chap looks like Grant Mitchell ) .
What power out put has it got ? 120 or 150 .
Easy way to know is look at the oil filler cap position
Left hand side then it's a 120 ( so no swirl flaps )
Right hand side then it's a 150 ( with swirl flaps )
 

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Discussion Starter #7
lizzard-t,

The oil filler is on the left ( N/S ) of the engine so no swirl flaps. One less thing to worry about.

Once I get this sorted is it worth fitting a DTUK add on chip ? I happen to have one lying about.

Paul @ Kippen
 

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Discussion Starter #8
lizzard-t,

With the engine cover off, the engine is a twin cam so must be the 150 bhp.. I guess that you mean right side you mean looking from the front. If I can, I will attach a photo.

Paul @ Kippen 20180203_120931[1].jpg 20180203_120931[1].jpg
 

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Discussion Starter #10
Guys,

So far I have removed the catalyst. What a pig to get the heat shield out ! The cat was pretty choked so has been flushed in the reverse direction. Now removed the DPF. Doesn't look too bad but cleaner just sits there with nothing coming out the other end. Took lizzard-t's suggestion and bought some Mr Muscle oven cleaner. Currently sitting soaking.

Probably take out the EGR and see how coked up it is before deciding whether it's worth taking off the inlet manifold.

Paul @ Kippen
 

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Guys,

So far I have removed the catalyst. What a pig to get the heat shield out ! The cat was pretty choked so has been flushed in the reverse direction. Now removed the DPF. Doesn't look too bad but cleaner just sits there with nothing coming out the other end. Took lizzard-t's suggestion and bought some Mr Muscle oven cleaner. Currently sitting soaking.

Probably take out the EGR and see how coked up it is before deciding whether it's worth taking off the inlet manifold.

Paul @ Kippen
Take off the big inlet hose ( top right as looking from front ) and get a touch and see what the inlet looks like through there . If it's spent it's life tootling around the peak District then it's probably choked .and removal is the only way to clean it properly ..on those the heat shield is the worst thing to remove.. that was the worst part of replacing the turbo on my old 120

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Discussion Starter #12
lizzard-t,

EGR off now. Pretty sooty but I don't know how bad is bad. It seems fairly soft and easy to scrape out. Is it OK to put 12v across the contacts to check that it open. Is it a momentary thing or does it stay on for longer periods ?

Rain stopped play but not before I cleaned out the DPF with Mr Muscle oven cleaner. It's fairly sticky stuff so doesn't dribble down through it easily. I eventually blocked the engine end and the port for the temp gauge and dribbled water in as I sprayed in the foam. Left it for about 20 minutes and then flushed with water. Repeated twice more and the rinsings became clear. It's currently draining beside the fire and will get lifted up onto the top of the stove overnight to dry completely.

If I can get a decent look inside the inlet manifold with a torch and mirror I might try a bottle brush and vacuum cleaner since it looks to be a real pig to get it off. Needs a lot of other bits and pieces taken off as well. Awkward to get to the bolts as well by the looks of it !

Paul @ Kippen
 

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At the egr valve you can get a blanking plate and then drill an 8mm ish hole in it. this reduces the amount of crud going through the egr but without triggering the engine light.

As said above remove the map sensor (one bolt on the inlet manifold). It has a small cage around it that will be filled with crud.

I whipped off the throttle body to clean out the intake as best i could and it was well worth the effort as i was able to scoop and vacuum a lot of crud out.

Replacing and partially blocking the egr and cleaning the map sensor made a mahooosive difference to the cars lower end pick up
 

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As Kwob says whip out the MAP sensor out , I did that with mine as a matter of curiously
Ans it was furred up , so a bit of electrical contact cleaner and a few cotton wall buds and put it back in .
.
 

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Discussion Starter #15
kwob,

This'll be my next task then. DPF and Cat both cleaned off the car and now back in place. EGR cleaned and oil changed. It was VERY black but didn't smell of diesel. Since I don't knoow much about the service history of this car I'll probably do a second change after a hundred miles or so.

So far this has improved things a bit, still sounds a bit rough on cold start up but that might just be normal diesel engines ? It does seem to be running a bit more smoothly and seems to pick up a bit quicker, around 1800 rather than the 2000 before.

Is the blanking plate a purchase job or should I just make one up ? I'm thinking of borrowing an endoscopic camera from a friend to have a look inside the inlet manifold. I can fabricate some long tubes to attach to the vacuum cleaner and use a bottle brush to dislodge as much as I can.

Paul @ Kippen
 

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They do those blanking plates on that well known auction site .
Look under Vauxhall vectra C , same engine
They do sound a bit rough at first start up ,esp when cold air temperature but up where you are the ambient temperature is lower than down here so at the mo , as long as it don't misfire or cough then it's just normal diesel sound .
 

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Just a thought but is your swirl rod still properly attached. Mine came loose causing the car to run roughly on start up. If so, replacements are available on eBay for a few quid.


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Discussion Starter #18
wessel,

I had a feeling that swirl flaps would rear their head sometime. Don't know or understand anything about them so could do with some education.

Paul @ Kippen
 

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Most of the Z19DTH inlet manifolds are well and truly gunged up to the point where you can literally spoon the goo out.
This only becomes a real problem if the swirl flaps start to stick and the control rod comes off.
The long term solution is either hardware ie remove/clean followed by deflap and also blank/restrciting the EGR.
You can do the same thing more elegantly with a simple remap and avoid the hardware mod hassle and cost.

The original Z19DTH inlet manifolds fitted to the Alfas and the Saab 1.9TD 120 didnt have them however some bright spark decided that introducing
turbulent flow in the manifold along with 2nd burn of recirculated combustion gases would improve emissions and efficiency.
Unfortunately the design engineers didnt consider the longer term effects of the crud build up and the additional problems that result.

In real life removing the EGR and flaps has little effect other than the engine takes a bit more time to get to full temp

If you remove the EGR/Throttle body and take a look it will look bad.....but it isnt the end of the world!
https://www.youtube.com/watch?v=8dzb0xJ1PJU

 

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Had a very similar problem with my 55 plate 1.9 16 valve last summer. Had dpf cleaned professionally but limped home again after 300 miles. Turned out to be previous owner had a non genuine SAAB dpf fitted that simply did not have the capacity to run between regens without triggering the dreaded blocked dpf fault code and resulting limp home. Fitted a good second hand genuine SAAB dpf, forced regen with tech2 and problem was solved. 6000 miles later and it regens regularly on it's own. As an old SAAB technician once said to me, "you can't have champagne motoring at beer prices".
 
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