Stalls and won't crank

[AKAIE15]

I am less than a novice mechanic so I'll probably not have all the details needed --- sorry

I have a 72 with a 90's SBC. Downey @Downey aux tank is my only gas tank. I have the same fuel pump that was in use when I got the truck - gas tank was the snorkel tank under passenger seat. I didn't like having the tank in the cab -- thats why I m moved it. I couldn't get over the gas leaking onto the floor (smell, mess, etc).

From a rust and body perspective - its a great truck. I think the engine/powertrain are solid too (the SBC is mated to a Toyota 4speed tranny with the split t'case -- I think).

My issues tend to be electrical... It's wiring wasn't really done right by whichever po did the renovations (claimed to be frame off) to it - for instance, there is always power to the fuel sending unit and the odometer (aftermarket cluster from BTB products) and last year all connections to the tail lights went bad and were rewired.

Since the battery always had a current drawing from it, the first battery died and I replaced with a Die Hard from Sears. Any time I let it sit, I would disconnect the battery or connect it to a battery tender.

A couple months ago, even with a full charge I noticed clicking when starting the truck but it would crank and fire up. Now I have had several occasions when I would make a turn (so far only to the right) and it would stall. When I tried to start it, it wouldn't crank. If I wait a few minutes, it'll fire up. I curse a lot when this happens.

Initially the thought was that all the battery disconnecting (to prevent draining it) messed with the connections, so local mechanic tightened everything and installed a battery disconnect for convenience - It's really a circuit breaker that I can trip from the drivers seat.

Despite that 'fix', the problem persists. At this point our thought is that there is a problem with fuel delivery (like the fuel pump), maybe the carburetor (it is a Demon carb installed by a po), and I am concerned about the starter....

NB - the tank was full the last time this happened.

Are we on the right track?

Should I have an in tank fuel pump with the Downey tank?

Any input would be appreciated.

 

[thebigredrocker]

So is something still drawing down the battery when it's parked?

Sounds like you need a plan of attack. The "wouldn't crank" issue might be a good one to figure out. I assume "wouldn't crank" means you turned the key and the starter didn't spin the motor. I recently read a guy was having a similar issue while turning and it was a loose wire. I would start with the basics. Clean up battery cables and terminals. Test the battery. Clean the starter terminals, distributor terminals, alternator wires ect. Make sure you have a good clean engine to frame ground.

Never hurts to post up pictures of how the PO wired things, it's amazing what mudders can find wrong if they have pictures to look at. Of particular interest might be how the fuel system is wired.

If you can get your rig to at least crank when asked, then you'll be moving on to the next logical system: fuel or spark

 

[pjohnson]

With the engine running, gently jiggle the wires coming off the battery and see if it stumbles or dies. If it does, use the technique to figure out which wire is causing it. Start with the main power to the ignition if you can find it.

 

[AKAIE15]

First of all - thanks for the input...

So is something still drawing down the battery when it's parked?

When it's parked, I was disconnecting the negative terminal to the battery until the breaker was installed or I would connect to a battery tender.

I assume "wouldn't crank" means you turned the key and the starter didn't spin the motor.

Exactly

I recently read a guy was having a similar issue while turning and it was a loose wire. I would start with the basics. Clean up battery cables and terminals. Test the battery. Clean the starter terminals, distributor terminals, alternator wires ect. Make sure you have a good clean engine to frame ground.

I've cleaned the battery terminals and harness. I'll check the distributor terminals and the engine ground next.

Never hurts to post up pictures of how the PO wired things, it's amazing what mudders can find wrong if they have pictures to look at. Of particular interest might be how the fuel system is wired.

I'll get some pics.

With the engine running, gently jiggle the wires coming off the battery and see if it stumbles or dies.

With the engine running, I know I can disconnect the negative terminal and the engine keeps running. I haven't tried the positive terminal.

 

[sggoat]

With the engine running, gently jiggle the wires coming off the battery and see if it stumbles or dies. If it does, use the technique to figure out which wire is causing it. Start with the main power to the ignition if you can find it.

If the engine is running, this should not have any effect, as the alternator will supply any electrical needs-you could completely disconnect the battery and the engine should still run.

 

[pjohnson]

Let me clarify. I don't mean the battery cables, I mean the wiring harness with the ignition wires in it. As I recall, there is a wire that provides power to the harness and another that provides power to the ignition.

I had the same type of issue where it would run fine in the driveway, but stall and not start once I was around the corner. After a few minutes or more, it would magically start again. I was checking wires as it was idling in the driveway and suddenly it stumbled, but didn't die. I jiggled the wires near my arm and it died. It turned out to be a main ignition power wire that looked fine but was bad. Replaced it and no more problem.

 

[AKAIE15]

I jiggled the wires near my arm and it died.

I ended up playing with the wires at the ignition switch behind the dash...

At first, a little jiggling and the stall (reproduced the symptom). I pushed the connectors on the back the switch and jiggling the wires stopped reproducing the stall.

Now I need to drive it around to see if this solves the problem.

Btw. Taking pictures under there is now easy- dark and blurry.

That spring is for the clutch. Seems to jiggle the wires a bit. That area is full of spaghetti. Sometime I just want to totally start over with wiring.

 

[69LC]

It's too bad we're on opposite side of the state. I'm no electrical gremlin guru, but I'd love to help. I'll be back that way the second weekend of September.