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Topic: one bank lean, one bank rich (Read 3020 times) previous topic - next topic

one bank lean, one bank rich

ok, last week i noticed a rattling noise in my exhaust. by the way, i have a custom exhasut thats true dual with no balance pipe on a 88 5.0 tbird. i knew i blew a cat cause ive heard that sound too many times in friends cars. i brought it to the ler shop to check it out thinking it was jsut a bad cat. well, they looked at it and told me it was all burnt up and couldnt warrantee it. well, i also looked in the tail pipes and the left one was all white on the inside, the right all black. i get home and i pull all the plugs and the left bank was running lean, the right bank seemed slightly rich, but not too bad. i guess from the pipes you already knew that one. but heres my question, what the heck could be causing this. i have no idea what it could be other than maybe something clogging up the fuel rails. any help here would be great.

Re: one bank lean, one bank rich

Reply #1 –
Are you still running the stock manifolds?  If not, did you move the 02 sensors from the manifold to the "h"pipe?

Re: one bank lean, one bank rich

Reply #2 –
yeah i still have the stock manifolds, and o2 sensors are fairly new, bout a year and a half, so im not thinking its them.  im really out of ideas.  im probly bringing it in to a dealer tomarrow to see if they can fix it, but yeah if i can do it, id like to save that money, any other ideas would be great.

Re: one bank lean, one bank rich

Reply #3 –
Whoa, a dealer's not gonna be cheap.

Re: one bank lean, one bank rich

Reply #4 –
yeah well, i dunno what choice i may have.  although, today i thought about it, maybe theres something with the ignition coil or something along those lines.

Re: one bank lean, one bank rich

Reply #5 –
Unless it's the plug wires it ain't gonna be iginition, coil is common to both banks. I'd be suspect of the fuel pressure regulator, it sometimes leaks a little and the excess fuel is drawn in through the vacuum line. Otherwise its prob 02 sensor(s), has it been scanned for codes??

Re: one bank lean, one bank rich

Reply #6 –
its not throwing off codes.  and i started to think about the regulator also.  but heres an update.  i hadnt run the car in a lil over a week, so i figured id take it around the block and at least let it run a lil.  well, when i was on my way back home, BOOM!  my cats blew up.  metal flying out the tail pipes and a bunch of black smoke with it.  well, i drove it down to the dealer and theyre gunna look at it.  but yeah, that wasnt fun.  it was jerking around and bucking like a wild bronco.  kinda funny though, when i had it at the dealer it sounded like it had a bad ass cam when we were listening to how bad it sounded while idling.  oh well, sometime tomarrow ill find out what happend i guess.
 

Re: one bank lean, one bank rich

Reply #7 –
thats it! got it looked at, my vaccume lines were all cracked and corroded and all.  so, getting those fixed and the bird will fly again!