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[Nosebolt]

a while back I acquired a used HEI for the V8, never fitted it on the old engine but decided to use it on this build, problem is I'm not getting a spark, was assured it was a working unit (and I trust the bloke who sold it).

I have been through the basics and all parts are there and what i can test has been tested, have also run a 2mm cable (12v) direct from the battery to B+ incase it was a power deficiency but still have the same problem.

can't get the coil pack tested till monday but is there anything else I can do?

don't really want to go back to old dizzy yet as I have modified the loom for the HEI and to rerun the required wires would be a PITA

[Nosebolt]

thought I had found the problem, the main coil wasn't earthing due to a striped thread on the corner that connects to the earth, anyway a helicoil in the cap and now has earth, still no spark though 

[Panic mechanic!]

will this help at all?

http://www.jeepforum.com/forum/f8/gm-hei-dizzy-wire-diagram-help-733155/

[Nosebolt]

thanks but that's the set up diag, I need test procedures for the module and capacitor

[Panic mechanic!]

ok ok calm down

Easy tests for HEI system:


1.  Test for power at the pink BAT terminal.  You should have battery voltage w/ the key in the start and RUN positions.


2. Connect the ground side of your test lamp to the battery POSITIVE cable.  Probe the TACH terminal on the dist. cap while a helper attempts to start the engine.  The test lamp should blink repeatedly as the engine cranks.  No blink= bad module or pickup coil.  Further testing is required to pinpoint the problem. Blink but no spark = bad ignition coil.


3.  Remove the cap & rotor.  Remove the green & white leads from the module.  Connect your ohmmeter to the green & white leads.  You should have approx. 800-1500 ohms depending on the ambient temperature.  Open circuit (infinite ohms) = bad pickup coil.


Wiggle the green & white leads as you test.  Ohm reading should remain constant if the leads are good.  If the reading varies as the leads are wiggled, the pickup coil is bad.  You'll often find broken pickup coil leads this way.


4.  DVOM (meter) still connected to green & white leads.  Set your DVOM to AC VOLTS.  Have a helper crank the engine as you watch the AC VOLTS reading.  A good pickup coil will produce about 3V AC when cranking.  Less than approx. 2V AC indicates a bad pickup coil.

 

[Nosebolt]

not tried no 2 on that list so will give it ago when i get a chance, thanks

[Nosebolt]

does look like the Hei module has gone, new type now comes complete with capacitor as a single assembly now, at £108

so bit the bullet today and had a play with the loom and got the old dizzy refitted, will have to relocate the coil and used the old mounting hole to fit the manual choke conversion but thats no biggy lots of places to choose from and can get the coil up a bit higher now.

did need to chase the coil trigger wire and found this very useful, thought I'd post it as it may help someone else

[attachment=1]

[Nosebolt]

got around to fitting the HT leads and trying to fire up the old girl, battery was low due to the false start with the Hei, but did notice the solenoid was getting very hot, even a bit of smoke from it.

did get a spark and it tried to fire so batteries now on charge, but worried about the hot solenoid, any ideas?

[Dave69]

what are you saying is hot? if you cant hold your fingers on it for a long time then i'd be cautious.

The solenoid should be pretty resiliant but if you turn the key and nothing happens it would have then answered your query

[Nosebolt]

all turns over ok but the terminal that runs to the starter gets very hot

[Panic mechanic!]

its probably getting a little old and building up a bit of resistance.

[Nosebolt]

fitted new 3 months before CJ came off the road