computer bypass- guess I blew it

[jim]

I did the bypass and installed the Motorcraft carb.  Eagle won't start.  Plenty of gas to the carb.
It would not hit except it would try to when cranking stopped.  Off to Harbor Freight to buy a spark tester.
From coil to dist, while cranking, no spark.  Stop cranking and get a single spark.
I must have done something wrong with the bypass. 
Maybe I'll put it back to original and see if it will at least start, and if it does try again on the bypass.
The problem I have now is time.  I'll watch the final race at Homestead tomorrow.  Anyway it's supposed to rain from tonight thru the next 3 days.  Then we'll be out of town for the Thanksgiving holiday.   The following weekend my mother is having a basil cell carcinoma removed from near her eye.  We'll be prepared to stay with her a few days if necessary.  Otherwise I'll have to work at night between rains and after work.  Looks like it'll be a while before this one is back on the road.

[shanebo]

How does that bypass work? I know it eliminates the old carb, but does it also do away with the stock ignition control module replacing it with point style ignition?....Ive heard about this but I was never quite sure what all got bypassed.

[eaglefreek]

 but does it also do away with the stock ignition control module replacing it with point style ignition?....  

No, it just bypasses the ECM that controls the stepper motor.

Jim, there is a chance you may have a faulty ignition switch. With a volt meter make sure you have power going to the coil when trying to start it.

[carnuck]

Sounds like the 12vdc pickup on the solenoid may have burnt out. There are 2 little wires on them. One marked S (which engages power to the starter when cranking) and "I" which bypasses the ignition resistor and feeds battery power directly to the coil + to boost spark while cranking.

[jim]

While cranking I had 3+ volts from the starter side of the solenoid to the coil.  I had planned to eliminate the resistor wire but didn't think I needed to until it was running.

[shanebo]

Thanks for clearing that up for me guys...I was wondering exactly what it involved.

[Jurjen]

Maybe this helps a little:

http://www.jeepforum.com/forum/f8/ECMTest-bypass-377632/

Scroll down a bit for the schematics.

[jim]

That link doesn't work for me, but  I have the schematic.  I did the bypass successfully on the 83 wagon.  I'm disappointed that this time doesn't work.

I wondered if I had reversed the wires to the coil when I did the ignition upgrade, but I think I started it after that upgrade.  However, I did have the wires reversed according to the 83, which has an identical Petronix coil, so I switched them to match the 83.  No difference - no spark from coil to dist except when releasing the switch, and then a single spark.

[jim]

No.  I will.  I hadn't tried it because I wasn't sure it would turn over with a bad solenoid and it certainly spins over.

[Jurjen]

Repaired the link ^^

[jim]

The yellow wire goes to the positive side of the coil and the green goes to the negative.

I know.  The problem was figuring out which was which.  I really thought I had it backwards but it started and ran that way.

[Jurjen]

Coils work both ways, but with + and - swapped sparks will jump from the ground electrode to the centre electrode.
This also happens on wasted spark ignitions (one coil for two cilinders).
That is why they use double platinum (and not single) for wasted spark ignitions, both electrodes wear at the same pace.

[GRONK]

Jim, just saw this.  Any luck yet?

with the N U T T E R bypass, it either works (if correctly wires) or it doesn't (incorrectly wired)  You can't do it wrong and have it run.

2 wires, I'm assuming you have a orange and a violet wire at the ICM?

If orange (you can substutitute light green w/ a tracer for orange) you have the ICM in this order:

ICM-wiresA-connector-wiresB

You will create a 3 way pllice (add a 3rd wire) to violet at wiresA and run it over to violet at distributor.  The orange (light green w/ tracer) ar wiresB will get cut and barreled to a new wire and routed to the orange at the distributor.

Use 16ga wire, don't cross them.

I always recommend running new wires instead of fishing through the bundles and guessing which are correct.

[jim]

It has not run since the ECM Test but it turns over.
I'll have to go back through the ECM Test process and make sure I spliced the correct wires.  I really thought I did it exactly the same way I did it on the 83, but I may have messed up somewhere.

[jim]

I've been studying the schematic again and I see that I may have done the bypass incorrectly. 

It's altogether unpleasant out there in the dark to mess wth it now.  We've had flash floods last night, all day today, more expected tonight and tomorrow.  I30 and the best alternate route were closed for a few hours today because they were under water.