intermittent starting problem

howell72

New member
I've got an '04 with 286K on it. It stopped while stuck in traffic last week and I posted here about it. I got it started by clamping off the 2 fuel return lines at the banjo and once started it ran OK. The problem started when in FL and I had just gotten fuel at a small station. Thinking the fuel filter may have been clogged, I changed it with a new WIX filter and that seemed to solve my problem. It started right up for the next few days and then all of a sudden I stopped at a rest stop and it wouldn't start. A few tries and it started. Started fine for a few more days and then wouldn't start again after stopping. Clamp the lines and it started. It seems the problem only occurs when stopping after a long time of driving. If I let it sit overnight, it always starts in the morning. I don't have a code reader. I suspect that the fuel pressure solenoid is not sealing fully when starting but before I replace the fuel rail I would like to be sure this is the problem. Diesel in Florida all seems to be bio-diesel with up to 20% mix. Is it possible that the new fuel filter is clogged again and giving low fuel? I have plenty of fuel pressure to the high pressure pump.
 

SneakyAnarchistVanCamper

Reading till my eyesbleed
Yes it's possible that you got some more bad fuel. I fill up with 20% biodiesel every time, works great. It's always a good idea to change the fuel filter before replacing expensive fuel components; you may have contamination in your tank (take a sample by removing the inlet line at the fuel filter). I would perform a fuel rail solenoid leak test: https://sprinter-source.com/forum/showthread.php?t=27663 with 3/8" hose installed on injector return fittings, cam sensor unplugged so it doesn't start, and fuel rail solenoid plugged in, it should leak nothing while cranking. Europarts has fuel rails for only $450 now, half off.
 
D

Deleted member 50714

Guest
2004? As you may or may not be aware, as vehicles age, rubber components, particularly, fuel hoses, can become as brittle as uncooked spaghetti noodles. And to assume a certain component is malfunctioning without the use of a diagnostic gizmo is not an approved industry diagnostic practice. You are just spinning the expensive "Wheel of Wallet Flushes" and the odds of winning are certainly not in your favor.

The intent of this is not to be harsh but hopefully help you realize your vehicle needs to be interrogated by the proper diagnostic equipment. Please keep the forum posted of any successes as it may assist others similarly situated.

Good luck my brother and may the winds of resolution blow your way!

NOx
 
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howell72

New member
I replaced the fuel hoses from the filter to the high pressure pump. Leak down test when cold passes. Starts right up no engine light. I run it till it completely warms up, shut it down and wait 5 minutes and it won't start. Did the leak down test again and this time I've got fuel in my tube. I guess the solenoid is not causing the plunger to seat when warmed up. It's an intermittent problem. It will start right up about 8 out of 10 times. I'm going to pull the fuel rail and replace because I can't see anything else that might be causing the problem.
 

freestyle72

New member
To run biodiesel you have to have Viton seals and hoses or the biodiesel will eat them away. From what I've read before I don't think Mercedes use this. Hopefully the HPFP has these seals (which it should since bosch started using those seals).
 

MillionMileSprinter

Millionmilesprinter.com
Wait. If I understand your post, you get little to no leak off at the injectors when cold, but more when hot? How much when hot? I know the leak off thread has gotten very long, but one important thing is to test them when the engine is hot. Measure and report or snap a photo of the test. You may just need a new injector, not a whole fuel rail. Feel free to contact me through my website below and I'll help you as much as you need.
 

howell72

New member
I've got the injector return line clamped off so the only fuel I'm getting on the leak test is coming from the rail itself. Tried it again today when cold and still got a lot of fuel leakage. I'm going to order the new fuel rail since I've had no luck finding a used on.
 

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