I was on my way to work this morning on my 1990 LWB and 1/4 mile from home the engine died. Brought it home, cranked it and nothing, it has fuel as I can hear the fuel pump running but it shows no spark.

I tested the coil per the FSM. Tested the primary coil resistance (from + to Hight voltage terminal the standard value calls for .72-.88 ohms I get .9ohms.

Then tested the secondary coil resistance. Standard value calls for 10.3-13.9 Kohms, I am getting 11.

Also tested the power transistor also per the FSM and it tested fine. Still went to the auto parts and got a new one and still no spark (they were nice to accept it back).

So, what now? the ECU is freshly rebuilt. What else could it be?

I cannot enjoy driving this thing.

Javy

Optical sensor in the dizzy is your next suspect. If you have a friend with an old DSM datalogger you can test while cranking to see what the tach is sensing for a signal (the stock gauge isn't sensitive enough to diag). If it's all over the place or not registering, there is your fault.

Unfortunately I have no access to a data logger.

Javy

MarkG had one.

If it is the optical sensor the only way to replace it is by replacing the distributor unit, right?

Javy

A friend (or junkyard) with a distributor to swap in would narrow it down for sure. I have evoscan and the cable here which can read MUT language but the turnaround time would be long...

Did you check for actual primary voltage? I believe you can also connect a 12v test light to the primary and while cranking engine watch it blink as primary is switched off and on. If not blinking then it'll be the primary switch. I think the switch was the power transistor with signal from ECU.

I picking up a 91 which had the ECU rebuilt. ECU took a crap again. Owner is tired of dealing with it.
My point is, see if you can borrow a ECU to rule out this theory.

Never do a reman ECU ... The ECU is wounded and they just fix what they see as bad then the ECU just keeps dying on some other part down the line in the ECU ... Get a good used ECU ..

I bet its the igniter "plug" at the igniter .. Not the igniter but the plug ...

Captain Gear Box

Hazardous Toys inc ..

I must say my repaired ECU, done by avproecm.com, has been great. Repaired several years ago and no problems - great price and turnaround. Unfortunately the web address is not active any more. But there may be another one out there worth a try.