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2006 scion tc rough running engine
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choproxy
New User
Apr 26, 2009, 9:08 PM
Post #1 of 2
(3717 views)
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2006 scion tc rough running engine
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2006 Scion TC. Runs fine untill warmed up. The rough idle and no power. Codes
P0335 and P0340. Both sensors replaced and wave forms look good at the ECU. Wiring
and grounds check out fine. Codes come back as soon as engine is warm and car runs
for a few minutes.
Took it to a Toyota dealer to have a 2nd ECU installed, which did not help the
problem. But I did find out the timing is changing from a normal range of +5 to +28
(BTDC) when warming up to -64 (ATDC). For some reason the ECU is retarding the timing
to a rediculously late spark. The problem is very late TIMING! And this occurs the
moment the ECU is in closed loop.
I did check the valve timing by checking the timing chain marks at TDC and it is on the
money. Also replaces, MAF, coils, and plugs before I found the timing was whacked
Is the spark timing derived from the crank sensor or the cam sensor? And what
conditions would make the ECU apply such a huge retardation."
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Loren Champlain Sr
Veteran
/ Moderator
Apr 27, 2009, 4:15 PM
Post #2 of 2
(3712 views)
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Re: 2006 scion tc rough running engine
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A knock sensor can cause timing to retard. But, should set a code and be seen on a scanner.
Loren
SW Washington
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