After a year now iam getting SES codes po 420/430. I have long tube heaers no cats, and have turned off all o2 sensor with the Diablo. Could a small exhaust leak cause this problem. The PCM was tuned when it had an exhaust leak last year.(not knowing there was a leak). I fixed the exhaust leak this weekend, but it still throws these codes, after a test drive a random missfire code came up as well. Cleared it, and it never came back. But still po420/430. Has anybody had this problem before?
P0420 is Bank 1 and P0430 is Bank 2 Catalyst Efficiency Below Threshold. Since you have no Cats on the truck---You need to have those 2 codes deleted in the tune.
Jeff
98 GMC RCSB 2wd, 100% internally stock 305, w/twin T-3 junkyard turbos,Ramjet intake w/42lb inj,12200411 PCM. 4675lbs w/me in it. Best time in 5 passes 13.01@110
I have turned these off
They can't be off if they are coming up as codes.
Jeff
98 GMC RCSB 2wd, 100% internally stock 305, w/twin T-3 junkyard turbos,Ramjet intake w/42lb inj,12200411 PCM. 4675lbs w/me in it. Best time in 5 passes 13.01@110
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