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I would check first of all to see if any codes are stored to indicate whether or not that could be the cause of the intermittent no start issue. To check for any trouble codes stored, here:
See Figures 3, 4, 5 and 6
The quick reference troubleshooting charts (located at the front of the diagnosis part of the section) covers the most common failure modes for the PGM-FI. The probable causes are listed in order of most-easily-checked first, then progressing to more difficult fixes. Run through all the causes listed. If problem is still unsolved, go on to the more detailed troubleshooting. Troubleshooting is divided into different LED displays. Find the correct light display and begin again.
For all the conditions listed, the PGM-FI warning light on the dashboard must be on (comes on and stays on). This indicates a problem in the electrical portion of the fuel injection system. At that time, check the LED display (self-diagnosis system) in the ECU/ECM.
There is only one LED display. The LED will blink consecutively to indicate the trouble code. The ECU/ECM is located beneath the access panel, under the carpet on the passengers side of the vehicle.
Sometimes the dash warning light and/or ECU/ECM LED will come on, indicating a system problem, when, in fact, there is only a bad or intermittent electrical connection. To troubleshoot a bad connection, note the ECU/ECM LED pattern that is lit, refer to the diagnosis chart and check the connectors associated with the items mentioned in the "Possible Cause" column for that LED pattern (disconnect, clean or repair if necessary and reconnect those connections). Then, reset the ECU/ECM memory as described, restart the car and drive it for a few minutes and then recheck the car and drive it for a few minutes and then recheck the LED. If the same pattern lights up, begin system troubleshooting; if it does not light up, the problem was only a bad connection.
The memory for the PGM-FI warning light on the dashboard will be erased when the ignition switch is turned OFF; however, the memory for the LED display will not be canceled. Thus, the warning light will not come on when the ignition switch is again turned ON unless the trouble is once more detected. Troubleshooting should be done according to the LED display even if the warning light is OFF.
If the LED blinks codes that don't exist, clear the ECU, road test the vehicle and check them again. If the same codes repeat, replace the ECU.
There is a 2 wire service check connector that you will need to jumper with say a paper clip to help retrieve the codes. It is located in passenger side kick panel, here:
Once you do that turn the key to the ON or II position & if any codes stored within the ECU the check engine light should begin to blink. You will need to count the blinks, like this for example:
Do not use the lower chart for the accurate codes, just use the top part to decipher how to count the blinks. When all codes are given the sequence will begin all over with the first code.
Fig. 4: Self-diagnostic code chart -1992-95 vehicles.
There are some other things that may be the cause of the no start condition, they would be:
-ignition switch (electrical part0
-distributor (internal mechanical failure)
Some of theses items to test you will need a DVOM (digital volt ohm meter). If you have one or can get one then we can proceed to some troubleshooting steps for the items. I would first see if you can pull any trouble codes. Any other questions, please let me know. Thank you.
Did you need any other help or have another question?
Please let me know. Thank you.
I checked for codes, but the MIL light would just stay illuminated. No DTCs flashed, just a steady CHECK ENGINE LIGHT. Does this indicate a faulty ECM?
At other times when ignition is turned ON, the MIL will go out after 2 seconds, then the engine would start at this point. But when ignition is turned ON and the MIL just stays ON, engine will cranks, but will not start.
Replace the PGM-FI relay, but it wasn't the problem after all.
At other times when ignition is turned ON, the MIL will go out after 2 seconds, then the engine would start at this point. But when ignition is turned ON and the MIL just stays ON, engine will crank, but will not start.
Replaced the PGM-FI relay. Also, I was going to perform the circuit check at the ECM, but without a breakout box, it's going to be hard. How about backprobing the terminals?
Yes you can back probe the terminals, you just need to be careful doing this. It can be done, just be careful, I have heard of people messing things up because they get frustrated & lose patience because they just could not understand how to do it & causing more problems for themselves, but you sound like you should be able to handle it & you mentioned about it. The breakout box, yes is easier, but back probing you can get the same results.
It definitely sounds like something may be going on with the ECM.
Are you getting any spark also when the check engine light is on?
Has there been any modifications done to the engine that could possibly causing any problems, or is it a stock motor?
Are you using some type of service manual?
Any other questions, please let me know. Thank you.