balancing exhaust temperatures

[oilteq]

I have a 2.0 Duratec with Jenvey throttle bodies.  Using an infrared thermometer on the header pipes, #3 is about 75 degrees higher than the others.  I guessed there might be an air leak and sprayed starter fluid around the intake.  No difference.  Thinking that the starter fluid on one cylinder may not make a noticeable difference in idle speed, I installed a new intake gasket.  Maybe it is fuel—I swapped #1 and #3 injectors.  No difference.  My next step is to try balancing the air flow with a flow meter like this.

https://www.dellortoshop.com/contents/en-us/p290_Synchrometer_airflow_meter_for_Dellorto_DHLA_and_Weber_DCOE.html

Am I on the right path, or am I overlooking something simple?

[MV8]

How do the plugs look? Compression test, move coils and plugs around. Oil consumption dilution on #3 rings can slowing burn rate so it is delayed in to the exhaust, #3 exhaust valve lash too tight, soft/broken valve spring strong enough for compression test but not so much driving allowing the exhaust valve to float so reduced heat xfr to the valve seat, increasing heat through the valve to the guide increasing sticking, etc.

Maybe you need to work on the other three cylinders.

[oilteq]

Wow. Impressive list. Thank you.  New plugs, valve lash is in tolerance on all 16 valves, no measurable oil consumption. I try the easy stuff first, so compression test and swapping coil packs. 

[Vovchandr]

For what it's worth, I've had one cylinder grossly out of temp over the years that I shot with a thermal gun in my thread. Then over the years troubleshooting thing it has moved to a different cylinder but still not resolved.

 

It bothered me so much I bought a FLIR gun for myself instead of borrowing it. 

 

Pictures are in the thread somewhere

[MV8]

13 hours ago, Vovchandr said:

For what it's worth, I've had one cylinder grossly out of temp over the years that I shot with a thermal gun in my thread. Then over the years troubleshooting thing it has moved to a different cylinder but still not resolved.

 

It bothered me so much I bought a FLIR gun for myself instead of borrowing it. 

 

Pictures are in the thread somewhere

After some digging (topic not under member rides and 35 pages with no mention of the key word "Flir", I found your post with the pic showing the thermal of the exhaust with #4 not appearing to be firing at all. This one is much more subtle at a 75f difference.

[jbcollier]

Certainly checking the throttle sync is the place to start.  Check it at higher rpm as well.

[MV8]

Also, check the running voltage at injector #3 compared to the others (wiggle the wires while checking for an intermittent connection). If that is lower than the others, the cylinder would be lean by comparison.

[oilteq]

I am still going to try to get a better balance, but Vovchandr is right, and 75 degrees is subtle.  Are you saying I may not have a problem?

[MV8]

I'm not saying it is ok. You have a problem that is more difficult to find than a cylinder not firing. 

[oilteq]

Swapped coil packs. No change. 

[Vovchandr]

Any follow up?