Hi again guys.

Got another slightly worrying question just days before my IVA!

Today i got my engine up to temp, after changing my fuel pump and heat wrapping the exhaust (after the cat just to the silencer, to cover my exhaust clamps). Once the engine was warm, the cat was glowing red hot. I had to tweak the fuel settings slightly for the new pump, but the excessesive exhaust temp seems odd.

My spark table seems ok compared to other peoples, and its the one that came with my base map.



Any ideas? As i need my emmisssions spot on for the test, and this can't be doing it any good!

Also, if i cut an aluminium plate to cover the burnt side panel, will this deflect the heat or retain it?

Hope someone can help.

Cheers

Dave

[Edited on 4/6/11 by David_17]

Do you have a lambda sensor fitted?
If I recall correctly, the CAT converts carbon monoxide into less harmful substances, you may be running very rich. Perhaps take it to a friendly garage and ask for it to be put on their emissions analyser?

Sorry, forgot to mention, AFR is around 14.7 once i'd tweaked the settings.

quote:

---

Originally posted by David_17
Sorry, forgot to mention, AFR is around 14.7 once i'd tweaked the settings.

---

I've been mapping (or trying) for a while, but my fuel pump got worse and worse. I changed it and all seemed well.

I'm sure the lambda's working fine.

All that's really changed is putting a little bit of heat wrap on after the cat.

Cats always run really hot its part of the conversion reaction, I had one on the fury for sva inside the bodywork and it got much hotter than the exhaust does now. The problem with wrapping the exhaust, which they don't recommend on furys etc. for the risk of fire, is you are not allowing the heat to dispate dowhstream of the cat which keeps the gas temperature high. The increase in gas temp is then making the tube hot and keeping the upstream gas bulk temp high. I would say the best thing to do is remove the wrap and if you need to cover the exhaust extend the heat shield.

regards pete

by wrapping before/after you've created a hot spot for the heat to escape from. I hope you've not done it any damage.

If you wrap the manifold the rest gets hotter. I'm not overly sold on the advantage it gives apart from a few deg less under bonnet temp

[Edited on 5/6/11 by franky]

Looking at a screen grab of a fuel map AFR runs mainly in the 12's & 13's you may be running a bit lean this can cause a lot of heat.

Thanks for all the replies.

@ Snapper, not quite sure what you mean 12 - 13 is rich?

Have you tried it on the same map with the wrap off?

quote:

---

@ Snapper, not quite sure what you mean 12 - 13 is rich?

---

That looks a lean mixture thats still burning when the exhaust valve is open - richen the mixture or advance the timing.

Andrew

quote:

---

Originally posted by Andy S
That looks a lean mixture thats still burning when the exhaust valve is open - richen the mixture or advance the timing.

Andrew

---

does it run on when you switch the ignition off? if so its a sure sign that the ignition is too retarded.

for a non turbo exhaust to get that hot you have combustion happening in the exhaust system which makes it very hot. it is caused by the exhaust valves opening before the combustion is finished, which is caused by the spark happening too late (retarded timing) this will also damage the exhaust valves.

Have you checked your TDC marks and the ignition timing with a strobe?
It might be that your table is correct but that the timing is offset.

Thanks for all the input guys, turned out to be a dodgey spark plug.

All good now.

Need to figure out accel enrichment next.