Loss of Power/limp mode

Last year We purchased a 2001 Mercedes Sprinter 313 cdi RV which had done 43000kms. Since then we have done 25000kms often in limp mode. We are very familiar with Mercedes service centres around Australia but no one can determine a solution for us as to why we lose power after 10 mins start up. Sometimes just a slight hesitation then it pulls away strongly. Other times if it loses acceleration no amount of coaxing or foot flat to the floor will encourage pick up. It has a new boost pressure sensor, a new pressure control valve, and brake pedal switch. Nothing shows up in the computer (s) and the problem appears to be worsening. We have to stop and wait sometimes 10 mins, sometimes an hour or two. Then it might take off as if nothing wrong. When going well it is running superbly. Getting very frustrated and broke! Can anyone shed some light?

Check the rubber tube at the end of the thin brown pipe which runs from the boost pressure centre to the heater valve on the right side of the engine bay on the fire wall. This small rubber tube may look ok but can perish and needs to be replaced. It can be temporarily cut back and pushed on again or sealed off temporarily with a plug.

Cheers

Ross

Buy yourself a hand help vacuum pump/gauge, they cost about $20 off Epay.
Check each vacuum hose separately plus the diaphragm on the turbo, sounds like you have a vacuum leak.

Thanks guys for your input. This has been checked. At times it loses power instantly but still runs in limp mode. Its like the ignition has been turned off /on although there is nothing wrong with the ignition switch. All filters have been replaced too. It seems like it’s a sensor problem or the computer is playing up randomly. All input is appreciated.

suendave said:

no one can determine a solution for us as to why we lose power after 10 mins start up. Sometimes just a slight hesitation then it pulls away strongly. Other times if it loses acceleration no amount of coaxing or foot flat to the floor will encourage pick up.

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Does the engine work properly for 10 minutes whether idling or loaded then lose its get up and go?

How frequent is the loss of boost? Any relation to outside temperature or to speed or to . . . ?

Another remote possibility if you are positive it is not a vacuum leak - I had a cold/broken solder joint in the ECU of my 2003 long and tall here. Took for ever to find. And it was not found by an M-B workshop.

Where in Australia are you now? Perhaps in a hotel celebrating the continuity of Gray Nomad's franking credits.

Bob M. 2002 MWB 4x4 in Brisbane. 2003 long and tall 2WDs in Brissie and New England

I have had similar issues with Injectors before in a 300c (Chrysler with merc engine). Intermittent loss of power as you describe. Try and have a leak back test done to determine if that is the fault. It's worth a try

You need to get a scanner with live data, and monitor the engine sensors. Any relevant codes? Lots of strange stuff can happen. For example the oil temp sensor could go wonky. If the ECM doesn't get the signal, it thinks the oil temp is really high, and then cuts the power. No MIL or anything.

I would first check the vacuum hoses, and test the turbo actuator solenoid valve. Then check the ambient temp sensor. This assumes you have checked for codes, and none show.

Bob Mac: Yes. Engine runs beautifully when on song. Loss of boost occurs when engine shuts down. No association with temp or speed.
Currently in Kalgoorlie.

Timbo30aus: At 70000kms shouldn’t need a leak test done. However it’s becoming more frequent so worth a shot.

Midwestdrifter: you’re right no codes show. However will get the temp sensor and turbo actuator solenoid valve checked this morning at local garage if he has the gear.

Are the codes being read with the official MB Star diagnostics computer? is so is it able to connect to all of the various ECUs in your van? Is your van a sprintshift trans?

owner said:

Are the codes being read with the official MB Star diagnostics computer? is so is it able to connect to all of the various ECUs in your van? Is your van a sprintshift trans?

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Not all scanners are created equally. And the sprintshift (6 speed semi-auto) is basically star/MB only. The other trans and modules can be read by the Autel 802/808 with correct 20-14 pin adapter (for early years without the standard OBDII socket).

Yes to various scanners. Yes, a sprint shift. Currently in workshop.At this stage it there is a sticky lever that controls the air in the turbo at fault. However having freed that when the key is turned off there is a dump of air which sounds like air brakes. Will keep you posted but it sounds like a minor adjustment is needed now that the lever has been freed.

Have you tried to determine if the problem exists when the air vent is recirculating & or in the fresh air position. A vacuum leak from the fresh/recirculate air vent will only show up if recirculate is set on the dash otherwise the solenoid valve shuts off part of the vacuum line before the leak.

Some information on Sprinter turbo problems
http://www.mercedes.gen.in/mercedes-sprinter-turbo-limp-home-los-diagnosis-fault-finding/