I recently faced some misfires. First thing I did was checking the plugs which seemed very old and thus I changed them. Car ran very fine for about 4 weeks, with low milage though.

Now it again begins not to run smooth and is getting better when warmed up. Next thing I did was measuring the plug wires with an ohmmeter . Values vary from 8kOhm to 12kOhm, which seems very high to me. I am very familiar with VW and Audi engines where the plug wires are supposed to be between 4 and 7kOhms.

How much Ohms are the Olds V8 wires supposed to be with stock ignition? I could not find information about that in the CSM.

Thank you for any help!

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Andi

 

Your resistance measurements are not unusual. How old are the wires? It's more likely that you have insulation breakdown, causing the spark to ground instead of going to the plugs. Open the hood in the dark with the engine running and look for flashing around the plug wires. Or, if there's any question, just replace them.

 

I don't know how old they are since I am owning the lady just for a year. But they are looking old. I will run the engine in the dark, but I think I will replace them just to be sure!

Thank you very much for your help.

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Andi

 

I knew a guy who sprayed foaming engine cleaner on the plug wires while running. Any leaks are exacerbated and poor running ensues. And, you end up with a cleaner engine.

 

Those numbers are about right on ,the longer the wire the higher the number will be.Spray bottle with water is what i use to check for leaking wires.

 

I don't think that the cables are wrong. I pulled out the plugs again and found out that all 8 are black. Then checked CO which was too rich for the left cylinder row only, right one was good. CO is corrected now and plugs cleaned, now I will try if it is still running too rich. No problems so far, but I just drove 5mls.

Plugs are AC Delco R45S which were replaced 4 weeks ago. I chose this because this was what was in there.

Now my dealer tells me R46S was originally for the 350 but is not longer available. He recommends to go ahead with Champion plugs with the right heat value.

CSM tells me R45S for 4bbl carburator engines. My car has a 4bbl 600cfm Edelbrock performer carb. Should I chose the same plug as was recommended for the stock 4bbl carb?

Any opinions about that?

Thanks and Greetings

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Andi

 

Has anybody suggestions about spark plug choice in my case?

Thanks

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Andi

 

Audi VW etc. often use copper wires with a resistor at the spark plug connection providing lower, more even values. Guessing your wires are not metal core, are they? If not carbon core wires will give those numbers.

The plugs being dirty is to be expected with non-HEI (is this the case?), carburetion and short trips. I would not be in any rush to get rid of the R45S until the plugs are viewed after a long trip. In five miles it can almost be guaranteed they will look very rich.

Have seen cars get moved around lots, just start move and shut off with fuel injection, the plugs would get so fouled they would not start. In short, drive it get it thoroughly warmed up for an extended period and then sample the plugs.

Good luck!

 

If the plugs are black you probably have a carb problem. No more than a set of plug wires cost just replace them. But I'd be looking at that carb, may need a good cleaning at the least.

 

Thank you so much guys!

I am learning a lot from you here about older non efi engines.

I didn't even think about the possibility that the wires could have different cores!

I did not see something like this on smaller (4 to 6 cyl) efi engines with a correct tunt up. But it makes very much sense to me that the plugs are fouled and have caused misfires. I really just drove very short distances lately!

I will do some longer runs, check the plugs and then come back to you!

Greetings

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Andi

 

After cleaning the plugs, adjusting the rich idle and changing one broken vacuum hose the car runs fine. No more fouled plugs even after short distances!

Thanks again for the help!