I just got a 99 1500 with a 5.2. The reason I have it is that "it changes timing" and the previous owner said he changed the mechanical timing stuff (chain, I assume) but I'm assuming that it's an electrical problem. The dizzy is out so I'll have to figure out how to get that reinstalled (no marks, etc -- so if anyone has any tricks for this, I'll take 'em. I'm just planning on finding TDC on #1 and matching with #1 on the dizzy but I've read that I'll have fuel injector timing issues).

The main question is: Where should I start with this "changing timing" issue? He said he set the timing, it would be fine and then magically change so that it almost wouldn't run. I'm not an expert on these ignition systems so I'd thought I'd run it by the experts here. Give me a place to start looking on this thing so it'll at least run! Thanks.

 

If he has recently changed to the chain and you have verified its good my next thought would be to check the oil pump drive shaft and distributor drive shaft for wear.

 

The distributor drive shaft is perfect. Is the oil pump drive shaft what drives the distributor? To check it, do I simply look for play with a screwdriver where the distributor is normally mounted?

 

The oil pump drive shaft is what the disty mounts into. Its got that big gear on it. If the cam is connected to it and connected to the crank, there shouldn't be much play clockwise. Counter clockwise, it'll lift right up the gear teeth.

The 2 main sensors involved with timing are the cam position sensor and crank sensor.

 

If he "set the timing" which is not possible with this system, then I suggest you put it back in to factory position and have the fuel sync reset by the dealer or someone with a scanner capable of doing so.If it still doesn't run right, then I'd start looking at the other various sensor's in the system.

 

I'll check the oil pump shaft once I get back home tonight. Is there a way to set the timing back to factory? I've got a Haynes manual at home, too but if there's a link here that I didn't see, I'd appreciate it if you point it out -- I'll keep looking!

It sounds to me like a sensor issue but not knowing the inner workings of this ignition system leaves me a little in the dark. The engine doesn't run at all now (hasn't for three years or so) so I'm not starting with much. If there's a way to test components (sensors or the computer itself) by removing them, I'll do that. Thanks for your help.