Hi guys im totally new with this forum, I have some questions to ask about my ride, maybe you experienced it already. So here is my story : My 01 sunfire mpg was increasing suddenly and ive got some stalls when hot problem. I opened my catalytic converter, all busted inside! I took a pry bar and smash thoses honeycombs, hallowed out my cat and plug it back. The cel pop because of the sensor 2 reading that cat is not doing his job. Since there, my car started to idle a bit roughly when cold, a lot more noisy and has some sort of hesitation when 50% throttle below 2k rpms. After that I chopped the empty catalytic can, because I was thinking that was creating some sort of exhaust turbulences, so i welded a staight pipe instead of leaving my catalytic can empty. Now its better, but still have some sputtering/bogging (very slightly) at idle and when cold if i ride the car it sounds like a subaru wrx engine? wtf? the straight pipe made the sound even louder than before too.. any ideas to fix this? Im thinking about welding a O2 extension to trick the pcm? does it work? Im low on cash that's why im not putting a brand new catalyst now. Can it cause mechanical failure or some kinds of problems? thx guys for helping me out and sorry for my english loll im a french canadian haha thx!
It sounds like you never found the problem that ruined the converter, I would look into the rich/lean conditions that could have caused this fromthe get go, and look into a universal cat from Magnaflow they are only around 100.00 dollars compared to the OEM.
The car was stalling when hot after 30mins or so.. I took it to a garage and here is the list of the parts they changed : Coilpack , Ignition module, Spark plugs and cables, Cam sensor, Crank sensor, Used PCM... 600$ later the car was still stalling after 30mins.. I was so pissed off to pay 600$ for nothing! I drove back home, skinned all the PCM harness and try to look fo some corrosion ; I did find one or two wire corroded, i repaired them , car still stall.. I removed my downpipe and see that my catalytic converter was plugged very bad!! I hallowed it out and since then, no stalling issues!! but now its more a driveability problem, I noticed that the car hesitate when declutching on a stop ,like hesitation under 2k rpm but pass 4k rpm, the car seem to have more torque than before.. since the cel is on, if I unplug o2 sensor 2 ,no changes is gonna be feeled? I assume that when the cel is on, all the sensors are in ''safe mode'' so they didnt read anything? Oh yeah forget to mention that when i got like 75% throttle and shift, some backfire sounds at the end of my exhaust , and also when I downshift a gear. BUT yesterday i noticed something fishy ; On my used pcm its written : MT 2.4 but my car is MT 2.2 non ecotec..i was wondering if it was not the good pcm for the right engine the car would not even start? correct me if im wrong! thx
You could have some pieces of the cat lodged further down your exhaust causing it to run badly.
Having no cat should not do anything to the car in terms or running badly. You should get a code for p0420 since there is no cat but it doesn't affect anything.
It does seem a little odd that it says that on your pcm. If it was me id try and look for a new one at a junker and swap it out.
Should do a back pressure test. They make a kit that hooks into a o2 sensor bung
Thx guys for the help. The catalytic converter was only destroyed by the engine side, the other side was ok, so no pieces are stuck in the muffler. And by the way, a 03 dodge caravan round shaped muffler with curved tip is my catback(cutted the tip and welded a nice stainless steel tip) I was wondering if putting that on the car could mess my backpressure. Tomorrow im gonna go in a junkyard trying to get the right pcm, they sold it for 15$ if I go in the car take it myself so I can take this 15$ guess. And as soon as possible i will get the universal magnaflow cat I hate running a CEL all day. Thx again 4 the help, I will keep you in touch for what happened!
magnaflow cats are garbage... they are known for breaking up without any engine failure... perhaps they had a pretty large bad batch, since there are a few that have not had any issues...
If you want a good high flow cat, you can get them for 40 bucks from performance-curve.com
^The ceramic cores are indeed crap. But if you get the heavy metal metalic ones from magnaflow they are alot better, and are very close to OEM
Not saying the performance curve ones are bad but clarifying.
pcm is now changed for another one in the junkyard, i did the gm passlock the car ran fine, but stalled again after a 30kilometers trip..first time stall with the cat deleted.. so you guys are right when saying I didnt find the correct problem that destroyed the cat, and for the pcm, maybe it was tagged 2.4 by mistake.. So now im heading about perform a gaz pressure test with a gauge taped to the windshield, any advice?
What?? You think it's a fueling problem?
Well its worth a shot... but a better and more clear explanation of whats going on with your car would help us help you.
From the last post it sounds like it ran perfect after the PCM was changed till it stalled.
Things like check engine light codes and such would help.
Hi guys, I scanned the car with a genisys, and here is the codes I found : U1016 Loss communication with PCM
U1000 Generic loss of communication
P0336 Crankshaft Position Sensor A Circuit Range/Performance
P0341 Camshaft Position Sensor Circuit Range/Performance
P0422 Main Catalyst Efficiency Below Threshold
