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W210 320cdi bad crank when hot and limb-ish mode

4K views 29 replies 6 participants last post by  Torkil 
#1 ·
Hello and first of all pardon me for my possibly bad English; since im from Finland.

So, to the issue:

Background:

-320cdi
-2001 facelift
-297000km driven
-crank- and camshaft position sensors replaced
-maf recently by old owner
-turbo and cylinder head due to egr fail -> all changed and egr disabled via ecu and mechanical plug
- motor flush + oils and filter
- transmission oils
- less than a year old battery is (stress) tested -> all good

So the actual problem is that the engine cranks bad when its warm. Now that they changed cps/cam pos. sens. it cranks little bit more frisky, but when warm; problem is still there. Should i change the start motor next? Battery voltage is ~8 when cranking and 13 when driving.

The garage fixed some fuel leak next to rail pipe/or something like that and one Fuel gasket are to be replaced next week.

Second problem is that the automatic gearbox goes into limp mode*/ it changes bigger gear fast and kickdown isnt working. When i stop and restart, problem goes away for awhile until randomly it comes back.*

*Soo i recall its not actual limb mode, with only 3000rpm and 2nd gear only. When problem ia there, all gears are used and if i manually select for example 3rd, it goes to redline and there is plenty of power.

(Im wondering if the gearbox itself is failing or some sensor limits the power output)

[When the transmission works fine, all power is there and car runs normally.]

Sucks to have ~200hp diesel when all the Japanese rice-cups overtakes all the time*[https://mbworld]

Last thought: is it just me or is there a big turbo lag on such big (3.2l) engine? I feel like its only 2700-3000rpm when it pulls hard and the best pull is over 3500rpm.

Compairing to wife's 2.2dci laguna which pulls waaaay friskier and from like 2100rpm. Merc has more power at higher rpm tho.

Thanks for your time

-Happy merc owner from Finland
 
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#2 ·
Couple of things come to mind:
8 volts cranking seems too low.
A good battery will show 12.5+ resting volts after an overnight sitting.
Are your glow plugs working and are they the correct voltage? (I've read that some are 6 volt from the factory and inadvertently get replaced with 12 volt ones. At your km's it's possible that they've been replaced or may not be functioning.
The quick shift to high gear and no boost is an indication of limp mode. Can you get the vehicle scanned for codes?
On my OM642's there is no perceptible boost lag, but they are newer and have lower use than yours.

Skippy
 
#3 ·
Okay. Battery is 8volts when i turn the key, ~11,7v when on standstil and plus 13 when driving. Its tested and loaded; proven to be good.

Engine starts nicely when its cold, so it shouldnt be glow plugs(?)

Fault codes from today:


P1664-008 (status: current and stored)
Electric heater booster

This i know to be broken, so not s new thing.

P0100 (status: stored)
Hot film maf sensor
(I took the maf plug off yesterday; no effect on engine running, but limb/no kickdown mode didnt go off with restart)

P1470-016 (status: stored)
Charge pressure control Positive control variation [charge pressue is too low]

P1190-008 (status: stored)
Fuel pressure control valve open circuit.

^new seals are coming next week.

-Ville
 
#4 ·
"Engine starts nicely when its cold, so it shouldnt be glow plugs(?)"

Agree. While the battery volts are on the low side (in my view) it's probably not the critical item.


I'd be inclined to think it's an electrical connection. It's fine when cold, but as it warms the resistance increases.

Low fuel pressure could be a cause of poor starting.

If the cranking is not slow, I'd be not inclined to replace the starter yet.

I did have one fail on my '08. Symptoms were slow crank when warm. Cold cranking was not problem.

Need to have others comment.

Skippy
 
#5 ·
Additional thought:
Did this problem appear after the EGR was eliminated and 'disabled' in the ecu?
If it's not an obvious thing like a funky electric connection, you may need to rethink the EGR work.

Manipulating the emission systems adds a wild card in diagnostics.

Skippy
 
#6 ·
The easiest thing to check is the battery.
Are the given number taken directly at the battery, or from cluster, who usually gives 0.5V less?
11.7 even if you adjust it to 12.3 is low for battery with no load.
Other possibility is bad coil in starter, so checking the amps would be next.
 
#7 ·
Thanks for the replies!

Egr is deleted like a year ago, shouldnt be that.

Cranks rather nicely when cold, like 85% from normal fast start (compared to wifes laguna, where you slighty touch the start button and it instantly starts). Like now when i got home, i had to start/for a while, 2-3secs. But when warm it sort of "promises" and then starts: taaaaaaaaaadada taaaaaadadda tadada tada tada and *start*

Hope that those fuel pressure adjuster (?) seals help.

New starter is like ~200€ so no biggie to swap that. One guy from shop said "change the starter, if its original (16yrs old).

But im thinking that is there two separate faults going on, i.e. starting and powerloss/limb-ish​ mode?
 
#8 ·
In addition:

So the battery is stress tested in the garage/shop. Guy said its even better what the markings/info on the battery says. Battery is about or less than a year old.

Sometimes when engine is warm the cranking sounds/seems like it would have empty battery. You all know the way it cranks when battery is almost empty.

Had this once when leaving grocery store. F-fing nice to wait engine to cool down; and after thermometer went to about 65c it cranked pretty ok. This was BEFORE cps/cam sensor replacements tho..

Cheers
 
#19 ·
In addition:

So the battery is stress tested in the garage/shop. Guy said its even better what the markings/info on the battery says. Battery is about or less than a year old.


Cheers
Even though it is stress tested as you call it, the numbers speaks for itself, 11.6 Volt fully charged is to low.

It is a indicator that the battery is not where it is supposed to be. As a 12 Volt battery the fully charged status should ofcourse be well above 12 Volts, else it would have been called a 11 Volt battery.
 
#9 · (Edited)
I hate it when member come here with "mechanic told me so" story.
Such topics go into multi-pages with no conclusion, when everybody is tempted to add 2 cents.
I think you have 3 possible explanations.
-battery is weak regardless "what he said" and 11.7v is not good start
-your starter has bad coil
-your injectors leak and flood hot engine
As I said, the first one is very easy to check, the other 2 would require amp measuring or SD computer with a guy at keyboard who knows what he is doing.
Deplore did simulated compression test on my 2008 Bluetec, where computer was measuring starter current during turn and could translate it to cylinders psi.
My jaw drop at the time, but I doubt W210 do have such program.
 
#10 · (Edited)
Have you tried to stop the hot engine after a long crank and start, and then turn the ignition off and turn the ignition to crank again ? If you do this, do you still have the same lousy crank ?

I do not think it is related to fuel. The computer turns the start relay on, and the starter engages and turns. When the rpm signal comes to above certain level, it turns the relay off. So with fuel issues the cranking will just be longer, but not lousy and slow.

I would first make sure the connections to the battery terminals, and starter are tight and corrosion free, especially the starter ground. When under the hood gets hot, the starter coils / solenoid will hot too. This increases the electrical resistance (heat soak) , and maybe just the tipping point when you consider other issues like weak battery, corroded terminals, bad ground straps (get your mechanic remove the underbelly cover check under the engine). People replace their starters, and the problem is sometimes solved and they think it was the starter. Sometimes yes, but in many cases, it is fixing the bad connections :). Maybe, in your case, you have a starter that just does not like getting hot :)
 
#12 ·
Well the mechanic is a good friend of mine, so i'd trust his words.

But yep, ill ask him to check the connections/cables, ill ask for a new battery to take in for a test.

And i will today test cranking again after a bad crank when engine is hot, but if i recall correctly i did it once and it worked. And when i was stuck in the grocery store it didn't work tho. Cranked only when engine cooled down.

If the seal replacement and new battery will not work out, i think i'll need to drive to a super-merc specialist, on in 100km from my place.
 
#13 ·
Hmm. I now tried ti crank when hot a few times. No difference between tries. It just promises few times and then fires up. I have a feeling in the back of my neck that it doesnt get Fuel what to ignite or something like that. But idle and running otherwise is so smooth!

Lähetetty minun FRD-L09 laitteesta Tapatalkilla
 
#16 ·
Hey Finland!

In my opinion 11.6 Volt on the battery itself is too low. It is a 12 Volt battery and should have at least 12.4 to 12.6 Volt charged. As someone have mentioned before, these cars electronic sensors are sensitive to low voltages, all kinds of sensors can work the wrong way if they dont get the correct operation Voltages.

As it is a diesel it has higher battery usage(glowing). Even though the battery might be just a year old, i would for sure start there. It is not just the Voltage on the battery, but the Ampere capasity is important aswell. In example a 12 Volt / 55 Ampere battery would be almost useless to youre car, in the arctic conditions.

Ask the local dealer if you can "rent or borrow" a new battery for a few days, and if it solves the problems you tell him that you are gonna buy the battery. Make sure you get a battery with at least 12 Volt & 105 Ampere capasity.

Good luck!
 
#17 ·
Well its a 12v/100amp capasity.

Now that i tried to crank it few times on the parking lot and the asphalt is wet, there is a oily/shiny pudlle/stream coming under the car. So the pressure adjuster seal is leaking quite nicely. Thank god i get new one next week.

Lähetetty minun FRD-L09 laitteesta Tapatalkilla
 
#21 ·
My car behaved like a lunatic aswell with the battery it had when i bought the car, it had bad cranking, or no cranking at all, and as soon i replaced the battery it all sorted itself out.

In the thread i started someone mentioned that these cars sensors are sensitive to low voltages.

Start with that and see what happens!

GL!
 
#24 ·
Useful to know that those readings are 0.5 to 0.6 volts lower than at the battery. Difference is due to distance and small wiring.
It brings your battery closer to 'normal' for discussion purposes.

As I reread your posts I'm still thinking marginal electric connection somewhere. It's OK when cool, but is failing when warm.
The cure can be tedious as it requires taking connections apart, cleaning surfaces and retightening. I've found that you cannot tell by looking at a connection if it's good.
I recommend starting at the battery and proceeding to the engine compartment. Remember that both positive and negative legs are equally important.
Doing this work will help eliminate some factors and may solve the warm starting problem.
Skippy
 
#29 ·
Soooo finally i got the time to fix this problem.

The reason was bad starter. With new one and all fuel leaks fixed it starts like new!


Next is to figure out why it goes to limp mode (gearbox).

When i have time i Will put it into star and read whats causing it!


Also on to do list is sunroof maintenance. Does some one have a good guide for that?

Lähetetty minun FRD-L09 laitteesta Tapatalkilla
 
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