I am trying to advance the timing to take up for timing chain wear and to help starting. I understand the tdco relearn procedure but unfortunately don't have access to a scanner at the moment. Would it be possible and worthwhile to turn the pump 1or2 scribe marks to change tdco and hopefully get a more negative value still within the computers parameters?
It can be done, nut a PITA without right tools, do you have a IP turn tool, it's hard to rotate IP withouth one and lock in place at sametime. DO NOT ROTATE IP WITH SILVER THINGY on top of the IP, it is easliy broken and you will have a bad day for sure after that.
How much timing chain wear do you suspect, get a scan tool if desired and actual are less than 1 degree apart I wouldn't worry over it, many shops/folks have a Snap-On scanner which will work, I personally would not make any movement without a scanner, including bumps. Have you gone through the scan tool locator above in sticky's section maybe one is closer than you think.
I have made an ip turning tool as per the measurements found on one of the threads on this forum. My tdco is -.25 actual and desired timing is at 8.7 degrees as per dealers scan test. truck has 200k and has been harder to start after pump replacement. truck will start very easily when coolant temp is low and ecm allows max cold advance, or when the coolant temp sensor is unplugged during cranking. would changing the tdco improve starting? (glow plug circuit checks out good)
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