Diagnosing a diesel

H

HuntingTarg

Tuner
Points
52
Location
Cali USA
Car
'02 Kia Spectra LS
Hoping for a stop-gap quick fix.
My wife has a diesel workvan - 2005 Sprinter 5cyl 4.2(?) Mercedes engine. The known problems are a torn turbo recirc hose (AFTER the spool ass'y. , leads back to air manifold) and 4 of 5 glow plugs have failed. We live in a temperate climate where it rarely reaches freezing, so the glow plugs are not a big issue.
The vehicle has been going into limp mode progressively more often, and sometimes will not start afterward for up to 45 minutes. It loses a modest amount of oil (about 1 qt/10K miles) and requires frequent coolant fills (about every 5-10 driving days, no evidence of liquid leaks or oil contamination). I found out a few days ago that in a 26-gal (100 liter) tank, she cycles through about 1 tank a month. Is this more likely a turbo problem, or could it be fuel contamination?
 
Used an OBDII reader; I don't know what I did with my readout scribble, but the codes pertained to the turbo and the glow plugs; one other one I can't bring to mind.
As far as I can observe the turbo doesn't emit any smoke; on high revs or high torque loads the exhaust is a sooty grey-black - not thick, but definitely dark-colored. In typical operating conditions there's little or no color.
 
If you don't have an oil leak and there's no excessive oil in your turbo you could be burning oil through the piston rings or a gasket.

Also glow plugs as I understand it are needed for more than just starting, even in hot countries they can be used for a while after starting to help the combustion process in the cold engine.
 
Yugguy said:
If you don't have an oil leak and there's no excessive oil in your turbo you could be burning oil through the piston rings or a gasket.

Also glow plugs as I understand it are needed for more than just starting, even in hot countries they can be used for a while after starting to help the combustion process in the cold engine.
Click to expand...
How could blow-by or gasket loss induce limp mode? My observations suggest the losses aren't serious.
I mentioned coolant loss. Could the turbo be overheating and boiling coolant?
 
Diesel particulate filter. It's an exhaust treatment device which basically traps soot particles in a mesh filter. These are periodically burnt off by increasing exhaust gas temperatures. They weren't especially common in 2005, although I had a 2001 year model Peugeot thus fitted. If you had one you'd know because it would be blocked by now with because of the non working glow plugs.
 
You know, that is something I was unaware of. I know the engine is already dreadfully sooty: Did an oil change with nice watery synthetic; all done, check the dipstick - BLACK. Could soot be the problem? Might I need to do a flush/burnoff?
What I'm about is figuring out why it goes into limp mode so often and why it has problems restarting afterward. Just performing maintenance items out of desperation isn't problem-solving; it's being a muppet. I made that mistake already on the brakes.
 
It's quite normal for diesel engines to black the oil almost immediately. That, contrary to popular thought, is a good thing. It means that the oil is holding the soot particles in suspension rather than it accumulating elsewhere. This is nothing to do with a DPF, it's a characteristic of diesel combustion.
 
Well then, that corrects one myth I never knew about.
It sounds to me like there is insufficient information to isolate the problem. The two existing ideas I have are 1) replace the turbo recirc hose and drive it 500 miles; 2) put a bacticide treatment in the fuel tank and drive until near empty, then fill up. A third idea I have from this thread is to perform an engine flush/oil change, and replace the DPF if it has one and it is servicable. Comments, advice, other ideas?
 
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I wouldn't rush at engine flushing to be honest. I think it's unlikely you have a DPF as if this was clogged there would be a diagnostic light on the dashboard to advise of this. I've attached a generic DPF warning lamp image. Over time manufacturers seem to be standardising on these things.

Definitely replace the glow plugs - these are important to avoid polluting the catalytic converter. Quality fuel and some diesel engine additive such as you mention. Even without a DPF it's worth buying a bottle of DPF cleaner/regenerator cerium based diesel fuel additive. Cerium is used as a fuel borne catalyst to reduce the temperature at which accumulated soot will ignite. This will definitely help unclog the exhaust manifold (header) and the turbocharger of accumulated soot.

Drive it fairly 'prescriptively', too. The irony with diesel engines is that in order to keep them running optimally and economically they need to be driven uneconomically ;)

I really wouldn't rush at an oil flush though.

View media item 4591
 
Got it. I think I will start with the turbo hose, then treat the fuel. Some of the anti-microbe additives mention clogged fuel filters and injectors, "slime films", and "sediment". (Also fuel tank corrosion. yikes!)
'Thanks dudes!' |B(8})
 
Hope we can get you running properly again without serious expense. BG244 is good, however, I am not sure if it is a cerium based additive.

Both Wynns Diesel DPF Regenerator and Diesel Power 3 are cerium additives. I suspect that they are one and the same product in different packaging. I have used them in my non-DPF Passat to good effect. The cerium stuff is actually what was used in first gen DPF cars as a fuel borne catalyst. My Peugeot 406 was 2.2 litre 2001 model. This was the first production car to be fitted with a DPF.

The earlier systems such as these were less problematic than later passive ones. Yes, you were charged about £90 every 50,000 miles of so to replenish the cerium additive reservoir. The actual name of this product was Eolys (Rhodia, formerly Rhone Poulenc). This is much cheaper than a new DPF as seems to be happening now.
 
Yugguy said:
Can of BG244 to start with then 250ml of mineral-based two stroke oil into your fuel tank with every full fill. This will help to keep the injection system clean.
Click to expand...
Whoa whoa; two-stroke mineral oil?! 1) I am not one for mixing products across different operating principles unless I know EXACTLY what I'm doing and why. I have access to a score of fuel additives that pass DOT basic standards. 2) I actually did a chemical cleaning of the fuel system around 5,000 mi. ago. If there is fowling of the fuel system, I'm more suspicious of the fuel itself than buildup in the system.
 
Two stroke is widely used as a diesel fuel additive. I have used it in the past but am not sure about long term effects and injector clogging. Having stopped using it I can confirm anecdotally that there was nothing notable about 2T oil in diesel fuel. If indeed confirmation can be anecdotal :eek:
 
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There's a lot admittedly anecdotal evidence on the Net regarding putting a small amount of 2-stroke into a full tank of diesel - acts as a preventative cleaning agent, stopping carbon build-up in the fuel system if you use it long term. This may have been more useful years back when we didn't have the modern diesel that has some cleaning agents already in it.
 
I am thinking pretty much the same. I definitely wary of these piezo PD injectors. At £450 each I don't want to take any chances. Then again, at that kind of price they should work for a million miles. Except...... It's a bloody. Volkswagen so they won't.
 
-=UPDATE=-
Replaced the intake turbo hose and LIMP MODE IS GONE. Test drive was completely succesful. My wife is 100 miles away and didn't lose power once. It is a Gates hose, the biggest name in automotive hosing, tubing, and ducting, so I do not expect to see THAT problem EVER again on this vehicle.
There is still oil in the turbo system (exhaust emits dark smoke as it goes into boost mode), and I bought an additive I believe will help; its a new product by Lucas to clean injectors and sooty particulate from the fuel transfer and exhaust systems. I also need to install the other hose run (from the crankcase to the intercooler/sensor housing) and clean oil off of the intercooler (outside at least; not certain if it will uncouple from the radiator) and check the airflow sensor (also coated with oil).
It still stalls on starting occasionally - so wondering what's causing that if it ought to start on compression alone.
Everything else will have to wait until new tires.
 
Since my post about 2 stroke I've learnt that if you have a dpf you should use jaso fc semisynth or jaso fd fully synth 2stroke.

Fd is expensive. I am using fc in my merc and it has made cold starts quieter.
 
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