50+ Degrees of Timing? Help
06-01-2016, 07:31 PM
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50+ Degrees of Timing? Help I have a 03 5.3 in a 81 malibu th350 trans. Car was running great, started it yesterday and was running rough. Most noticable between 2-3000 rpms then smooths out as rpm increases. I noticed that the timing advance climbs to 53 degrees by 2000 rpm then slowly starts to drop back down as the rpms continue to climb, is that not way too much timing? Scanner is picking up a lot of misfires on almost all cylinders once it gets above 3500 rpm it doesnt detect any misfires. O2 sensors are a week old and switching voltage properly, and LTFTs are with in +-1%. Stock tune on stock pcm, so what would cause so much timing. Any help is very appreciated.
06-01-2016, 08:27 PM
#2
TECH Resident
Interesting problem. My experience says it is one thing, not multiple.
no codes?
crank position sensor?
manifold pressure sensor?
PCM failure? Do you have one to swap?
Are you sure it isn't a vacuum leak?
What else did you do recently?
no codes?
crank position sensor?
manifold pressure sensor?
PCM failure? Do you have one to swap?
Are you sure it isn't a vacuum leak?
What else did you do recently?
06-02-2016, 03:27 PM
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Also no codes that should be related. It does have a tcc code and tfp code, that I need to get programmed out yet. And a random misfire code pops up every now and again since it started running like garbage.
