Engine Quiting
#1
Engine Quiting
I have a 1998 ML320. Every now and then we will be driving and the car will completely shut down. It restarts again in a minute or so. I have tested for spark and everything seems to be ok with the plugs. The check engine light is on, but the code for that is a bad EGR valve. I have talked to a few techs and they said this would not make the car shut down. I am not sure if this is a fuel problem, bad relay or possibly a loose connection at the fuel pump (ground or something). Has anyone had a similar problem? Any advice would be greatly appreciated.
Thanks,
Eddie Rodgers
Thanks,
Eddie Rodgers
#4
i thought as much they are both linked P0173 fuel trim bank 2 malfunction, cause = intake leak/air system/fuel pressure/fuel pump/injectors/EVAP canistor purge valve and HO2S heated o2 sensor, any of these will give the egr valve a code because the emmisions is suffering so i dont think its the egr valve, im going for a leak in the intake gasket/vacuum line off or split or lastly a faulty cannistor purge valve wiring connector... code P0400 is the egr valve flow malfunction probably a hole in the pipe feeding it or gasket
#6
I almost guarantee you, its the crankshaft position sensor. When it fails, it will not set any fault codes, the computer can't see the flywheel trigger points, and does not know when to fire spark plugs or injectors. The whole motor just shuts down. This typically only occurs when vehicle is hot, and the vehicle will restart after is cools and run just fine. EGR won't keep the engine from running unless the valve is stuck wide open, then it would likely set misfire codes instead. I think you have a restricted egr tube or bad solenoid. The usual fix is to replace the egr valve/solenoid combo along with the egr tube.
#7
I am currently a tech with MB,as long as the vehicle doesn't "sputter" or "bog" before it dies,the crankshaft position sensor is most likely the problem. Be sure to check the wiring on the back side of the crank sensor (cut loom apart) for corrosion-this has also been a problem for these vehicles. Water runs down the harness and corrodes the back side of the connector-you will not be able to see any corrosion on the sensor side.
Good luck.
Good luck.
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#9
i mentioned the fuel pump in my diagnostics i have only been doing cars for 40 yrs "time served" and would never garantee a fault unless i was 100% sure, so im still going to guess its an air leak but if i were there i would garantee i would find the fault very quickly
#12
Originally Posted by ahopeter
whoa! two techs say crank... how about the fuel pump gentlemen?
#13
Originally Posted by azinn
Where is the crank sensor located and how much do they cost?
#14
Its buried at the back of the engine. Its located on top, where it reads the flywheel position. Might be best to have someone change it for you, its tricky sometimes, and usually quite hot. Just one of those things.... Sometimes they come right out, other times they fight you all the way. I believe its an E8 torx bit, a long 1/4" extension and universal, and ratchet. Pull off engine cover, climb on top of motor, reach down on the drivers side at the back of the motor. Unplug, replace.
#15
not totaly happy with this crank sensor theory it seems too much like mb tech guess work $100/200 well that would be nice for them but an upevil for a loose/corroded pipe for pennies
#19
Originally Posted by teky
mercedestech1 meet saturn becuse i dont think either of you know what your talking about apart from you must have shares in crank sensors, learn to diagnose problems
#20
yes i know all about that toilet paper i was there you know and i have many degrees HNC/HND, the difference was hands on as opposed the paper/classroom i learned more when i was working than in school/uny, i went to university to learn and met guys/gals who knew more than me because they had hands on and they beat me hands down so i went to trouble shooting which is my 4t and with the later cars its paid off but i know many who dont have this toilet paper and do extreamly well
#24
The crankshaft sensor can be tested with an ohm meter, the problem is it usually only fails when its hot. It will test fine until it fails, then it will read open circuit. Trying to heat one with a torch is pretty futile also, its best to pull it out right when the engine dies, and the opportunity is rare. It might have cooled down enough by the time you have removed it and will test ok.
#25
Originally Posted by saturnstyl
The crankshaft sensor can be tested with an ohm meter, the problem is it usually only fails when its hot. It will test fine until it fails, then it will read open circuit. Trying to heat one with a torch is pretty futile also, its best to pull it out right when the engine dies, and the opportunity is rare. It might have cooled down enough by the time you have removed it and will test ok.