Continued M60 problems: hesitation/rough idle

[danieljames]

Step 1 in E38 multi-misfire diagnosis: cats cats cats cats

Somebody spent 20k fixing literally everything on his beloved 740, cats were bad even though they tested good.

Alright....feeling more confident with every post from you guys.....will post again post cat removal.

Sent from my VS995 using Tapatalk

[danieljames]

Alright....feeling more confident with every post from you guys.....will post again post cat removal.

Sent from my VS995 using Tapatalk

Cats cut and emptied. Car runs smooth and revs freely. Fixed. Passenger pre cat had collapsed into the main cat which was subsequently blocked. This caused the passenger bank of cylinders to shut down.

[Psykick5]

Cats cut and emptied. Car runs smooth and revs freely. Fixed. Passenger pre cat had collapsed into the main cat which was subsequently blocked. This caused the passenger bank of cylinders to shut down.

Congrats, man! Glad that fixed it.

[fo3]

Cats cut and emptied. Car runs smooth and revs freely. Fixed. Passenger pre cat had collapsed into the main cat which was subsequently blocked. This caused the passenger bank of cylinders to shut down.

Yeah, people need to look at cat converters more. In my aussie ford falcon my cat blocked up. It ran fine when cold but when warm it killed power and fuel economy. Also it's right next to the auto gearbox and I'm pretty sure it ruined a gearbox due to heat, even the replacement g/b runs terrible on warm days/long drives and I think the cat was cooking the repaired g/b. When the repaired g/b was cool, and the exhaust/cat was cool everything ran great, engine power and g/b shifting right. When exhaust hot, engine sucked, g/b sucked.
When a car runs terrible and it's not spark and fuel, look at cat converters. It's a shame there's no easy way to check them without cutting them out and visually inspecting

[danieljames]

Yeah, people need to look at cat converters more. In my aussie ford falcon my cat blocked up. It ran fine when cold but when warm it killed power and fuel economy. Also it's right next to the auto gearbox and I'm pretty sure it ruined a gearbox due to heat, even the replacement g/b runs terrible on warm days/long drives and I think the cat was cooking the repaired g/b. When the repaired g/b was cool, and the exhaust/cat was cool everything ran great, engine power and g/b shifting right. When exhaust hot, engine sucked, g/b sucked.
When a car runs terrible and it's not spark and fuel, look at cat converters. It's a shame there's no easy way to check them without cutting them out and visually inspecting

True true my Aussie friend in Gondwana land!! You have an XB!?!?
I'm originally from NZ and have settled now in Pennsylvania.
So your running hx of the falcon is similar to mine, but heres something you are missing. I discovered this closed loop open loop computer thing the cars do on start up. Basically a rich run environment and long flames going into the cat to heat them up. My car as yours did run fine for the first few minutes, that would be in the closed loop not taking signal from the cat in the warm up cycle......Funnily enough the right amount of time for fools like you and me to think all the tinkering on everything else had fixed the problem and we drive happily for those precious few moments. Then...........going into open loop the car "see's" the bad signal from the cat in combination with the back pressure and whamo!!! Shut down of the the bank of cylinders with the corresponding bad cat.
I am so happy now and kinda stupid feeling for not doing this 5 months ago.
Attached a couple pics of my M60 installed and the cat job and my car parked outside the house ready to cruise, wife and two kids in tow.24781.jpeg

Sent from my VS995 using Tapatalk

[Mykk]

When I cut out the cats on my 540 for the "Off Road" exhaust system the cats came out in pieces. Including a big chunk of cat rattling in the rear muffler

[Psykick5]

Well I guess I'll factor in a yearly cat change into the cost of owning the car.

[ross1]

. It's a shame there's no easy way to check them without cutting them out and visually inspecting

A vacuum gauge can be used to check for restricted exhaust