Hunting for an engine miss. Goes flat if I punch it. 550 RPM idle miss. Everything is new AC Delco parts.

Took my distributor a part to inspect. Nothing looked out of place.

Now that I look, is that a crack in the rubber around the center shaft and magnet star?

I did grab the magnets and they were all firm. No play on the shaft.

 

Looks like the shaft bushing is deteriorating. Drop in a new distributor. There's nothing special about them and they're inexpensive unless you want to go with something like a MSB distributor.

 

Thanks. I just ordered a cheapo from Amazon for $50 and same day delivery. Dang! I will throw it in today and report back.

Distributor spins at half of engine RPM which seems like a lot. I can see how once that rubber warms up that reluctor may vibrate around a bit.

 

How Long Have Those Pugs Been In The Engine.

 

about a month. And its not my daily driver.

 

in my experience, replacement white box small cap distributors are hit and miss. have seen a couple misbehave right out of the box. I ran an MSD for years with no problems but am out of the small cap business for now.

 

Yep.. Amazon Prime. If it doesn't work back it goes.

 

BTW, damn good pictures. What camera did you take them with?

 

I ran a small cap distributor in my engine for a couple of years. All I was using it for was the magnetic pickup. The big difference between these distributors and an older HEI or MSD is the shaft size. These use a much smaller shaft size. Although they work in a street engine, I don't recommend them in a performance engine.

I've replaced a few older HEI distributors over the years. High mileage ones just wear out. If the shaft starts wobbling around, it cause all sorts of problems.

 

The shaft has no play. Its really good. This may be a replacement dist. I just don't know. I just put my white-box one in. I'll be taking it around. Will report back.

 

Thanks. Yeah, they came out amazing actually. Apple iPhone 6 Plus. Just a quick snap.

 

Well that wasn't it.

I think I'm gonna take a break from this for a few days.

The car is a little better. The miss at 550 RPM is better (but still there).

The big symptom is complete misfiring and power loss above 4,000 RPM at full throttle. The engine just makes a sputtery sound and goes flat on power. Every time.

The other big symptom is that it doesn't happen until 10-15 minutes of driving and if its cooler outside, the problem takes longer to start so it's engine bay heat related.

 

I would check fuel pressure and ohm you resistors

 

Done. Thoroughly.

I was looking up at the ceiling last night. Staring into the dark. Soul searching about this amazing and amazingly expensive journey my car has me on.

Then I wondered if it could be plug wires routed up against hot metal or a signal wire. I was able to find myself yet more hope! Surely only to be cruelly slapped down- but I have hope again for the moment

I will spend some time routing them away from everything. See if that does anything.

 

Well whaddya know.

Four pinched, burned cracked spots on the 2 and 4 cylinder wires. Must've been pressed up to the manifold. Cracked right down to the core.

Sloppy routing job. Geez. Slipped vac hose over it and about four layers of electrical tape and the idle problem is gone. The high RPM missing is still there but noticeably better.

New wireset, plugs and careful routing coming up. Will report back.

 

"I was looking up at the ceiling last night. Staring into the dark. Soul searching about this amazing and amazingly expensive journey my car has me on."

 

Hah! That was me!

 

Nice one Bob.

So when Tootie drifts off to sleep, he dreams of his IROC turning into a Sopwith Camel?

 

Machine guns on the front of car would look cool. And its a convertible so the goggles, cap and scarf make sense.

 

So I put the AC Delcos wires in replacing my new Taylors, two of which had gotten pinched, baked, and cracked against the exhaust manifold (cylinders 2 and 4). There was no improvement over the repaired Taylors. Gotta say the AC Delco wires snap onto the plugs much more positively than the Taylors. But the Taylors just seem like much better quality all around and the Delcos have specific cut lengths and three straight boots but they don't tell you which goes where. The extra length of the Taylors let's you play around.

Engine runs perfect except for a high RPM under WOT misfire. The whole engine goes flat. It's either my Multecs or the NGK Iridiums. Though the new "white box" distributor in there does not give me confidence (I can squeeze the distributor cap and cause it to hit the rotating rotor inside, its that thin. And half the time I unplug a cap wire, the electrode slides out with it.

Anyway, the nice thing is I have replacement parts for all three- dist, plugs, injectors.

I will start with the plugs since the misfire is only under WOT. If I rev it to 4500 it's smooth, so I think the plugs are doing something funky. I already have a set of new AC Delco OEM plugs. If that doesn't do it, distributor. And if that isn't it, I'l check the BLMs and then throw the Bosch D3's back in and see if its the Multecs. My guess is the plugs.

I will report back.

 

Update: I replaced the very thin cap that came with my white box distributor with my AC Delco cap and rotor.

The engine runs near perfect. Idle is very smooth and stable at 550 RPM. Slight misfire at WOT above 4000 RPM. Reving in idle to 4,000 and above is fine.

I will be changing the plugs later and report back.

Last update: Put new AC Delco OEM plugs in. No difference. Thinking Multec culprit. Troubleshooting continues here: https://www.thirdgen.org/forums/tpi/...rpm-power.html