doesnt fire from coil, wont start - PeachParts Mercedes-Benz Forum

jun · #1 01-23-2006, 10:23 AM

...i have this 92 300TE-24 euro version, it stalled last new years eve and til now the problem hasnt been solve yet... no sparks from the plugs, and also to the coil. we replaced the coil to a new one but still no sparks during cranking... has anybody experience this? help!

Oreo · #2 01-23-2006, 12:10 PM

Jun

Get the multimeter and test the distributor hall effect coil. If that is OK, then its probably the iginition amplifier.

stevebfl · #3 01-23-2006, 07:24 PM

Nothing in the distributor on that guy cept a rotor. The primary is controlled by the ignition controller based on the input from the crank sensor which is off the flywheel at the back of the drivers side of the motor. Not too accessible.

I would verify that the coil isn't being switched by placing a test light onto the negative side of the coil and watching for a blinking light when the car is cranked. If the light stays on then the controller isn't grounding the coil. I might expect a crank sensor at that point but they don't fail often.

If you get a blinking light when cranking I would suspect a grounded or open dist rotor or cap.

waybomb · #4 01-23-2006, 09:09 PM

Quote:

Originally Posted by stevebfl

I would verify that the coil isn't being switched by placing a test light onto the negative side of the coil and watching for a blinking light when the car is cranked. If the light stays on then the controller isn't grounding the coil. I might expect a crank sensor at that point but they don't fail often.

Not to hijack, just trying to learn. My neighbor has had three crank sensors fail and I've had one. 98ML, 99ML, 04CLK. And I've read alot on the forums about these failing. I've never had one fail on my other MBs, knock on wood, just on the 98. So is this a failure phenomenon with only newer models? Is it heat that's killing them?

stevebfl · #5 01-23-2006, 09:40 PM

The crank sensor in 112/113 motors does fail regularly. The ones on 116/117/103/104 motors don't. But anything made by man fails sometime.

Carlos Serrano · #6 01-24-2006, 09:50 AM

Mine failed at 50,000 miles 99 SL 113 engine, and it's becoming more common on this engine

jun · #7 01-27-2006, 09:17 AM

Quote:

Originally Posted by stevebfl

Nothing in the distributor on that guy cept a rotor. The primary is controlled by the ignition controller based on the input from the crank sensor which is off the flywheel at the back of the drivers side of the motor. Not too accessible.

I would verify that the coil isn't being switched by placing a test light onto the negative side of the coil and watching for a blinking light when the car is cranked. If the light stays on then the controller isn't grounding the coil. I might expect a crank sensor at that point but they don't fail often.

If you get a blinking light when cranking I would suspect a grounded or open dist rotor or cap.

...thanks guys for the replies

we already check the distributor and coil, the two wires on the coil which i think is the - and + are ok and have been checked, my mechanic says he suspects the ignition control module (part # 0125452132), do you guys happen to know how to check the module or do you have a wiring diagram of it, thanks!

stevebfl · #8 01-27-2006, 10:22 AM

If your tech doesn't have a wiring diagram, why do you call him a tech. No professional would look at a system like that without the capability to access a wiring diagram. And that is a simple system.

#9 01-27-2006, 10:51 AM

Steve has aptly pointed out that your tech is not a tech, he is a parts changer. There are MANY parts changers out there that call themselves techs. Beware of them, they are everywhere.

Good luck,

jun · #10 01-30-2006, 02:53 AM

yup, thanks for the warning but i think he's a technician alright, just the diagram that he doesn"t have, got books from mitchell (professionals'), haynes and chilton... i just wanted to be sure that its the module that's causing all the trouble, and cant find any available replacement in the country, still have to order it abroad... any info will do! man! need your help!

dave_rose69 · #11 01-30-2006, 05:59 PM

Jun: You can test to see if the CPS is shorted or open. Use a good quality VOM and test the resistance at the CPS Plug. Its the smallest round plug on the EZL (ign module) 750 - 780 ohms, and .465 - .505 AC volts during cranking. The part is 117.00 bucks if you shop around.
Its a tough job getting it out, you'll need a helper or just let your "Tech" get it in for you....
Dave...

"93" 300TE 4 matic 187,000 miles

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