300CE starting issues - PeachParts Mercedes-Benz Forum

dubadaddy · #1 01-04-2010, 05:48 PM

We have a 1992 300CE with starting issues. Seems to be fine when the car sits for a while and then when it does start and warm up the car won't start again when it is warmed up. Once the car cools down then the car will start again. Seems to be getting more frequent.

My indie says that it is probably a fuel injection problem and that it would be about $1000K. Can't do that right now as I am unemployed.

Any help out there regarding some DIY stuff I could look into doing myself?

ps2cho · #2 01-04-2010, 10:01 PM

"Probably" a fuel injection problem sounds to me like a mechanic you should never go back to again! Especially for $1,000,000! No but really jokes aside, $1000 for a "probably" is a big no.

I am not too familiar with the M104, so I'll let others start you off.

Is this starting issue only? Or does driving get progressively worse as it warms?

dubadaddy · #3 01-04-2010, 10:26 PM

Sorry, your right, he did say $1k. Sorry for the misprint. This is a starting issue only. I have asked about this question previously on another post awhile back and was told it could be the camshaft sensor. Could this be the culprit? How would one go about diagnosing a sensor defect? When the vehicle is cool it seems to start well...not fine but is livable ( I am really particular about how a Mercedes should start and ride). My indie says that if we have this problem to step on the accelerator and open the throttle a little. I haven't told my son this so I don't know if it will work.

prmichael · #4 01-05-2010, 09:13 AM

Quote:

Originally Posted by dubadaddy

We have a 1992 300CE with starting issues. Seems to be fine when the car sits for a while and then when it does start and warm up the car won't start again when it is warmed up. Once the car cools down then the car will start again. Seems to be getting more frequent.

My indie says that it is probably a fuel injection problem and that it would be about $1000K. Can't do that right now as I am unemployed.

Any help out there regarding some DIY stuff I could look into doing myself?

I'm experiencing the same problem with a buddy's '92 300E. If you search through some of the threads here you'll find links to testing some of the components such as the CPS, temp sensor, OVP, etc. I can't find the links to them right now, but here's another link for the manual that may be of use: http://mb.auto.pl/index.php/Dok.-serwisowa-CD1.html . I think I've ruled out the O2 sensor, temp sensor, CPS, cold start injector, OVP on this particular vehicle.

ohiomike · #5 01-05-2010, 10:21 AM

Start with the Temperature sensor for the fuel injection. There is another sensor but it is for the engine temp guage. It is cheap fix and just screws in. Always do the Oxygen sensor even though the system doesnt say it is bad.

dubadaddy · #6 01-05-2010, 01:50 PM

Indie say start with the check valve for the fuel pump then the fuel pumps themselves, working my way up to the EHA valve and then the fuel distributor.

Sound right? I don't know where the fuel temp injection sensor is!!?

ohiomike · #7 01-05-2010, 02:56 PM

the fuel injection engine sensor is up on the front, top side of the engine block on the drivers side. I think the engine temperature sender in close by.

Ferdman · #8 01-06-2010, 06:33 AM

Fuel pump check valve sounds like a good start. If the fuel pumps run I would move on down the list of likely causes.

dubadaddy · #9 01-06-2010, 09:56 AM

Quote:

Originally Posted by ohiomike

the fuel injection engine sensor is up on the front, top side of the engine block on the drivers side. I think the engine temperature sender in close by.

Do you have a diagram or such for the location of these? My indie says that they are not there due to it being a CIS M104 engine.

Do you have any more specific info you can share??

bsmuwk · #10 01-07-2010, 07:32 PM

long and short, you heard wrong.

there's only one sensor you should worry about and it's the only one shooting into the bellhousing. it's right above the starter and is a total PITA to get out and back in on a CIS M104. ask me how i know.

the one you should be looking for is this one available here at fastlane: http://catalog.peachparts.com/ShopByVehicle.epc?q=&yearid=1992@@1992&makeid=63@@MERCEDES+BENZ@@X&modelid=6176%3AMBC|1498%3AED|10000018@@300CE&keyword=crank@@crank&catid=All@@All&subcatid=P%3A242838@@Crank+Position+Sensor&applicationid=W0133-1715281&mode=PA

dubadaddy · #11 03-20-2010, 12:15 PM

Ok, replaced the crankshaft sensor and now I am having problems with the cold start as well.

Where to go from here as far as the DIY??

Need help!!!

mak · #12 03-20-2010, 12:52 PM

CIS systems are prone to hot start problems as the fuel accumulator fails to maintain pressure , the first item to replace along with the fuel filter , then continue with a systematic check of pressures and ignition components .
mak

dubadaddy · #13 03-20-2010, 03:05 PM

Would that fuel accumulator apply to cold start problems as well??

dubadaddy · #14 03-20-2010, 07:26 PM

I have replaced the fuel filter approx. 6K miles ago but did not do the fuel accum.

It is a starting issue otherwise it runs fine. I have not been able to confirm that the M104 motor has a temp. sensor for the injection system.

I have replaced the fuel check valves to no avail. At least it did not affect the issue which is starting. It was starting when cold but now it seems cold or hot it has intermittent problems starting, stranding me at times. Then when I go back later it starts.

Got up this AM and no starting at all.

dubadaddy · #15 03-22-2010, 05:49 PM

Seems it is the ECU that is providing and intermittent spark to the coil. When you wrap on the ECU it seems to start fine.

I will be looking for a good used ECU.