HT4100 4.1, 4.5, 4.9 Discussion, 1993 Distributor, and Minimum Air in Cadillac Engine Technical Discussion; I'm slowly working my way through all the problems that need to be fixed on my '93 Deville. So, I ...
I'm slowly working my way through all the problems that need to be fixed on my '93 Deville. So, I have two questions. First, I'm trying to adjust the timing, however I can't figure out how to even get a wrench at the distributor hold-down bolt. Is there any particular way to do this that I've missed? Second, how do you adjust the minimum air screw? Do you have to take the ISC motor off first to get to it?
The bolt for the distributor is a 15mm, you can use a crows foot with an offset, but it's a pain in the ass. Much easier to take the air intake assembly off and fiddle with it, then reassemble. You can usually slide a 15mm wrench right where the bracket and housing would normally be.
That minimum air screw , yeah, the only way I could reasonably keep my sanity was to remove the ISC motor bracket. Since the ISC is taken out of the equation (by procedure) to set the idle speed anyway, this really isn't a problem other than R&R'ing the part.
Thanks for the information, it helped tremendously. Now, I'm having a problem with the minimum air adjustment. In the directions it says to disable to generator by grounding the green harness connector plug adjacent to the generator. What green harness is it talking about? And also why does the generator need to be disabled to adjust the minimum air/idle speed?
Follow the harness that connects to the back of the alternator. Follow it down about 12 inches from the end and you should see a green clip on a short bud with "Ground" labeled on it. Ground this out to a good source.
IIRC, this isolates the alternator from the system; to eliminate any electrical "noise" or interference that may throw off the diagnostics.