- This topic has 10 replies, 7 voices, and was last updated 12 years, 11 months ago by
.
-
Topic
-
-
Replies
-
I would say possible but not likely. to me if the cat was clogged the vehicle would not start at all or start and stall Are you having a misfire?
the car starts and runs great but in idle on R and D its idles rough it is poping up bad catalyst bank 2, bank 2 running lean,and misfire cylinder 2. replaced plugs,wires and swapped out the coil pack and iac valve from a wreck 3.8l mustang (ihave a 3.8l 1997 cougar xr7) and the sames codes have popped up soo nothings changed i am trying to see about replacing or if there is a way to run a straight pipe but im at a lost??????
HELP ME
I would check the fuel pressure as well as the injectors. A Noid light would be ideal to rule out an electrical problem with the injectors. if you don’t have and no auto parts store near you will rent you a set I’d just use a multimeter. If their current flowing to the injectors remove them and see if they’re clogged. I’d be suspicious of cylinder 2 because of its misfire that doesn’t necessary mean that’s what’s causing the problem. I don’t’t have much experience with the make. Did this just start all of a sudden out of the blue? Do you feel the misfire?
What brand of plugs did you use?
There is still several reason’s why you may have a misfire on cylinder #2 such as a injector issue as already stated or a burnt valve, to excessive carbon build up.
I would be still checking for spark going to cylinder 2 by stress testing the ignition system.
For the lean condition, i would be looking at your o2 sensor voltage to make sure you dont have a lazy o2 sensor as well as doing a good visual inspection for vacuum leaks (smoke machine is the best method) as well as looking for vacuum leaks from vacuum hoses or gaskets.
For the Cat. they best way to test those is with a exhaust gas analyzer. You can also use a temperature probe to check the temperature readings before and after the cat. The difference should be around 100 deg hotter after the cat.
You can also do an exhaust back pressure test too with a gauge that goes in place of the o2 sensor. If you suspect your cat is clogged, you could remove the pre-cat o2 sensor on bank 2 and see how it runs.
It’s the other way around, misfires can kill catalytic converters hence the reason they monitor misfires as not only can they damage the engine but misfires can also damage the cat.
If it says it’s running lean check for vacuum leaks and for exhaust leaks before or near the O2 sensors.
http://www.youtube.com/watch?v=9CPqbaSgcok+ok well why am i misfiring? i used motorcraft plugs gapped right autozone duralast wires with lifetime warrenty now the coil pack i just swapped outta junk yard car but do you think cylinder 2 on both are bad? besides that im guessing imm check the injestors
As Eric and Dreamer mentioned, msifires can destroy your cats as the unburnt VOC’s can wreak havoc on your cats as its overheats and starts clogging because it can’t do it’s job if it’s flooded. If it got clogged enough it could choke out your engine, but you’d see that at neutral too and usually it will start and then choke out as it’s like someone putting a straw in your mouth and asking you to run a mile. The problem will increase as your rpms increase (as you ask the engine to breathe faster). This will cause a stall/choke out at higher rpms. If you really want to test it, unhook your catalytic converter and run the engine, if it’s backpressure it suddenly run better. Also you can temp test it as someone mentioned or do an exhause analyzer… chooose whatever you can get your hands on.
I’d start by making sure you have the manu’s recommended plugs in, as aftermarket plugs can cause misfires. And then I’d support the above posts and run some diagnostics first before you throw parts at it. You need spark, air and fuel to get a good running engine (and compression) so start there and work through each system. Check Twice… Fix once.
You can also use a vacuum gauge to check if your catalytic converter is clogged without removing it but i don’t think that is your issue.
+1 dreamer. I am with you for vacuum leaks.
A vacuum gauge will help provide some good information on how the engine is running. You want to see at least 18 inches of mercury (Hg) for vacuum whi
If you suspect a coil pack the best place to start is with a power balance test. Also not a bad idea to check for vacuum and voltage leaks as suggested. Let’s not forget checking for any check engine lights and addressing those first.
power balance
http://www.youtube.com/watch?v=bAOmUjAjNjEVacuum leaks
http://www.youtube.com/watch?v=9CPqbaSgcok+Voltage leaks
http://www.youtube.com/watch?v=x-U9WqJfaJs
- You must be logged in to reply to this topic.