PeachParts Mercedes-Benz Forum - View Single Post - 300E start drive 3-5 miles won't start until cools

olpos · #17 10-18-2006, 12:30 AM

I vote to test the crank sensor. Do you have an OHM meter?
When my 88 300E ran the sensor tested good,but when it did not start the specs where way out.you test it at the ignition modual(SPELLING?).Very easy to get to.You can buy a DVOM from sears for about 40-80 dollars.This tool does volt,ohms and amps and bakes pies

.Easy to use and pays for itself on the first or second use.If you think you have a fuel problem squirt some green brake clean(COLOR OF CAN,RED CAN DOES NOT BURN BUT WORKS GREAT AS AN ELECTRICAL CONTACT CLEANER) into the intake track.BE CAREFUL IT IS FLAMEABLE,MAYBE MORE THAN ETHER,STARTING FLUID OR CARB SPRAY .Some times when you have the no start and if you have someone to crank the car tap on the fuel pump relay,ovp relay.computer and wiggle the crank sensor relay wire. When i pulled my crank sensor to replace it I found it was damaged,maybe when someone had replaced the starter before i bought the car. if i had wiggled that end it would have started,but it was still bad.ohm test only with no start .You may have a bad ignition modual. To me the only way to test that is to put a known good one in its place,but that is last and only if there is no spark when car does not run.Sensor on front of motor will not cause no start.I have a spare modual if it comes to that.Fuel pump relay can be tested with a jumper wire with pins 7 and 8 or by tapping.Work on crank sensor first when you have no start or during wiggle test

GOOD LUCK

Rich