Modded Mustang Forums banner

1 - 20 of 58 Posts

·
Registered
Joined
·
7,991 Posts
im still stickin to the cats
 

·
Registered
Joined
·
2,795 Posts
Discussion Starter #5
im still stickin to the cats
its just one cat thats dinted though, :(

also i fixed the missfire in cylinder 5 (i drove 17 or so miles) and the light came out and when i brought it to autozone to check (didnt feel like taking out my laptop in the dark) and the lean codes where the only ones that popped up. but it feels like a lot more cylinders missfire after WOT (but only sometimes)
 

·
Registered
Joined
·
3,415 Posts
You can tell really quick if one of your cats is screwed. Pull the rear 02 sensors and feel the pressure coming out of each hole. If they don't feel equal, then you have a clogged or damaged cat on the side that there is more pressure.

A back-fire after WOT would make me think more of a rich condition. You might want to check your 02 sensors themselves too. Do you run any fuel additives or anything? Ever run any weird fuel system cleaner?
 

·
Registered
Joined
·
7,991 Posts
misfire after going WOT, but fine before hand

5 month old coils and plugs, new pump and filter


Id do the above take out the 02 sensors and see what the pressure is.
 

·
Registered
Joined
·
2,795 Posts
Discussion Starter #8
misfire after going WOT, but fine before hand

5 month old coils and plugs, new pump and filter


Id do the above take out the 02 sensors and see what the pressure is.
the coils arent 5 months old (its a used engine we dropped in, the coils look stock, and i grabbed some to replace the bad ones from my other engine and those where motocraft and i dont know how old they are)

and 2 o2 sensers where changed (if im not mistaken there are 4 and the 2 behind the cats where changed)

but i can pull them and check the pressure.

the autozone guy said my fuel filter might of gotten clogged up again.

lol i just want my car to be fixed all the way, ive never had a car that didnt have the check engine light now :(
 

·
Registered
Joined
·
7,991 Posts
when you get it to act up, pull over and listen to the exhaust, does it sound quieter/chocked at all?
 

·
Registered
Joined
·
7,991 Posts
lol, just when it happens pull in somewhere and listen, will sound quiet/different than it does before, almost choked like its got 1 inch pipes
 

·
Registered
Joined
·
2,795 Posts
Discussion Starter #12
i could just let it idol for a while, after like 7 mins it will start doing that, or i could drive fast and see lol
 

·
Registered
Joined
·
3,415 Posts
It is definitely possible that your fuel filter is clogged again. If you have datalogging capabilities with a tuner like a diablo predator or sct xcal, then datalog your fuel pressure and see what it is doing when you have these drivability issues. That will tell you if it is a fuel delivery problem. Also you said you swapped your motor? Are you sure you are running the same injectors as before the swap?
 

·
Registered
Joined
·
2,795 Posts
Discussion Starter #14
i am not running the same injectors.

this is the old ones, there all like this, i dont know what the lbs is
but the engine we put in was made is the same week at the old engine
but has yellow injectors..

i dont have a tuner im to poor
 

·
King Trashmouth
Joined
·
21,891 Posts
Yeah, cats should not affect lean. Lean means somehow you're getting too much air and not enough fuel. This could mean a bad/dirty MAF, vacuum leaks, or bad injectors.

I would lean towards a bad/dirty MAF, vaccuum leaks, or possibly a fuel system restriction upstream of the fuel rails. If both banks are lean it isn't a single side issue, so it's unlikely to be a single injector or oxygen sensor.
 

·
Registered
Joined
·
21,024 Posts
I say the fuel rail pressure sensor. Maverick can you view live data? You need to check your fuel pressure. That would narrow it down so much for you.
 

·
Registered
Joined
·
7,991 Posts
Yeah, cats should not affect lean. Lean means somehow you're getting too much air and not enough fuel. This could mean a bad/dirty MAF, vacuum leaks, or bad injectors.

I would lean towards a bad/dirty MAF, vaccuum leaks, or possibly a fuel system restriction upstream of the fuel rails. If both banks are lean it isn't a single side issue, so it's unlikely to be a single injector or oxygen sensor.
Ok so when cats get clogged or even start to get clogged and air backs up through the exhaust system, causing a stacking effect, when the exhaust valve opens, the waiting old exhaust is shoved back into the combustion chamber, putting more air than fuel into the combustion chamber.

If he goes WOT then gets a missfire, it sounds like the cats arent fully clogged/busted, but getting there.


If he had a vacuum leak, the car would stumble at idle and hardly run, wouldnt really cause a missfire after going WOT.

if you know someone with a working car, swap maf's real quick, look for a vacuum leak.
 

·
Registered
Joined
·
7,991 Posts
P.S. last car these 3 exact codes came up with and had almost identical problems, car had 83k on the odometer. Other than the slight miss that couldnt be traced through the fuel/ignition system, vehicle drove fine
 
1 - 20 of 58 Posts
Top