: Hesitation on an 83 cadillac fleetwood brougham with HT4100 motor

01-03-12, 11:33 AM
I'm having an 83 cadillac fleetwood brougham with HT4100 motor.
I live in THAILAND and this car used to be an American Embassy car here.
At the moment it is running fine. Start up easily but just have a bit of hesitation on accelelation.
If I pull the throttle suddenly from the idle, the motor get nearly stall and no power for a second before the RPM going up.
As I check it with timing light, it stay at about 18-20 BTDC at the idle. Once I pull the throttle suddenly from the idle,
It's retard to about 10 BTDC for a second and the engine nearly stall and Then it move up to 20 BTDC and the RPM comes right up.
Apart from that it's running fine.
So has anybody used to have similar problems to mine?
I suspected the Distributor (Ignition module) or an ECM.
Engine oil look OK, no coolant leak.

Anyway sorry about my english.

01-05-12, 02:02 AM
Behind the distributor is a green plastic connector that must be disconnected before checking the timing with a light. Base timing is 10 degrees Before top dead center. They run better at 12 degrees. Disconnecting that wire removes the ECM from trying to adjust the timing. Some people unfamiliar with this engine will set the timing incorrectly, leaving that wire connected and it will be retarded.

01-17-12, 11:06 AM
It stay at 12 degrees when the green connector disconnected. the timing does advance a little bit when i rev it up. but not as much as when green connector is connect. The other day I replace ignition module and condenser but still does the same. timing retard from 20 degrees to 12 degrees before it advance to 22 degrees. Or could it be a throttle position sensor? or an ECU?


So the timing has been set correctly at 12 Degree. but just wonder why the timing retard instead of advance when i rev it up. and make it have no power.

01-17-13, 11:22 AM
This problem fixed after I check the trouble code and found faulty throttle position sensor and replace it. It's running sweet now.