Help...1972 350 W/HEI
 

Any insight would be appreciated.

Stock 350 with HEI, and i converted to a 1 wire Alt.

I replaced the Module, Rectifier, Cap and Rotor.

New Carb, Sending unit, lines.

Fires right up. Idles Great.

BUT...she dies under load, only when shes warm and in motion.

Air fuel mixture? Open Circuit from my alt? (its charging the battery just fine at idle)

Re: Help...1972 350 W/HEI
 

What carb?
What’s your timing like?

Re: Help...1972 350 W/HEI
 

Plug gap? With an HEI you should open them up to around .045

Gary

Re: Help...1972 350 W/HEI
 

Check the easy things first.

Couple of things to look at.

When idling, check to see if you are getting at least 14.5 to 15 vds when measured across the battery posts using a volt meter.

Check fuel flow from fuel pump by remove inlet line to carb, place in plastic container and see if you get at least a pint of fuel in less than 30 seconds. If you don't, it could be bad fuel pump or restricted fuel lines.

Re: Help...1972 350 W/HEI
 

Volts are 14.7. Will mess with fuel pump today.

That's where they are.

Q-JET, Checked my timing last night. 20-24 degrees

Re: Help...1972 350 W/HEI
 

20-24 degrees!
Did you Check it with the vac advance plugged off and at the lowest idle rpm?

Where’d you get the carb?

Re: Help...1972 350 W/HEI
 

I'm using a borrowed light, I burned mine up like a dummy.

That's another issue I need to figure out. Ported or manifold vacuum? My advance is plugged into my carb, I have read conflicting statements.

Don't know, Had a shop order it, it was running great. Now its not.

I'm heading home to mess with it today.

Re: Help...1972 350 W/HEI
 

Make sure you plug off the vac advance when you check the timing.
Ported or manifold vac? Let your motor decide. Try them both.

Re: Help...1972 350 W/HEI
 

Original HEI or points? If points, did you remove the resistor wire/block from the power wire to the HEI?

Volt reading with headlights on, blower on max and wipers running while revved up a bit? (quick and dirty alt check while on vehicle). A downside to one wire setups is no allowance for voltage drop in main output wire under high load.

Double check for vacuum leaks.

Accel pump on carb working?

I run manifold vac for the advance but like others have said, try both.

With vac advance pot disconnected, a good start timing is around 8. Once you have your problem fixed, add more until it either gets hard to start hot or you pick up some pinging on load. This gives some allowance in case your timing mark is off a bit from true TDC. (It happens) Mine likes around 12 by my simple timing light.

Re: Help...1972 350 W/HEI
 

Just as an fyi: When checking timing, plug or cap the vacuum port on the carb that goes to the vacuum advance. I'm sure you already know this but I've seen some do it wrong.

Re. ported vacuum or manifold vacuum. After you check the timing you can hook it up either way to see where it runs better. Manifold vacuum is below the throttle butterflies on the carb and ported vacuum is above them.

Re: Help...1972 350 W/HEI
 

Intuition tells me either fuel pump or coil. Both of them will get worse when hot when they are failing.

Some thoughts:
How do the plugs look?
If you take the air filter off and open the throttle, do you see the accelerator pump spray gas? Does it happen after it dies?

The hard part here is you stay it happens with the vehicle in motion. Can you have the vehicle in drive, foot on the brake, hit the gas a bit to put load on it and have it die? If so, to test spark, you can try putting the timing light on a plug wire and see if it stops sparking as soon as it gets a load on it. Try it with a couple different wires. For fuel, you can try squirting some fuel in the carb when it starts to die. Can use starting fluid (in a spray can, so this might be safest), dropper, or a bottle. Might be able to use carb cleaner. If spraying fuel makes it come to life, it is a fuel issue.

Re: Help...1972 350 W/HEI
 

was itt running ok before you messed with the charging system. There is “ask a mechanic” option on your phone. Lol. Maybe it’s a APP
Posted via Mobile Device

Re: Help...1972 350 W/HEI
 

You removed the points, installed an HEI and started having problems - correct?

I didn't see a voltage check at the dist mentioned so here's a question.

Did you run a dedicated wire to the HEI or remove the in-line resistor? If not, then even with good batt voltage the dist. won't see 12v. To confirm with 100% certainty that your voltage is good at the dist, grab a volt meter, pull the connector from the HEI and measure the voltage to ground. It should be the same as your battery.

Re: Help...1972 350 W/HEI
 

Let me start over.

It's a 1971 350 with HEI that was in my 71 C10 BURB, running and driving with zero issues.

Pulled it and put it in my 72 K10 Burb that was still points. I had a well known hot rod shop in my area do the swap for me.

New tank, New Lines, New Q-Jet Carb.

Ran great, even driving it @ 50-55 MPH went about 40 miles, but......

It didn't charge. Even with new Alt, New Regulator, New battery.

so I decided to convert it to 1 Wire.

(1) 6 Gauge wire strait to the battery. It charges with no issues.

I disconnected the external regulator and linked the wires as i have seen in multiple diagrams.

I re-checked the timing again last night. disconnected VAC ADV(which was plugged in below butterflies)

Set it @ 8 Degrees with vacuum advance open, and the vacuum from carb capped .

Plugged it back in to same port- no change.

plugged VAC ADC (into port above butterflies) and the timing advanced a good bit, so id decided to take her for a spin and same problem.

Obviously it has to do with the ALT right? It ran fine before hand.

What am i Missing? Since its a one wire and I have no idiot light, do I need to convert it to a 3 wire?

Could that possibly be my issue?

Thanks again

Re: Help...1972 350 W/HEI
 

Did you check the fuel pump output to the carb?
Pull the line off the carb, put it in a quart jar, unplug power to distributor, crank it over. It should fill the jar in under 30 seconds.

Re: Help...1972 350 W/HEI
 

Quick question. What does the amp gauge read when idling or at higher speeds?

On a fully charged battery with AC, radio, lights turned off you should be able to run the truck for a few miles at highway speed. I've done that on mine. I have a one wire alternator I bought at NAPA for my tractor and it's worked great for many years.

Other things to check all the ground straps -especially from engine to cab. On my 68 my gauge wouldn't work until I installed several ground straps including one from radiator support to the battery ground.

Re: Help...1972 350 W/HEI
 

Will do.

Don't have one.

Re: Help...1972 350 W/HEI
 

And while you have the fuel line off, check the fuel filter in the inlet to the carb

If the pump checks out then leave the filter out for a test.
Be extremely careful removing the inlet fitting. It's fine Threaded and easily stripped.
.

Re: Help...1972 350 W/HEI
 

Did this well known shop replace the resistor wire/ballast resistor with a new wire for the HEI power? If not, your dizzy is probably running on low volts.

The whole point of a 1 wire is it doesn't care about any outside connections other then the primary charge output wire.

Re: Help...1972 350 W/HEI
 

^^^^^^^^^^^^
What he said 100%

If the work was done by a well known shop then it should be fine - but it isn't.

I bought my 73 from a mechanic who works at a reputable shop. When I asked why he hadn't converted to HEI he said he tried and it didn't work.

The reason it didn't work was because he used the old ignition wire with the resistor. The first thing I did was run a new ignition wire and install an HEI. Haven't had a single issue since the first start.

Re: Help...1972 350 W/HEI
 

Don't have one.[/QUOTE]

Re. my comment on amp gauge... Only reason I mentioned is you asked if the alternator could be the problem. I haven't used a single wire on a vehicle but my tractor has a volt gauge that I use with no problems. You may be able to rewire an amp gauge in series using heavier gauge wire or or add a volt meter to your truck.

Re: Help...1972 350 W/HEI
 

You said "6 Gauge wire strait to the battery. It charges with no issues." Why do you think "Obviously it has to do with the ALT right? It ran fine before hand."

If it charges fine with the new alternator, then what's the problem? What makes you think it has to be the alternator? What is the voltage showing while you are driving. The alternator not charging shouldn't affect the way the engine runs. It will run off the battery just fine.

Verify the charging system is the first to do. Hook up a volt meter to see what is actually happening.

Re: Help...1972 350 W/HEI
 

Did not get to mess with it yesterday, it was pissing and a small river developed under the Burb.

The reason I asked is because that was the ONLY thing that I messed with.

I didn't think it was the issue just wanted another opinion.

Re: Help...1972 350 W/HEI
 

Make sure you are grounded good....

Did you check the timing, seems like that is a hot item to check on this forum.

Re: Help...1972 350 W/HEI
 

I will re-check that as well

You guys, might be right on the money, checked my wires and it seems like the pink wire was soldered(adding 2 wires) under the hood and had one wire running to the Ignition on the Distributor and one went down to the starter, I read about this shortly after and it seems that they did this because:

https://www.americanautowire.com/vie...d-connections/

But: Once I realized that i could start and keep the truck idling (even with the other wire running to my starter not connected) I deleted the wire to the starter.

I did not replace the entire wire yet because I am seriously debating getting a painless harness because someone has already been in there messing with it.

Took it for a test ride and same Problem.


Did this and it pumped out a full pickle jar in 30 seconds, clean filter and clean fuel.