Fuel issue?

[Doug&Deb]

I have a 52 Coronet. I’m having a problem with what seems like fuel starvation at full temperature. I just ran all new nickel copper line and installed an electric pump for priming and percolation issues. The electric pump has no effect. This occurred before I ran the new line. The filter is new and there’s nothing in the sediment bowl. I’m wondering if there is some water in the fuel. I drove occasionally through the winter and we’ve had some crazy temperature swings. I added some dry gas to the tank and topped it off. Am I mis diagnosing an ignition problem? The car ran great until the temperature warmed up. Help!

[Plymouthy Adams]

if you suspect water, merely pump some into a clean clear drink bottle and let set...it will separate quick enough, and show collected on the bottom on the bottle.  However. if this is not the case and there is no water in the fuel...well you have eliminated one possibility.  This is an easy let's not guess but prove test.

Edited April 24, 2022 by Plymouthy Adams

[Bryan]

5 minutes ago, Doug&Deb said:

I have a 52 Coronet. I’m having a problem with what seems like fuel starvation at full temperature. I just ran all new nickel copper line and installed an electric pump for priming and percolation issues. The electric pump has no effect. This occurred before I ran the new line. The filter is new and there’s nothing in the sediment bowl. I’m wondering if there is some water in the fuel. I drove occasionally through the winter and we’ve had some crazy temperature swings. I added some dry gas to the tank and topped it off. Am I mis diagnosing an ignition problem? The car ran great until the temperature warmed up. Help!

Is the tank new, or been cleaned out?   Maybe open the line before the pump or filter and see if gas runs into a container. Does the car run at all, or won't start?

[keithb7]

Some assumed fuel related issues can be tracked to ignition system issues.  Good troubleshooting and eliminating variables should yield good results. 

[TodFitch]

3 minutes ago, keithb7 said:

Some assumed fuel related issues can be tracked to ignition system issues.  Good troubleshooting and eliminating variables should yield good results. 

Yes, something like 80% of all carburetor and fuel pump related issues on old cars are electrical in nature.

 

A classic symptom of a weak coil is that it works well when cool and poorly or not at all when hot. I believe the condensers can have similar problems.

 

With respect to a weak coil: The higher the pressure in the cylinder the more voltage it takes to make a spark jump across the plug electrodes. So a weak coil can make an engine seem like it is starving for fuel when climbing a grade, etc.

[Doug&Deb]

That’s when it cuts out, climbing a grade. The coil is new ( not that that’s a guarantee). I did have a problem with the new condenser and I swapped an old one in. I thought that when the ignition cuts out unburned fuel would cause a backfire. 

[keithb7]

Sometimes what seems like fuel related issues can be tracked to ignition system issues.  Good troubleshooting and eliminating variables should yield good results. What have you eliminated and proven so far?

[Doug&Deb]

Other than definitely checking for water in the fuel I haven’t done any ignition troubleshooting yet. That’s next. Unfortunately I’m still recovering from back surgery so I have to go easy. Regardless of whether it fixed the problem or not running a new fuel line and installing the electric pump were things that needed done. Now I’ll tackle the ignition.

[kencombs]

1 hour ago, Plymouthy Adams said:

if you suspect water, merely pump some into a clean clear drink bottle and let set...it will separate quick enough, and show collected on the bottom on the bottle.  However. if this is not the case and there is no water in the fuel...well you have eliminated one possibility.  This is an easy let's not guess but prove test.

IF you have one of the pumps with a glass bowl, it will show there also.

[kencombs]

24 minutes ago, keithb7 said:

Sometimes what seems like fuel related issues can be tracked to ignition system issues.  Good troubleshooting and eliminating variables should yield good results. What have you eliminated and proven so far?

Yep, one of the best mechanics I ever knew once told me that 99% of the carb problems people brought him where ignition!

[Doug&Deb]

Mis diagnosis is my curse unfortunately. I’m still learning.

[keithb7]

100% agree on the electric fuel pump and line. 
 

To review: engine runs just fine until everything warms up to full operating temp. Then it seems to surge, stumble and miss? Or does the engine flat out die, and you coast to the curb until things cool down again.  At this surging stage what happens if you pull your choke on partially? (If you have a manual choke cable)

Any other clues? Backfiring? Engine timing and dwell set set recently? Distributor Vacuum advance hooked up and working? Are you still running the 6 volt system? How old is your ignition coil? Do you have a spare?  Do you have a dwell meter and timing light? Spark plug wires age? Plug wire boots tight? Threaded teeny little caps on top of spark plugs tight?

[Sam Buchanan]

2 hours ago, Doug&Deb said:

Other than definitely checking for water in the fuel I haven’t done any ignition troubleshooting yet. That’s next. Unfortunately I’m still recovering from back surgery so I have to go easy. Regardless of whether it fixed the problem or not running a new fuel line and installing the electric pump were things that needed done. Now I’ll tackle the ignition.

 

Where is the electric pump located and is it the only pump you are using? The pump, especially if it is the only pump, needs to be located near the fuel tank so it is pushing fuel. If it is located near the engine so it has to pull fuel, this is more likely to result in vapor lock issues or introduce air into the fuel line (which reduces fuel pressure) if there is a tiny leak at a fitting.

[Doug&Deb]

The pump is near the tank. It’s only used for priming the system after the car sits. I just installed this yesterday and It didn’t solve the problem. I’m beginning to understand it’s probably an ignition problem. 

[Doug&Deb]

Keith, plugs and wires are new. Coil is new but I have another to use for a check. Dizzy was rebuilt but the condenser was bad so I installed an old one I had. I’m thinking it’s the problem. Dwell is correct as per the manual. The car doesn’t shut off or surge it just cuts out momentarily when climbing a hill. No backfire. I don’t have to restart. It picks up again but feels sluggish. Kicking on the electric pump has no effect so I don’t believe it’s fuel starvation. The new fuel line and electric pump were things I needed to do anyway. Checking the distributor is next.

[Bryan]

3 minutes ago, Doug&Deb said:

 Dizzy was rebuilt but the condenser was bad so I installed an old one I had. I’m thinking it’s the problem. 

Like my brother used to kid about Advance's lifetime warranty for starters.."you'll be replacing the starter every 4 month for the rest of your life".   He's had problems with new electronics before. 

[Sniper]

Most people focus on heat casing fuel issues.  It can also cause ignition problems.  Had a coil that started to fail only when very warm.  Once it cooled off it started working again.  Started out failing momentarily.  Eventually, it failed long enough for me to troubleshoot the problem and put in a new coil.  Problem solved.

[TodFitch]

30 minutes ago, Sniper said:

Most people focus on heat casing fuel issues.  It can also cause ignition problems.  Had a coil that started to fail only when very warm.  Once it cooled off it started working again.  Started out failing momentarily.  Eventually, it failed long enough for me to troubleshoot the problem and put in a new coil.  Problem solved.

I also had this problem once years ago. Took me about 6 months to finally figure it out.

[desoto1939]

3 hours ago, Doug&Deb said:

Keith, plugs and wires are new. Coil is new but I have another to use for a check. Dizzy was rebuilt but the condenser was bad so I installed an old one I had. I’m thinking it’s the problem. Dwell is correct as per the manual. The car doesn’t shut off or surge it just cuts out momentarily when climbing a hill. No backfire. I don’t have to restart. It picks up again but feels sluggish. Kicking on the electric pump has no effect so I don’t believe it’s fuel starvation. The new fuel line and electric pump were things I needed to do anyway. Checking the distributor is next.

Doug: even thought the dizzy was rebuilt take a good look at the small lead wires inside the dizzy. Check that they are tight and also no frayed insulation these are very small gage wires and they do lose the insulation at times.  Also check to see if you should have a rubber insert where the breaker plate comes through the body of the dizzy. On some dizzy's they had a rubber insert that was to stop the car from going to ground also there might be a piece of brown bakelite material attached to the breaker plate at this same point to also protect from grounding. Since climbing a hill the vacuuum advance might be hitting a wire and grounding out for a second and then when you leave off the throttle the A arm comes back and does not make contact with any bare metal.  Just some thoughts on the situation. 

 

Rich Hartung

Desoto1939@aol.com

[Doug&Deb]

Thanks everyone. I actually have two different dizzys for my car. An IAP and an IAT. The IAP is correct for 49/50 with the M6 and was on the car when purchased. I’m going to swap them and bench test the IAT. If swapping doesn’t fix the problem I’ll probably cry like a baby lol.

[Bryan]

4 hours ago, Doug&Deb said:

Thanks everyone. I actually have two different dizzys for my car. An IAP and an IAT. The IAP is correct for 49/50 with the M6 and was on the car when purchased. I’m going to swap them and bench test the IAT. If swapping doesn’t fix the problem I’ll probably cry like a baby lol.

Maybe just change the condenser first.  Easy things first then the more difficult stuff.