C270 CDI Starting Problems

[rsmarais]

Hi Everyone,

C270 CDI '02 160 000KM

So here are the facts: Long post but please read

-The car starts fine in the mornings. It does about 8 cycles/4 sec before firing up. I believe this is not optimum.

-When I drive a fair distance, 30km's or more and stop, the engine will fire up again if I try right after turning it of, but it cranks for a while longer.

-If I leave the car for 20 minutes or more, it will crank but not fire up. I then need to labour the starter for around 3-4 auto-cranks before it takes.

-The problem is getting progressively worse to a point where now, when the engine is hot and I turn it off and back on immediately, it really struggles. At least 2 auto-cranks.

-At one stage the car would have no prolems starting but dies about 3 second after firing, then would not start again. At least not without straining the battery.

-No loss in power and no problems when running.

Here's what I know.

- It could be the cam sensor, crank sensor, worn injectors/diesel leak back causing the common rail to lose all pressure?? but then why does it start when cold. Could someone please confirm this for me!

Here in South Africa Mercedes want R25 000 for a set of injectors, converted to sterling its roughly 2000pounds. Yes!!! my pockets are burned full of holes by them already.

Ive done a leak back test on the injectors and all of them gush diesel through the leak back pipes except for one I recently replaced.

I also dont want to throw new sensors at the problem. Ive read many posts where people have changed these to no avail and wouldn't want to make MBSA rich for no reason.

The Question. Based on symptoms and situation, where is my problem most likely to be.

Please help, Im ready to drive an injector through my heart with my bare hands

 

[television]

If it starts fine from cold,, then no air bubbles,, CPS I think,,thats all I can come up with, £47 from Bosch

 

[rsmarais]

If it starts fine from cold,, then no air bubbles,, CPS I think,,thats all I can come up with, £47 from Bosch

Thanks, I suppose I will go and get one tomorrow. Is the cps located on the front of the engine or somewhere around the bell housing?

 

[rsmarais]

Okay.......

So it turned out to be the injectors that required an overhaul. It cost a packet but the car has never been better. It now fires up on the 3rd cycle of the starter (about 1.5 seconds of cranking) irrespective of temparature or any other variable. And consistent every time.

They replaced the nozzles and seals and found broken components (according to them) in two of the injectors.

What I would however be interested to know, is how the ECU knows the injectors are leaking and refuse to fire them? Or was it loss in pressure

 

[Cole@MBS]

The rail pressure sensor see's a lack of pressure, then refuse's the ecu a start signal based on its findings!!!

Its a common fault seen very easy on a star machine!

 

[Richie270]

Cole@MBS,
This seems very much like my recent symptoms, starts ok from cold, but just cranks and not fire after a while having been parked up, e270 cdi W210. I have had suggestions of CPS failure when the sensor is warm/hot.
I took it for a service recently but no mention of injector problems. Would that have shown routinely.
Two manifold flaps had dropped out and replaced, no limp mode or whooshing anymore!! Otherwise runs fine, just warm starting problem.

 

[romi7519]

The rail pressure sensor see's a lack of pressure, then refuse's the ecu a start signal based on its findings!!!

Its a common fault seen very easy on a star machine!

Hi Cole! When you says its easily seen on a star machine, how easy is it?

Seeing a low fuel pressure reading can lead to anything right? How would you narrow it down to injectors/sensors or even high/low pressure pump?

I know you have the knowledge hence the question.

 

[airport Joe]

Airport Joe

Hi all
Ihad the same problem with my c270cdi.Had all the usual suspects checked out,but was none of the afore mentioned.you will probably find the problem is the fuel inlet manifold linkage pins have sheared on one or more of the five swirl flaps.NOT a job for the faint hearted.New manifold £400 and labour about £500.Job took approx 3 days and while engine stripped down replaced crankcase sensor because of easy access.Sensor cost£70. Car now running like new.Good luck

 

[Phillip james Needham]

Hi Everyone,

C270 CDI '02 160 000KM

So here are the facts: Long post but please read

-The car starts fine in the mornings. It does about 8 cycles/4 sec before firing up. I believe this is not optimum.

-When I drive a fair distance, 30km's or more and stop, the engine will fire up again if I try right after turning it of, but it cranks for a while longer.

-If I leave the car for 20 minutes or more, it will crank but not fire up. I then need to labour the starter for around 3-4 auto-cranks before it takes.

-The problem is getting progressively worse to a point where now, when the engine is hot and I turn it off and back on immediately, it really struggles. At least 2 auto-cranks.

-At one stage the car would have no prolems starting but dies about 3 second after firing, then would not start again. At least not without straining the battery.

-No loss in power and no problems when running.

Here's what I know.

- It could be the cam sensor, crank sensor, worn injectors/diesel leak back causing the common rail to lose all pressure?? but then why does it start when cold. Could someone please confirm this for me!

Here in South Africa Mercedes want R25 000 for a set of injectors, converted to sterling its roughly 2000pounds. Yes!!! my pockets are burned full of holes by them already.

Ive done a leak back test on the injectors and all of them gush diesel through the leak back pipes except for one I recently replaced.

I also dont want to throw new sensors at the problem. Ive read many posts where people have changed these to no avail and wouldn't want to make MBSA rich for no reason.

The Question. Based on symptoms and situation, where is my problem most likely to be.

Please help, Im ready to drive an injector through my heart with my bare hands

Hi Everyone,

C270 CDI '02 160 000KM

So here are the facts: Long post but please read

-The car starts fine in the mornings. It does about 8 cycles/4 sec before firing up. I believe this is not optimum.

-When I drive a fair distance, 30km's or more and stop, the engine will fire up again if I try right after turning it of, but it cranks for a while longer.

-If I leave the car for 20 minutes or more, it will crank but not fire up. I then need to labour the starter for around 3-4 auto-cranks before it takes.

-The problem is getting progressively worse to a point where now, when the engine is hot and I turn it off and back on immediately, it really struggles. At least 2 auto-cranks.

-At one stage the car would have no prolems starting but dies about 3 second after firing, then would not start again. At least not without straining the battery.

-No loss in power and no problems when running.

Here's what I know.

- It could be the cam sensor, crank sensor, worn injectors/diesel leak back causing the common rail to lose all pressure?? but then why does it start when cold. Could someone please confirm this for me!

Here in South Africa Mercedes want R25 000 for a set of injectors, converted to sterling its roughly 2000pounds. Yes!!! my pockets are burned full of holes by them already.

Ive done a leak back test on the injectors and all of them gush diesel through the leak back pipes except for one I recently replaced.

I also dont want to throw new sensors at the problem. Ive read many posts where people have changed these to no avail and wouldn't want to make MBSA rich for no reason.

The Question. Based on symptoms and situation, where is my problem most likely to be.

Please help, Im ready to drive an injector through my heart with my bare hands

 

[Phillip james Needham]

Been through all this with my 2003 270
Run for 20 miles
Stop for 1 minute and would not restart
There are rubber fuel pipes from bulk head to the fuel filter via what I think is a non return valve
I change the pipe to the filter with clear plastic. Once the engine stops the fuel typhoons back to the tank, hence the none start
Fitted a new none return valve and car starts fine, but over night the fuel typhoons back again
The remaining rubber pipes must be perished, so replaced the rubber totally with the plastic and bypassed the old non return valve which wasn't working
Problem now sorted.
Will now fit new rubber fuel pipe and keep the new non return valve in situ
Total cost of repairs £13.00
The siphoning back to the tank is the problem due to air leaking back into the fuel pipes

 

[mersum1es]

there is originally no check valve, and tight fuel system prevents draining back to tank. Leaky system can be bubblegum-repaired with check valve.

 

[stumo]

It happens when cold because the fuel is more viscous when cold. So a leaking off injector or worn fuel pump is masked somewhat at cold start. So it only shows up at hot start.

This is complicated by the fact that cam and crank sensors usually start to fail when hot as well. So sometimes it is hard to diagnose at the side of the road because they are totally unrelated causes, but have similar symptoms. BTW the way to check if its cam or crank is to spray some freeze spray or similar on the sensor to rapidly cool it down, then try the hot start again.