1992 300SL No Start Condition

[choo-choo]

Merry Christmas to all.
I have a 1992 300SL that was running fine until one evening back in April after church it would not start. I've had it at a local mechanic since and to date he has not been able to figure out the problem. It turns over fine just won't start. Long story short, we have new plugs, wires, distributor cap and rotor, battery, fuel pump, etc. He has tried two different new crankcase position sensors, a new coil, two used EZL's (reported to be working - we haven't been able to find new EZL's). He has been troubleshooting using All-Data and all of the voltages, etc. are checking out per specs and reportedly fuel pressure is good and within specs. I bought a Model 129 CD online but it does not run on even older computers with Windows XP, so he is currently limited to what he can troubleshoot with All-Data. I think this is the first time he has admitted being whipped by a problem. So I am trolling for any additional thoughts, maybe somebody out there has run into this problem and fixed it doing something different than we've tried so far. Also, if anybody out there should have some working PDF's of the wiring diagrams for this car, that would be greatly appreciated. For example, is there something else to check such as an alarm system or door lock interlock with the ignition system? Anything that could cause a no-start situation. Or if anybody has a Model 129 CD that does work on the later computers you would be willing to sell or loan out, that would be helpful.
Thanks in advance for your help!

[500slindia]

hi, any luck with the car. would like to know what the problem was

[optimusprime]

Choo choo as your car got an alarm and immobiliser fitted .? It may be worth your time to check this out first . I went through this last year after lay up .I did all the usual things .In the end it was the alarm at fault . Had to call auto electric in and,he found the problem a fault in the alarm .He disconected it at the coil ,this was an aftermarket alarm system

[tecqboy]

I just came across your post. I've been away for a while. But I have a 91 300SL and I would be very interested in knowing if or how this was resolved. These cars have a notorious ignition switch problem, but you can trouble shoot it with electrical checks. Have you looked on the other forum for help? (BW)? With fuel pressure and spark, it ought to start.