I just finished putting a set of ported 081 heads on my l03. They had just gotten the valves and seats recut and new seals put in. (Also put in a new distributor, plugs, and wires. Already had open air element, headers and 3in exhaust). Since I got it back together and running I've had a bad misfire. Also just noticed when running the car just now that my #6 cylinder's exhaust runner was starting to glow red. Is it possible I have a lean condition due to the stock tbi and tune? I also know that when I set the valve lash the first time I had them too tight. Could I have bent a pushrod? Cam is stock as well as the lifters and they looked perfect when I put them back in. Any help is appreciated because I'm running out of ideas and I don't want to pull the motor apart again if I don't have to.

 

Idle vacuum steady ?, have you shot the other cylinders exhaust ports with an infrared temp gun ? What does int/blm
show ?

 

Vacuum seems to be fine. I did use the temp gun and that's when I discovered the glowing runner. I was expecting to find a colder tube not a red hot one

 

This Is a link to a video of the car running

 

I would start with the basics first:

1. With a lean condition witnessed on cylinder #6 I would pull the passenger valve cover and check. Would seem like taking two steps back but well worth the time and effort in the long run and give you the peace of mind that it's sorted.
2. Because it's easy I would check the oil dipstick and see if there's in water/antifreeze in the pan.
3. May be worth a quick compression check to ensure you're head gaskets were torqued down correctly and that you're getting a good seal.
4. With the new distributor, plugs and wires I would validate the firing order and make sure you don't have anything crossed. Speaking from experience here
5. I would also ask how did you set the timing? With the EST plug disconnected I would run 4º - 6º advanced.
6. With the car running I would next visually check to see if you're getting a good spray pattern from the injectors and consistently the same between the two.

As Tuned Performance suggests, the easiest, most effective next step would be to connect an OBD1 scanning tool. Checking the BLM and INT's (high BLM (greater than 128) = lean; low BLM's (less than 128) = rich) will let you know if you're running lean or rich and at what load and rpm. But I don't think your current tune/ecm fuel trims would be that off to create the lean condition you describe and the mods completed.

Also, assuming you installed an O2 sensor in your header/exhaust set up? If so, connecting the scanner will show you if it's operating correctly which can affect fuel delivery.

With upgrades on the exhaust side of the airflow equation you may want to consider doing the TBI mods to include porting the flutes, removing the flute risers, installing a pod spacer and adding an adjustable fuel pressure regulator. But with reconditioned heads and stock cam, it all may be a futile effort.

One thing that I would highly suggest is adding a fuel pressure gauge and ensure you're somewhere between 9 - 13 psig. It'll help in the future with troubleshooting and tuning should you take the deep dive.

Just some thoughts to consider.

 

I appreciate the reply and advice! It wound up being a combination of bad injectors, vacuum leak, and a burnt plug wire. Got her running smoothly now 🤘