Hello from Spain. I just changed the catalytic converter. Shortly after starting the car, the catalyst and its tubes turn cherry red. I turn it off and let it cool and start it again, and it turns red but less so. I turn it off and let it cool and start it again and this time it's not red anymore. Has it burned? It is a 3.1 from 1990. The catalyst has a tube that I have covered since it is not used in the V6. thank you

 

Sounds like it was plugged up with something or it burning out production oils.
do you have fuel leaking from the engine internally?

 

Hello. The smoke test gave me very high CO2, for that reason I changed the catalyst. When I took it out, I saw that it was empty inside. I put a photo of the catalyst I put in. Today I had the engine running for 3 minutes at 2000 rpm and from the catalyst to the muffler it was red. The catalyst has a small air outlet that I have left covered.
Maybe the new catalyst had a cover inside that I haven't removed?

 

Wow thats bright. I suspect you have a leaking or stuck injector cauing unburnt fuel in ther exhaust. I would not run it much before you figure out the issue. Could be a fire hazard and will ruin the cat.

 

I've seen really retarded (late) ignition timing cause some glowing in the exhaust, but never to the point where pretty much the whole exhaust is glowing.
I second Midas' post, it takes quite a bit of fuel to light an exhaust up like that, and that's what I think is happening too.
Have you checked the vacuum line connected to the top of the fuel pressure regulator for the presence of raw fuel yet?

 

Yeah, that's not good. Retarded timing and/or lots of excess unburned fuel would cause that. That's likely what killed the old converter and will kill this one in short order.

 

I have reassembled the empty catalyst. I checked the fuel pressure at the connector behind the manifold and it was correct. I had a spark plug that was a little wet with gasoline. I have looked for a workshop that dares to check my injection but in Spain it is very difficult because it is a very exclusive car. Tomorrow I have the last opportunity to pass the inspection, do you know of any tricks to make it give lower C02? For example, remove the air filter, cover any air recirculation tube, cover the PCV, cover the air inlet after the filter to lower the rpm, separate the EGR so that it expels gases outside.....only for the inspection. If I don't pass it, I will have a very difficult time taking it to a workshop because they won't let me drive with it.

 

You probably mean CO, not CO2.

You’re not going to pass with an empty cat and whatever issues are going on with your motor. I would not take it for the test until you get it sorted out.

There are a lot shops here in the states that don’t know how to work on these cars given their age, I can imagine it’s more the case in Spain.

Your best bet is going to be to learn and do the work yourself. I’d probably start with a full tuneup (plugs/wires/cap/rotor), set ignition timing (will need a timing light) per spec and replace the fuel injectors. See where you are then. If the new car you just put on is still good after being overheated, then try to run it. If not, then replace it again, but only after getting the motor to run right and not have the exhaust get red hot.