Distributor Module 620

[ERBooks]

Looking for a source for my '78 620 distributor electronic module which failed. Suggestions? Thanks

[bananahamuck]

They replace them with inexpensive  GM HEI modules

 

 

They are in almost every middle 70s- 90s GM product in the junkyard

 

Link to explain ,, clickity -clickity

 

http://community.ratsun.net/topic/17444-electronic-ignitions-for-l-motors-4-cyl/

 

 

 

.

[datzenmike]

Just to confirm. This is the '78 distributor...

 

 

If it looks like this it's a '79 ot '80 L20B EI distributor. Does the same thing but has the module on the side...

 

 

So which one do you have????

[mhub91]

Looking for a source for my '78 620 distributor electronic module which failed. Suggestions? Thanks

 

 

Are you talking about the control module on the passenger side kick panel area?

 

If so, I have one. $30 shipped. Let me know. Please send me a message and we can go from there.

[distributorguy]

Mike, Where did you get the photo of the 79/80 distributor?  Just wondering, as it looks like one I rebuilt.  

 

The HEI modules are commonly wired as shown in the diagram above, but normally you also want to add a condenser from a points distributor to the power input wire to help control voltage variations and help absorb plug wire noise issues (not radio noise interference, but rather noise that disrupts the ignition signal.)  Module grounding is 100% critical, so make sure its perfectly grounded to the chassis or it won't work at all.  Grounding may be why your current module doesn't work.  

[datzenmike]

I was in a hurry and grabbed it off Google images. I think it was a Ratsun post.

[ERBooks]

After reading more on the subject, It is a '79 "matchbox" module, which is why I'm having difficulty finding. Suggestions? 

 

[datzenmike]

First, these modules hardly ever go bad so make sure it's the module first. What's wrong? no spark?

 

1/ Is there 12 volts to the coil + side?? when cranking and when key in the ON position?

2/ Is there 12 volts to the B terminal on the module??? when cranking and when key in the ON position?

You HAVE TO HAVE 1/ and 2/ above.

 

3/ Install a separate ground on the distributor like the one below. Distributor MUST have good ground

4/ Is the coil good?

 

 

 

You have the matchbox module with the red and green wires inside..
 


Just use the diagram below and wire up an HEI module in it's place. Wrecking yards are full of them and they are a perfect fit into your back pocket, or $20 at NAPA

 

[distributorguy]

Rockauto.com

Look up a 1980 720 Nissan pickup ignition module.  $125.  I've seen plenty fail, usually from a poor ground over a long period of time.  Again, a poor ground will also cause it to "play dead."

[ERBooks]

Thanks, very helpful-I'll double check the ground, and then get the GM HEI module it the ground isn't the problem. It runs until warm, and  then cuts out. So far, it has always re-started! 

[datzenmike]

Lots of reasons for cutting out when warm.

 

Idle jet plugged.Not noticeable when choke is on.

Idle cut solenoid not connected. No idle fuel.

Coil (specially if after market) may over heat and quit.

 

 

Next time it quits pull plug wire off and see if there is spark. Don't assume.

[distributorguy]

If you have a tester, measure the resistance of your plug wires.  They should be under 3000 Ohms.  Over 10,000 Ohms will overheat the coil and it will stall out.  

So will a bad module ground/distributor ground/engine ground.  You can ground the module directly to the battery as a test if you like.  Remove it and clean the back, and remove the piece behind it and clean that too.