74 Formula 455 Won't Start
 

This car has always started after just a few revolutions, even after sitting for long periods between starts. Was headed to a club event not long ago and it would not start. Battery is strong, starter is working and engine turns over just fine. It is getting fuel, so I think it is in the ignition system somewhere. Doesn't appear to be getting any fire.

It has the electronic ignition interlock module under the driver seat, and the relay mounted on the driver side fender well. Not sure where to start troubleshooting, so any suggestions would be appreciated. Hoping it is a relay or fuse, or a module in the distributor?

Thanks,
BJ

Points or HEI?


If points put a new set in.
The seat interlock would just keep it from cranking, not starting.
(no starter spinning)


:confused:

It's an HEI Car

Not sure on that, HEI stuff usually won't go bad just sitting.
Look for any mouse activities?
(chewed wires etc)


I guess looking at the inside of the distributor cap for corrosion maybe?


:confused:

One of the constant failures in HEI since GM started using them is the white and green wires that go from the 8 toothed pickup coil/pole piece, to the module. Every time the vacuum advance moves that unit, it twists the wires. After so many movements the metal core in the wires becomes fatigued, and breaks a few strands at a time. Eventually the wire is down to a few strands and won't carry current, and failure happens.

Grab the insulation on both of these wires (green, and white) and give them a good yank. If they are frayed they'll rip off, you've found your problem. Sometimes they'll make the ignition cut in and out before they fail, but not always, sometimes they just shut off the ignition without warning, never to restart again. Any distributor with 50,000 miles on it should be suspect, sometimes they fail sooner, sometimes they go 150,000 miles and never fail.

I've seen numerous wire failures on the pole piece, I always test the wires if the ignition is suspect to a no start condition. I've seen most ever component in HEI s fail, this is one of the most overlooked pieces, because it isn't easy to change. The distributor has to be removed, and the shaft has to come out to replace it, so in the way parts changers assess a problem, they by pass it because of the complexity of changing it. It can't be changed with just 2 screws, but you can easily test for broken wires by yanking on them while the distributor is still in the engine.

Another well known failure point is the rotor, it burns a hole from the thin contact strip right through the plastic to ground out the spark of the shaft. You'll likely see a faint rainbow colored stain if you raise the thin contact up with your finger, and examine the plastic in the center of the rotor, it can also be seen if the rotor is removed by looking at the bottom, center area. The early black rotors were especially prone to burn through, the white redesigned ones were less prone to burn through.

Any, and all of the components can fail, and I've seen all of them fail, but the two examples I've posted, are sometimes overlooked. There are of course tests for most all the HEI components done with meters, however backyard mechanics usually resort to replacement, rather than testing. Keep screwing parts on, until it starts. That can get expensive, but if you don't have knowledge, or the tools, it requires little effort.

So it cranks but no shart?

Do you smell gas in the carb bowel?

If you pull a plug wire do you see an arc?

With the vehicle in question being a 1974 with a 455, could it have a unitized distributor (early small diameter HEI)? Just a thought.

The 74 TA I had did have a HEI, early release. It was h*ll finding parts. (455 engine though)


Steve's post has good stuff, I just figured it ran when parked, so figured if it had a problem with that stuff it would have shown it before parked.


:confused:

Thanks for all the good info guys. Turns out that it just needed to crank for a while to refill the fuel pump and carb bowl. We couldn't find any electrical issues and confirmed that it had spark. Gave it a shot of starting fluid and it tried to crank. So kept cranking until it fired. Idled just fine and runs like a champ. I let it set too long without starting.

BJ

Mine does that sometimes if she sits all winter so I prime the carb with a tiny bit of fuel.

Glad it's sorted...

Glad it was something as simple as no fuel in the carb.....:thumbup:

Just to clarify my post was for the large body HEI, not the smaller early style. I've had a lot of experience with all different types of failures with the later unit, being in the automotive repair field during the 70s and for years after. I've seen about every part fail in them, at one time or another.

I had a 73 G/A with the early small body, and even in the 70s it was difficult to buy parts for. I had a module fail in mine, and because of the expense, and difficulty of obtaining a module, and a plug wire set, I converted my car back to a point distributor. My 73 T/A also had the early unit, and it never failed, but to be fair the car had very low miles on it, under 20,000.

I hope yours never fails as the parts are only available as NOS leftover stock. GM never supported that unit even when they were fairly new, and parts were quite high priced.