'86 300E Just Died DEAD! - No Spark!! - PeachParts Mercedes-Benz Forum

Phalcon51 · #1 07-15-2003, 04:34 AM

I was driving home after picking up my wife today when the engine went dead without any warning at all. We were driving down a slight incline and I had taken my foot off the gas for a few seconds. The car had been driving beautifully. When I went to accellerate again, there was nothing! A quick check of the instruments showed that the engine was spinning, but no response at all. As I slowed down to stop, the tach just went to zero and it wouldn't restart. The engine spins over fine, but no go.

After I found out that AAA would cost me over $200 to tow it home ( a little over 30 miles), I decided to call my brother and have him bring a few tools.

We quickly determined that there was no spark at the plug or the coil lead. The coil ohm'd out at .44 ohms on the primary and 11 k-ohms on the secondary windings, all within spec. The position sensor read 922 Ohms, where the normal range is 730-910 Ohms, probably OK within the accuracy limits of my brother's cheapo VOM. It seems at this point to be pointing to the Ignition Control Unit.

I can't find this part listed in Fastlane. Does anyone know where I can get one, new or used, and a ballpark idea on price? Does anyone know of any Mercedes salvage yards in the San Gabriel or San Fernando Valley area of So. Cal.?

Can anyone give me any other ideas? Are there any sensors that will cut the coil trigger impulse if it senses a fault? The only thing that has happened recently is that the car was rear-ended back on June 3rd hard enough to tear the front flex disc. Since then it's developed a leak in the A/C system and now this. Could a sudden sharp impact cause these types of problems on an older car like this? There wasn't much exterior damage, so how can I get the insurance company to consider it if it's caused by this?

Also, when I was removing the aircleaner yesterday I inadvertently broke the small diameter plastic pipe that goes from the back of the Diaphragm Control Valve to the cam cover Breather Hose. In trying to pull the other end of the hose out of the rubber connector at the Control Valve end, the rubber connector pulled out of the back of the valve and tore, so I've been driving with it missing. Could this play any part?

Any help or suggestions would be greatly appreciated

Thanks,

Gary

joe p · #2 07-15-2003, 07:31 AM

Sounds less like a EZL and more like a crank sensor. (which is a lot cheaper than a EZL) 008-545-64-32 is the EZL#, 002-153-90-28 is the crank sensor.

Joe

Phalcon51 · #3 07-15-2003, 11:27 AM

joe p,

According to the manual I've got, the crank sensor (green coax cable plugged into the ign.module) should read 730-910 Ohms and mine measures 922 Ohms. Is this enough to cause a failure?

Also, is the "crank sensor" the same as the "reference sensor" listed in FastLane: "Reference Sensor - Speed - Located at front crank pulley. Optional with 002 153 22 28"? It lists for about $64.
It lists one at the crank pulley and one at the flywheel. Does my car have both or just one of these?

Thanks,

Gary

joe p · #4 07-15-2003, 12:38 PM

flywheel. You've got to look for a a/c voltage when cranking. MB "resistence" specs aren't the most reliable method of diagnosis, I use a scope and look for a a/c wave in the 3v range or so. (cant remember the spec and my brain hurts too bad to try and find it)

Joe

psfred · #5 07-15-2003, 06:49 PM

Check to see if you have switching voltage on the primary side of the coil while cranking -- that is, a voltmeter or test lamp should show high/low transitions. If so, the coil is open and you have no spark. If not, it's the crank sensor or EZL.

Are you sure you don't have spark from the coil? I've heard of rotors or rotor carriers falling apart, so that you have spark but it cannot get to the cylinders!

Peter