96 Grand Am 3100 No Spark

Purchased a 96 GA 3100(M vin) on Craigslist with a locked up engine for my grandson so he could learn the internals of the engine and give him some experience. The engine had spun #1 rod bearing, and broke the camshaft in half due to lack of oil.

We purchased a 3100(M vin) from a wrecked 98 Lumina, replaced the LIM gaskets and installed the engine. Everything went well with the exception we did not get the negative battery cable on the transmission stud when first trying to start engine. It did backfire a couple of times, but would not start, after rechecking all found and installed cable.
Now we are getting no spark when cranking, we did leave both crankshaft sensors, the camshaft sensor,coil and wires, and injectors, from Lumina.

Things checked so far:
1. 12v at ICM, pink and black wires.
2. Replace 7X CKP sensor, still only show 1.1 AC volts at plug disconnected from ICM when cranking, Alldata online states I should be getting 2 volts???
3. Removed ICM and took to Autozone, they checked with tester, checked ok after 3 test cycles.
4. Removed one of the coils and placed test light between primary coil terminals on ICM, NO light when cranking, also tachometer doesn't move when cranking.
5. Coils all check out around 6K ohms on secondary side.
6. Have removed top air cleaner housing and sprayed starting fluid while cranking, no backfire.
7. Compression around 150lbs.
8. Theft light comes on and stays on when cranking, no blinking, tried leaving ignition on for 12 minutes, light did not go out. No chip on key.
9. The original fuel injector harness under the upper intake had to be used because the lumina harness had another large connector on it.

I feel the problem is no spark, because starting fluid has no effect and the test light doesn't light up at primary coil terminals on ICM when cranking. My understanding it will start and run without the cam or front crankshaft sensors, correct me if I am wrong on this.

I hate to spend money on a camshaft sensor or a front crankshaft sensor if it doesn't need them, the old crankshaft sensor that came out of the block has the same ohm reading as the new one from Autozone.

Any help would be appreciated.

- good work that is what I like to see.

- icm has 3 conectors (2 on the right and one on the left). Check that one on the left is plugged in.

- you are correct this engine will start and run without cam signal or 24X sensor that is located by the balancer.

- the most important and the critical sensor for starting is 7x ckp with purple and yellow twisted wires. This connector should be connected on the right side of the icm not on the left. So check that you did not accidentially swithc connectors.

- disconnect the two pin connector at the right side of the ICM with purple and yellow wires, connect DVOM set to mV AC, ask someone to crank the engine while you are observing AC voltage it should be in the range of 200 mV AC. If you get some mv AC that is good sign. Now if everything was connected correctly and if you tested your icm the way you said with the test light then ICM is bad. Use icm from the old engine then.

- so if you tested icm by removing coils and then bridging male terminals for each of the coils with test light and looking for test light flashing while someone is cranking that is correct. No light means bad ICM (if ckp is sending signal as I described in the test above).

keep us posted

- good work that is what I like to see.

- icm has 3 conectors (2 on the right and one on the left). Check that one on the left is plugged in.

- you are correct this engine will start and run without cam signal or 24X sensor that is located by the balancer.

- the most important and the critical sensor for starting is 7x ckp with purple and yellow twisted wires. This connector should be connected on the right side of the icm not on the left. So check that you did not accidentially swithc connectors.

- disconnect the two pin connector at the right side of the ICM with purple and yellow wires, connect DVOM set to mV AC, ask someone to crank the engine while you are observing AC voltage it should be in the range of 200 mV AC. If you get some mv AC that is good sign. Now if everything was connected correctly and if you tested your icm the way you said with the test light then ICM is bad. Use icm from the old engine then.

- so if you tested icm by removing coils and then bridging male terminals for each of the coils with test light and looking for test light flashing while someone is cranking that is correct. No light means bad ICM (if ckp is sending signal as I described in the test above).

keep us posted

Thanks so much for your help,

I removed all coils, and plugged in ICM off of old engine, then bridged male terminals with a test light. No terminals would flash light, added a ground to the base of ICM with a jumper wire to - side of battery, still no light.

Disconnected six wire connector on ICM to PCM, and now test light flashes when cranking, tried both ICM's, the same on both.

The plug on ICM I disconnected has 4 wires:
1. A - Tan/Black Stripe
2. B - White
3. C - Empty
4. D - Empty
5. E - Purple/White Stripe
6. F - Red/Black Stripe

Autozone online Fig. 4 Ign sys diagnosis 3.1 engines shows:

1. A - 424 Tan/BLK to C28 on PCM Ignition Control
2. B - 423 WHT to C27 on PCM Ignition Bypass
3. C - 121 WHT - Tach Signal - Empty on my connector
4. D - Empty
5. E - 430 PPL/WHT to C30 on PCM 3x REF HIGH
6. F - 453 RED/BLK to C31 on PCM 3x REF LOW - Noticed this is also terminal C on the CMP and 24x CKP Sensors



How should I proceed?

Could I have damaged the PCM when trying to start with the - battery cable disconnected at the transmission stud?

do you have scanner?

-ignition key into run position check for codes


- if you have all data you will notice that az and all data's el. diagrams for the same year and model show different pcm pin#.

Check ground 110 that main engine ground to the left of vacuum modulator on the engine block, (so make sure there are no loose black wires in that area)

Disconnect negative battery cable, disconnect the pcm (blue connector) (you will need 7mm socket) , then disconnect 6pin connector at the ICM, test for continuity at the 6 pin connector between each of the wires to make sure there are no shorts. Then check from terminal B of the ICM 6 pin connector to terminal 53 of the PCM blue connector (both should be white wires) - so check for continuity to eliminate open. Also terminal A at icm with pin 52 of the pcm blue connector (both ends should be tan/black)-check for open the same way. And do the same for terminal E with pin 44 - make sure you have same wire colors at both ends. Terminal F with pin 45 do the same way.

if your multimeter black and red wires are to short for this testing, use jumper wire with alligator clips at both ends to extend one of the testing leads.

do you have scanner?

-ignition key into run position check for codes


- if you have all data you will notice that az and all data's el. diagrams for the same year and model show different pcm pin#.

Check ground 110 that main engine ground to the left of vacuum modulator on the engine block, (so make sure there are no loose black wires in that area)

Thanks again for your help,

I checked out a scanner at autozone a few days ago, did not show any codes so I took it back.

I went to library and printed out the alldata "Engine cranks, But will not run" troubleshooting chart, I didn't realize that the 2 electrical diagrams were different until you pointed that out.
I have noticed some other discrepencies in the Autozone online charts(specifically checking the camshaft sensor states "Place a socket and breaker bar on the crankshaft pulley bolt and rotate engine by hand. Observe th volt meter and verifty the the voltage singal varies from approximately zero volts to slightly less than supply voltage. The voltage will switch on when the target passes the sensor and will show little or no voltage when the target is past the sensor." On mine it would show voltage until is passes the target then goes to zero, just the opposite.

I have checked all the grounds at the transmission stud next to the vac modulator, this is where I previously noticed we had left the negative battery cable off.

Thanks again for your help,

I checked out a scanner at autozone a few days ago, did not show any codes so I took it back.

I went to library and printed out the alldata "Engine cranks, But will not run" troubleshooting chart, I didn't realize that the 2 electrical diagrams were different until you pointed that out.
I have noticed some other discrepencies in the Autozone online charts(specifically checking the camshaft sensor states "Place a socket and breaker bar on the crankshaft pulley bolt and rotate engine by hand. Observe th volt meter and verifty the the voltage singal varies from approximately zero volts to slightly less than supply voltage. The voltage will switch on when the target passes the sensor and will show little or no voltage when the target is past the sensor." On mine it would show voltage until is passes the target then goes to zero, just the opposite.

I have checked all the grounds at the transmission stud next to the vac modulator, this is where I previously noticed we had left the negative battery cable off.


please read my previous post again, I think that I was editing it while you were writing your last post.

do you have scanner?

-ignition key into run position check for codes


- if you have all data you will notice that az and all data's el. diagrams for the same year and model show different pcm pin#.

Check ground 110 that main engine ground to the left of vacuum modulator on the engine block, (so make sure there are no loose black wires in that area)

Disconnect negative battery cable, disconnect the pcm (blue connector) (you will need 7mm socket) , then disconnect 6pin connector at the ICM, test for continuity at the 6 pin connector between each of the wires to make sure there are no shorts. Then check from terminal B of the ICM 6 pin connector to terminal 53 of the PCM blue connector (both should be white wires) - so check for continuity to eliminate open. Also terminal A at icm with pin 52 of the pcm blue connector (both ends should be tan/black)-check for open the same way. And do the same for terminal E with pin 44 - make sure you have same wire colors at both ends. Terminal F with pin 45 do the same way.

if your multimeter black and red wires are to short for this testing, use jumper wire with alligator clips at both ends to extend one of the testing leads.

Disconnected battery and pcm, checked for grounds on terminals A,B,E,&F of ICM connector, found no grounds, then checked for continuity between same to corresponding terminals on pcm plug.

All checked good for continuity and no grounds.

I previously removed all the coils from the ICM and I would be able to get my test light to flicker when I would crank the engine only if the 6 wire connector to the ICM was unplugged, if I plugged it in I would get no flashing light across the primary coil terminals.

I also noticed when I reinstalled 2 of the 3 coils I would not get a test light to flash on the terminal with the coil off either way..either 6 wire connector on or off. In other words is it necessary to remove all coils to test if the ICM is sending signals to to coils?

Thanks again "3100" for your help in troubleshooting this.

- when you have coils installed and all connectors plugged in at the icm, what happens when you remove one of the spark-plug cables from the spark-plug and insert screw driver into the boot? No spark at all?

- when you have coils installed and all connectors plugged in at the icm, what happens when you remove one of the spark-plug cables from the spark-plug and insert screw driver into the boot? No spark at all?

No spark at all

On the PCM, is all the programming done on the prom?

Can I purchase a used ECM with the same Service # then install my PROM in it?

I have about came to the conclusion that I may have damaged the PCM.

On the PCM, is all the programming done on the prom?

Can I purchase a used ECM with the same Service # then install my PROM in it?

I have about came to the conclusion that I may have damaged the PCM.


That is what I was thinking, but not that you damage it, it could be that pcm did not work at first place, and I did not want to blame pcm right away. You can buy used pcm at yunk yard as long as the year and accessories are about the same as your 96 GA.

not expensive at all, bought myself one just for testing purposes and as a backup and it cost me $20 from junk yard.

I know I need the same Service # of the computer I get at the junk yard.

What about the BSKS that is after the Service #, isn't that the programing of the prom?

What I am would like to confirm is:

1. If I buy a 16211539 BSKS, could I just install it, prom and all, and be the same as mine? or
2. If I buy a 16211539 xxxx, can I just remove my prom and install in purchased computer and will that work also?(assuming the prom is good in my computer now)

I understand if a dealer done some updates that there may be some minor differences in the software, but is the BSKS what the factory put in my 96 GA, designate the options it came with?

Thanks 3100 for your help on this, if this car had a distributor and a carb I could handle that.

I wold get the complete unit. I did not have to do anything with prom. When you install new pcm you will have to do relearn procedure, attempt to start and leave key in run position until security light stops flashing, then start.


-try this relearn procedure again. So attempt to start and just leave key in run position til light turns off or stops flashing don't remember exactly.

-don't forget to connect all connectors at the ICM before doing this.

- you said that you already waited 12 min
try again and wait longer

I found this:
GM:

10 Minute Learn Procedure
Tools Required:
None

Turn ON the ignition, with the engine OFF.
Attempt to start the engine, then release the key to ON (vehicle will not start).
Observe the SECURITY telltale, after approximately 10 minutes the telltale will turn OFF.
Turn OFF the ignition, and wait 5 seconds.
The vehicle is now ready to relearn the Passlock™ Sensor Data Code and/or passwords on the next ignition switch transition from OFF to CRANK.

Important
The vehicle learns the Passlock™ Sensor Data Code and/or password on the next ignition switch transition from OFF to CRANK. You must turn the ignition OFF before attempting to start the vehicle.


Start the engine. The vehicle has now learned the Passlock™ Sensor Data Code and/or password.
With a scan tool, clear any DTCs if needed. History DTCs will self clear after 100 ignition cycles.


I did this:
Cranked engine, left key in ON posistion for 20 minutes, THEFT light remained on, Light Stayed ON...never blinked...never went OFF...Turned the switch to OFF, waited for 5 seconds, retried to start...

I also checked the pink wire when cranking at the ICM, voltage at 11.5 volts when cranking. Found these cars had a recall on Ignition switch because the switch would melt due to excessive current through the switch. The engine was locked up when I bought the car, so I sure it had excessive current when trying to crank.

put the heat on and fan set to to HI, turn switch into run position is blower motor engaging? are wipers working in run position?


- here is one crazy idea but it should tell us if pcm is reading signals. Please try this, but use deep socket for this because you can damage sensor connector. I think it is 19mm or 17mm deep socket that you will need to remove ECT sensor. once you remove ect sensor reconnect the connector, have some hot water ready in a cup, turn key into run position tell someone to submerge only the tip of the sensor that goes into engine block while you watch temperature needle move to hot. This will partially test IPC and PCM. If needle does not move then we will have to investigate further.

Also under the key cylinder is a connector with yellow and black wires that is the pass lock see if it is connected, at that time you will be able to see ignition switch look for signs of melting at connectors.

after you complete tests mentioned in the previous post

remove pcm connectors (blue and white )

find pins 21 and 60 on both connectors they all should be grounds so you can use dvom with continuity setting with sound to see if you have continuity from those pins to any good ground.

Also disconnect map sensor connector: gray wire is 5v reference from pcm with ignition key in run position you should have close to 5v at gray wire of the map sensor. This tests will at least tell us something about pcm. If ect sensor test, and this test do not show any signs of life I would replace pcm.

put the heat on and fan set to to HI, turn switch into run position is blower motor engaging? are wipers working in run position?

Yes, blower motor and wipers work.



- here is one crazy idea but it should tell us if pcm is reading signals. Please try this, but use deep socket for this because you can damage sensor connector. I think it is 19mm or 17mm deep socket that you will need to remove ECT sensor. once you remove ect sensor reconnect the connector, have some hot water ready in a cup, turn key into run position tell someone to submerge only the tip of the sensor that goes into engine block while you watch temperature needle move to hot. This will partially test IPC and PCM. If needle does not move then we will have to investigate further.

Removed Cooling Temp Sensor near the thermostat, put in hot water, temp guage moved to the 1st line above the bottom line.


Also under the key cylinder is a connector with yellow and black wires that is the pass lock see if it is connected, at that time you will be able to see ignition switch look for signs of melting at connectors.

I pulled the plastic shroud around the column, connectors look good, wire looks good. Should I trace the yellow and black wires back to the PCM since I have read where some people cut the yellow wire behind the radio?

find pins 21 and 60 on both connectors they all should be grounds so you can use dvom with continuity setting with sound to see if you have continuity from those pins to any good ground.


Pins 21 and 60 on both PCM connectors are grounded

Also disconnect map sensor connector: gray wire is 5v reference from pcm with ignition key in run position you should have close to 5v at gray wire of the map sensor. This tests will at least tell us something about pcm. If ect sensor test, and this test do not show any signs of life I would replace pcm.

I am getting 5.04 volts on terminal c of map sensor unplugged from sensor.

WOW, I don't know what to say, pcm is showing signs of life,


do you have enough oil in the engine, sometimes engines will be prevented from starting as a preventive measure if there is not enough oil. Check that.

yellow and black wires do not go to pcm if I can remember correctly, they go to IPC

check all the fuses with test light and key in run position all of them should show light

also disconnect the 10 way injector connector
see if you are getting spark now

we have to ask ourselves, why theft light is not turning off, but again this should disable injectors not spark.

Is bracket where ICM sits clean? if not clean with wire brush bracket and bottom of the icm, I will look more into pcm's inputs and outputs and will get back to you again.


- disconnect both connectors at the pcm, crank engine and test for spark at the spark plug cable (this is called bypass mode, it should still fire spark but engine will not start) just want to see if pcm is preventing spark in our case.

I stuck a phillips screw driver in #2 plug wire held it 1/8" off the intake manifold with both pcm plugs disconnected, NO Spark.

The bracket that the ICM sets on is clean.

Have put in a little over 4.5 qts oil, vehicle is jacked up in front, tires off ground about a foot.

Have previously checked all fuses, currently have the courtesy light fuse removed to keep off the interior lights.

Haven't tried spark without the injector wires unplugged because I still had the PCM unplugged.

What is interesting is without the PCM, I still have no spark, and the only time I get an indication of the ICM working is when I removed all the coils and removed the 6 wire connector, it would flash my 12v Snap On test light when cranking at the primary coil terminals.

Replaced ICM and coils with the parts from original engine, no difference, ICM had already checked good at Autozone but wanted to make sure.

****SUCCESS****

Installed the wire harness from the 3x crank sensor to the ICM off of the original engine. Fired up on 1st crank.

This wire must have a certain amount of twist or plug was bad..

The Alldata troubleshooting chart said I should have 2 volts and I was showing 1.1 volts, haven't checked voltage since putting old harness on, just happy it works and I still have some hair left.

Thanks "3100" for all your help.

****SUCCESS****

Installed the wire harness from the 3x crank sensor to the ICM off of the original engine. Fired up on 1st crank.

This wire must have a certain amount of twist or plug was bad..

The Alldata troubleshooting chart said I should have 2 volts and I was showing 1.1 volts, haven't checked voltage since putting old harness on, just happy it works and I still have some hair left.

Thanks "3100" for all your help.

Hey at least we practiced how to test pcm LOL. :cheers:
sometimes we expect problems to be more difficult to find, and at the end it is usually something as simple as poor connection.
-when you have time check the voltage at the twisted wire now just curious what it will show.