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does it use a cam button to keep it from walking forward?
I don't see one in the pic (I'm not real sure about LT1 motors though), if the cam is walking that may effect the spark timing.
while you have it apart you might as well degree the cam, just to check it.
i don't know enough about it to know, but how do you degree the cam? do you have to remove it?
As I recall, you just replace the chain and the top gear, right? It is possible, but highly unlikly that the cam is shifted enough to cause the hot headers. i.e. No need to degree it, but it is apart, so if you wanna check it, now is the time. Of course, you need the cam card (info), a degree wheel, and a piston stop device to degree it. Degreeing is done in the block. Hot headers would lead me to believe the cam is advanced. As long as the dot on the cam sprocket is correct, you are not off by a tooth. Dots go straight up n down. It does not matter the config, just as long as they are on a straight line. (Crank turns twice as fast as the cam, always.)
I don't remember you checking the cats to see if they are semi clogged.
I'm not that familiar w/ the opti, but is the base timing in spec? i.e. Is it settable?
Earlier I responded to another post about the same problem, so here's my take on it.
Okay, if the engine was not backfiring or down on power BEFORE the opti was changed, then it has to be something that occurred during the changeover.
As I posted before, glowing headers is almost always due to retarded IGNITION timing and/or lean Air Fuel ratio. Since you worked on the ignition side of the equation, I'll put my money on that as the cause.
Sometimes, only 2 to 4 degrees is all it takes.
I've never worked on an opti engine, so you'll have to get the specifics from one of the other guys here.
well, i got the car apart...and the chain looks fine as far as i can tell
i am running out of ideas as to what's wrong with my car.
where should i get a fuel pressure guage? what's the best diagnostic cable to buy to hook up to a laptop?
thanks
cheers:
Diagnostic cable?
Diacom is a software/cable kit you can buy that will read out what's going on with all the sensors in real time, but it's really pricey. Somewhere in the $500 plus catagory. I think that must be what you're referring to.
AutoZone and other stores sells a handheld ScanTool that will also show you what's going on and it's a whole lot cheaper.
Degreeing in a cam really isn't that difficult, but for a first timer, it will seem like doing the math calculations needed to pilot the Discovery to the moon. You'll either need someone to walk you through the procedure or get a video on "How To", watch it several times, before you wade in to that job.
Try to find a Opti guru in your neighborhood and have him take a look at your setup.