My friend was working on a truck, 99 2500 hd 5.7 vortec. all that I know is that he couldn't fix it and brought it to me & another friend. He said before he got it another shop tried to fix it and couldn't....
it runs somewhat rough and sluggish, sometimes bucks and hiccups coming on or off the throttle. I hooked the scanner up and it said the CMP (cam position) was -39, from what I understood it should have been 0* +/- 2.... and timing was steady at 13* advance. tried to advance the dizzy but lo and behold it had a v6 hold down on it (these do not allow the distributor to turn). I had a v8 hold down and put it on, set the timing by the scanner to -2* and the truck acted like the timing was REALLY far advanced. I did get it to start and it ran much better showing as much as 36* of timing on the scanner, but again with the CMP set on 0* like it calls for it will not start, drags the starter BAD.
right now i have 2 thoughts.... it is a v6 dizzy (hence the v6 hold down) OR the cam timing has jumped. anybody dealt with this before? I think I can check the cam timing without pulling the cover by using a degree wheel and pulling a valve cover (looking for around a 40* ABDC IVC right?)... OR can a V6 dizzy do this do this? are they even different, suspect so? any other ideas here...
it runs somewhat rough and sluggish, sometimes bucks and hiccups coming on or off the throttle. I hooked the scanner up and it said the CMP (cam position) was -39, from what I understood it should have been 0* +/- 2.... and timing was steady at 13* advance. tried to advance the dizzy but lo and behold it had a v6 hold down on it (these do not allow the distributor to turn). I had a v8 hold down and put it on, set the timing by the scanner to -2* and the truck acted like the timing was REALLY far advanced. I did get it to start and it ran much better showing as much as 36* of timing on the scanner, but again with the CMP set on 0* like it calls for it will not start, drags the starter BAD.
right now i have 2 thoughts.... it is a v6 dizzy (hence the v6 hold down) OR the cam timing has jumped. anybody dealt with this before? I think I can check the cam timing without pulling the cover by using a degree wheel and pulling a valve cover (looking for around a 40* ABDC IVC right?)... OR can a V6 dizzy do this do this? are they even different, suspect so? any other ideas here...
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