Checking EZL ??? 190E 2.3 won't start... - PeachParts Mercedes-Benz Forum

jay123 · #1 05-30-2002, 05:23 PM

How do you know if the EZL is bad and needs replacement? How do you check it? Specs, procedures, pin-outs, etc...

Thanx..

mbdoc · #2 05-30-2002, 05:47 PM

Of course the most common failure is when the engine won't start & there isn't any dwell signal to the ignition coil. OTHER than that what seems to be the problem??

jay123 · #3 05-30-2002, 06:02 PM

Car won't start. OVP and fuse seem to be good. This is a very costly part. I want to check everything possible before considering to change this part on my Dad's 93 190E 2.3..
Any and all help/suggestions are very much appreciated.

mbdoc · #4 05-31-2002, 05:46 PM

The ignition module must send DWELL signal to he negative side of the ignition coil. The flywheel position sensor must provide a/c voltage signal to the EZL for this to happen.

jay123 · #5 06-01-2002, 01:03 PM

Thanx.. I definitely know now that my EZL is working. Car didn't want to start. It would kick over and sputter. This proved to NOT be the EZL, since it is attempting to fire up. Checked the OVP fuse..Good. Did find the vacuum line going to the fuel regulator from the the valve cover hose broken. But in a new hose and cranked it out 3-4 times and the car started. Left it alone for over 1.5 hours and the car stayed on all the time. Turned it off and restarted it. Fired up instantly. It seemed like a fuel issue. Maybe that vacuum hose was the culprit. Checked the fuel pump relay and it is not hot to the touch. Thought it might be the fuel pump or the relay also. The fuel pump is kinda loud. You can definitely hear it run. Plugs, cap, rotor are good. No wear.
Also, am considering checking the pressure on the fuel pump and checking the fuel accumulator to see if it is holding pressure. While under the car, I'll definitely change the filter.
This is on a '93 190E 2.3 we just picked up.
So, any ideas on this one guys? MBDOC ??

jay123 · #6 06-03-2002, 04:49 PM

Well, checked the fuel pressure from the fuel distributor and got 65 psi. Let it sit for 10-15 minutes and it slowly went down to 50 and stayed there. This tells me that the fuel pump and accumulator are working well. Tried to start it today..turns but will not start. I am not getting a spark again. I'm still wondering about that EZL. Usually, an ignition module will work or it won't. Internittent issues with ignition modules are very rare. i did see it a few times with a GM HEI system.
Before I consider replacing this part..which isn't cheap, any suggestions as to what else I may look at?

Thanx..

jay123 · #7 06-04-2002, 09:51 PM

Anyone have experience with this????

jay123 · #8 06-05-2002, 10:13 PM

Well, I changed out the EZL/Ignition Control Module and still no spark. I checked the coil again, and it is good. Something needs to be sending a signal to the EZL, which sends a signal to the coil and then to the distributor.
Someone please help !!!!!!!!! I am stumped. I wonder if the problem is with the position sensor off of the front crankshaft. But how do you check this? What are the pins and what readings should I be getting? Any takers or experience with this?

jay123 · #9 06-06-2002, 10:58 AM

Anyone want to take a stab at this? No pun intended...

Mike Richards · #10 06-06-2002, 11:10 AM

Doc mentioned that the flywheel sensor sends voltage to the EZL.

Voltage is checked betwen 2 points in parallel vs. in series. A VOM could be used. I suspect you'd hope to see 12v.

I'd try this test next.

Arthur Dalton · #11 06-06-2002, 11:29 AM

Checking the fuse on the OVP does not mean the OVP is good.
They are known for intermittent fault..
Try giving it a tap w/sdrewdriver handle

jeffsr · #12 06-28-2002, 12:32 PM

Did you check the primary and secondary windings in the coil for resistance values. I believe #4 HT to #15 terminal should be around 5-8k, primary side should be less than 1 ohm. BTW, a coil can open under load and test OK with a VOM.

euro 287 · #13 06-28-2002, 06:58 PM

Ok when you have no spark do you get the voltage at the posotive side of coil with key on? If not then ck for bad connection or fuse problem. Do you have pulse at the negative side of the coil? If not then I would find someone with a lab scope and ck the pickup sensor at the flywheel ( little green wire going to EZl) Replaced many of these. Only times I have ever replaced an EZl is from a car wrecked in the drivers fender. You can also do a resistance test on the pickup sensor with an ohm meter . I dont have spec offhand. If you have pulse at the coil and voltage with the key on then see if you are getting any spark from coil.If not throw a coil on it , if you are see if you loose it at the cap.Just cause it looks good doesnt mean it is.Suspect everything during diagnosis.

fasthair · #14 06-29-2002, 02:59 PM

HI Jay

I'm with Euro on this one. Can't tell you the coils I've replaced over the year on this system. Just replaced one a 420 yesterday for a no start. Never have replaced a ELZ in my 20 years of fixing these beast. Do you have dwell on the coil? I haven't seen you answer that question yet. If you got dwell you got a bad coil, end of story. If no dwell then the crank sensor is suspect. You can test it with a volt meter set to AC volts. It should put out at least .8 volts cranking which would be 1.6 volts peak to peak on a scope. Just my 2 cents worth. Good luck.

fasthair

jay123 · #15 06-30-2002, 03:03 PM

OK everyone. Here is the deal..
Pulled coil out of car and tested on bench. Gives a Shocking GOOD spark. Put back in car, no spark when attached to the factory wiring. Got another EZL ($300.00) and put it in..No spark. So, I know it's not the coil or the EZL. Checked the schematics on the engine wiring and found that the only other part that works with the EZL and the coil is the Crankshaft Sensor, which is by the oil filter housing.
Turned car over while attaching a volt meter to the crankshaft sensor and got no readings. Pulled the sensor off, used the meter again, and got a reading that was way under the tolerance according to the CD. Replaced the sensor, and car turned on with no problems. No hard start..nothing. Turned on the dime.
So, I have continued to turn it on for the past week, everyday, and it goes.
Apparently, the sensor triggers the EZL, which in turn sends a signal/voltage to the coil to fire a spark.

I appreciate evryones help on this issue. This is one of the reasons I enjoy this forum. The crankshaft sensor cost me $85.00 online.