1994 roadmaster randomly shut off in traffic. Not raining and the water pump has been replaced recently with a new msd opti and new wires and plugs. Will crank and crank but will not start. The fuel pump is turning on and I am getting no spark. Only vehicle I have atm and its putting me in a bind .Any help would be much appreciated. Will respond fast. I tested spark with the spark plug arching it. No arch

 

Can suggest some likely suspects.

MSD Opti is known to have issues, especially if it's within a few years old.
ICM can also cause no spark and random motor shut off and a no start after condition. Way easier and cheaper to swap but it could be Opti

Coil could also cause it but more likely Opti or ICM.

"Hearing" the FP come on does not mean you have enough fuel pressure. You need to use a FP gauge

 

how about spark from the coil? how do you know for sure it isn't the opti? could also be ICM

 

Changed the ICM. Took the rest of it off and cleaned it all and put thermal paste back on both pieces and still no start. (90 dollar part). That msd distributor is a year and a half old and has never had water on it. This is killing me. Has been a hell of a car till now.

 

I think you should make sure there is spark coming directly from the coil, not just one of the plugs.

 

And how should I do this.

 

not 100% if a roadmaster is different tho-
http://shbox.com/1/4th_gen_tech2.html#opti_test
http://shbox.com/1/coil_testing.jpg

 

This has worked great for me. It's an in-line spark tester.

 

I bought one of these at harbor freight today. I am checking it out of the coil tomorrow. If it is getting fire what would it be? And if it doesnt its either that or that turd MSD opti

 

if the coil is firing it's your opti. if it's not, it's the coil since you already replaced the ICM

 

Changed the ICM and coil. Still no start. Should I restart the computer by taking the battery terminal off and back on? 20000 miles on this msd distributor. Arcing on the coil when I pulled the old one off. Depressing .

 

Any help will be very much appteciated. What part inside of the msd can go bad? No corrosion on any of the connectors. I am about to have to resort to taking it to a shop and I'm really not in the financial position to but need to.

 

if im wrong on this i appologize but is not that it goes bad per say, i remember reading that some optis when manufactured have a defect when the shells are pressed together. the spacing of the disc causes it to rub on the sensor.

there are threads about rebuilding an opti and fixing this issue and some that replace only the optical sensor within it.

 

Have you scanned it for SES codes? If it's not attempting to fire you've got to diagnose if the opti is working right. This is a good place to start.....


This "crank but no run" chart is for an F-Body, but might help you.
http://www.ace1252.com/1996_Z28_Fact...ut_no_run1.JPG
http://www.ace1252.com/1996_Z28_Fact...ut_no_run2.JPG
http://www.ace1252.com/1996_Z28_Fact...ut_no_run3.JPG

 

OP

The MSD Opti has had many issues with their optical sensors in the last few years. Given you have changed both coil & ICM....it is the MOST likely suspect

There was a thread on another forum where a very qualified member, injuneer, dealt directly with MSD on trying to resolve chronic MSD Opti failures. MSD was never able to correct the issue

 

I looked at that video. I guess my next step is taking water pump off and getting to that damn distributor. Sickening that could have blew out that fast .The coil I changed looked awful and the ICM tested to be replaced at auto zone. Would MSD not reimburse me or refurbish it?