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Old 02-25-2009, 02:51 PM
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ps2cho ps2cho is offline
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Location: Chandler, Arizona
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Quote:
Originally Posted by pawoSD View Post
Have you ever tried swapping out the ignition control unit on the fender? Or the computers back by the battery? Perhaps one of those devices has a glitch thats causing an electrical irregularity....and thus a misfire.?
Yes the EZL is the ignition control unit on the fender.

Quote:
Originally Posted by babymog View Post
Have you pulled your spark-plugs and compared them to look for one that is different than the others?
I haven't since the head removal...but the misfire has been with me since I got the car...I will pull the plugs tomorrow to see if there is any indication if I am running rich or lean.

Quote:
Originally Posted by slk230red View Post
You have certainly done a lot to your car. Your head gasket job was done very well with attention to detail.

Have you checked for any DTC codes?

The next thing I would do is:

1. Test the fuel pressure
2. Measure the EHA Current
3. Test the Throttle Position Sensor
4. Test the Air Flow Potentiometer
That is for sure
How would I test the air flow potentiometer? In the M103, I know there is an electrical connector that goes to the pot, but what does that control? I thought there was no traditional potentiometer on this engine...
Also does the M103 have a TPS?

Quote:
Originally Posted by pentoman View Post
I believe you should not get a misfire, correct. You could check by pullnig the hoses off and seeing what happens.

FWIW, I have found these CIS cars will run with the ECU removed without misfiring. Throttle response will be a bit weak and cold running will suck, but it shouldn't have a single cylinder misfire or anything. May help you rule out certain problems that info?
Good luck; bear in mind it could be something you thought you've checked!
By the ECU, you mean Jetronic brain? With that removed, what components of the ignition system are turned off exactly?

That is always my fear...but if that part was replaced and it made zero difference I couldn't have got a part that was an exact replica of the misfire I experience...any change at all -- I would notice.

Quote:
Originally Posted by pawoSD View Post
He said it was still misfiring after his head gasket replacement, I'm assuming he had brand new plugs in it at that point....

I vote for an electrical irregularity. If I was you I'd have probably had a MB tech diagnose it at the dealer at this point though....
That is the plan if I don't find anything wrong with the aforementioned. Would I get charged astronomical prices for a diagnosis only? I have only been to the dealer a few times for parts and they were crazy prices...That's why I am afraid of asking them to look at the car...
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