+1 give Kevin Meade a call.

Are EGT’s normal range compared to the other cylinders. It might help determine if it’s indication or actual problem

Do the CHT probes read the same at rest cold in the hangar? (internal problem in CHT gauge for that channel)

Engine ground cables correct? Alternator #1 or #2 off make any difference?

Intake runner hairline crack at the flanges?

Spark plug torqued correctly or missing a gasket? This should have not followed between engines or new cylinder but possibly if firewire plugs were reused in the same spots.

With a cold engine (in the hangar) do all CHTs show the same ambient temperature?

EGTs are ok,
on the ground, after start, all CHTs are normal....
Yes... have spoken to Meade... he mentioned possibility of exhaust problem...but there are no heat marks anywhere else...

As sanity check you could try and slap on a caliper temp sticker in a few places.
Not sure you will be able to find a spot though. But maybe it would help to isolate something.

Hope you get a solid kill with something.

Larry,

I couldn't find a photo of your nosegear doors, but I assume your 1985 plane has SB 892A installed?

Things, I've noted from some photos you've posted elsewhere:
I haven't seen photos of your engine since the OH, but the previous ones had all the plug wires laying on the top of the #4 instead of affixed to to the intake tubes. On the other side it was bundled but laying between the #3 and #5 cylinders.
You replaced your baffling, but your original photos showed a lot signs where they were not touching the cowl and potentially laying down in the back on the pilot side. Were the seals at the back around the intercooler completely sealed?

Hello Ryan, Fellow Malibu driver...
You leave few posts....so...thanks for any ideas...I have the louvre nose wheel doors
I have some post OH I’ll upload...
See what you think...
Larry

Looks much better than pre-OH. Any photos of the pilot-side?

Just confirming you have 2 sets of louvers on the doors? The original doors had the two fwd built into the door and the SB added two more aft. Just being 100% certain. I can't believe there's any Malibus out there w/o the SB, but just checking.

Not exactly how I would have installed the baffle seals in the aft corner, but I'm not an A&P either. I'd also have everything sealed with RTV (e.g. around the aft center and around the intercoolers). How does the seal around the oil cooler look?

My scarce posting is somewhat intentional for at least a few more years. If I post infrequently and I can't get myself in trouble.

They're never "fine" unless it was installed just prior to overhauling the engine.

What instrument are you using the monitor the engine? Is it possible the instrument is defective?

I've heard of many cases of the inter-cylinder baffles not being properly installed (or even missing entirely!).

Gentlemen,
Yes, the nosewheel door louvre openings go full length. I know that well because they are hard to clean.
No RTV used anywhere.
Using an EDM 700. It actually is one of those upgrades from an old insight that had no numbers. I’m not sure if there is data downloads. I’ll see when I get the plane.
The shop’s latest plan is to replace the cylinder. I’m not convinced.

Larry
I may have missed it in the earlier discussion but have you tried switching the wire for the offending cylinder and one that is registering correctly? Like you I would not let them switch or pull a “new” cylinder till I had exhausted all other options. Good luck..

What do you mean by "no problem"? What temps are you seeing in cruise?

What Lance said.

The exhausts on my engine have a slip coupling at the number 3 and number 4 cylinders. Particularly on climb out the airflow is different than at cruise and descent and of course so is the power setting.

Exhaust gas can leak out that slip joint and make the CHT's for number three and number four go high. I would eliminate this possibility very carefully before I put too much into anything else.

Ok...I’ve got the most votes for an exhaust problem. Yes that is the only link between the old engine and the new. It was not OHd. I’m still at work. I’ll check the engine diagrams later. Maybe there’s a slip joint there. The shop doesn’t think so. So what testing should I ask about?

Ok... I’ve studied the maintenance and parts manuals... there are no good figures showing the exhaust system precisely in relation to the engine... any body have a good diagram? What’s near cylinder #4 in the exhaust system? Remember it’s a continental which numbers cylinders different from lycoming... it’d be the left middle cylinder...
I’m looking at the Piper manuals—-

You said you switched the CHT probes. Did you try switching the probes while leaving the wires connected to the same leds from the JPI? It would be an incorrect cylinder indication on the JPI, but it would isolate whether the problem is truly an engine related issue, or a JPI related issue.