#1  
Old 04-23-2022, 07:05 AM
convgto convgto is offline
Senior Chief
 
Join Date: Sep 2003
Location: nw florida
Posts: 456
Default HEI dist. volts running

What should the HEI dist. volts idling be on a stock 389 1965 GTO. Just purchased this car and went from points to HEI. I was getting stalling problems driving, it is a 4 speed so I could restart driving and limp home a couple miles. Checking voltage wired the way my son wired it, voltage idling would be sporadic then drop to 0 and stall. He has now wired in a relay from battery, not stalling idling now but volts are still sporadic is that normal, what should voltage be idling. I also had a large vacuum leak at back of AFB carter carb, put a new gasket on slowed it down a lot but still there after spraying starting fluid. How to stop that? thanks

__________________
1967 Firebird under -DONE
1965 GTO under construction
  #2  
Old 04-23-2022, 08:45 AM
Kenth's Avatar
Kenth Kenth is offline
Ultimate Warrior
 
Join Date: Feb 2003
Location: The Kingdom of Sweden
Posts: 5,457
Default

Check voltage at battery, you should see the same at HEI.

Sporadic voltage may be a faulty alternator or voltage regulator.

__________________
1966 GTO Tri-Power
1970 GTO TheJudge
http://www.poci.org/
http://gtoaa.org/
The Following User Says Thank You to Kenth For This Useful Post:
  #3  
Old 04-23-2022, 09:00 AM
25stevem's Avatar
25stevem 25stevem is offline
Ultimate Warrior
 
Join Date: Jan 2022
Posts: 1,744
Default

If your Alt / charging system is good then the voltage seen across the battery with the engine warmed up and idling and the headlights on should not drop down below 12.5 volts.

The HEI needs a constant 12 volts or better to perform right.
If it’s constantly getting less then 12 volts then the module in it will run hot and fail at some point.

That cars stock points system only gets the full battery voltage when cranking , once the motor starts and the key is out of the crank position a inline resistive wire supplies only 9 volts to the coil.
If that’s a stock iron AFB intake and you have the right 1/4” thick gasket under that AFB carb, and the manifold itself is not cracked then there should be no leak.

I don’t understand/ follow why your Son put in a relay feeding the HEI.

__________________
I do stuff for reasons.
The Following 2 Users Say Thank You to 25stevem For This Useful Post:
  #4  
Old 04-23-2022, 09:10 AM
62posbonny 62posbonny is offline
Member
 
Join Date: Jun 2020
Location: Omaha, NE
Posts: 89
Default

Not OP, but I have used the stock 9v ignition wire to trigger a relay for steady 12v to an HEI in the past. It's just one way to be sure that you are getting full battery voltage without hacking up the original harness in case you ever want to go back to original.

The Following 2 Users Say Thank You to 62posbonny For This Useful Post:
  #5  
Old 04-23-2022, 03:58 PM
SRR's Avatar
SRR SRR is online now
Ultimate Warrior
 
Join Date: Sep 2005
Location: San Diego, California
Posts: 1,225
Default

What size wire is being used?

__________________
“Nothing in the world can take the place of persistence. Talent will not; nothing is more common than unsuccessful men with talent. Genius will not; unrewarded genius is almost a proverb. Education will not; the world is full of educated derelicts. Persistence and determination alone are omnipotent. The slogan Press On! has solved and always will solve the problems of the human race.”
― Calvin Coolidge
  #6  
Old 04-23-2022, 04:19 PM
25stevem's Avatar
25stevem 25stevem is offline
Ultimate Warrior
 
Join Date: Jan 2022
Posts: 1,744
Default

Ok, got it!
That will fly.

__________________
I do stuff for reasons.
  #7  
Old 04-23-2022, 04:21 PM
convgto convgto is offline
Senior Chief
 
Join Date: Sep 2003
Location: nw florida
Posts: 456
Default

Thanks for replies. Volts at battery 14.6 same as volt gauge in car. 12 guage wire copper strand. I went for another round the block, barely could get up my driveway little hill no power stalled got back to the garage after restarting a few times. My vacuum leak after checking tightening still leaking. 25stevem do have a pic or link for the correct gasket. i used a mr gasket #55c. The old gasket was about 5 stacked gaskets. I took carb off to detail engine and bay, I thought the multi gaskets were for heat spacer. Car did have power before dist. change. Is the guts of a chevy HEI the same as a pontiac ie module, coil. I have a new module and HEI coil for chevy HEI dist for my 60 c10. I may switch them out and check things. thanks again

__________________
1967 Firebird under -DONE
1965 GTO under construction
  #8  
Old 04-23-2022, 04:45 PM
25stevem's Avatar
25stevem 25stevem is offline
Ultimate Warrior
 
Join Date: Jan 2022
Posts: 1,744
Default

Gut wise those HEI are the same, but your pickup coil could be bad also.

To change that out you have to pull the distributor out and remove the drive gear.

This is one part that just due to age I would replace even if it’s not bad now.
Vibrations most times makes them fail.

__________________
I do stuff for reasons.
  #9  
Old 04-23-2022, 05:35 PM
77 TRASHCAN's Avatar
77 TRASHCAN 77 TRASHCAN is offline
Ultimate Warrior
 
Join Date: Oct 2008
Location: 31May2013 Temporary home to the world's widest (that we know of) tornado. Lord, NO more Please...
Posts: 6,591
Default

Bob Suntuned talked here, couple of years ago about problems with several different brands of aftermarket modules.
What module is in theHEI?

__________________
1977 Black Trans Am 180 HP Auto, essentially base model T/A.
I'm the original owner, purchased May 7, 1977.

Shut it off
Shut it off
Buddy, I just shut your Prius down...
  #10  
Old 04-23-2022, 05:47 PM
Sun Tuned Sun Tuned is offline
Ultimate Warrior
 
Join Date: Oct 2002
Posts: 2,113
Default

No one mentioned it here yet that I saw but you can run a jumper wire straight from the positive side of the battery directly across the engine compartment to the “BATT” terminal of that hei to either get where you’re going or rule out the junk in the middle.

DO NOT FORGET WHEN YOU TURN OFF THE KEY THE JUMPER WIRE MUST BE DISCONNECTED AS IT WILL BE ONE HELL OF A BATTERY DRAW if you don’t.

No fires please!

The Chevy electronics will fit/work, pickup coil, module (same for both), in cap coil etc.

  #11  
Old 04-24-2022, 06:01 AM
Kenth's Avatar
Kenth Kenth is offline
Ultimate Warrior
 
Join Date: Feb 2003
Location: The Kingdom of Sweden
Posts: 5,457
Default

Quote:
Originally Posted by convgto View Post
Thanks for replies. Volts at battery 14.6 same as volt gauge in car. 12 guage wire copper strand.
Does this mean you have 14.6 volts at the coil?

Internal parts in Chevy and Pontiac HEI are NOT the same, mixing may cause all sorts of issues.
Attached Thumbnails
Click image for larger version

Name:	HEI1.PNG
Views:	103
Size:	250.3 KB
ID:	589266   Click image for larger version

Name:	HEI2.jpg
Views:	142
Size:	47.7 KB
ID:	589267   Click image for larger version

Name:	HEI3.jpg
Views:	131
Size:	50.6 KB
ID:	589268  

__________________
1966 GTO Tri-Power
1970 GTO TheJudge
http://www.poci.org/
http://gtoaa.org/
  #12  
Old 04-24-2022, 08:47 AM
convgto convgto is offline
Senior Chief
 
Join Date: Sep 2003
Location: nw florida
Posts: 456
Default

14.6 at battery car running.
25stevem is this the gasket you mentioned.
https://butlerperformance.com/i-3164...1-4-thick.html
good info. thanks all

__________________
1967 Firebird under -DONE
1965 GTO under construction
  #13  
Old 04-24-2022, 08:55 AM
25stevem's Avatar
25stevem 25stevem is offline
Ultimate Warrior
 
Join Date: Jan 2022
Posts: 1,744
Default

Yes that carb gasket will work, but if I recall right the original has nylon spacers in the mounting holes so it could only crush down a given amount, and even the Fel Pro replacement was made the same.

__________________
I do stuff for reasons.
  #14  
Old 04-24-2022, 09:10 AM
Kenth's Avatar
Kenth Kenth is offline
Ultimate Warrior
 
Join Date: Feb 2003
Location: The Kingdom of Sweden
Posts: 5,457
Default

Quote:
Originally Posted by convgto View Post
14.6 at battery car running.
25stevem is this the gasket you mentioned.
https://butlerperformance.com/i-3164...1-4-thick.html
good info. thanks all
14.6 at battery is good, can you verify 14.6 volts at the coil (distributor +) too?

If you have an AFB the Holley squarebore gasket will NOT fit.
This will:
Attached Thumbnails
Click image for larger version

Name:	AFB flange gasket.PNG
Views:	51
Size:	211.5 KB
ID:	589269  

__________________
1966 GTO Tri-Power
1970 GTO TheJudge
http://www.poci.org/
http://gtoaa.org/

Last edited by Kenth; 04-24-2022 at 09:17 AM.
  #15  
Old 04-24-2022, 10:09 AM
convgto convgto is offline
Senior Chief
 
Join Date: Sep 2003
Location: nw florida
Posts: 456
Default

I have a AFB carb with stock intake.

__________________
1967 Firebird under -DONE
1965 GTO under construction
  #16  
Old 04-24-2022, 12:51 PM
george kujanski's Avatar
george kujanski george kujanski is offline
Ultimate Warrior
 
Join Date: Jan 2000
Location: palatine, il. USA
Posts: 7,832
Default

One possible prob with the pickup coil....... if the 2 wire connector is plugged in backwards (from what the module expects) the signal polarity will be reversed.

The vac advance on a Chev works in the opposite direction...... I suppose if installed correctly in a Pontiac distributor it might work.... things to look for.

george

__________________
"...out to my ol'55, I pulled away slowly, feeling so holy, god knows i was feeling alive"....written by Tom Wait from the Eagles' Live From The Forum
  #17  
Old 04-24-2022, 05:11 PM
convgto convgto is offline
Senior Chief
 
Join Date: Sep 2003
Location: nw florida
Posts: 456
Default

i couldnt even pull it up a slight grade today moving it, cant seem to get over 1500 to 2000 rpm without it stalling. stick car.

__________________
1967 Firebird under -DONE
1965 GTO under construction
  #18  
Old 04-26-2022, 02:26 AM
Schurkey Schurkey is offline
Ultimate Warrior
 
Join Date: Aug 2002
Location: The Seasonally Frozen Wastelands
Posts: 5,891
Default

1. What is the fuel pressure?

2. Will the ignition system reliably fire a spark-tester calibrated for HEI? There are several kinds, some of which are practically useless. This is the kind I prefer:
https://www.amazon.com/Performance-T...=3HE3HUCPW3QFV

If it won't fire the spark-tester at the spark plug end of the plug wires, flip the distributor cap upside-down WITH THE WIRES STILL CONNECTED, and try from the center button. Use the spark tester, a grounded jumper wire, and a cut-down spark plug boot.
http://hbassociates.us/HEIsparktesterandboot.JPG


http://hbassociates.us/HEIsparktesterincap.JPG


The carbon button in the center of the HEI distributor cap should be replaced with a low-resistance aftermarket button/brush.
https://www.summitracing.com/parts/fst-730-8412

MSD 8412 is the same thing.

Accel has--or had--a similar product.


There are a dozen other possible causes--plugged exhaust, incorrect ignition timing, massive vacuum leak(s), dead cylinders, failed torque converter (on an automatic-equipped car), dragging brakes, etc.


Last edited by Schurkey; 04-26-2022 at 02:39 AM.
  #19  
Old 04-26-2022, 09:32 AM
convgto convgto is offline
Senior Chief
 
Join Date: Sep 2003
Location: nw florida
Posts: 456
Default

This car cranks immediately and idols good. but wont go up a small hill as stated. Schurkey compression is all good, just had to put a new fuel pump on last week (need to check tho). exhaust is new, it does have a vacuum leak , i have the correct gasket now felpro 13834, putting on today. Timing is at 8 (stock motor), Brakes just done, we are getting spark on all cylinders and tach is working. Were gonna along with new carb gasket install, put on a new coil and then a new control module on this NEW hei dist., we have the power on 12 guage wire and on a relay, probably gonna do the straight to battey thing to. hopefully we get it today. Thanks all. going nuts lol Ken

__________________
1967 Firebird under -DONE
1965 GTO under construction
  #20  
Old 04-26-2022, 10:02 AM
400 Lemans's Avatar
400 Lemans 400 Lemans is offline
Chief Ponti-yacker
 
Join Date: Dec 2007
Posts: 552
Default

Did you set the initial 8 degrees timing with the vacuum advance unhooked? If not then retime it and also make sure the firing order is correct on your plug wires.

Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 09:01 PM.

 

About Us

The PY Online Forums is the largest online gathering of Pontiac enthusiasts anywhere in the world. Founded in 1991, it was also the first online forum for people to gather and talk about their Pontiacs. Since then, it has become the mecca of Pontiac technical data and knowledge that no other place can surpass.

 




Copyright © 2017