TD5 Smoke screen

[Daniel]

I need help!

Every time I drive my Disco 2a td5 in the same spot after driving along at 100 kph and lifting off the accelerator the engine totally looses power and produces a huge black unburnt diesel smoke screen behind me.

Can someone help with a diagnosis for this?

:wasntme:

[Blknight.aus]

collapsing intercooler hoses.

[nice1guv]

Since it happens when you lift off the accelerator after cruising along at speed, I would be thinking about the airflow.

The turbo hoses maybe delaminating inside and blocking the airflow as you slow, thus black smoke.

Undo the hoses to turbo, starting with the intercooler to intake one at the top and take a look inside.

Edit: Damn phone interrupting my typing!

[Daniel]

collapsing intercooler hoses.

Thanks for that - is the solution to replace with LR hoses or is there something better?

[nice1guv]

Thanks for that - is the solution to replace with LR hoses or is there something better?

LR rubber hoses are fine, but an upgrade would be to silicone ones that last longer and can hold pressure better.
Usually cost a bit more though, but rubber ones from LR can be costly too.

[Daniel]

Thank you for your advice.

I've pulled the hoses off and the turbo to intercooler hose had a huge bubble inside almost totally blocking the duct. I guess when it heats up it stretches so much that it totally blocks the air flow and hence the motors stops.

Who is a good supplier of silicone replants? :D

[discowhite]

go to the bell auto services web site, you can get them here in a week from the UK, for the initial outlay you will never have to replace them. there are lots of ppl on here running them.

cheers phil

[Blknight.aus]

try tombie2.

[Daniel]

try tombie2.

"tombie2" - what is that?

[discowhite]

"tombie2" - what is that?

it equals bell auto services.
tombie2 is a forum member, he dosnt have any in stock and get his from BAS.

cheers phil

[RuaTD5]

Hey all,

My TD5 seems to be getting smokier. It's a D2a with a Graeme Coopers 'chip' and I've already fitted BAS's silicone hoses.

I've cleaned the MAF and MAP sensors with CRC cleaner and checked all the hoses and doesn't appear to have helped much. While doing so I noticed that there is an oily residue on the rigid bit of tubing connected to the silicone hoses between the turbo and the intercooler. I have the silicone hose on the intercooler side clamped on to the tubing where there is a large indent on the tubing. Can anyone tell me if this is correct or should the clamp be placed on the silicone hose side of the indent (hope this makes sense!!).

[td express]

As long as the hoses are over the raised lip, at the very end of the pipe and on far enough to fit the hose clamp, then that is all that is required. Maybe a couple of centimeters.

If you can see oil on the steel section of pipe then this tells me that the hoses are loose and the oily residue from the intercooler is escaping. Re tighten them and clean the area and check again after a while or replace clamps with new ones.


If the hoses are all in good condition, then your smoke issue will be from something else

[Daniel]

Oil seepage around turbo/intercooler hoses/ducts is normal for an older motor.
Exhaust smoke - when? on acceleration? Is your air filter OK?

[Hendrik]

Yep definatly go silicon, the delaminating seams to be more common with the D2a td5s'. Mine had no delamination after 260kms even, but replaced with silicon ones anyway, plus they look siiiic :D

[Daniel]

Yep definatly go silicon, the delaminating seams to be more common with the D2a td5s'. Mine had no delamination after 260kms even, but replaced with silicon ones anyway, plus they look siiiic :D

Thanks for that - only the turbo pipe duct to intercooler hose delam'd -

Have ordered new silcone hoses from England - in the interim instituted a temporary fix by inserting an internal spiral made up out of 3mm fencing wire - yet another 'bush mechanic trick' to add to the list.

Motor runs better than it's ever run since I've owned it - had 180 k and now 205 k.

[discowhite]

in the interim instituted a temporary fix by inserting an internal spiral made up out of 3mm fencing wire


wouldnt you want it on the outside of the hose?? to stop the hose expanding?

cheers phil

[Daniel]

wouldnt you want it on the outside of the hose?? to stop the hose expanding?

cheers phil


If the whole flex duct was expanding, as hypothesised by you, then we would be loosing turbo pressure and the flex duct would be a throw away.

The delam occurs on the inside between the inner 2 layers of flex duct - they cop the full heat.
The outer 2 or 3 layers stay together and hold pressure - they are cooler and therefore stronger.

[discowhite]

If the whole flex duct was expanding, as hypothesised by you, then we would be loosing turbo pressure and the flex duct would be a throw away.

correct, if a hose that contains pressure expands then you loose pressure. like a weak brake line and the fix is often bradided lines, and the braid is on the???outside, to stop the hose swelling. so again i still cant see why you would put the wire coil on the inside of a turbo hose on a td5:eek:

The delam occurs on the inside between the inner 2 layers of flex duct - they cop the full heat.
The outer 2 or 3 layers stay together and hold pressure - they are cooler and therefore stronger.

cheers phil

[Daniel]

Sorry, I assumed that you read the above posts fully - just to fill you in, the flexible duct between the metal duct and the intercooler had delaminated internally (as they seem to want to do) causing a large bubble that expands when its hot and closes off the air flow (internally).

The solution (bush mechanic) was to puncture the bubble and insert a spring wire coil internally into the duct to stop the now loose flap of duct material from closing up the flow.

A brake line is a hose that usually fails by loosing pressure leakage externally.
Any decent brake hose is multiple layer braided and I've also seen them fail by internal delamination causing lack of braking on the circuit that they feed.

If my intercooler duct had failed as you describe it, then I wouldn't have had the smoke screen effect - just increased smoke when the ECU couldn't cope with the sensor inputs relating to air flow/pressure/temp into the intake manifold.

My smoke screen was severe and sometimes accompanied by an exhaust explosion.
How severe? - when follwing at 100 kph and 50 metres behind - total non visibility of 3 lanes of road way immediately behind my td5. James Bond would've been proud of its effectiveness!

[discowhite]

sorry mate it wasnt that clear in my head, you had me myfed as to what this flexable duct was?? no one uses that term here.
usually when the hoses fail the hose delaminates, the pressure gets between the other layers and being thinner now due to the delamination the hose swells and you loose pressure whilst retaining the fuel delivery hence the smoke.

[Daniel]

s
you loose pressure whilst retaining the fuel delivery hence the smoke.

OK - my knowledge of the td5 is not that good but even the most basic EMS for a turbo with electronic fuel management has fuel volume delivery compensation for air intake pressure & temp etc.

I'm sure that the td5 EMS ECU would have all of that otherwise it just wouldn't work.

I'd think that the only scenario where the EMS would not be able be able to cope/compensate is in the final injector tip fuel delivery/spray pattern.
Something as basic and prehistoric as air pressure input would have to be accounted for.

[Tombie]

TD5

AAP sensor at Airbox
MAF after airbox
IAP at inlet manifold

Scenario is boost coming up, fuel delivery rises
AAP + MAF read increased consumption of air
IAP reads increasing pressure at manifold

Hose delamination expands, rapidly blocking flow to IC

IAP pressure drops rapidly
AAP + MAF still reading high

Large burst of fuel then fuel cut off as boost drops
MAF reading drops
Fuelling drops

Delamination bubble deflates

Flow returns, boost increases, fuel increases...

Blockage returns.....

More smoke!

Repeats as long as your holding down the throttle!!!!

[Daniel]

Thanks Tombie

I'm glad someone else 'knows' about the bubble delam issue and not assumes that a delam results in a burst duct!

My td5 didn't have this repeat scenario but instead the EMS detected the total air blockage and shut the whole thing down.

I had to lock it, immobilise it and then unlock, restart and keep repeating until it worked. Eventually had to remove battery connection and do a 'full reboot' - until I discovered the issue and did the internal duct reinforcement repair.

[discowhite]

so where in any of my posts did i mention that
delam results in a burst duct!


none... maybe you should listen to whoever said this


Sorry, I assumed that you read the above posts fully


youve taken my comments way out of context, so dismount and get on with your life.
ive manned up and said i got the wording of your post confused so whats the issue.


cheers phil

[discoveryseries1]

im off to buy some fully sick hectic new pipes for my turbo, mean wile my td5 chews on its cigar. thanks for the tips boys. ;)