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View Full Version : Partial Limp Home Mode - did Incorrect Fuel or Blown Exhaust do it?


Gwilym
11-05-2015, 10:28 AM
208CDi, Year 2000, 130,000m, Sprintshift

Revs freely to begin then refuses to go above 2800rpm.

Reading other threads on the forum this apparently points to 'Fuel Rail Pressure Sensor Failure'.

Merc have run diagnostics and found no error codes.

Is it possible either of the following caused this LHM?:

1) :thinking:I put 1 gallon Petrol in empty tank at fuel pump then realised error, filled to top with diesel and hoped for the best.:popcorn:

2) Exhaust was blowing for some time before I had it repaired.

Is it possible sensors have been contaminated and an 'additive' might help?

Any other ideas?

Aqua Puttana
11-05-2015, 11:41 AM
The diesel mantra remains. "Operating problems? First change the fuel filter."

My experience.

A gallon of petrol mixed with my 26 gallon fuel tank didn't negatively affect my OM647 diesel. LHM wasn't triggered.

I ran for a while with my inlet pipe rusted off and muffler hanging on baling wire. No LHM issues.

My opinions.

Things like rev limits and DTC's are often clues and not necessarily a specific road to the problem.

I suppose it is possible that the petrol "solvent" loosened something to lodge somewhere in fuel system. I doubt that it hurt any sensors.

So many times these LHM events with no DTC's trace to charge air system leaks. Check all the turbo hoses and other system components very carefully for problems. Often oil on those components is a clue as to a leak in the area.

:2cents: vic

Gwilym
11-05-2015, 11:18 PM
Thanks I am planning to change the fuel filter this weekend and will report back...I realised it hadn't been changed at the last service and could well be the culprit...certainly one of the easiest to rule out and thanks for the other good tips!

Gwilym
01-31-2017, 12:22 PM
It wasn't the fuel filter.

I only rarely road tax and use my sprinter nowadays but it still has this issue.

Revs freely until it reaches normal temperature then refuses to rev above 2800rpm

No fault codes.:thinking:

Aqua Puttana
01-31-2017, 01:36 PM
"Revs freely until it reaches normal temperature then refuses to rev above 2800 rpm."

To me that might point toward a wonky sensor being temperature sensitive. Some sensors become temperature sensitive before eventual failure. Ultimate failure isn't necessarily assured. Harness and connection problems can also be affected by temperature.

Some additional information may be gleaned by using live data monitoring.

vic

PATECO
02-01-2017, 09:38 PM
Check your intake hoses If you have an Intake leak, it will rev fine in neutral, but then under load on the road it will go to LHM.

Gwilym
02-03-2017, 12:03 AM
Will check those things mentioned by previous 2 posters.

Have just received a conversion cable for a cheap diagnostic tool I bought on EBay for 10! and I have the Sprinter road taxed this month, so l'll wake it up and do a few checks. Currently it's snoozing in a storage yard:snore:

Gwilym
02-05-2017, 09:12 PM
Unfortunately the cheap MaxiScan doesn't talk to my Sprinter, despite the EBay ad' saying it would, so I can't do a live diagnostic.

Is a year 2000 sprinter OBD ll compatible at all? Even with the correct conversion cable?

Can't find any air leaks.

If I switch ignition off and re-start it revs as normal for a few minutes then goes back to capping revs at 2800. Both in neutral and while driving.

Think I'll have to find a mechanic with the correct scanner and do a live check.

Thanks for the suggestions.

Gwilym
02-10-2017, 02:26 PM
Could this be anything to do with my partial LHM?:thinking:

82953

While on the subject what is the filter dangling down here?

Aqua Puttana
02-10-2017, 02:39 PM
Could this be anything to do with my partial LHM?:thinking:

...
I wouldn't think so, but I will quickly defer to others with more specific knowledge.

While on the subject what is the filter dangling down here?[/QUOTE]
:idunno:

This could be out in left field.
If it is not filled with fluid, could it be that someone added a filter to the vacuum system? I can't imagine why except to possibly create a bit of a reservoir.

vic

Gwilym
02-10-2017, 07:13 PM
My Sprinter has loads of odd 'extras', some of which were disconnected or deactivated before I bought it.

When new it was converted with what is, or was, called a 'Motability' grant in the UK.

Basically that means that the owner was given a grant of about 20,000 because he was severely disabled and many features were added to the van by a specialist....like automatic fire extinguishing system(removed) and automated system for moving him in to the rear of the Sprinter on his wheel chair through the van on rails to the driving position where, once in position, he had single handed driving controls...or perhaps controls via his mouth I'm not certain because all of these systems were deactivated or removed before I bought it.......This is a very long winded way of saying that the dangling air filter in the pic' above could well be 'left field'!

I wonder how many countries in this world treat their disabled citizens with this sort of respect? :cheers:

Cheyenne
02-10-2017, 07:34 PM
......This is a very long winded way of saying that the dangling air filter in the pic' above could well be 'left field'!



Hi gwilym,

Nice theory but unfortunately incorrect :thumbdown:

I have the exact same filter on my 'standard' T1N!

It is on the end of the vacuum relief line from the turbo actuator valve, the one below the air cleaner. Follow the rubber tube and you should find it leads down there.

Its purpose is to prevent the valve sucking in dirt and dust when the valve changes over to relieve the vacuum in the turbo actuator.
If you think about it, when there is a vacuum applied to the turbo actuator and then the valve switches over (not sure which way though?) the turbo actuator has to draw in air as the vacuum 'dies'.

Does that make sense?

Keith.

Gwilym
02-11-2017, 09:37 AM
If this filter isn't replaced what will eventually happen?

It doesn't look dirty but could that be causing my partial LHM?:thinking:

:doh:By the way I might actually have miss-understood Aqua Puttana's use of the term 'left field'?...is that an American Football term?....we've got 6 Nations International rugby this weekend in UK!:D::drink: