2000 E320 Starts, Runs for 1-2 Sec then Stalls - PeachParts Mercedes-Benz Forum

Lance Allison · #1 07-21-2017, 06:21 PM

2000 E320 90k miles.

A few times now, after sitting a short time, the car will start, run long enough to show oil pressure/tach/fuel level, then stalls. At most it will run 2-3 seconds.

Every time this occurred, repeated attempts at starting was eventually successful. Generally after 5-8 start/stall/restart attempts it stayed running and would be fine for a week or two.

Fuel pressure is normal at the rail and there are no codes, stored or current.
No check engine or security messages.
Swapping keys during one of these episodes made no difference.

I've got the scanner connected to capture any strange readings in live data, but so far I've got nothing.

Any ideas will be greatly appreciated.

Mxfrank · #2 07-21-2017, 08:44 PM

When I had my '99 E320, I would always replace the crank position sensor when mysterious things like this happened. It's a bit of black magic, but it's usually the cause.

Lance Allison · #3 07-21-2017, 10:27 PM

Probably should mention before this issue, I did have to replace the crank sensor. IIRC it was sometime in the Spring. The car would start and run normally most of the time. But when it would stall out, it needed to sit for awhile before starting again. It got progressively worse. Changed the sensor and all was fine till now.

I was leaning toward it being something with the security system / key, but given the scenario is the same with both keys, i'm not so sure. The other key has been largely unused.

Maybe there's something to the 5 or 6 start/stalls followed by a successful start/run as if nothing was wrong??

My fleet has always been MB and VW diesels and GM gassers so this MB gasser is mostly unknown to me so far.

The simplicity of the 240D/300D (while still much appreciated) is, unfortunately, a thing of the past.

97 SL320 · #4 07-22-2017, 07:39 AM

Does this car have a metal bit key or the fob only smart key? The DAS security on a metal key will allow a start / stall if it does not get a good read. Far as I know, if the smart key unlocks the steering when inserted ( but not turned ) it is working properly.

Are you saying the fuel pressure remains good as the engine stalls or that it checked good once the car is running?

Lance Allison · #5 07-22-2017, 11:09 AM

The the gauge/meter I have is not analog so it doesn't update nearly as fast as I'd like.

Pump startup pressure appears to be consistent. Obviously it drops off when it stalls, but when the motor is running, there is nothing with the reading that would indicate a problem.

The key is a smart key I believe. It has a metal bit folded inside the key fob and it's not needed to start the car. I've attached a pic in case I'm not explaining properly.

97 SL320 · #6 07-22-2017, 12:06 PM

If the engine stalls due to an ignition or injector operational issue, the fuel pressure should remain high. ( or at least with in 10 psi or so. )

If the fuel pump is causing the engine to stall, the pressure should be very low.

I'd hook a light to the fuel pump terminals and look for a light out then motor stall condition.

You have the smart key, if the column unlocks / key turns you should be past the anti theft system.

Lance Allison · #7 07-22-2017, 02:50 PM

Thanks for the replies :-)

This isn't the first instance where a "real" fuel pressure gauge would be handy. I'll run out later on and grab one. In the mean time, I'll throw a light on the pump terminals and see what happens.

As with my luck every other time, the car has been acting fine since the incident shortly before I made this post. It may happen again in 5 minutes or in 5 days.

Will post back if/when it acts up again.

puzzler · #8 07-22-2017, 09:26 PM

Well if it stalls and the FP is still high even if it will not start, okay its not fuel pumps. But on my 95 E320 I had this issue with the car running fine for weeks then not starting and then into the start/die mode just like yours. I took the fuel pumps out and changed filters, tested and they were good, then again it happened. At one point I found pulling the wires off one fuel pump would cause it to run OK but then reconnected it would not! Finally after being sure it was NOT The fuel pumps it died and I took it to a very good indy and becaus he is so good it was ten days to get to my car and before he did I finally replaced the fuel pump myself and it ran great with only one of the pair working, I ordered the second pump and installed and now have the proper two in tandem, no more issues. Point being this failure can be deceptive! They will work and then not..banged on the end they will work again but then again not work. And those little check valves can hold a particle that forms a clog under pressure that bypasses when not pressurized..like a check valve pointed the wrong way in the line. I like the starting fluid test which checks for system function and replaces the fuel supply telling you its a no gas issue. If it runs on spray fluid, its probably the fuel pumps..unless its not!

mpolli · #9 07-23-2017, 12:09 AM

Does it make any difference if cold vs fully warmed up?

Once it runs, does it run rough at first or just great like nothing happened?

Lance Allison · #10 07-23-2017, 03:40 PM

When cold, it starts and stays running every time. As smooth as a 17 yr old car can be. The same is true when it starts and stays running while warm.

I did put a light on the fuel pump circuit...nothing out of the ordinary.

The crank sensor I put in awhile back was likely not of great quality (think URO parts for VW). It started acting up again this morning. I unplugged the crank sensor connector and it did exactly the same thing. Ran for a short time and stalled. Cleaned the connection with de-oxit and reconnected. Not much change.

So I swapped the crank sensor with another installed in a different car that wasn't experiencing any issues.

It fired right up and has been acting normally since.

I'll let it go a few more cold start / run for awhile / try to start cycle and see what happens. I'm leaning toward a wonky crank sensor, time will tell.

puzzler · #11 07-23-2017, 04:04 PM

Thanks so much for filing us in on the result!

So Id suggest a starting fluid test I like would have shown the engine still dies and you'd know it was not fuel pumps? If I understand, he bad Crank position sensor caused the ECU to not operate the injectors and/or the ignition system..No fuel and/or spark as a result of the bad crank sensor.

Let us know if another issue becomes clear since, as you described, its come and gone several times and you may seem to have it fixed and then not..The old wiggle a wire and it runs again, false ah ha! and no it was not the wire.

Lance Allison · #12 07-24-2017, 12:52 PM

So far, so good.

I'm not ready to consider the issue fixed yet...but indications are pointing that way.

If no more trouble in the next week or two, I'll leave well enough alone with the sensor in this car...and put a new one in the car I took it from.

As always, thanks all for your help.

mpolli · #13 07-24-2017, 01:50 PM

Sounds like you have found it. The only definitive test would be to observe a bad crank signal with a scope. Maybe you could observe some jittering in the Tach since that gets its signal from the crank sensor. I don't know if that is necessarily a reliable test though. When buying crank sensors I only buy ones that are verified to be the same as the OEM. Anything aftermarket is iffy in my experience. Not sure why crank sensors are so hard to get right. Good luck.

Mxfrank · #14 07-24-2017, 01:55 PM

Yup. I always found that black magic worked on my W210. Best to fill the cauldron with eye of CPS and toe of cat. Sensor of O2 and sensor of air mass. Shifter fork and broken spring. Fuel pump and some black box things. For a charm to fix your trouble, like a hell broth boil and bubble.

If that doesn't work, the next step would be to have the sybil slaughter a chicken and consult the entrails.