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FSJ Guy
11-29-2011, 02:19 PM
Thank goodness for cellular Internet access so I can post to IFSJA while I wait for the rollback wrecker. I think my distributor pickup went out. I was cruising along and then suddenly I had no engine.

Fortunately I was data logging at the time so I have a capture of the event, but that won't get me home. :-(

Yes, I already checked the wiring, swapped out the ignition module (GM TBI) and I even disconnected the MSD to see if that helped. No change.

The datalog show tach correctly at one point and then two points later it's zero.

Wrecker's here. Bye!
Blake
11-29-2011, 02:21 PM
Chewed up a dizzy / cam gear?
FSJ Guy
11-29-2011, 03:19 PM
Chewed up a dizzy / cam gear?

I don't think so. The rotor wouldn't move when I tried to turn it manually and when I cranked it and looked again, it was in a different position.

When I munched a dizzy gear before, it stumbled and died. This was an instant off thing. Leads me to believe it's electrical. Jeep is home.

I'll be testing the distributor tomorrow. The dizzy is supposed to show AC voltage on a meter when cranking. Visually, the starwheel and pickup look fine.
bigun
11-29-2011, 04:11 PM
Good luck!!!
grand_wag_85
11-29-2011, 04:20 PM
Which distributor are you running? I guess Murphy knocks on everybody's door every now and then.:o
jaber
11-29-2011, 05:18 PM
I was having the same problems last weekend, but mine was cutting out real bad. Mine was a wire inside the dizzy. Plays hell when your trying different tunes in the 'putor...:rolleyes:
710 Burner
11-29-2011, 06:21 PM
I had the exact same thing happen once on an HEI dizzy I was running on a Chevy motor.
Pman
11-29-2011, 06:29 PM
Ethan,

You think the 'ole column mounted ignition switch may be worth looking at?

Data Logging....haha...that's pretty hard core. Is that like texting with your Jeep?
Blake
11-29-2011, 06:43 PM
If it's an HEI dizzy, there is a 4 or 7 prong module in there. They are known to go bad. Usually they don't die while it's running though...
FSJ Guy
11-29-2011, 07:07 PM
It's the stock motorcraft distributor. I just disconnected the vac advance and welded the mechanical advance solid. I read that a bad ground will cause it to stop working, too.
FSJ Guy
11-30-2011, 09:31 AM
Went to diagnose the problem this morning and of course it started right up!!! :rolleyes:

I really wish the component had PERMANENTLY failed. Now I'm just left guessing that it was the pickup module in the distributor. :-/

It is cold this morning and that tells me that the failure was heat related. It was warm out yesterday, but not "summer hot". The coolant temp was between 180-195F like it should have been.

Going out to replace the stator pickup and will buy a new cap and rotor as the old one was looking sad.

Hopefully I won't screw up the firing order too badly when I swap caps. :lol:
FSJ Guy
11-30-2011, 11:01 AM
It's back together again. And yes, it runs. I picked up an extra pickup module for my spare parts box. It's got me paranoid, now.
puckettj
11-30-2011, 11:35 AM
Could it be vapor lock?
grand_wag_85
11-30-2011, 12:07 PM
Could it be vapor lock?

He's running fuel injection on that Jeep, still possible but unlikely.
Pman
11-30-2011, 12:54 PM
Ethan,

I might be missing something in your first part of the thread, but see my post here from 2010:
http://www.ifsja.org/forums/vb/showthread.php?t=119648&highlight=ignition+switch

Drove me crazy until a couple of members brought up the ignition switch. I think it was 12 bucks at the auto parts store and was the culprit. Exhibited some of the same symptoms you are experiencing.
Gambler68
11-30-2011, 03:39 PM
Mercury Retrograde just LOVES FSJs :P

Glad you got it sorta fixed till it dies again.:thumbsup:
FSJ Guy
11-30-2011, 05:42 PM
Ethan,

I might be missing something in your first part of the thread, but see my post here from 2010:
http://www.ifsja.org/forums/vb/showthread.php?t=119648&highlight=ignition+switch

Drove me crazy until a couple of members brought up the ignition switch. I think it was 12 bucks at the auto parts store and was the culprit. Exhibited some of the same symptoms you are experiencing.

Thanks!

But my ignition switch doesn't control my electronic ignition. It turns on the PCM. If the PCM were being shut off, I wouldn't have any data from it. Aside from one hiccup in the data stream, the PCM kept feeding me data.
Pman
11-30-2011, 05:44 PM
Ethan, I'm a moron. Just saw the mod in your sig. I'll shut my trap now.;)
FSJ Guy
11-30-2011, 07:30 PM
Could it be vapor lock?

Vapor lock shouldn't cause the tach signal to suddenly disappear, however.
FSJ Guy
11-30-2011, 07:30 PM
Ethan, I'm a moron. Just saw the mod in your sig. I'll shut my trap now.;)

No worries. I've missed more obvious things than that before!