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93 LeSabre no spark


brian_k24
08-30-2007, 08:28 PM
I am working on friends car. It is 93 LeSabre 3.8 about 195,000 miles. She started it the other day and drove about 100 feet and then it died. Car cranks fine but no fire.

I checked fuel pump relay and felt like it worked, then checked fuel tank and could hear and feel pump running. Checked for spark and it had none, checked all three coil packs and none have spark. Went through and checked all electrical connections, removed and reset all relays and fuses and still no spark. Tried to pull codes by jumping the A and B terminals, just keeps flashing 12 which was suprising because the SES light has been on the last year or two.

Not sure where to look next, I was think the computer is bad but don't want to throw parts at it.

Need help,
Thanks

richtazz
08-31-2007, 10:42 AM
I would bet it's a crank position sensor.

brian_k24
08-31-2007, 03:48 PM
I thought about that too after I posted when I realized I probably erased the codes when I was checking the connections.

Mickey#1
08-31-2007, 07:33 PM
Ignition control module & crank sensor are the top suspects. Did you check the fuses under the dash on the passenger side? Sometimes the oil pressure sender shorts out & blows a fuse there. That fuse (#6?) also supplies power to the ICM.

brian_k24
09-04-2007, 12:19 PM
I have checked all the fuses and they are good. I replaced the crackshaft postion sensor still no spark but now have codes. The codes are 16, 17, 18, and 42.

richtazz
09-04-2007, 02:20 PM
code definitions as follows:

16- Charging system voltage was either below 9 volts or above 17 volts for 10 seconds
17 PCM did not detect any spark reference pulses within 240 fuel control reference pulses (80 crank revolutions) while engine was running below 1200 RPM.
18 Cam/Crank Error
42 The EST signal did not change when the ECM applied bypass voltage to the ignition module.

17, 18, 42 all point to a bad crank position sensor. The code 16 suggests a slipping belt, bad alternator or other charging system anomaly.

brian_k24
09-05-2007, 06:44 AM
I have replaced the crankshaft position sensor and still get the same results. Is there anyway for me to test the sensor to see if the new one is bad?

HotZ28
09-05-2007, 06:11 PM
If you have a tachometer or scanner, check for engine rpm while trying to start. No rpm would indicate, no CPS signal. In addition, you should remove the ignition control module and take it to AutoZone for testing.

brian_k24
09-06-2007, 03:49 PM
I brought the ignition control module and coils into Autozone last night and everything tested ok. I don't have access to a scan tool so I guess will have to bring it in to a shop.

Thanks for all the help.

HotZ28
09-06-2007, 05:17 PM
Tried to pull codes by jumping the A and B terminals, just keeps flashing 12 which was suprising because the SES light has been on the last year or two.

It may be time to replace the ECM/PCM.

brian_k24
09-07-2007, 03:34 PM
Well for $20 at the local salvage yard I bought an ECM. Cleared the codes installed the ECM and still no spark, now have just code 42.

richtazz
09-07-2007, 04:12 PM
When you changed the ECM, did you swap the prom chip from your old one to the new one? The same ECM number can have several different prom chips in it for different engine combinations. If you didn't swap the proms, that could be your new problem. The code 42 is still pointing toward the EST circuit (Electronic Spark Timing) which involves the crank and cam position sensors, the ignition module and the ECM.

brian_k24
09-07-2007, 04:31 PM
Yes, I did swap the PROM. The only part the EST circuit I haven't tested or replaced is the cam sensor.

HotZ28
09-07-2007, 05:47 PM
Yes, I did swap the PROM. The only part the EST circuit I haven't tested or replaced is the cam sensor. The cam sensor has nothing to do with spark! You must have a "failure to communicate" from the CKPS to the ICM, or the ICM to the PCM. Did you check for 12v input to the ICM? IIRC, there is a fuse on the firewall fuse/relay panel for this.

brian_k24
09-08-2007, 06:35 PM
Well just spent all day looking for a bad connection or broken wire and no luck :banghead:. I have 12 volts on the red wire w/black strip at the ICM. I checked continuity from the CKPS plug to the ICM plug and every thing was good. Checked continuity from ICM plug to the 8 conductor plug above the rear rocker cover and was good there also. Opened up all the wiring harnesses that come from the fuse/relay center and from firewall to the engine for a visual inspection all looks ok. Just to make extra sure took the CKPS and ICM and put in my Olds and it runs fine. Wow, don't remember ever being so stumped

Mickey#1
09-08-2007, 10:54 PM
The ICM gets power from the pink/black stripe wire at the P terminal. Is that the wire you checked?

Besides checking the wires for continuity you should check for a short between the wires & short to ground. Or just swap the wiring harness that runs between the ICM & crank/cam sensors with the one from the Olds.

You should also clean any corrosion off the ICM mounting plate & mounting bracket & check for a good ground at the mounting bracket. I like to use a 12v light bulb to check the ground. Just connect the bulb between the mounting plate & positive battery terminal.

spinne1
09-08-2007, 10:57 PM
I have replaced the crankshaft position sensor and still get the same results. Is there anyway for me to test the sensor to see if the new one is bad?

According to the factory service manual for a 92 LeSabre (it may have the exact same info as for a 93 for this issue), the code 42 does not involve the crank sensor in any way. The possible problems are:

Ignition module or wiring to and from
PCM or wiring to and from

I'll give my homebrewed test procedures:

First, an explanation. The ignition module has a white wire in position A and a tan/black wire in position B. These both eventually lead to the PCM's 32-pin black connector in positions BC7 for the white wire, and BC6 for the tan/black wire. To get a code 42, either your PCM or ignition module are bad, or one of these two wires is shorted to ground or open at startup. Let's assume for now that the PCM and ignition module are fine. If so, you MUST have a faulty wire. Let's test each:

Disconnect both the ignition module wiring harness and the PCM black 32-pin wiring harness. Now, hook an ohmmeter to the white wire near the ignition module at position A. Hook the other end to the battery's ground. Is there infinite resistance or zero resistance? If infinite, the wire is not shorted to ground. If zero, you must find where the wire is shorted to ground, or replace the wire somehow (it's not easy getting a wire through the firewall).

Next, repeat the same test using the tan/black wire at position B of the ignition module. Again, you are seeing if it is grounded or not. If not, you are fine to do further tests. If so, you must eliminate the ground and fix or replace the wire.

Now, you want to check for opens in the two wires. Connect one end of the ohmmeter to the white wire A, and the other end to position BC7 of the PCM wiring harness. If resistance is zero, there is no open and the wire is fine. If resistance is infinite, the wire must be repaired or replaced. Repeat the same test using the tan/black wire at position B and BC6 of the PCM wiring harness. Same rules apply for the results of this test.

If your wiring checks out, it is the PCM or ignition module. You already replaced the PCM and you said the ignition module was good. If the wiring checks out, you may have an intermittent problem (the worst kind of problem to diagnose) with the PCM, ignition module, or wiring.

brian_k24
09-18-2007, 09:20 PM
Just a quick follow up, after checking all wires again I gave up and we brought it in to a shop. Shop said they cleaned the ICM mounting plate and bracket for ground and that was it. I don't know how clean that needs to because I had cleaned those areas with a wire wheel in my drill and also had tried a ground jumper wire from the battery to the ICM and could not get it to work.

steven david
09-20-2007, 08:14 PM
check some old posts, i think there is a spark enable under the driver side dash that has to do with the anti-theft

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