Still no start - HELP!? - PeachParts Mercedes-Benz Forum

JEdwards · #1 08-07-2007, 11:22 AM

car: 1987 300E

Whats been done: OVP relay, fuel pump relay, inspected vacuum lines

Symptoms: Car doesn't start now that the OVP has been replaced w/ a known working relay. Car attempts to start, almost catches, and then doesn't. Every so often it does the growl and a puff of white smoke comes from what I assume to be the fuel distributor.

I pulled the airbox apart to see if that was a pos problem, and the brass piece to suck in air is kinda dirty.

I can only assume its a fuel delivery issue and not an electrical, but I don't know what to do next. It seems that the distributor is a little on the expensive side, and thats kinda not something I want to shell out for if there is something else that can be done.

Is there anything else I have missed as far as what to check for the car? I can't seem to gather anything from other posts on the issue.

#2 08-07-2007, 03:57 PM

that's why one should drive a diesel.
so the car ran before replacing that relay?
anyway, does it get a spark? take off one of the sparkplug wires, stick a screwdriver in it and crank the engine whilst holding it close to the block. it should spark.
also, maybe the injectors don't open up. you can check that with a voltmeter, is there power going to them or not?
keep that lip clean, under the airfilter. that can cause difficulty adjusting the idle. but clean in cautious, don't spray blast the dirt inside...
cap and rotor can very well be the issue here. or somehow it's flooded. take out a spark plug and check. (then you can also check if it gets a spark)
the 300e is junk. they have mechanical injection, which sucks and eats gas like crazy.

david s poole · #3 08-07-2007, 04:20 PM

check that fuel pump[s] will deliver 1 litre of fuel in 30secs.

manny · #4 08-07-2007, 04:28 PM

Quote:

Originally Posted by henrydupont

that's why one should drive a diesel.

Lots of help here.

#5 08-07-2007, 06:01 PM

Quote:

Originally Posted by manny

Lots of help here.

indeed, sir, diesel-men are more helpful and tend to be better mechanics.
did you find it yet? and, did it run before you changed that ovp?

BENZ TEK · #6 08-07-2007, 06:51 PM

Check the rotor button housing to make sure its not broken!! I've ran into that problem several times. The camshaft is turning but the rotor button is delivering spark off time. Sometimes when you pull the distributor cap off it will fall out but you will still have to deal with the broken piece inside the cam.

manny · #7 08-07-2007, 08:02 PM

Quote:

Originally Posted by henrydupont

indeed, sir, diesel-men are more helpful and tend to be better mechanics.

And they don't know squat about spark-ignition engines.

saumil · #8 08-07-2007, 11:33 PM

You have to first determine whether it is a missing spark or missing fuel.

Do you hear the fuel pump buzz when the ignition switch is turned on, before the start ? The sound should be near the right rear side.

You can buy a spark tester from auto parts store that will let you check for a spark without opening the spark plug. Check for spark when you are cranking. If you dont get a spark on all the sparkplug cables, it could be the coil or the crank position sensor or the ignition control unit.

Also at the auto parts store is a chemical called quick start fluid. Spray this chemical in the air sensor housing, i,e in the unit that has the air sensor plate, and then crank. If the car starts, then the problem is that you have too little fuel going in during startup. Then the problem could be related to the EHA valve, cold start valve (though this is a questionable issue), coolant temp sensor, fuel pump, etc etc

#9 08-07-2007, 11:47 PM

Quote:

Originally Posted by manny

And they don't know squat about spark-ignition engines.

apart from me then. but boy do I hate them. unless made by BMW or Porsche of course.

#10 08-07-2007, 11:49 PM

Quote:

Originally Posted by saumil

You have to first determine whether it is a missing spark or missing fuel.

Do you hear the fuel pump buzz when the ignition switch is turned on, before the start ? The sound should be near the right rear side.

You can buy a spark tester from auto parts store that will let you check for a spark without opening the spark plug. Check for spark when you are cranking. If you dont get a spark on all the sparkplug cables, it could be the coil or the crank position sensor or the ignition control unit.

Also at the auto parts store is a chemical called quick start fluid. Spray this chemical in the air sensor housing, i,e in the unit that has the air sensor plate, and then crank. If the car starts, then the problem is that you have too little fuel going in during startup. Then the problem could be related to the EHA valve, cold start valve (though this is a questionable issue), coolant temp sensor, fuel pump, etc etc

the EHA valve, is that that expensive black thing under the airfilter that tends to leak and make gasoline smell enter the pass compartment?

zcc · #11 08-08-2007, 02:10 AM

Check the rotor/cap. I faced the same problem on a 300SE 1987. Most likely it's an ignition related issue.

JEdwards · #12 08-08-2007, 07:48 AM

checked the rotor and cap last night... seems to be the culprit - I'll know for sure when my replacement arrives here in 2 days from FCPonline. Rotor looks like it is toast.

JEdwards · #13 08-09-2007, 10:55 PM

Replaced the distributor cap/rotor tonight - still no start.

Thus far: have replaced cap/rotor - established that there is spark at the spark plugs. Have swapped OVP relay, have swapped Fuel Pump Relay. Fuel is reaching the engine, can hear the pump running.

Engine possibly could be flooded, however the spark plugs were all pulled and allowed the gas to evaporate for around an hour or so. After doing so the car almost caught. Tomorrow I will check the EHA valve as recommended, as there may/may not be gas smell in cabin (gas smell after no start, but windows were open and the car was jacked up in the garage).

Any other ideas, because I'm at a loss.

BENZ TEK · #14 08-10-2007, 09:38 AM

Quote:

Originally Posted by JEdwards

Replaced the distributor cap/rotor tonight - still no start.

Thus far: have replaced cap/rotor - established that there is spark at the spark plugs. Have swapped OVP relay, have swapped Fuel Pump Relay. Fuel is reaching the engine, can hear the pump running.

Engine possibly could be flooded, however the spark plugs were all pulled and allowed the gas to evaporate for around an hour or so. After doing so the car almost caught. Tomorrow I will check the EHA valve as recommended, as there may/may not be gas smell in cabin (gas smell after no start, but windows were open and the car was jacked up in the garage).

Any other ideas, because I'm at a loss.

Check the engine timing. It may be off by a tooth!!

saumil · #15 08-10-2007, 11:52 AM

I could not follow: after you changed the distributor cap and the rotor, the car did not start because it was flooded. After you dried for an hour, the car started fine, right ? So then what is your problem now ? Is it that the next time you tried to start the car, it would not start again and it was flooded again ?

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