Hi everyone,

I've got a 1992 Toyota Celsior that's idling very rough the exhaust has a "put put put" kind of sound. There's also a misfire on the 7th Cylinder and the car has no power as if it struggles to get the rpms up over 3000-4000. I've changed the spark plugs, spark plug leads I've also cleaned all the terminals in the distributor cap. I've tested another ECU out of my Lexus ls400 so I'm sure that it's not an ECU problem. Could the problem be one of the ignition coils? There's only a misfire on the one 7th cylinder all the other spark plugs are firing fine. The catalytic converter has glowed orange a couple times on the same side as the misfire so I will be replacing that cat as well

Any advice would be appreciated.

Thank you

 

You need to do some old-school diagnostics here, but do it efficiently . . . your catalytic converter will thank you.

You KNOW you have adequate fuel delivery, that is why the catalytic converter was glowing orange. That rules out the ECU stuff for the most part.

You need to carefully swap a wire/connector with another cylinder to see if the misfire follows the wire or stays at that cylinder. Then rev the engine before it gets too warm, up to 4,000 rpm about five times (as stated in the workshop manual), then pull the plug. Does it show combustion/heat? If yes, I'd do a compression test next.
Colin

 

Any update ? Did you have a code ? Doesn't sound like a coil as I don't think they generally throw codes or cel

 

I agree with Amskeptic, (for the most part also) but I am wondering if you opened the ECM to look for leaking caps, since it only takes a screwdriver if you have it in hand??

 

You've replaced the plug and wire, so that's good. May as well replace the cap and rotor, sometimes it takes more than cleaning the cap or rotor contacts if it has worn sufficiently. As much as we like to think these are perfectly round, they may be off a bit so as they wear one contact begins to have a greater gap so spark efficiency is reduced. One sign of this is contact material on the bottom of the cap when removed.

After that I would suspect an injector issue.

On a '92 I would give the ECU an inspection to make sure there is no leakage as well as doing the ripple test.

 

If he has checked the ecu my bet is injector . I had a similar issue with my celsior but it didn't give me a cel or code. Mine was a coil.
my Ls400 is missing currently and I replaced plugs, caps, rotors , capacitors, coils, o2 sensors, cats, plugs , fuel pump and filter. Still misfiring . The only thing I haven't done is injectors.