First of all, why do you need to adjust the timing? If you want to run regular fuel, you can without engine damage. The engine has a knock sensor that can adjust for lower octane fuels. You might get a little pinging at WOT, but for just normal driving around town or cruising on the highway, it shoudl be fine.
Second, the timing is all computer controlled. Unless you can change the parameters set in the PCM, there's no real way to manually adjust the timing. There no mechanical assenly to move, or reposition like a distributor. You would have to go into the PCM and change the sofware to do so. This can be done by the use of an aftermarket EEPROM chip, but they are expensive, and in most cases require premium fuel to be used.
My engine just got a major overhaul (had lots of problems), but now the timing is not correct. I'm trying to adjust it back to the original setting. Any help with doing that, or is that only done through the PCM?
It's off when you check with a timing light? How far off do you think it is? Do you have the procedure to check it? There is usually a connector to plug (or unplug) before you can check it with a light.
Damn, I forgot to mention Cam timing, but you shouldn't need to mess with that at all. Is it just the spark timing that's off, or do you think it's mechanical. The ignition is control by the cam and crank sensors. If they are on their way out, that could cause a problem, but usually it result in a stall, or no start condition. What exactly was done to the engine? Did they pull the head's off for any reason? If so, then perhaps they didn't get the timing chains line up correctly when they reinstalled the heads.
Its the cam timing. The spark timing is ok. I replaced new head gaskets, and replaced a broken camshaft, and when i switched the car on it kept smoking and stalls sometimes. Even when i press on the gas the RPM only moves upwards very slowly.
I am just looking for a way to adjust the cam timing, any diagrams would be helpful. Any tips or ideas?
The cam timing is strictly mechanical, controlled by where the cams were when the timing chains were installed. You adjust the cam timing by pulling the timing cover off, removing the timing chains and lining up the timing marks. Doesn't seem like it's feasable to do in the car...
If it's the cam timing, then your probably going to have to either take it back to whoever worked on it (at this point, I wouldn't recommened that) or find a local caddy dealer than can give you a good price on timing the camshafts. I would try to at least go back to where the work was done and see if you can get them to fix it, or at least pay to have it fixed, since they obviously have no idea what they are doing. They would definitely have to fix it for free in this case, as it's there fault that they don't knwo how to time the car properly.
Primary chain marks are aligned facing each other.
Secondary chains are installed so the appropriate timing marks are perpendicular to the top of the cyl head. The rear head is the right head. So you would have RE and RI marks up. Left head would show LI and LE.
If you turn the engine at this point the cams seem to go out of time, you turn them 7 revolutions and they will realign. This is something I still have problems with!