Hi all I have a 92 RS wired up as an 88 305 tpi. The car is running okay but I would like to set the timing to the L03 setting 6*. However, when I unplug the tan wire, the timing goes nuts and I can't get a steady reading. Any idea what could be causing this?

 

Only the computer can change the timing. Your timing chain is stretched.

 

He's talking about setting the base timing, but if your timing is erratic with the ECM disconnected from the Dizzy then yeah, I'd hazard to guess that your timing chain is perhaps stretched.

 

Is there an easy way to check if the chain is stretched? I don't want to spend the money and the time swapping that out just to find out thats not the case.

Also, some of the other guys have said you don't need to unplug the tan wire to set base timing, but I do not believe that is correct. Can anyone confirm this?

 

The only other possibility I can see it being is the centrifugal advance springs have broken or fallen off. Odds are pretty good though it is a bad timing chain. Sometimes I have even seen the nylon coating on the cam gear break apart and cause slop. here's a prime example of this.

The engine is 21 years old, almost certain to need a timing set.

 

Anyone who tells you that you don't need to disconnect the tan wire to set timing do not listen to, ever about anything!!!!

There are no weights and springs in a tpi computer controlled distributor.

 

The picture Joe Tag posted is exactly how the the cam gear in my 130K-mile L69 motor looked like after the timing chain popped off of it and caused 11 bent valves. Change your timing gears and chain before it is too late. The timing would jump a couple of degrees back and forth with the computer advance disconnected and I never put 2 and 2 together until I was left on the side of the freeway.

 

Also check condition of dist + cam gears for excessive wear. Define 'timing goes nuts' - just drifting around a few degress with engine at steady idle, or something else?

 

Verify the reluctor on the distributor shaft is solid, shaft/bushings are not worn, and pickup connections are good.

 

also check the distributor for play up and down, as the gear can ride up down it alters the timing degrees considerably. You can shim up the distributor end play.

 

Thanks for all the suggestions but one thing at a time.

By going nuts, I mean that the timing is incredibly inconsistent. With the engine running at the recommended 600 rpm and the tan wire disconnected, the mark I made to read the timing on the indicator jumps all over the place. I'll see it at 6* quickly then it will disappear for a second and next itll be at 10*. It's tough to describe but I'm sure you get the idea. I plan on ordering a new timing chain and am hoping this will not be incredibly laborious to swap out.

As far as the distributor goes, I haven't noticed any play either up and down or rotation-wise, then again I haven't really tried to move it out of its current position.

Thanks for the help, I will try to investigate more when I can and get back to you.

 

try to pull the shaft up and down, illing to bet there is excessive play there.