[B][/B]Test of compression on 316cdi with DAS

jwt

New member
Test of compression on 316cdi with DAS

Hi,

Does any one know what reading you should get on a test of compression from the MB Diagnosis Assistance System on a 2.7L cdi engine with 10k miles?

The result I have got on mine is 209 1/min, is this good?

Thanks

jwt
 

autostaretx

Erratic Member
Re: Test of compression on 316cdi with DAS

I don't understand the units of your measurement (liters per minute? Is that a leak-down test?).

The 2004 2.7L service manual cites a maximum compression of 29-35 bar (420-507 psi),
a minimum compression of 18bar (261 psi)
and a maximum -difference- between the cylinders of ± 3bar (± 44 psi)
((if the symbols get mangled, "±" means "plus or minus"))

The manual's leak-down tests results are in terms of percentage from 10% to 25% depending upon the exit path.
(but they don't specify the -time- for that pressure loss, so i'm at a loss...)

good luck
--dick
 

sailquik

Active member
Hi jwt,
Why are you testing the compression on an engine with only 10K miles.
The rings haven't even seated yet.
Is there some problem.....?
To check the compression to get the results that Dick cited, you have to remove the glow plugs on all cylinders.
Also something very questionable to do on an almost brand new engine.
Or do you have some other type of compression test.......say a measure of the starter current and how smooth it is or something?
What device are you using to get the numbers you provided?
Roger
 

contractor

New member
Hi jwt,
Why are you testing the compression on an engine with only 10K miles.
The rings haven't even seated yet.
Is there some problem.....?
To check the compression to get the results that Dick cited, you have to remove the glow plugs on all cylinders.
Also something very questionable to do on an almost brand new engine.
Or do you have some other type of compression test.......say a measure of the starter current and how smooth it is or something?
What device are you using to get the numbers you provided?
Roger

Excellent points.
 

autostaretx

Erratic Member
Re: Test of compression on 316cdi with DAS

Thanks, I understood the "per minute" as a probable translation of 1/min.
But that still leaves the question of
The result I have got on mine is 209 1/min, is this good?
as a -compression- reading?
209 (unknown units) per minute?

Perhaps an extended character didn't survive the posting process?

--dick
 

sailquik

Active member
Hi Docktor A,
So, the "compression test" jwt has performed with the DAS diagnostics is really just a test of
how fast (RPM's or 1/min) the engine turns over on the starter, right?
209 RPM=209 1/min.
Wouldn't this test be "skewed" by battery voltage, starter condition, engine temp (if done on a cold day) and
a few other "factors" I can't think of at the moment?
Yes, if the engine turns over at 209 rpm...1/min with 13.8 volts and a good starter with the engine at normal
operating temp, you could say the compression is OK, but what if it turns over faster... or slower?:thinking:
Just playing devil's advocate here!
Roger
 

abittenbinder

Doktor A (864-623-9110)
209 1/min translates to 209 rpm.

Why only one number was listed here is the question. The actual diagnostic test (using DAS, DRBIII or SDA) gives a readout of rpm for each cylinder during a timed cranking. And yes, the test can be skewed by starter and battery issues but it is somewhat useful for quick diagnosis which can then lead to a more traditional test using a mechanical compression gauge. Doktor A
 

jwt

New member
Excellent points.
Hi,

I am experiacing some blue smoke on start up, so the MB dealer carried out this test on the computer pluged in to the diagnostic point on the van, bit I still have the problem of a little blue smoke on statup and idle from cold??

So I am thinking is the 209 1/min per cylinder a good reading, or should I look to have a michanical compesssion test done??

thanks for your help

john
 

jwt

New member
Hi Docktor A,
So, the "compression test" jwt has performed with the DAS diagnostics is really just a test of
how fast (RPM's or 1/min) the engine turns over on the starter, right?
209 RPM=209 1/min.
Wouldn't this test be "skewed" by battery voltage, starter condition, engine temp (if done on a cold day) and
a few other "factors" I can't think of at the moment?
Yes, if the engine turns over at 209 rpm...1/min with 13.8 volts and a good starter with the engine at normal
operating temp, you could say the compression is OK, but what if it turns over faster... or slower?:thinking:
Just playing devil's advocate here!
Roger

Hi Roger,

Yes I suspect the same!!!



I am experiacing some blue smoke on start up, and have been from 4k, so the MB dealer carried out this test on the computer pluged in to the diagnostic point on the van, bit I still have the problem of a little blue smoke on statup and idle from cold??

So I am thinking is the 209 1/min per cylinder a good reading, or should I look to have a michanical compesssion test done??

thanks for your help

john
 

jwt

New member
209 1/min translates to 209 rpm.

Why only one number was listed here is the question. The actual diagnostic test (using DAS, DRBIII or SDA) gives a readout of rpm for each cylinder during a timed cranking. And yes, the test can be skewed by starter and battery issues but it is somewhat useful for quick diagnosis which can then lead to a more traditional test using a mechanical compression gauge. Doktor A

Hi,

all five cylinders have a reading of between, 209, and 210, so the MB dealer says that the compression is good?

I think this is the cranking speed for all 5 cylinders in 1 minute, on the MB hand held DAS computer??


I am experiacing some blue smoke on start up, so the MB dealer carried out this test on the computer pluged in to the diagnostic point on the van, bit I still have the problem of a little blue smoke on statup and idle from cold??

So I am thinking is the 209 1/min per cylinder a good reading, or should I look to have a michanical compesssion test done??

thanks for your help

john
 
Last edited:

autostaretx

Erratic Member
(this was written after reading Andy's last, but before the clarification that it was done to multiple
cylinders by JWT)

Okay, since the US service manual doesn't describe this test, what -is- the "valid range" for decent compression?
And since you say "for each cylinder", is the test (usually) done with only -one- cylinder generating compression?
(hence glow plugs or injectors removed from the other four)

If the answer to that is "usually one", then if all cylinders are generating compession, what is a decent crank speed range?
(the compressing cylinder delivers much of its force back to the crank on the down stroke (less leakage and friction), doesn't it?)


thanks
--dick
(mental picture of hundreds of Sprinter owners heading out to estimate their starter speed before it fires up...)
 

jwt

New member
Hi jwt,
Why are you testing the compression on an engine with only 10K miles.
The rings haven't even seated yet.
Is there some problem.....?
To check the compression to get the results that Dick cited, you have to remove the glow plugs on all cylinders.
Also something very questionable to do on an almost brand new engine.
Or do you have some other type of compression test.......say a measure of the starter current and how smooth it is or something?
What device are you using to get the numbers you provided?
Roger

Hi,

I am experiacing some blue smoke on start up, and have been since 4k, so the MB dealer carried out this test on the computer pluged in to the diagnostic point on the van, bit I still have the problem of a little blue smoke on statup and idle from cold??

So I am thinking is the 209 1/min per cylinder a good reading, or should I look to have a michanical compesssion test done??

thanks for your help

john
 

jwt

New member
Hi jwt,
Why are you testing the compression on an engine with only 10K miles.
The rings haven't even seated yet.
Is there some problem.....?
To check the compression to get the results that Dick cited, you have to remove the glow plugs on all cylinders.
Also something very questionable to do on an almost brand new engine.
Or do you have some other type of compression test.......say a measure of the starter current and how smooth it is or something?
What device are you using to get the numbers you provided?
Roger

Hi,

I am experiacing some blue smoke on start up,and have been since 4k, so the MB dealer carried out this test on the computer pluged in to the diagnostic point on the van, bit I still have the problem of a little blue smoke on statup and idle from cold??

So I am thinking is the 209 1/min per cylinder a good reading? as the MB Dealer says it is??? or should I look to have a michanical compesssion test done??

thanks for your help

john
 

jwt

New member
Re: Test of compression on 316cdi with DAS

I don't understand the units of your measurement (liters per minute? Is that a leak-down test?).

The 2004 2.7L service manual cites a maximum compression of 29-35 bar (420-507 psi),
a minimum compression of 18bar (261 psi)
and a maximum -difference- between the cylinders of ± 3bar (± 44 psi)
((if the symbols get mangled, "±" means "plus or minus"))

The manual's leak-down tests results are in terms of percentage from 10% to 25% depending upon the exit path.
(but they don't specify the -time- for that pressure loss, so i'm at a loss...)

good luck
--dick
hI,

I think this is the cranking speed for all 5 cylinders in 1 minute, on the MB hand held DAS computer??


I am experiencing some blue smoke on start up, and have been from 4k, so the MB dealer carried out this test on the computer plugged in to the diagnostic socket on the van, but I still have the problem of a little blue smoke on start-up and idle from cold??

So I am asking is the 209 1/min per cylinder a good reading on the DAS, or should I look to have a mechanical compression test done??

Because the way this test is done, I did suspect flaws???

thanks for your help

john
 

sailquik

Active member
Hi John,
How much smoke do you get.... how long after the engine starts does is the smoke visible?
Since you only have 10 K miles is this issue not covered under your warranty?
If the smoke is not real "objectionable" I'd keep after the MB dealer on the warranty issue, but
continue to drive the van and see if a bit more mileage doesn't help things get "seated in" and
take care for this issue in the longer term.
White/blue smoke makes this a bit more interesting vs black smoke.
White/blue smoke would seem to be from oil burning... like it's getting past the oil control rig (s)
or down the valve guides...something like that.
Black smoke would indicate excessive fuel (in my experience).
Roger
 

jwt

New member
Hi John,
How much smoke do you get.... how long after the engine starts does is the smoke visible?
Since you only have 10 K miles is this issue not covered under your warranty?
If the smoke is not real "objectionable" I'd keep after the MB dealer on the warranty issue, but
continue to drive the van and see if a bit more mileage doesn't help things get "seated in" and
take care for this issue in the longer term.
White/blue smoke makes this a bit more interesting vs black smoke.
White/blue smoke would seem to be from oil burning... like it's getting past the oil control rig (s)
or down the valve guides...something like that.
Black smoke would indicate excessive fuel (in my experience).
Roger

Hi Roger,


when I start the engine from cold and while on idleing you often see a little blueish smoke form the exhaust, if not you just give small plips of the throttle for the blue smoke to show, and will continue like this until warm on adle, or I drive just half a mile or so, when it would have stopped?

When the van is hot, and on tickover it can smell like an old bus /oil burning? but no sign of blue smoke under load etc!!!

The dealer replaced a faulty Turbo 2 months back, as about 1 litre of oil every 2k miles was being burnt? oil consumption seems much better now, as done 1k mikes with no noticalbe usage, but the blueish smoke is still their, they have also checked the injectors on the DAS system and they come back ok, like the compression?

The MB dealer said that he has done all he can under the MB Terms, as the van is within the MB specifications, and MB will not pay them to do any other investigations!!!

The warrany expired last week, but MB are very aware this is still a exsisting fault from nine months back, but and are now saying that the possible cause is low miles, and the van should not be left to idle??

Thanks for the help

John
 

sailquik

Active member
Hi jwt,
Your warranty is only 10k miles? That seems odd.
Have you been idling your engine for long periods of time?
Seems like some sort of an "oil getting into the cylinders" issue to me.
Where do you live.... do they have a "lemon law"?
Beyond that I have no idea what to tell you to try except to drive the van
until it really breaks down/quits...starts throwing codes..... so the MB dealer
can diagnose what's the real problem.
That's the "bad" thing about diagnostics..... they often show nothing wrong
when obviously something is wrong, or they throw a code and the dealer "reacts"
by changing stuff that's probably not broken.
Mine threw a low voltage to the injectors code, shut down on the road until I restarted it.
It cleared the ECU light in 3 starts but the code stayed in memory, and I now have a
new injector in cyl #1. Replaced under warranty at about 25k miles!
Roger
 

rlent

New member
jwt,

I have an '06 T1N with the 2.7L 5 cylinder .... while your oil consumption is excessive, I would say the blue/whitish smoke isn't necessarily abnormal - neither is any "stink" you might smell. My son's '04 T1N stinks (especially after idling) ..... my '06 does as well.

Seems to be a particular smell that is unique to the Sprinter (my RAM with the Cummins certainly doesn't "stink" as much as the Sprinter - it may have it's own unique smell, but if so it's definitely not the same - the Sprinter's smell is very unique and rather noticeable ......)

I have around 135K on the motor - and no excessive oil consumption - in fact, the oil consumption continues to decrease the more miles I put on it. My Sprinter has seen lots of idling (hundreds - if not thousands - of hours) - it is not abnormal for my motor to smoke after it has sat idling for say 4, 6, or even 8 hours or more.

It is particularly noticeable when taking off after idling for long periods and then driving at night with a car behind you - look in the righthand (passenger) mirror and their headlights will be illuminating a blue/white cloud coming from my tailpipe - at least for awhile ...... until it burns off :D:

My guess is that the excessive oil is due to the engine not really being broken in yet, as others have mentioned. Still, checking compression with a compression gauge probably wouldn't be a bad idea.
 

jwt

New member
jwt,

I have an '06 T1N with the 2.7L 5 cylinder .... while your oil consumption is excessive, I would say the blue/whitish smoke isn't necessarily abnormal - neither is any "stink" you might smell. My son's '04 T1N stinks (especially after idling) ..... my '06 does as well.

Seems to be a particular smell that is unique to the Sprinter (my RAM with the Cummins certainly doesn't "stink" as much as the Sprinter - it may have it's own unique smell, but if so it's definitely not the same - the Sprinter's smell is very unique and rather noticeable ......)

I have around 135K on the motor - and no excessive oil consumption - in fact, the oil consumption continues to decrease the more miles I put on it. My Sprinter has seen lots of idling (hundreds - if not thousands - of hours) - it is not abnormal for my motor to smoke after it has sat idling for say 4, 6, or even 8 hours or more.

It is particularly noticeable when taking off after idling for long periods and then driving at night with a car behind you - look in the righthand (passenger) mirror and their headlights will be illuminating a blue/white cloud coming from my tailpipe - at least for awhile ...... until it burns off :D:

My guess is that the excessive oil is due to the engine not really being broken in yet, as others have mentioned. Still, checking compression with a compression gauge probably wouldn't be a bad idea.

Thanks for your considrable input!!!

Regards

John
 

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