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View Full Version : 2003 Sprinter dying because of fuel rail overpressure


billnation
03-03-2017, 03:13 PM
2003 Sprinter conversion from Leisure, ~ 190,000 miles, recently had filter, filter assembly, all non-metallic fuel lines, and HP fuel pump replaced with new parts. (Van purchased from father-in-law at 140K about 3 years ago - he was original owner and took good care of it.)

Prior to these repairs, the engine would instantly die with heavy throttle and rpm ~ 3,200 and would reset after coasting to a stop and cycling key to start. After $3K, the engine is doing the same thing. Also had intermittent starting problems prior to work, and these persist as well.

I love the Sprinter conversion for its RV use, but I'm about to shoot the engine. This vehicle has been towed more in 3 years of ownership than all vehicles I've driven in > 40 years. Finding people who know Sprinters is difficult, and finding people to work on them is even more frustrating.

Mostly venting but would greatly appreciate anyone who can help.

lindenengineering
03-03-2017, 05:31 PM
Well of course no scan live data or fault codes offered!!!
But given what you have state as a proper repairs to fix, my thoughts move to a rail pressure control fault.
If there is excess pressure "spill" it will cut out!

Equally if there is excess through flow through the injector(s) due to wear, at full demand the rail pressure control can't adjust for it so it throws a code as excess pressure fault!
That is simply because the system gives its all but cannot cope with the demand at full throttle /demand so it cuts out!

All simple stuff if you had some training on common rail FIE systems

So either a rail control pressure kit at about $12.
OR
The big Kahuna!!!One or more injectors at about 275 to $350 a pop!

My bet would be the injectors!
Hope that helps
Dennis
Mechanic

talkinghorse43
03-03-2017, 07:34 PM
2003 Sprinter conversion from Leisure, ~ 190,000 miles, recently had filter, filter assembly, all non-metallic fuel lines, and HP fuel pump replaced with new parts. (Van purchased from father-in-law at 140K about 3 years ago - he was original owner and took good care of it.)

Prior to these repairs, the engine would instantly die with heavy throttle and rpm ~ 3,200 and would reset after coasting to a stop and cycling key to start. After $3K, the engine is doing the same thing. Also had intermittent starting problems prior to work, and these persist as well.

I love the Sprinter conversion for its RV use, but I'm about to shoot the engine. This vehicle has been towed more in 3 years of ownership than all vehicles I've driven in > 40 years. Finding people who know Sprinters is difficult, and finding people to work on them is even more frustrating.

Mostly venting but would greatly appreciate anyone who can help.

Reminds me of the issue I had with mine after picking up water-contaminated fuel. Your title says rail overpressure, so if that's what the DTC tool says, then your fuel rail pressure control solenoid (back of the rail) might be sticking or sticky. Meaning it's not doing what the ECM asks it to do to control rail pressure within prescribed limits. My issue was repaired by cleaning out the fuel tank (removed and dumped) and replacing the rail w/ pressure control solenoid and pressure sensor. Just the rail pressure control solenoid can be replaced on an '03, so that might be all you need. But, I'd also think about how it got that way and look for signs of fuel contamination (cloudy fuel, rust-stained plastic fuel hoses, rust inside rail, etc.) and act accordingly.

hkpierce
03-03-2017, 10:07 PM
Equally if there is excess through flow through the injector(s) due to wear, at full demand the rail pressure control can't adjust for it so it throws a code as excess pressure fault!
That is simply because the system gives its all but cannot cope with the demand at full throttle /demand so it cuts out!

One or more injectors at about 275 to $350 a pop!

My bet would be the injectors!
Hope that helps
Dennis
Mechanic

So, maybe a DIY injector leak-off test may be the next low-cost step? https://sprinter-source.com/forum/showthread.php?t=17149

lindenengineering
03-04-2017, 03:20 AM
So, maybe a DIY injector leak-off test may be the next low-cost step? https://sprinter-source.com/forum/showthread.php?t=17149

Well yes of course but more often than not it affects cold starting abilities .

Under full load/output the HP pump's flow volume control valve is in full operation controlling the flow. With the right scanner in data you can observe it in operation on the road as you floor the pedal.
Obviously the first thing to check is the fuel filter & fuel supply pressure since any excessive restriction or filling deficiency will of course affect HP pump's pumping abilities to keep up with the demand of the injectors to fuel the engine's demand under all conditions. If it can't cope it will cavitate and the engine will cut out.
Dennis

talkinghorse43
03-04-2017, 02:14 PM
...HP pump's pumping abilities to keep up with the demand of the injectors to fuel the engine's demand under all conditions. If it can't cope it will cavitate and the engine will cut out.
Dennis

Just how does "fuel rail overpressure" fit with the above? Seems to me, if the title is right, the volume supplied from the HP pump is more than adequate, leading to a higher rail pressure than that specified by the ECM. Again, if the title is right, the rail pressure control solenoid is not dumping enough fuel to the line back to the tank to keep rail pressure from climbing past the goal set by the ECM.

Aqua Puttana
03-04-2017, 03:57 PM
Depending upon the failure mode of the component(s), it is not uncommon for a low fuel rail pressure condition/problem to trigger an over-pressure DTC as the system tries to control the pressures. The improperly controlled pressures can swing.

FWIW.

vic

billnation
03-04-2017, 05:33 PM
Thanks to all for your feedback. I didn't realize when we bought our Sprinter I'd need to become a full-time diesel mechanic.

In addition to what I described above in my first post, the fuel pressure regulator ($535) was replaced; fuel tank dropped and found "gel-like substance" in the bottom of the fuel pickup module; tank cleaned; removed connector on fuel rail pressure sensor and cleaned grease and oil from it.

Yes, lindenengineering, I don't have the specific codes...because I don't have a code reader. I'm just going by what the mechanics told me. By the way, since I began this thread, the Sprinter is parked in my driveway unable to start. Cranks fine but does not start. That, plus the engine suddenly dying at relatively high rpm with ~ half throttle, were the same issues I was dealing with prior to the 5 week stay in the shop.

My mechanics tested the injectors and say they're all good.

When the Sprinter runs, it runs great -- excellent power, mileage roughly 23 mpg on highway. I can almost tolerate the sudden engine shutdowns (well, not really), but the engine not starting is obviously 100% unacceptable.

Talkinghorse43, the fuel lines show no signs of rust nor other gunk, and I see no air bubbles either. From what I gather, the fuel pressure sensor at the back of the rail was replaced with new.

Aqua Puttana, so just because the code is fuel rail overpressure doesn't mean that's what's going on. Thanks.

Again, thanks to all who've taken the time and energy to respond.

By the way, where can I find a Sprinter engine diagram that is thorough and useful? Part of my problem is knowing what I'm looking at under the hood. Granted, I'm not as skilled with the Sprinter and diesels as you folks are, but I have done considerable car work over the years. Our Sprinter is the first diesel I've owned, and while I have a good understanding of how diesels work in general, the specifics of the MB engine are where I lack knowledge.

Thanks in advance for further help and feedback!

Cheyenne
03-04-2017, 08:12 PM
... fuel tank dropped and found "gel-like substance" in the bottom of the fuel pickup module; tank cleaned;



That will be 'Diesel Bug' (Google it) and likely the cause of all your problems.

I would suggest you need to strip and blow out every single fuel line, pump, spill return, etc and then replace your fuel filter to try and eradicate the problem. You may even have to drop your fuel tank again to be certain you have got rid of it although I believe there are additives to help prevent it.

Others may have different suggestions to cure it so watch this space, but it seems most likely the 'gel' has clogged something on your fuel system causing your over-pressure.

Keith.

talkinghorse43
03-04-2017, 08:38 PM
That will be 'Diesel Bug' (Google it) and likely the cause of all your problems.

I would suggest you need to strip and blow out every single fuel line, pump, spill return, etc and then replace your fuel filter to try and eradicate the problem. You may even have to drop your fuel tank again to be certain you have got rid of it although I believe there are additives to help prevent it.

Others may have different suggestions to cure it so watch this space, but it seems most likely the 'gel' has clogged something on your fuel system causing your over-pressure.

Keith.

From my experience, water only will also result in gel (see pic below of the "clean" side of my fuel filter after a water-in-fuel episode). I do agree that the OP is fighting a bad case of fuel contamination from some source.

talkinghorse43
03-04-2017, 08:49 PM
By the way, where can I find a Sprinter engine diagram that is thorough and useful?

Although in Spanish, the attached .pdf contains many useful diagrams.

lindenengineering
03-05-2017, 12:44 AM
Moi buena informacion hermano!
Mucha gracia!
Dennis

billnation
03-06-2017, 02:42 PM
Although in Spanish, the attached .pdf contains many useful diagrams.

¡Muchas gracias, Señor Caballohabla!

This is better than I had hoped for.

SprinterTeck
04-12-2017, 10:39 PM
Here is the English Version I have translated in 2 parts for ease of downloading or printing.

talkinghorse43
04-13-2017, 02:38 PM
Just ticking the thanks icon seems inadequate in this case, so MANY THANKS!!

SprinterTeck
04-13-2017, 05:21 PM
Thank You for providing the Spanish version.. I was able to get my IT guy here at Coke to translate it and wouldn't have to pay the fees that normal sites charge. LOL... He had it done in 20 min for me. I made a few color print outs and laminated one of them for my personal records and then I sent a email to all the other Sprinter Techs through out Coca Cola for them to have. So thank you again for posting the Spanish version!!!!!

Granola
03-11-2019, 07:48 PM
Some one suggested that the " fuel pressure regulator " and the " fuel pressure sensor " need to be " synchronized " . Using code reader capable of editing
ECU data . Any ideas on this ?

Thanks

Aqua Puttana
03-11-2019, 11:52 PM
Some one suggested that the " fuel pressure regulator " and the " fuel pressure sensor " need to be " synchronized " . Using code reader capable of editing
ECU data . Any ideas on this ?

Thanks
To my knowledge that isn't true for the T1N Sprinter models.

The sensors work to provide feedback for the control, but there isn't any "handshake" needed when installing replacement parts.

:cheers: vic