I always say the same thing, ugg and grumble all the way out to the garage. Then once I’ve torn into it, I find myself absorbed in the task and usually I really enjoy it. These are our hobby cars, after all......

 

I know, I really enjoy it too but I like driving it better. I just like finding the smoking gun. That way I know exactly what happened.

Valve train looks good. Valve move up and down nice. On compression stroke the pushrods will turn with my fingers with a little resistance as I expected and the lash is good (ZZ4 is zero + 1/2 turn). Back to ignition I guess. I did tear the cap boot so I've got some on order.

 

have you swapped the #7 plug to another cylinder to see of the problem moves?

 

No, I actually bought a new plug for #8. It was the first thing I did. I'm going to take all the plugs out anyway to read them and clean/check gaps etc. so I'll try the original one in another hole to see what happens.

 

Compression, fuel and fire are the three main players at this dance. Compression checked in at 150 psi and the dizzy appears to be throwing some fire so that leaves fuel. Can't think of a single reason only one cylinder would not be getting fuel other than a huge vacuum leak (unlikely) so that drives us back to fire.

Run down to your local FLAPS and buy a spark tester, I like this one.

https://www.lislecorp.com/specialty-...e-spark-tester

 

Worlds quickest compression test. Disable spark. Crank the motor and listen to it while cranking. You will hear reduced compression on the one cylinder if one is significantly lower than the rest. One will be quicker and higher pitched. Like it is firing on that cyl.

 

Could there be a bad connection between the terminal on the spark plug wire and the socket in the distributor cap? Terminal on the wire not making good connection with the 'wire' inside the insulation jacket?

If they were made in China, disregard this message.

 

I too am a Big MSD "supporter" and have used their wires and other products for decades.

However in the recent past couple years I have had two sets of MSD Super Conductor Wires FAIL pre-maturely. The problem on my C3 was they had sparks jumping between cylinders where the wires got too close. I forget which cylinders but I think maybe #5 and #7 were touching or very close. I saw this in the darker hours of the day and was amazed that these wires could/would do this. I installed a New Set of the 8.5 Superconductor wires and withing two months I started a noticing a miss. I opened the hood at night and again the spark was jumping from the Spark Plug Cap Outer skin to the frame. My plugs weren't even getting the power to spark in the first place. My C3 has a MSD 6AL Box, MSD (tach drive) Billet Distributor, MSD Digital Retard box, MSD Ignition Coil and MSD wires. I removed the original Factory T.I. system Distributor, coil and Control Box and had the parts rebuilt and bagged and tagged them before putting them away.

I do not know what happened to MSD but I got a "feeling"... I am not sure I can stick with them if this is the "new" normal for them. I will only pay the price IF they last and provide a benefit.

If you run a higher voltage ignition system you risk the possibility of getting Carbon Tracking inside your distributor Cap. This happens and you can only see it under a Black Light or something equal.

 

I just fixed my possible misfire,, I just knew it was off,, but chased every clue i was given by all the best mechanics,,, sounds like yours, same symptoms, ,, turned out to be a bad valve spring, , only found out by accident when my buddy rolled the head over on the floor, and saw a valve move,,,WTH,,, So started looking , ya could push the spring by hand,,, it was not broken,,,
So , we threw new heads on and all is fixed,,
.
. But really, just one spring???,,, ya never know,,

Hope ya find a easy fix,,,,

 

Wow! Must have been a spring that completely missed the heat treat operation. I would bag that up and send it back directly to the manufacturer. I'm sure they will want to see it and find out how it got thru the production system. Don't bother with the outlet vendor; they'll just look interested and throw it in the trash once you've left the building.

P.S. If the part was made in China, disregard this post....

 

👍 Its on our wall of shame now,,,,,,😂

 

Update
It's fixed. Had my son turn over the engine while I watched the valves. They are opening/closing just fine. It's hard trying to see the valves and hold the clutch pedal in at the same time

Turned out being the plug wire. I replaced it, used my old points file to file the rotor and cap, new wire ohmed out to 116ohms vs the old wire in the K ohms range which I think was causing the spark to be weak enough to get blown out instead of igniting the air/fuel. That is why the timing like still showed electricity in the wire so it was just enough to strobe the light. Started it up with my TC connected and the temp went up where the other cylinders run @500ish on the header right near the head.

Took her for a little spin to get up to temp and it really makes a difference when all 8 are working. Thanks for everyone's input. I'm going to get some more wire and replace all of them.

 

Great to hear thats all it was. Sometimes we just can't imagine it really is something simple. Enjoy your cruzein with full power again.

 

Do a celebratory burn out for us!!!!

 

Thanks, I work in the semiconductor industry as an equipment engineer and I should know better than to go for the big ticket item before making sure the washer was in place.

 

Already did that.

 

It never ceases to boggle my mind why people go after the big things first. On the C4 section we hear of people always trying to blame the ECM and trying to replace it before doing any real troubleshooting.

Good Job there theandies!

I see that you are a Veteran!

I would like to thank you for your Service to the Greatest Country in the World! I have been in 44 countries other than ours and NOTHING compares to the United States of America!