2004 3500 High Fuel Rail Pressure and more, help appreciated

needasprinter

New member
Hey guys, hopefully someone can bare to read this whole thing and have some pointers, I'm new to sprinters and struggling to address the vans issues. For your reference when understanding my knowledge on engines, I'm a basic mechanic on my cars and motorcycles, handle the basics and general understanding of what's happening but I am still pretty green mechanically, especially with sprinters.

I'm new to the forum and just got my first sprinter and have had nothing but untraceable problems so far. I bought an 04 3500 with 143k on the odometer. I'm building this out to be 50/50 dirt bike race rig and camper (not doing any plumbing or gas hook ups, just solar, crating some "rooms" and making it play/work/ lightly livable for a few weeks at a time) I had spent 4 months looking and had quite a few vans sell out from under me, so I finally had to just pull the trigger. I landed on this one because the body is extremely clean (aside from old vinyl residue, it was a "Serv Pro" van previously) The van seemed to have sat for a bit and they picked it up on auction I think and then flip them. Test drove it, for 10 minutes or so, everything felt great, power felt great all the way throughout, no rumble in the trans like a few other friends sprinters, so I pulled the trigger and here is the timeline of things since leaving their lot.

150 miles into the drive everything get great, then my dad called me as he was following me and said I was dumping fluids. Instantly smelled it and then saw the CEL kick on. Pulled over, it was the return fuel line to the tank, it blew off. The pressure clamp was shot, we were in the middle of nowhere on 94E. We went into town, found an auto zone and got more clamps. This happened 3 more times after putting clamps on, I could see that the inner sheath of the gas line looked like it was torn/folding in on itself and it was building up so much pressure it would just pop off. I had to have it towed the rest of the way home since everything was closed, it was a long night. I towed it to a mechanic my friends take their sprinters to, he assessed that the return line was in fact clogged and replaced it and that was it, didn't see any issues with the high pressure pump or elsewhere, so I had him do the fluids/filters to be safe as I had planned regardless when getting home. I drove the van for a week and was apprehensive to think I was a lucky one with not lurking problems. I was doing 62 and something just subconsciously felt funny in the pedal, looked down and the CEL was on, gave it gas and it dropped to 60 and just held there, so I thought the turbo might have cut out, or limp mode (I'm learning) I called the mechanic, took it in and the scan/code was for high fuel rail pressure. I had a shitty experience with him holding the van for almost two weeks and I don't think he looked at anything, said he cleared the code, drove the piss out of it and had tons of power, no issues. (He's young, has a busy new shop and understaffed, so I will give him that, but the communication was no existent) I was confused and asked that he check the injectors, high pressure pump and pump in the tank as well to see if there was something going on and the light just hadn't come back on, he claims he checked it all and he would love to charge me for something but there's nothing going on that he can see. I went to pick it up and I start it up and the light was on, so I went back inside and it was just bullshit sales shit, like oh it's probably the glowplugs, I just stared in confusion and then just walked out. Drove it home and it did seem fine, but I noticed the gas gauge seemed to be dropping rather quickly. I have been googling and calling around locally in there Detroit Metro area for a good sprinter mechanic but I am having no luck. I came across a shop, HOEKSTRA in Troy, MI that has specific sprinter service as well as works on other big diesel rigs, cat etc. They were booked out 3 weeks and recommended a mechanic down the road they send sprinter work to, at a Tuffy Auto Repair. I was immediately apprehensive and told him that, but he swore the guys were great. I took it in (mind you, the van starts and seems to drive perfectly, but the gas gauge is dipping and the thermostat is holding only at 150 now) I dropped the van, explained the whole situation to them so they knew the backstory, 4 days later he called me and said they could barely start it and they didn't drive it because it was running so rough??? He said the atmospheric sensor was bad AND my ECM was bad and I needed a new one, $3700 out the door!!!!! I was so confused, I didn't even know what to say, other than, no, I'm not paying you to do that. Normally I spend more time thinking, but I instantly found a used replacement ECM for an 04 online that says it was parted out and works 100% it was. I might have wasted $275 buying it but thought it couldn't hurt to have just incase. Then from what I am reading, I will have to send it our or try and remove the immobilizer from my ECM and replace it into the used one? I went and picked the van up, it started up beautifully and drove perfect still, I wanted to give them the befit of the doubt that they had paperwork confused, but also, maybe it's just a Tuffy and they're wrong or thought I would pay, maybe they are right? I don't know. I filled the van up today and I am going to drive it 100 mies between city and expressway and see what happens and then check my mileage (I haven't had a chance to check it yet with so much shit happening, that I'm only driving 20-30 miles before I've take it to places)So my questions are the following:

1) Is it possible for an ECM to be completely bad, yet still fire and run (seemingly) great? I didn't think that was possible if it's dead.

2) I believe there is for sure an issue with the fuel from the High Fuel Rail Pressure code, however, I do not know where to start to see where that problem stems from. The injectors look clean, however, there is some rust color soot on the top of all of them? Is that common or the start of Black Death (even though it's not black and is more like brake dust for a visual) The high pressure pump is not leaking, nor can I see anything else leaking or leaving stains in the driveway. What would be my best place to start?

3) The temperature gauge is holding at 150. I will see what happens on the expressway today with the temp (and everything else) Is this probably in accordance to the atmospheric pressure sensor they said was bad?

4) Does anyone on here live in Michigan, but more specifically SE Michigan that has a good sprinter mechanic they trust or a mechanic on this forum?

5) I am hesitant to drive it much at all because I really don't want to make things worse, but I also just want to drive this bad boy.

Any help would be greatly appreciated. The light has not come back on since leaving the last shop (today will be the first day really driving it more than 5-10 miles around town though)

Thanks,
AJ
 

trc.rhubarb

Well-known member
Hi AJ,
Are you using a sprinter specific code reader/software or just generic?

It sounds like electrical issues outside of that bad hose... that's generally what causes inconsistent behavior.
It might even be that your gauge is dropping because of high resistance somewhere.

Start with your grounds, check the one behind the battery on the firewall... undo it and clean all the eyelets.
Then go to the chassis ground which is to the left of the battery, way down there. In places where there is snow/salt, that seems to corrode out quickly.

You could have a failing fuel level sending unit but that means multiple failures at once and I like to start with the assumption that if multiple things go out together, they are related.

There is likely a lot that needs to be done, it's not hard, but is expensive to pay for.
Check your intake hoses - all of them for tightness at the clamps and to ensure they aren't cracked... look for oil on them as a telltale sign.

If the temp doesn't get fixed with the grounds checking, you could have a bad t-stat but I would check it using a scanner and compare the 150 water reading to oil and trans temps to be sure it's not a bad temp sender or that your dash isn't acting up (fuel and temp)

Lastly, check the wiring for exposed copper at the bend under the fuel filter. You need to cut open the sheathing to check but just 4-5" is enough and you can wrap it after to keep it neat and clean.
 

needasprinter

New member
Hi AJ,
Are you using a sprinter specific code reader/software or just generic?

It sounds like electrical issues outside of that bad hose... that's generally what causes inconsistent behavior.
It might even be that your gauge is dropping because of high resistance somewhere.

Start with your grounds, check the one behind the battery on the firewall... undo it and clean all the eyelets.
Then go to the chassis ground which is to the left of the battery, way down there. In places where there is snow/salt, that seems to corrode out quickly.

You could have a failing fuel level sending unit but that means multiple failures at once and I like to start with the assumption that if multiple things go out together, they are related.

There is likely a lot that needs to be done, it's not hard, but is expensive to pay for.
Check your intake hoses - all of them for tightness at the clamps and to ensure they aren't cracked... look for oil on them as a telltale sign.

If the temp doesn't get fixed with the grounds checking, you could have a bad t-stat but I would check it using a scanner and compare the 150 water reading to oil and trans temps to be sure it's not a bad temp sender or that your dash isn't acting up (fuel and temp)

Lastly, check the wiring for exposed copper at the bend under the fuel filter. You need to cut open the sheathing to check but just 4-5" is enough and you can wrap it after to keep it neat and clean.
Thanks trc.rhubarb, that is helpful info for sure and does make a lot of sense. The original scan was from the mechanic with his computer scanner, I do not know if it's Mercedes/Sprinter specific or not, but I believe so as he only dorks on imports? I will start there and report back. Out of curiosity, am I possibly doing damage by driving it with these issues? The very little I've been able to drive it I have been driving it very gently. I will not plan on using it daily but would like to still drive it around to assess anything else that is going on. Thank you again for the insight and leads to start on.
AJ
 

trc.rhubarb

Well-known member
Likelihood of damage in short gentle runs is pretty low given the info we have but I wouldn't suggest dong too much until you know if it's staying at 150* or not. My guess is that it is not stuck at 150 but maybe something odd is happening.

They could all be independent issues but even then, i suspect the only damage will be to your wallet.
 
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billintomahawk

Guest
AJ,
Even if a shop does your work you need a scanner to help you both get on the same page.
Become a scanner expert.

Without a scanner you are just guessing.

Just learning the scanner is painful but it is the new form of/way with mechanics.
It is surprising how many old school mechanics have scanner problems with a sprinter.
Thay will ask to use your scanner.

bill in tomahawk
 

needasprinter

New member
AJ,
Even if a shop does your work you need a scanner to help you both get on the same page.
Become a scanner expert.

Without a scanner you are just guessing.

Just learning the scanner is painful but it is the new form of/way with mechanics.
It is surprising how many old school mechanics have scanner problems with a sprinter.
Thay will ask to use your scanner.

bill in tomahawk
Thanks bill in tomahawk,
I am going to research scanners and pick one up to keep on me as I plan to be on the road as often as I can (once this is initially sorted) This has been a very confusing 2 months since picking the van up. Do you have a recommendation on scanners?

First mechanic with a scanner that was the size of an iPad said it was high fuel rail pressure, hut he had awful service and kept it for 2 weeks and did nothing even though my friends have been taking their sprinters to him for a couple years now with great work and service ?‍♂

Used my friends scanner, it's a small scanner / app for smart phones, it also said high fuel rail pressure, so I cleared it and wanted to drive it and see how quickly it would come back on, but it didn't. I googled/called around and got some recommendations and took it to another guy.

I dropped it off, no lights, running great (it does start and run great) he called and said we can barely start it, tons of codes, your ECM is bad, $3700. I clearly knew it was starting and running fine and no lights were on when I dropped it off, so I went back, said no thanks, it fired right up and felt great and took it home. (Is it even possible for the ECM to be completely dead but still start/run and not throw any codes??? The)

Update from the initial post regarding the temperature and gas gauge. I said screw it, filled the tank back up and I'm going to drive it for a few days nice and smooth, temp has been holding at 180, gas gauge looks completely normal (I'll calculate mileage later this week, I pulled my back and pretty immobile for a few days) I have drove the van probably about 80 miles to and from my work and split it up between city and expressway driving up to about 75 on and off and down to 62. No lights have come on.

I'll be going through the electrical/grounds as mentioned by trc.rhubarb when I can bend over again haha and I'll decide on a scanner in the meantime as well. Appreciate all the help so far guys.

Thanks
AJ
 

Zundfolge

Always learning...
Many on here choose to get the Autel AP200 due to it being cheap (relatively) and the fact that it can talk to sprinters. MD808 would be the next-ish step. Scanners aren't diagnosis, but they will help point you in the right direction (most of the time), and are a necessary part of sprinter ownership. Note that not any scanner will talk to a sprinter, and the ones I recommend above are documented here to work for most things. Read in the scanner subforum here, rather than just googling it.

Too bad you didn't come here earlier, we might have saved you some time and headache.

Hard to tell right now what's going on with your van for me, but I will say that until you can read the codes yourself and stop wasting time with shops who so far are wasting yours, it's a bit of a waiting game.

These things aren't some random f*rd or some such that any Joe can work on, and it sounds like you have some mechanical prowess.

Through patience, lots of reading here and some other places, asking questions and providing details, and a few tools owning a T1N can be pretty great!

Where it's not so great is if you are relying on random mechanics. Find a trusted one too and they will make T1N ownership much more enjoyable. For now get that scanner on the way...
 

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