Diagnostic plug problems

Hi guys. After recently buying my 2002 2.7 Sprint Shifter Ex ambo in QLD and driving it home to South East SA, I decided its time to do some general servicing etc.
One major thing I noticed before buying it was the black smoke it blows when you put your foot down - either travelling or stationary. Obviously its overfuelling. The guy I bought it from told me he had the injectors done about 200kms ago (at $1250) and his mechanic told him the black smoke will go as everything beds in. If i take the black cover off, I can see the injectors have been played with (blue silicone evident) but certainly not replaced with new ones.
On the way home we tried replacing the air filter but this made no difference. I have a mate with a Snapon Scan tool. When we went to plug it in we noticed several of the pins were very corroded. Even after using contact cleaner, we cannot get the Scan tool to talk to the Sprinter - not even battery voltage will come up.
Does anyone know what the pin outs of the diagnostic plug are? I did my apprenticeship as an auto elec so testing it wont be a problem once I know what the pin outs are. Looking at the online manuals I cant find the info on the plug anywhere. Any help would be appreciated.

The other issue I have noticed is the Sprintshift is sluggish to down change - in 6th and put your foot down any amount it thinks about it for a few weeks and then drops back to 4th. Also it feels like it is lagging in too high a gear a fair bit of the time and makes like a faulty tailshaft vibration - (worse when cold) Where would be a good place to start looking for this one?

Google is your friend:

http://pinoutsguide.com/CarElectronics/mercedes_obd2_diag_pinout.shtml

If it has a round OBD connector then this may help.

I didn't want to jump in on this because I figured the round connector was OEM.

Geoffs got past that.

Be aware that incorrectly wired aftermarket devices can interfere with scan tool communication. Suspect anything like a new head unit (radio), fleet monitor type devices, GPS location devices, data loggers, etc.

The above said, that type of problem shouldn't affect a basic 12 volt reading as was mentioned.

vic

Or if you want pin outs for the 'rectangular' OBD connector try this...



And the full complement for the 14 pin round to 16 pin J1962...



Does this help?

Keith.

mija5290 said:

One major thing I noticed before buying it was the black smoke it blows when you put your foot down - either traveling or stationary. Obviously its over fueling.

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Its under boosting so its lack of air, not over fueling, the computer meters the amount of fuel so it cant over fuel.

mija5290 said:

The guy I bought it from told me he had the injectors done about 200kms ago (at $1250) and his mechanic told him the black smoke will go as everything beds in.

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Rubbish, just as well that you wont be using that mechanic.
Nothing has to bed in, it should just work as you would expect.

Look for a vacuum leak, disconnect and plug all the vacuum hoses except the one for the turbo and work from there.
Once you have found your leak you will be surprised at how much grunt the 2.7l actually has...

Beds in?? Ive never heard such rubbish......

You can pick up adaptor cables to go to/from the standard ODBII connector to the MB 14 pin on eBay.
I've had one to drive my scangauge, 5 years no problems.

http://www.ebay.com.au/itm/14-Pin-T...104232?hash=item1c59d34ca8:g:eikAAOSwEetV~8Dj

Thanks for everyones advice. I found an open circuit in the power to the diagnostic plug. Now I'll be able to take it back to my mate with the scan tool.

Tooth Fairy said:

Its under boosting so its lack of air, not over fueling, the computer meters the amount of fuel so it cant over fuel.


Look for a vacuum leak, disconnect and plug all the vacuum hoses except the one for the turbo and work from there.
Once you have found your leak you will be surprised at how much grunt the 2.7l actually has...

Click to expand...

I can see the boost actuator moving with vacuum. Tried just the vacuum to the turbo but no different. Put my hand vacuum pump on it and revved the engine but it still over fuels just the same. My guess is the boost pressure sensor is faulty (I guess it has one?)

I have noticed when you switch the engine off there is a vacuum noise for a few minutes from the vacuum switch down near the airbox. Any ideas please?

mija5290 said:

My guess is the boost pressure sensor is wrong (I guess it has one?)

Click to expand...

They all have a boost pressure sensor plus an atmospheric sensor, change them all.

OR, get a reading of what they are reading with a scanner.

mija5290 said:

I have noticed when you switch the engine off there is a vacuum noise for a few minutes from the vacuum switch down near the airbox. Any ideas please?

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There is an air equalizing doohicky that purges for ages after the engine is turned off, mine is on the firewall but could be anywhere i suppose.

Mija.
Fixing the diagnostic connector is good but the problem you have is not likely to show up with diagnostic tools.
Your problem is basic, it is an air leak from the turbo hoses or the intercooler unit. Look for oil leaks from splits in the hoses or the ends of the cooler. Eric

Thanks Eric,
On the way home from QLD the water pump seal went. So I have had the intercooler etc off. I did notice around the plastic pipe that holds the air temp sensor that it was very greasy, but I didnt notice any splits etc. I'll have a good look tomorrow. After refitting the water pump, etc, this "over fuelling" is exactly the same as when I first bought it.

BTW I bought a water pump from ebay UK for AU$93 incl 10 days shipping. Ebay australia was $180! Local autopro was $220!

So the problem could be an air leak between turbo and manifold. Ill report back tomorrow.

With the correct diagnostic tool the Sprintshift gearbox can have a clutch teach and also a gear relearn
The Snap on may be capable , I have had it done at a European car workshop with a Bosch diagnostic otherwise you need a MB Star diagnosis
This may help with the slow gear change

Personally I wouldn't chase any of the transmission issues until after the engine operating problems are resolved. LHM or loss of power can affect proper transmission operation.

Once the engine is operating properly the transmission may fall back into line.

vic

Blue silicon on the injectors is ringing alarm bells here. If you don't get anywhere chasing an inlet leak (pressurizing it with a compressor is a good way if finding it) I would look at pulling the injectors and reinstall them properly. I would wager that the turkey who put the silicone on the injectors also screwed up the critical seat/seal ring interface, probably by putting too thick a copper washer in there - which is known to cause black smoke.

Ok, so I couldnt find any vacuum leaks, or air pressure leaks. Today we used the Snap-on Scan gauge and the only codes I got were for 2 open circuit glow plugs - which I already knew about. Looks like its back to the drawing board.
A couple of questions i have are:

Ambient air was 995HPa. At idling RPM, air pressure was about 1100Hpa and approx 3000rpm was 1300Hpa - does that sound like the right amount of boost? These measurements were from the scan tool. Where is a good spot to fit my own boost gauge so I can check things whilst driving?

Injectors were at 10% and only 16.3% at approx 3000RPM - that doesnt seem right to me. Any thoughts?

One thing I should have tried was to use the hand vacuum pump straight on the turbo whilst it was on the scan tool and see what the boost pressure did then.

I am starting to think the problem is in the turbo. I did notice when I took the air outlet off from the turbo and revved the engine there is no typical turbo whine. Has anyone got a good turbo they want to sell cheap?

owner said:

Blue silicon on the injectors is ringing alarm bells here. If you don't get anywhere chasing an inlet leak (pressurizing it with a compressor is a good way if finding it) I would look at pulling the injectors and reinstall them properly. I would wager that the turkey who put the silicone on the injectors also screwed up the critical seat/seal ring interface, probably by putting too thick a copper washer in there - which is known to cause black smoke.

Click to expand...

I'll give the injectors a try if we work out I am getting enough turbo boost. Thanks owner!

Whip out the turbo and have a look, it should take no more than a couple of hours out and back in.

Don't be too quick to replace that expensive and mostly reliable Garrett turbo charger. The turbo is often the usual suspect. But... as in the movie Casablanca the usual suspect may be a red herring.

If the turbo is disabled by the computer(s)/module(s) then you have no turbo output. That doesn't mean the turbo itself is bad.

Your lack of communication indicates problems. Lack of communication between modules can definitely set LHM. LHM is a reduction in power output. Disabling the turbo control is one of the methods/tools that the ECU can use to limit power.

vic

Is the van in limp mode?
Your original question was about black smoke emissions while driving from QLD and slow gear change down from 6th
It's highly unlikely to attain 6th gear in limp mode

When I had a vacuum leak there was copious amounts of black smoke when accelerating, the engine seemed to run alright but had limited acceleration, all gears were engaged by the auto gearbox, no codes were thrown.

Once I had tracked down the vacuum leak there was no black smoke and acceleration was unbelievable.

NORTON said:

Is the van in limp mode?
Your original question was about black smoke emissions while driving from QLD and slow gear change down from 6th
It's highly unlikely to attain 6th gear in limp mode

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How do I tell if it a in limp mode? Still gets up to 6th gear, etc
The only warning light staying on is glow plug one - I have ordered plugs but they haven't arrived as yet.