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-   -   HEI dist. volts running (https://forums.maxperformanceinc.com/forums/showthread.php?t=858220)

convgto 04-23-2022 07:05 AM

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

Kenth 04-23-2022 08:45 AM

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

Sporadic voltage may be a faulty alternator or voltage regulator.

25stevem 04-23-2022 09:00 AM

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.

62posbonny 04-23-2022 09:10 AM

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.

SRR 04-23-2022 03:58 PM

What size wire is being used?

25stevem 04-23-2022 04:19 PM

Ok, got it!
That will fly.

convgto 04-23-2022 04:21 PM

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

25stevem 04-23-2022 04:45 PM

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.

77 TRASHCAN 04-23-2022 05:35 PM

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

Sun Tuned 04-23-2022 05:47 PM

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.

Kenth 04-24-2022 06:01 AM

3 Attachment(s)
Quote:

Originally Posted by convgto (Post 6336943)
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.

convgto 04-24-2022 08:47 AM

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

25stevem 04-24-2022 08:55 AM

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.

Kenth 04-24-2022 09:10 AM

1 Attachment(s)
Quote:

Originally Posted by convgto (Post 6337029)
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:

convgto 04-24-2022 10:09 AM

I have a AFB carb with stock intake.

george kujanski 04-24-2022 12:51 PM

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

convgto 04-24-2022 05:11 PM

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.

Schurkey 04-26-2022 02:26 AM

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/HEIsparktesterandboot.JPG

http://hbassociates.us/HEIsparktesterincap.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.

convgto 04-26-2022 09:32 AM

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

400 Lemans 04-26-2022 10:02 AM

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.


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