98 E300DT OM606 won't start when hot

[jay_bob]

Ok now it's my turn to have some troubles.

Car starts and runs great when cold.
Car runs great when warm. Never hesitates, stumbles, or shows lack of power once it is started and running.

If you shut off the car when it's super hot (like today, when it was 96 here) and then come back to it in a few minutes, it is very difficult to get it restarted. You have to crank it for about 30 seconds (so you have to hold the key in start or it will time out) and hold the pedal down about half way to get it running. It will cough and stumble to life the same way it did when I changed the fuel lines.

However, like today, I got to my office at around 8 am. It was about 70 degrees. Shut the car down (after driving for about 25 miles), went inside and went to work. It baked in the hot sun all day. I got out at 4 pm and the car started right up. Drove to the store and went inside for about 25 minutes to pick up some things on the way home. Got back in the car and it was difficult to start. Once it was started it ran perfectly and I got home with no troubles. And my drive has the gamut from 70 mph on the expressway to crawling in stop-n-go traffic.

Then when I got to the house, I parked on my fairly steep driveway nose up (where I usually park). Came back in about 45 minutes to run an errand. Again it was very difficult to start. Yet this morning, after the car sat all night, parked in the same location, it started with no problem.

The engine throws P0400 if it fails to start by the end of the cranking cycle, either by the timer, or if I let go of the key. I have the "diode - n - resistor" egr bypass and I think this is a byproduct of that. The engine will go into limp mode once it gets started, but if I break out the handy OBDII reader it will clear and the engine will run normally after being reset.

It acts like the fuel system has lost its prime. I can see air bubbles in the line from the fuel preheater to the pre-filter inlet.

I have changed all 6 of the plastic fuel hoses in the last year.
I have replaced the pre-filter and its o-ring.
I have replaced the o-ring behind the shut off valve.
One thing I have not done is change the main filter. It is probably due for one. (edit: filter has 30k miles on it, according to PO's records, so it's time)
All parts genuine MB from the forum or the dealer.

Ok what's next?

Change the main filter??
Crank position sensor - not getting any other OBDII codes though?
Lift pump?
Leak in the lines from the tank to the fuel heater?
Leak in the fuel heater?
Clogged screen in the tank?

[GregMN]

I had the same problem on a 601 engine. It drove me crazy for a year.

When you have the problem, pour water on the IP to cool it. Carry a couple of gallon jugs.
If that solves the problem, you need to rebuild or replace the IP.

The person who told me about this is a heavy machinery diesel mechanic. He said that they started seeing this after the introduction of ULSD.

I bought and installed a used IP and the problem was solved.

This may not be your problem. Might be a high probability that it isn't. But, pouring a couple gallons of water on your IP is cheap and easy.

[engatwork]

Temp is making something expand and allow air in. Disconnect the rubber supply line at the fuel heater and blow compressed air back torwards tank (remove fuel cap first) and see if you see bubbles come out of the line where the rubber hose stops and the hard pipe starts.

[shertex]

Have you considered reversing your EGR bypass to see what happens? I think I remember you mentioning once before you were not inclined to chip tune. But I wonder if, on the narrow issue of EGR delete, if that might be a better option.

[jay_bob]

I am now experiencing the exact same symptoms on both my IDI engines. Bad enough it caused my son to get stranded in the wagon yesterday. He was afraid to crank it too much so I had to go rescue him. He was about 15 minutes from the house, and by the time I got there it had cooled off enough that I could start it after about 3 crank cycles.

I am also getting it to a much lesser extent on my CDI. It will take just slightly longer to catch occasionally.

All 3 of my engines have *never* had a problem starting. Even the wagon, when it sat at vstech's for 4 months while we rebuilt the rear end, started with a glow and 3 seconds of cranking.

I refueled all 3 of them last week at the same station near my house. It is the same place I have been buying fuel since I started driving Diesels in 2011.

I checked the fuel filter on the wagon, since it is the only vehicle of the 3 that you can inspect the filter without having to disassemble anything, and it is crystal clear. No scum, no particles, nothing. Fuel is a slight amber hue like you would expect.

The only thing I can think of is somehow Gasoline got introduced into the fuel supply. The reason I think this is because the problem only happens when the engine is in heat soak condition. The engine is acting like it is getting vapor locked. If I crank it enough it will finally purge the hot fuel with vapor pockets through the system and draw in cooler fuel from the lines and tank. Then once it draws the cool fuel from the tank it runs fine.

I am having no issues with smoothness, acceleration, power delivery, any other aspect of performance once the vehicle gets started and running. That and the fact that my wagon pre-filter is crystal clear is making me discount the clogged filter theory.

I just went out and took the cap off the ML and the wagon and I would swear I smell a hint of gasoline in the fuel.

I personally filled all 3 vehicles the last time and I know I put Diesel in all 3. I always stop and double check before putting in the nozzle that it is the Yellow (Diesel) nozzle and I push the Diesel button on the pump. The Gas nozzles on these pumps are black.

When I was filling the ML the last time I kept getting whiffs of gasoline but I wrote it off to someone spilling fuel near me. Made my heart stop for a second but I was definitely pumping from the Diesel hose.

I wonder if the guy delivering the fuel made a mistake and dispensed some gasoline into the Diesel tank.

[barry12345]

High probability it may be the fuel. Gas dispensed from a diesel pump is not unknown or a gas component in the diesel. Especially if you think you smell it. Take a whiff of the fuel tank with the cap off.

May be simple to drive a car other than the ones you are having issues with back to the station and take a sample of the fuel and smell it. Or extract some from one of your two cars. I would tend to not drive them until I was pretty certain there was not gas involved or another undesirable component in the diesel fuel. Gas would be the most likely contaminate. You can also consider giving the station a phone call. Unfortunatly some will lie or may not be aware. You can damage the engines remember if gas is there. Depends on the percentage of it I suppose. Two cars at the same time on the same fuel is almost a certainty.

[funola]

Originally Posted by jay_bob

I am now experiencing the exact same symptoms on both my IDI engines. Bad enough it caused my son to get stranded in the wagon yesterday. He was afraid to crank it too much so I had to go rescue him. He was about 15 minutes from the house, and by the time I got there it had cooled off enough that I could start it after about 3 crank cycles.

I am also getting it to a much lesser extent on my CDI. It will take just slightly longer to catch occasionally.

All 3 of my engines have *never* had a problem starting. Even the wagon, when it sat at vstech's for 4 months while we rebuilt the rear end, started with a glow and 3 seconds of cranking.

I refueled all 3 of them last week at the same station near my house. It is the same place I have been buying fuel since I started driving Diesels in 2011.

I checked the fuel filter on the wagon, since it is the only vehicle of the 3 that you can inspect the filter without having to disassemble anything, and it is crystal clear. No scum, no particles, nothing. Fuel is a slight amber hue like you would expect.

The only thing I can think of is somehow Gasoline got introduced into the fuel supply. The reason I think this is because the problem only happens when the engine is in heat soak condition. The engine is acting like it is getting vapor locked. If I crank it enough it will finally purge the hot fuel with vapor pockets through the system and draw in cooler fuel from the lines and tank. Then once it draws the cool fuel from the tank it runs fine.

I am having no issues with smoothness, acceleration, power delivery, any other aspect of performance once the vehicle gets started and running. That and the fact that my wagon pre-filter is crystal clear is making me discount the clogged filter theory.

I just went out and took the cap off the ML and the wagon and I would swear I smell a hint of gasoline in the fuel.

I personally filled all 3 vehicles the last time and I know I put Diesel in all 3. I always stop and double check before putting in the nozzle that it is the Yellow (Diesel) nozzle and I push the Diesel button on the pump. The Gas nozzles on these pumps are black.

When I was filling the ML the last time I kept getting whiffs of gasoline but I wrote it off to someone spilling fuel near me. Made my heart stop for a second but I was definitely pumping from the Diesel hose.

I wonder if the guy delivering the fuel made a mistake and dispensed some gasoline into the Diesel tank.

Gasoline in diesel does sound like the problem. Around here the diesel pump handles are green, not yellow. I never go by the color,I always make sure it says diesel when I push the b I tton. That don't help if the fuel station filled it with the wrong fuel.

[vstech]

I don't think the clear filter should be amber... it should be green...

amber is the color of gasoline... or OOOOOOOOOOLD diesel fuel

[funola]

Originally Posted by vstech

I don't think the clear filter should be amber... it should be green...

amber is the color of gasoline... or OOOOOOOOOOLD diesel fuel

Yep, should be a greenish hue. I just installed these water clear nylon lines and this pic is a good representation of what #2 diesel should look like in a clear glass jar.

[vstech]

around here, it depends on the station what color the handles are...

at BP stations, RUG is green handle, and the Diesel is black.

at kangaroo, the Rug handles are red, and the Diesel is Yellow

at Circle k the Rug handles are black, and Diesel is Green...

at EVERY station, the Diesel hose is seperate from the Gasoline hose, some have a hose for each grade of fuel, some use a RUG/MID/PREM hose, and a Diesel hose...
also on every station, you have to push a button that says DIESEL to get diesel...

I LOVE the smell of diesel as I'm fueling... if I smelled Gasoline I'd stop and inform the station...

[vstech]

most likely if a percentage of gasoline is in the cars, the IDI cars will pass it ok...

but I'd drain the tank on the CDI ASAP!!!

[jay_bob]

Just called the corporate office of the station owner, I have a case number.

Taking the cars to the MB dealer now for flushing...

Will report back with details.

[jay_bob]

I found the 3 receipts in the trash can, I definitely bought Diesel all 3 times.

[barry12345]

Glad to hear you did not get just BS. Cost to drain a tank varies but volkswagon dealer wanted 190 plus tax just to drain one of ours. This was quoted by the stations insurance company so I asked for the cheque.

They sent it. With the understanding that if there was any residual damage they would cover that as well. My belief is with that much gas percentage the forty miles to the dealer may have totaled or damaged the engine was a possibility.

Fifteen minute job plus the fuel cost to refill. Back that long ago that cost was much cheaper for the fuel portion.

I did not want the car driven any further and the dealer was 40 miles away. It was almost all pure gas as the tank was low when she refilled.

They did not offer to flatbed the car in our case. Flushing the filter with diesel was the approach I used as well. Filled the filter with diesel and re installed it. Loosened the injector feeds and bled the system with diesel after putting diesel back into the tank. She had already drove all the way home with the issue.

I was not a happy camper as I had told her to always fill the tank herself or if unable. Or to at least get out of the car and make sure they are putting diesel in. This was before self service was pretty much the norm.

Personally I will not drive a diesel anywhere if a large portion of gas is suspect or known. Sometimes you get away with it and sometimes not.

The daughter got an attendant to put diesel in and they put in gasoline. The percentage of whatever is in that fuel is a concern. I would make sure they will pay the bill the mercededs dealer presents for certain before taking the cars in. Something tells me it might be substantial.

Actually no dealer is really required unless there is other damage. There also can be trust issues with dealers. Sad world at times but it is what it is.

Also get a sample container of the dumped fuel. The corporate offices may demand one from the dealer as well. Call it insurance. Have the dealer label the container you get. You did smell the gas at the fill neck? Although the color is also a good indicator as mentioned.

[jay_bob]

Pulled into the MB dealer - Dick Dyer in Columbia. Lots of wide-eyed looks from the service team when they saw all 3 of us pull in with our Diesels. Thought it was really cool that our 15 year old uses the 87 wagon as a DD.

They gave us a C250 loaner and said they would be able to get to them today.

Hoping no long term damage done, they all drive fine as long as you don't hot restart them. I told them when I pulled in, don't shut them off or you will have a heck of a time getting them restarted.