300D road trip - found some bad diesel along the way - PeachParts Mercedes-Benz Forum

renaissanceman · #1 04-07-2015, 01:47 PM

I just finished one 750 mile leg in my vacation to California from Western Oregon, and I experienced some nerve wracking misfires on the drive.

The first bit of the drive on Safeway B20 was uneventful. I filled up at a Texaco in Roseburg, OR and then the fun started (it was soooo cheap, though! 2.33/gallon). Climbing the first steep grade after the fuel stop, I had a hard shudder accompanied by a large puff of white smoke. The coolant temperature was about 85-90C. I really backed off on the throttle, and did not have another major missfire for a while. Pulling another grade, I had some stumbling and smoke, so I pulled into a rest area to check for problems.

The engine was idling nicely when I popped the hood. I was worried that disabling the air recirculation valve (as I found suggested on several threads here) was causing issues and I was going to enable it, but then noticed I had left a one wire sensor on the right side of the intake manifold unplugged from when I had replaced the aux circulating pump and had to get the windshield washer reservoir removed.

I connected it up and put in some Power Service Diesel Kleen and was on my way. The smoking problem slowly faded over the next 10 miles and all was well after that. The next tank of diesel got me from Yreka, CA to Fresno CA on 14 gallons, netting 32 mpg.

Scary stuff, though. Looking back, I should have been wary of a station that was 15 cents under everyone else in the area!

mach4 · #2 04-07-2015, 02:02 PM

Having heard the horror stories of bad fuel, I do everything possible to limit the risk of the bad stuff. Locally, I have a high-volume no-name station I frequent on a regular basis and on the road I limit my fuel stops to name-brand truck stops. Haven't had a problem in 70k miles and I'm on the same fuel filters for about 65k of that. (No, I'm not pressing my luck - I have a fuel pressure gauge downstream of the filter to alert me to any early stage blockage and I carry primary and secondary filters)

TnBob · #3 04-07-2015, 02:12 PM

Truck stops are best for fuel. They dont seem to ever have bad fuel or stale either primarily due to volume.

mach4 · #4 04-07-2015, 02:34 PM

Quote:

Originally Posted by TnBob

Truck stops are best for fuel. They dont seem to ever have bad fuel or stale either primarily due to volume.

If they ever did, word would get around really quickly in the trucker community and the economic repercussions would be extreme. With local stations, no one would ever know as there are no mechanism to spread the word.

biopete · #5 04-07-2015, 02:34 PM

Is that a manifold temp sensor ? What does it do?

funola · #6 04-07-2015, 02:47 PM

Quote:

Originally Posted by mach4

....... I have a fuel pressure gauge downstream of the filter to alert me to any early stage blockage and I carry primary and secondary filters)

What fuel pressure readings are you getting with a new filter and as it gets miles piled on? Where did you install the sensor? Do you have a sensor pre AND post filter or just one? Pics?

Maxbumpo · #7 04-07-2015, 03:02 PM

Quote:

Originally Posted by biopete

Is that a manifold temp sensor ? What does it do?

That is the manifold turbo-boost pressure sensor, used to control the over-boost protection valve. If the turbo-boost went too high, that sensor tells the OB protection valve to cut-off the signal to the ALDA, which then limits the fuel that the injection pump can put out. Prevents your pistons from melting, as long as you have changed ALL YOUR FUSES!

BillGrissom · #8 04-07-2015, 03:07 PM

Don't be too quick to blame the fuel since sounds like you didn't have any similar steep grades on the next tank. However, I have been amazed how much smoother my engine runs on the new Diesel HPR than regular diesel, and it is cheaper and no exhaust smells, so fuel can matter.

renaissanceman · #9 04-07-2015, 04:18 PM

Quote:

Originally Posted by Maxbumpo

That is the manifold turbo-boost pressure sensor, used to control the over-boost protection valve. If the turbo-boost went too high, that sensor tells the OB protection valve to cut-off the signal to the ALDA, which then limits the fuel that the injection pump can put out. Prevents your pistons from melting, as long as you have changed ALL YOUR FUSES!

The OM603 engines had a purely mechanical wategate, correct?

Maybe the boost got too high and with no feedback it popped the wastegate open and caused momentary loss of boost and incomplete combustion of too much fuel. Either way, I was really unhappy about forgetting that connector, but there seems to be no permanent damage done. I'm still new to this diesel/turbocharger game.

There are some pretty steep grades between Yreka and Redding, and I didn't get any smoke/misfiring on those.

mach4 · #10 04-07-2015, 06:25 PM

Quote:

Originally Posted by funola

What fuel pressure readings are you getting with a new filter and as it gets miles piled on? Where did you install the sensor? Do you have a sensor pre AND post filter or just one? Pics?

I didn't have the fuel pressure sensor installed when I did my last filter change 65k miles ago so don't know what pressures a fresh set of filters would show - probably not a whole lot different that what I'm seeing now.

The sensor is installed off a modified banjo bolt on the outlet of the main filter where it feeds the IP. I see between 10-15 psi normally.

A complete write up on the project is located here -> Adding a Fuel Pressure Gauge

renaissanceman · #11 04-18-2015, 10:30 PM

On the return leg, I had no issues with stumbling, on the flats or the steep grades, so it may have been an isolated problem. I pulled a lot of the grades burning HPR diesel fuel on the way back. I was hoping I did no permanent damage driving for 200 miles with that sensor wire hanging.

Has anyone ever experienced the mechanical waste gate opening? What does it feel like?

mytmousemalibu · #12 04-18-2015, 10:57 PM

Wastegate operation should be smooth opening/closing to limit the boost as loads change. If they are working properly, they don't just "pop" open. Its not something you should /would feel while driving, again as long as its working properly. The valve is more or less feathered open & closed. If it did suddenly blow open while the engine was under load and in boost, the car would probably feel like it lost power all of a sudden due to the turbo losing drive pressure.

renaissanceman · #13 04-18-2015, 11:08 PM

That's about what it felt like, accompanied by a puff of white-ish smoke. Who knows what it was, but thankfully it has not recurred since. Maybe the wastegate was stuck shut and finally opened, as the car was used for a lot of short trips in the years previous to me buying it.

This is my first diesel and also my first turbocharged car, so I don't have a good "feel" for it yet, but I'm learning!

renaissanceman · #14 04-18-2015, 11:47 PM

I watched a few videos on youtube of turbo stall...I had never heard of it before.

mytmousemalibu · #15 04-19-2015, 05:25 AM

Quote:

Originally Posted by renaissanceman

I watched a few videos on youtube of turbo stall...I had never heard of it before.

I have never heard any noticeable compressor stall on any of my Benz diesels. Gas & diesels can certainly have it happen. Besides compressor stall, turbo stall, its also called bark, or barking the turbo or surge. Usually occurs when at a decent boost output and you swiftly take your foot off the throttle. The full head of boost being pumped into the engine is held in from the force of the compressor creating it. If you remove your foot, drive pressure rapidly drops on the turbine side and all of a sudden, the boost charge can overcome the compressor and it begins to blow back out the inlet, making a distinct noise and sometimes violently even to the point of reversing the spin of the turbo, very hard on it and can twist the shaft apart on hi boost/hi performance applications. (gas or diesel engine with throttle plate, the boost has no where to go too).

Most fairly stock vehicles don't suffer from this issue. Sometimes it can be caused by tuning issues or improperly sized turbos for the application and the turbo operates within its surge margin. On my Duramax, I installed a blow-off valve to protect the turbo, it's just a big valve that on command, opens to the atmosphere to let the boost bleed off. It can actually help with the turbo respooling quickly if you get back on the throttle. If I had it spun up towards the 32psi I have it set for and pull my foot off the gas it will bark the turbo pretty good. I may end up putting one on my 606 build too. Some vehicles have a blow-off valve as OEM equipment and some just don't need one.

This isn't my truck, but sounds the exact same

https://www.youtube.com/watch?v=17qJ71xUVok