Application:
2007 Honda Fit Sport w/ A/T 292k Miles
History: 2 years ago replaced a failed aftermarket CAT
PO had stolen maybe? It was a cut out replacement rather than a Direct Fit so the factory CAT was gone when I bought it at 156k.
So, it imploded due to a misfire event at interstate speed and not stopping soon enough to address the blinking CEL. I suppose enough unburned fuel took it and the Upstream A/F sensor out. Both generated CEL codes for each respectively.
Fix 2 years ago:
1) A shop welded in a Universal MangaFlow Fed Emissions CAT; no codes since
2) I replaced Upstream A/F sensor w/ OE Denso; no codes since
Since then:
The ECU also generated an intermittent code P0139 for the Downstream 02.
I thought it was also taken out by the misfire event and CAT implosion, so it was replaced with an OE Denso. Only $50 bucks and my own labor.
Of course, the problem persisted.
I plugged in a cheap OBD-II scanner; which helped me diagnose the A/F sensor failing.
Then, it was pegged excessively lean almost all the time; like 46% additional fuel being added so it was obviously fouled. New one fixed that problem.
For this current issue, Scanner shows short-term and long-term fuel trims.
The short-term at idle fluctuates some.
During light to moderate acceleration, I get 4% to over 10% additional fuel being dumped in by the computer.
During heavy or WOT, the short-term goes to 0.
I’ve tried resetting the computer by leaving the battery disconnected and turning on lights, etc.
Question: Could an exhaust leak with the welded in CAT or an intake leak be causing the computer to think the mixture is lean?
I’ve tried listening to the fuel injectors and running cleaners through the gas tank, and they also all sound the same through a long screwdriver. The performance is fine under WOT.
I suppose it could be a problem with injectors, but I suspect the problem goes away when the engine is overcoming any air leaks at WOT, but they persist at light to moderate acceleration when vacuum is higher.
Just trying to get a sense before taking it into the shop. It’s my only vehicle.
Thanks!
2007 Honda Fit Sport w/ A/T 292k Miles
History: 2 years ago replaced a failed aftermarket CAT
PO had stolen maybe? It was a cut out replacement rather than a Direct Fit so the factory CAT was gone when I bought it at 156k.
So, it imploded due to a misfire event at interstate speed and not stopping soon enough to address the blinking CEL. I suppose enough unburned fuel took it and the Upstream A/F sensor out. Both generated CEL codes for each respectively.
Fix 2 years ago:
1) A shop welded in a Universal MangaFlow Fed Emissions CAT; no codes since
2) I replaced Upstream A/F sensor w/ OE Denso; no codes since
Since then:
The ECU also generated an intermittent code P0139 for the Downstream 02.
I thought it was also taken out by the misfire event and CAT implosion, so it was replaced with an OE Denso. Only $50 bucks and my own labor.
Of course, the problem persisted.
I plugged in a cheap OBD-II scanner; which helped me diagnose the A/F sensor failing.
Then, it was pegged excessively lean almost all the time; like 46% additional fuel being added so it was obviously fouled. New one fixed that problem.
For this current issue, Scanner shows short-term and long-term fuel trims.
The short-term at idle fluctuates some.
During light to moderate acceleration, I get 4% to over 10% additional fuel being dumped in by the computer.
During heavy or WOT, the short-term goes to 0.
I’ve tried resetting the computer by leaving the battery disconnected and turning on lights, etc.
Question: Could an exhaust leak with the welded in CAT or an intake leak be causing the computer to think the mixture is lean?
I’ve tried listening to the fuel injectors and running cleaners through the gas tank, and they also all sound the same through a long screwdriver. The performance is fine under WOT.
I suppose it could be a problem with injectors, but I suspect the problem goes away when the engine is overcoming any air leaks at WOT, but they persist at light to moderate acceleration when vacuum is higher.
Just trying to get a sense before taking it into the shop. It’s my only vehicle.
Thanks!
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