Im trying to set my timing on my 1984 monte carlo ss with a new distributor. My other distrubitor went out this is a new one . I did it before following this website and using a timing gun . When i unplug the 4 pin connector it wont start . The first time i did this it did start . Here is a link to the instructions .
Set timing on Monte carlo ss
- Thread starter SSmooth84
- Start date
- Status
Im still using the computer i have a 02 sensor installed i dont want to remove it . I think the problem might be i dont have it at tdc It cranks right up and runs ok but the power is just not there .
Ok, if the computer controlled carb is not hooked up it will not run right. If the carb is not hooked up and running with the rest if the system, you are essentially throwing the computer into "Limpy" which is the "Limp Home Mode" of the software.
The Computer is looking for all its needed inputs to have the engine run correctly based on the EPA driven OEM method to keep the exhaust at the current 1984 standard of outputs, which is NoX, SoX, CO2, CO and Un-burned Hydro-Carbon.
When running a stand alone Carburator, you need to have stand alone timing.
Otherwise it will never run correctly. Low power, poor acceleration, run-on, and potential detonation and or overheating. The engine will run "labored", timing will not be correct, timing curve will be wrong, and engine damage is possible.
If you are running with the computer controlled carburetor hooked up, then the rest of the system including the carburetor, needs to be at OEM standard.
You have to remember in simple terms: Air, Fuel, Compression and Fire.... All has to be in proper balance.
The engine is nothing more than a "heat producing air pump". Volumetric efficiency is key and that was how it was designed with notable exceptions of EPA limits placed upon it.
On the distributor, hand crank (1/2 inch ratchet handle and socket) the harmonic balancer to an area where you can access the timing slot. Clean the slot cut into the balancer and then use white, or red paint pen and paint that slot. Let it dry..., then rotate by hand until the paint marked slot is at zero on the timing tab. Pull the cap and see where the rotor is pointing.
The copper tab on the rotor has to line up to just at the drivers side edge of the copper tab in the cap.
The rotor is carrying about 50K volts, so if the tab is lined up dead center with the tab on inside of cap, you are already too far advanced. If you pull the cap and the rotor is pointing to the firewall, put your pickup for the timing light on number 6, as number 1 is currently on exhaust stroke.
Remember 1 8 4 3 6 5 7 2... You have 2 rotations of crank to one of the cam.
I got another distributor installed by a mechanic but now it idles rough and seems to have miss fire and it just runs like crap.
Did it run poorly when the mechanic was done with it? If so, find a new mechanic and have them diagnose and repair the issue. If not, have your mechanic come back and fix it right.
It did run bad before it took it to him but not this bad . So o checked the engine codes and got back codes 41 and code 42 .
Below are the codes. You need to have someone in your local area check it out.
It could be that these codes popped up because distributor was in hooked when you were trying to time it.
Code 42
Trouble Codes › GM OBD Trouble Codes › GM Code 42
During cranking, the timing is controlled by the ignition module while the ECM monitors the engine speed. When the engine speed exceeds 400 RPM, the ECM sends a BYPASS signal to the ignition module which switches the timing to ECM control. The ECM calculates what the timing should be then "tells" the ignition module via the EST circuit.
An open or ground in the EST circuit will stall the engine and set a Code 42. The engine can be re-started but it will run on ignition module timing.
Trouble Codes › GM OBD Trouble Codes › GM Code 41
CODE 41 - No Distributor Pulses, Cylinder Select Error
Trouble Code 41 indicates that the Camshaft Sensor is not functioning properly.
The ignition module uses the Cam Sensor signal for timing the spark firing. The ignition module also passes this signal to the ECM to enable sequential fuel injection. The inability to properly determine engine position from the Cam Sensor will generate Code 41.
The engine will continue to run if the signal is lost from the sensor, however it will not restart after shut down. If the Cam signal from the ignition module to the ECM is lost while running, the ECM will switch to the simultaneous fuel injection mode. The engine can be re-started but will continue to run in the simultaneous mode as long as the fault is present.
The conditions for setting this code are:
1) Loose or mis-adjusted Cam Sensor
2) Defective Cam Sensor-to-ECM connections
3) Defective ECM
Cam sensor installation and adjustment procedures call for very exact tolerances. It is for this reason that it is recommended that the service manual be consulted while performing any adjustment or replacement of the Camshaft Sensor.
Return to Chart
It could be that these codes popped up because distributor was in hooked when you were trying to time it.
Code 42
Trouble Codes › GM OBD Trouble Codes › GM Code 42
CODE 42 - Electronic Spark Timing or Bypass Fault
Trouble Code 42 indicates that there may be a malfunction in the Electronic Spark Timing (EST) system.During cranking, the timing is controlled by the ignition module while the ECM monitors the engine speed. When the engine speed exceeds 400 RPM, the ECM sends a BYPASS signal to the ignition module which switches the timing to ECM control. The ECM calculates what the timing should be then "tells" the ignition module via the EST circuit.
An open or ground in the EST circuit will stall the engine and set a Code 42. The engine can be re-started but it will run on ignition module timing.
Trouble Codes › GM OBD Trouble Codes › GM Code 41
CODE 41 - No Distributor Pulses, Cylinder Select Error
Trouble Code 41 indicates that the Camshaft Sensor is not functioning properly.
The ignition module uses the Cam Sensor signal for timing the spark firing. The ignition module also passes this signal to the ECM to enable sequential fuel injection. The inability to properly determine engine position from the Cam Sensor will generate Code 41.
The engine will continue to run if the signal is lost from the sensor, however it will not restart after shut down. If the Cam signal from the ignition module to the ECM is lost while running, the ECM will switch to the simultaneous fuel injection mode. The engine can be re-started but will continue to run in the simultaneous mode as long as the fault is present.
The conditions for setting this code are:
- the engine is running, and
- the Cam Sensor signal is not received by the ECM in the last 1 second interval
1) Loose or mis-adjusted Cam Sensor
2) Defective Cam Sensor-to-ECM connections
3) Defective ECM
Cam sensor installation and adjustment procedures call for very exact tolerances. It is for this reason that it is recommended that the service manual be consulted while performing any adjustment or replacement of the Camshaft Sensor.
Return to Chart
On the 1984 system there isn't a cam sensor per-se, the pickup coil is what is used for the ECM to pick up the pulses, so it doubles as the "cam sensor". Once GM started going "distributorless" is when cam sensors came into use.
Last edited:
I looked up those codes and came up on the computer needed to be reset . I unhooked the battery and all the codes were gone then set the timing and it runs great. When I set timing after I plug in the connector the timing advanced is this correct since that's when the computer takes over .
- Status
Similar threads
