lean engine

[GRIFF]

We just picked up an 85 Fiero GT. It seems to run ok but I noticed the exhaust manifolr nearest the firewll gets real hot to the point of glowing red. I would think it is a lean condition but it only seems to be the one side, any ideas what would cause this?

 

[my04gt]

check your cat i had a 88 formula that did the same thing and it was the cat would not hurt to change the o2 ether

 

[Dr. Sievers]

We just picked up an 85 Fiero GT. It seems to run ok but I noticed the exhaust manifolr nearest the firewll gets real hot to the point of glowing red. I would think it is a lean condition but it only seems to be the one side, any ideas what would cause this?

I found, through learning the fiero, that this is actually a lot more common with the 2.8L then you would think. It can deffinately be the cat, or, the manifolds on the 2.8L was heavily restrictive, to the point that the exhaust would collect in the a cause them to clog. If this is the case then hot air is just sitting in that manifold building up the pressure and heat which could cause them to glow red hot. you may want to pull you exhaust manifold and take a look at it. If it's clogged it could just need a good cleaning and maybe a quick refurbishing. If it's the cats, sorry, you may have to replace them.

I am going to tell you, though, before doing any of this to wait for one of our senior members to respond to this just incase if they know something that I don't and deffinately get a second opinion.

 

[Oreif]

Bad catalytic converter, dirty injectors, bad O2 sensor, cracked EGR tube (very common), cracked exhaust manifold, or vacuum leak are just some of the more common things that can cause the lean condition. I would start by checking for vacuum leaks first. The plastic vacuum lines that run just under the upper plenum can crack with age and heat. Next verify the EGR is working and the tube going from the EGR to the intake isn't cracked. Then check out the exhaust manifold for cracks and the Catalytic for clogging.

If all the above are good, replace the O2 sensor and have the injectors cleaned and balanced.