93 Lumina with 3.1L 1st Gen wont start

[elfutbolero]

hello:
JEFFCOSLACKER, please help!
I have a 1993 Lumina V6 3.1L first generation engine. It does not start. It cranks but not fire.
I also have the OBD I. I connected to it and all I get is code 12, which according to the book I am reading, the OBD is working properly and there are no more codes. Something very strange happends: Both of the cooling fans turn on when I tried to read the codes from the OBD I.
When I turn the key to the on position without the connection to the OBD I, the fans stay off and the vehicle still does not start.
I have checked/replaced the following components:
-There is fuel in the tank and I can hear whirlling sound from the pump.
-Starter motor and solenoid. No problem
-Spark plugs and wires.
-No spark at the secondary posts of the coils.
-The coils are OK, checked for proper resistance at primary and secondary.
-Since I was getting battery voltage at the wire harness connection to the Iginition Module, but not spark, I replaced the Ignition Module, with a brand new one.
-Pulled out an ECM from a junker and swapped it with mine. Also swapped the memory card like the instruction manual says to do.
Still same problem of no start and what's even more strange, both fans are still coming on when I try to read the codes from the OBDI, with the ECM from the junker.
-So I figured that the problem is a short in the circuit for the cooling system. Checked the sensor for the coolant temperature. At the electrical connection I am getting about 5VDC for the refrence signal from the ECM with the key on the ON position. I checked the sensor and because it is cold, I got a high Ohms reading.
-The relays for the cooling fans were tested for proper continuity.
30 and 87a are normaly close, and so are the connections for the battery voltage. connection 87 and 30 is open when the ignition key is on the off position.
-Checked the crankshaft position sensor. I was getting an AC reading at the meter as my assistant cranked the engine. it was about a 2V peak, as the engine cranked.
Sooooooo....
I will like to check the following:
There is a third connector for the IM with five wires. Those come from the ECM. will I hurt anything if I try to start the vehicle with the connection unplugged from the IM? I want to see if I get a voltage signal from the ECM.
Your help is greatly appreciated.

[jeffcoslacker]

The cooling fans coming on after the code 12 with the diag connector in place was a "all finished" signal from the ECM on the older ones. That is normal.

The crank sensor should be producing a square wave (if you were looking with a scope) to the IM as the magnetic field senses the cogs going by. I'd change the CPS before I did anything else. The most common cause of what you got is the Ignition module or CPS on those, and they tend to go pretty close together when they die, we'd replace both if one was bad if the customer would agree to it.

To be able to see the signal from it with a meter, you might have to turn the motor slowly by hand. Should get a high/low resistance reading with the meter in the correct range at the signal wire to the IM.

You could also connect a test light to the signal side of a coil, and see if you get on/off whe the motor cranks. There should be a wire from the CPS to the IM, if you show a good signal at the CPS, make sure it is making it to the IM. Occaisionally the wires gets damaged.

[jeffcoslacker]

Not sure about cranking it w/connector disconnected to the IM.

You shoot some ether in it, just for laughs?

[elfutbolero]

Thank you Jeffcoslacker:
Even though I had tested the CPS, I replaced it anyway under your advicement. The vehicle starts and it runs better. I also had to replace the TPS per the OBD code. And other things.
By the way, the car belongs to my mother in law, and she needs the services of knowledgeable, honest and affordable mechanic. Are you anywhere near the metro area?
Take care,
Elfutbolero

Originally Posted by elfutbolero

hello:
JEFFCOSLACKER, please help!
I have a 1993 Lumina V6 3.1L first generation engine. It does not start. It cranks but not fire.
I also have the OBD I. I connected to it and all I get is code 12, which according to the book I am reading, the OBD is working properly and there are no more codes. Something very strange happends: Both of the cooling fans turn on when I tried to read the codes from the OBD I.
When I turn the key to the on position without the connection to the OBD I, the fans stay off and the vehicle still does not start.
I have checked/replaced the following components:
-There is fuel in the tank and I can hear whirlling sound from the pump.
-Starter motor and solenoid. No problem
-Spark plugs and wires.
-No spark at the secondary posts of the coils.
-The coils are OK, checked for proper resistance at primary and secondary.
-Since I was getting battery voltage at the wire harness connection to the Iginition Module, but not spark, I replaced the Ignition Module, with a brand new one.
-Pulled out an ECM from a junker and swapped it with mine. Also swapped the memory card like the instruction manual says to do.
Still same problem of no start and what's even more strange, both fans are still coming on when I try to read the codes from the OBDI, with the ECM from the junker.
-So I figured that the problem is a short in the circuit for the cooling system. Checked the sensor for the coolant temperature. At the electrical connection I am getting about 5VDC for the refrence signal from the ECM with the key on the ON position. I checked the sensor and because it is cold, I got a high Ohms reading.
-The relays for the cooling fans were tested for proper continuity.
30 and 87a are normaly close, and so are the connections for the battery voltage. connection 87 and 30 is open when the ignition key is on the off position.
-Checked the crankshaft position sensor. I was getting an AC reading at the meter as my assistant cranked the engine. it was about a 2V peak, as the engine cranked.
Sooooooo....
I will like to check the following:
There is a third connector for the IM with five wires. Those come from the ECM. will I hurt anything if I try to start the vehicle with the connection unplugged from the IM? I want to see if I get a voltage signal from the ECM.
Your help is greatly appreciated.

[jeffcoslacker]

I live in Jefferson county. What area does she live in?

[elfutbolero]

south saint louis city

[jeffcoslacker]

That's close to here.

[richtazz]

You're in good hands with Jeff, he knows his chit!!!