06 honda ridgeline 3.5L melted cats.

God bless you my brothers and sisters.
Hey I have a quick question I have this ridgeline with melted cats. I removed all the crap from pipes question is will this cause misfire on all cylinders?
Thank you.

It can absolutely cause a misfire do to breathability.
It can cause internal damage to an engine if it goes unfixed.
A misfire can also cause a melted CAT. You’re going to want to figure out what killed the CAT and address it before the replacement gets damaged.

Other things to consider would be damage to the valve-train, crankshaft and bearings and piston rings.

God bless you my brothers and sisters.
Ok let me give you some history on this truck I replaced the engine on it because the timing belt jumped. Customer didn't want to fix the old engine. Upon removing the exhaust I seen one cat melted and the other one already dissolving "melting" I let the customer know . Installed the junk yard engine and it ran good . I'm in Ti Juana Mexico and the customer took it to LA Cali. two time with no problems on the third time the other cat.melted and plugged the exhaust. This is were I'm at now I cleaned all that was melted so it has no obstruction in the pipes so my question is with straight pipes will it cause a all cylinder misfire? I don't know if the truck was misfiring before the melted cat will have to ask customer.
Thank you.

If you remove the rear 02's as well as the cats, the front 02's can run the engine without problems unless the engine has other mechanical or sensor related problems. You will get rear 02 and cat codes.

God bless you my brothers and sisters.
Scannerjohn both bank 1 and 2 are empty. The third cat is still on and all 4 o2 sensors. Customer tells me there was no misfires before. Do u think if I disconnect the o2s the misfire will go away.

So it’s misfiring now??

Hey Gilbert! If your cats are empty, you should be good to go. As long as the customer can live with the CEL, anyway. :silly:

Do you still have a miss? I have seen plugged cats on this engine take out the lower end sealing ability. Shows up on a relative compression and leak down test.

Without knowing the cause of the misfire, there’s no telling. However, removing the 02s should make the ECM use default values. The result will be worse gas mileage.

If the 02s are indeed the cause of the misfire, then it is fuel-control related and you should be able to see that with live scan data.

Cherly yes on all cylinders I have long cranks also. Going two check compression tomorrow I think the belt might of jumped.

Hey Tyler I'm thinking this engine is shot. It is misfiring with a clean exhaust there is no more obstruction. I will check compression tomorrow to see what damage was done.

God bless you my brothers and sisters.
Hey Tyler you are right again the plugged exhaust damaged the engine compression on cylinder 5 was 45 psi.
Thanks guys for your help.

Sorry, sir. Mine was exactly the same way - Low on #5, low-ish on #4 and 6. It's remarkable how quickly the damage occurs on these engines.

I'll try to dig up a pressure pulse sensor waveform I took off mine. Connected to the crankcase, saw three clear pulses every 720 degrees. :silly: