Lost Spark during rebuilt engine break-in

[carguy87]

If you want to check, an oil pressure switch will give you the same symptoms you seem to have.  If you don't have it plugged in tightly or it is going bad, it will allow spark to flow when you first hit the key and at the end when you release the key, but you will have no spark in the middle.  It's an easy thing to check, and if you need to replace it, is only like $7 at Autozone.

[KyleB.]

I replaced the coil a couple of days ago when I wasn't getting spark, should be good there.
The oil pressure switch was new during the rebuild, should be good there.

I am a little lost on the vacuum to the dist. discussion  I have it going to manifold vacuum.  All engine vac. lines are new. Looks like PO has done some hacking on the ICM wires, maybe bypassed?
I tubed it to the diagram on the EN for a "high altitude modified to low altitude".  There's the part that has me wondering.  Also, I have seen where other people have a high altitude jumper wire that is supposed to be grounded to the block when at altitude.  Mine is double landed with another wire on a single ring lug.  I think I may need to seperate those two wires.

BTW, there is a decal on the firewall stating "this car has been tuned for primary use at high altitude".  What would be the things to change to make it for low altitude use?  Vacuum and that jumper to the block?

[KyleB.]

I am back in the same spot as before.

I started it this morning to start working my way through the tuning fun....3 minutes of run time then it shut off. The other day it was 10-15 minutes of run time.
Thinking it may be something with the computer, I pulled the + battery cable hoping for a "reset" of some sort.  But no luck.

Will these things shut themselves down if there is an operating parameter that the computer doesn't like?

As I had mentioned before, all ignition components are new....from starter to rotor.
And, it appears I have good ground from dizz to battery.

Anyone experienced and ICM go bad and act like this?   

[thereverendbill]

from the fords I have owned in the past the ICM will just "go out".  have you performed the ECM Test test yet?

[KyleB.]

from the fords I have owned in the past the ICM will just "go out".  have you performed the ECM Test test yet?

Nope...ready to do it now though
Can you shoot me a link?

[Smitch]

http://www.amceaglenest.com/~iowaeagl/guide/index.php?title=Diagnostic_ECM_Test

[ammachine390]

Normally, the ECM won't cause no spark conditions. However, the ICM can cause no spark and intermittent failure like your describing.

[thereverendbill]

I am onboard with gronk and the GM HEI upgrade.  I main reason I did one to my wagon is to nip the no spark situation in the but before i ever had a problem with it

[KyleB.]

Do we have a comprehensive "how to" and a parts list here on the Nest?
I am about ready to pull the trigger, this sux.

[thereverendbill]

if ya want a good setup send me a PM and I'll send ya a link to the unit I got from "the bay" the wires are real easy to get or if your inclined to do so you can make your own because they are GM units

[ammachine390]

Another option would be the junkyard HEI like shaggimo wrote up. That way you don't have to buy/change the distributor.

[eaglefreek]

Another option would be the junkyard HEI like shaggimo wrote up. That way you don't have to buy/change the distributor.

Or an MSD or other CDI box. I was also having intermittent spark problems. Installed an MSD Streetfire and threw the aftermarket replacement Duraspark box as far as I could throw it. It runs like a champ.

[Eagleearl]

Check the ICM connectors to make sure they are clean. Sounds like it could be something getting warm or hot after a few minutes and opening a connection.

[GRONK]

Can this be as simple as a faulty starter solenoid relay?  These have the run osition that powers the coil.  If the solenoid is faulty......  Under $20 part, bight be worth swapping just to be safe.  If you need the 1 wire HEI, sned me your info.  I also have 12V ceramic resistors for them (I alway run a resistor before the dist.)  No more DII ICM