Help with Electrical Gremlin

-
cudajames

cudajames

FABO Gold Member
FABO Gold Member
Joined
Apr 10, 2014
Messages
1,349
Reaction score
923
Location
San Jose, CA
Looking for some help tracking down an electrical gremlin that popped up this weekend.



Backstory

The 66 Barracuda hasn’t been driven a lot for reasons unrelated to the car. Other than that, the car was in great running order. Normal stating process: remove from trickle charger, partially turn the key for the electric fuel pump (in tank pump from Tanks Inc. installed in January 2021) to turn on, pump the gas pedal, and start the car. Over the past couple of months, when I went to start the car, the electric fuel pump would turn on and then just click when the key was turned to start. This would also take out electrical to the car. I would remove the negative from the battery which would restore electrical to the car and start the process over. It usually started on the second or third try. After research, it appeared to be related to a relay. There are two relays, a 50 amp for the fuel pump and a 40 amp for the fan. I would tap relays and the car would start. After the car started running there were not any further starting issues even after restarting later that day or even the next day. It appeared only after sitting. Sadly, I was busy doing other things to chase down this problem.



This weekend.

My daily car is in the shop, and I had to drive the Barracuda. She drove perfectly fine on Saturday. Early Sunday morning I experienced all the starting issues listed above before getting the car to start. My son and I then drove 35 mountainous miles with zero problems. The car drove great. On the return trip, she started up fine and ran great for about 2/3s of the way home when we hit some traffic.

The symptoms

The car started surging, on the AFR gauge it was leaning out. At times it appeared to die with the tachometer not showing any RPM. It would then come back. As mentioned, it is a mountainous drive and the area would have been super shitty to pull over. Thankfully, it was all downhill and I kept going. I made it a block from my house and the car died at a stop sign that I was rolling through. After 10 minutes I was able to get it started and mostly into the garage before dying. Of note, the electric fan was on and working and I believe that relay was clicking before the car died. The relays are 5 to 6 inches apart in the same area of the engine bay.



Trouble Shooting.

Assuming it was relay related. I’ve replaced both relays and have gone through the immediate wires from the relay to the circuit breaker to the battery. I’ve also tested removing the electric fan and starting the car. Initially, the car would not start. After a couple of attempts, I started the car without the fuel pump. It fired right up off the gas in the carb.

Reconnecting the fuel pump, I was able to get the car started but had surging before it cut off. Also of note, the fuel pressure is around 6.5 psi.



Next steps

I plan to trace all the fuel pump wires to find any faults. Other than that, I am at a loss



Any advice that I should look at? Would a circuit breaker go bad and cause this problem?

Thank you for the help
 
Did you post the distributor/ballast/coil/ecu combinations that you have installed. Any recent work, changes?
 
Stupid as it sounds, those symptoms perfectly describe loose battery connections, whether at the battery, grounds or as the starter. The surging and whatnot perfectly describes what the system would do if the battery was not getting a good strong charge. I would clean and check ALL main and power connections.
 
The distributor is a MSD Ready-to-Run that has been on the motor for 6 years. There has not been any work in that area for a long time. Timing was adjusted 6+ months ago
 
RustyRatRod said:
Stupid as it sounds, those symptoms perfectly describe loose battery connections, whether at the battery, grounds or as the starter. The surging and whatnot perfectly describes what the system would do if the battery was not getting a good strong charge. I would clean and check ALL main and power connections.
Click to expand...
THIS, and verify that the battery is good, and doesn't have some weird shorted cell or something.
 
Wow, I hope it is the battery. I have an extra battery to test when I get home.
The battery in the car has been on battery tender when not in use.
 
RustyRatRod said:
Stupid as it sounds, those symptoms perfectly describe loose battery connections, whether at the battery, grounds or as the starter. The surging and whatnot perfectly describes what the system would do if the battery was not getting a good strong charge. I would clean and check ALL main and power connections.
Click to expand...

Agreed!

This has all the symptoms of bad connections, especially grounds.
 
Quick update. Bad battery connections made sense to me. Currently running an Optima battery which has smaller diameter posts than traditional batteries. And the Optima battery is a couple of years old.
Swapped out to a traditional battery, the car fired up first try however, it exhibited a similar behavior of leaning out before dying.
When I get some time, I will check the wires back to the fuel pump. And check the starter connections.
 
I stole some time to work on the car. The positive connection was loose. I tightened it about a 1/4 turn.
Checked all other connections and everything looks good. All grounds are in place and good condition.
The car fires up with no problem but I am not able to keep it running before it dies out. This includes giving it throttle to about 2000 rpm.
The electrical problem has not reappeared, possible from a broken ring terminal that I replaced earlier.
Oh, and this time I did not use the Optima battery.

It seems one problem was solved and there is a new problem.

Open to suggestions?
 
cudajames said:
I stole some time to work on the car. The positive connection was loose. I tightened it about a 1/4 turn.
Checked all other connections and everything looks good. All grounds are in place and good condition.
The car fires up with no problem but I am not able to keep it running before it dies out. This includes giving it throttle to about 2000 rpm.
The electrical problem has not reappeared, possible from a broken ring terminal that I replaced earlier.
Oh, and this time I did not use the Optima battery.

It seems one problem was solved and there is a new problem.
Click to expand...

Here's what I would do in this situation.

Start the car and wait until it dies.

1. Pull an ignition wire off a spark plug and have someone turn the engine over while holding the boot close to a metal surface on the engine. If the ignition is working , you should see a spark at the boot jumping to the metal surface.

2. If you are getting spark, next, check to see if there is fuel going to carb. Disconnect the line going to the carb and run a hose from it into a container. Turn the engine over again and observe fuel flow into container. It should be a constant and very strong flow.

These simple checks should eliminate one of these as the cause of your problem and then you can concentrate on the components in the particular system that's failing.
 
Thank you Super-Cuda, I will look into these tests.

In the short term, I checked the distributor for any issues, but none were visible. One of the screws holding the rotor "seemed" loose. Afterward, I decided to start the car and last minute make a crappy video. Sorry for the quality. It does demonstrate the problem. I'm giving the car a little throttle to around 2000 rpm on a semi-cold start.

 
I learned my Optima 'lesson' a few years ago. New Optima red, about 18m old. Going down a hill, engine died, no warning. Pulled over, batt was down to about 7v. This was NOT a charging problem. After sitting for a few hrs, bat voltage came back up to 12v. Bat was under warranty, but Optima would not replace it because 'it tested ok'. I no longer use Optima. I was very lucky because when the engine died, I was going down a steep hill & car had power brakes.
 
harrisonm said:
Hey, @69FBCuda, what color is your car? My 69 FB is F8 Dark Metallic green.
Click to expand...
It's not a stock color I thought it was called Hemi green but it's a lighter green maybe more yellow
20240309_172507.jpg
 
cudajames said:
The distributor is a MSD Ready-to-Run that has been on the motor for 6 years. There has not been any work in that area for a long time. Timing was adjusted 6+ months ago
Click to expand...
Hi James, post up some under hood photos of your engine firewall and distributor configurations
 
The MSD distributor was configured back in early 2020 (with a tweak or two soon after) I am using two light blue springs for the advance rate and have the black (18 degrees) bushing installed.
16 degrees of initial and 34 degrees of total advance.

Cam information
110 Separation with @50 241i/247e and .545 lift

IMG_0519.jpg


IMG_0520.jpg


IMG_0521.jpg
 
Run the engine until it sputters and shuts off. Pull the air cleaner off and while looking down into the carb, cycle the throttle linkage and look for a squirt of fuel. Yes? Or no?
 
Here are a couple of videos
1st is a cold start. Car fires off and then cuts off after a short amount of time.


2nd start - idle to 2k


After the brief running, there is gas in the fuel line. I changed out the fuel filter wishing/hoping it was clogged.
 
You didn’t answer the questions in post 17. The videos tell us nothing other than you need tuning. And for testing purposes, adjust the choke so it is off when the engine is cold.
 
Thank you for the help, everyone.

There appears to have been two different problems—electrical and tuning. The electrical seems to be resolved by replacing a broken eye connector and tightening the starter cable. The symptoms of shortening out when starting has not reoccurred.
I was finally able to get the car idling long enough to get the timing light on it. The timing was way off. That has been reset to 16 initial and 34 total. I drove around the block and got gas without issue. I need to tweak the carb, it is running a little rich.

Thanks again for all the help
 
Last edited:
James
Whenever I make wires, after I crimp the terminals, I also solder them.This will go a long way to stop them from vibrating loose, causing problems.

Hey how do all them windows work in that B-Cuda,??. That was the BIGGEST pack, and ship I ever Did, HA HA.

Dave
 
@barracudadave67 I only used the rear passenger regulator. I've just kept everything else, mostly in your original packaging from 2015. Funny enough, cleaning the garage yesterday and snapped a picture.

IMG_0604.jpg
 
You must log in or register to reply here.
-

Back
Top