My car is having the dreaded multi cylinder misfire code. I have checked the spark plugs and wires, and everything checks out. I would like to do a crank sensor relearn on the car, but it needs to be in "neutral or park" according to the computer. I can do neither because mine is manual. Do I need to wire something up, or mess with the computer? Any help is appreciated.

You may want to try this. Lots of weird stuff to do.. May be better off with an interpreter while your jumping through the hoops.

https://www.g6performance.c...ndex.php/t-4830.html

Spoon

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"Kilgore Trout once wrote a short story which was a dialogue between two pieces of yeast. They were discussing the possible purposes of life as they ate sugar and suffocated in their own excrement. Because of their limited intelligence, they never came close to guessing that they were making champagne." - Kurt Vonnegut

Can't help but post on this.
I have personally owned 2 3800 sc and a few 3800 n/a engines.
Have been a mechanic from 1981-2001 and from 2014 to now.
Have never had to perform a "crank sensor relearn". IAC and/or throttle angle sometimes, but never crank sensor relearn.
The 3800 as far back as the preSeries 3800s have used a hall effect crank sensor. Not a magnetic like found Chevy based engines. Even if you loose a Cam sensor, you have a 1 in 3 chance of starting without it. But won't go into sequential injection without it. A hall effect sensor will give the same voltage rise no matter what frequency it is at. A magnetic sensor voltage will rise some the faster the frequency. That would be the only reason that you might have to do a crank sensor relearn. But, again this is very rare on a GM.
Though it was not required until ODBII, the ignition module on a 3800 is capable of detecting misfires since 1992, but the PCM couldn't report it. No PID.
You need to borrow a decent scanner that has capability to read misfire data and see if the counts are rising on any pair. 1/4 3/6 2/4. A flacky coil can cause misfire counts on 2 cylinders. Being a waste spark type system.
Also I have had on occasion lean conditions cause misfire counts.

quote Originally posted by Spoon: You may want to try this. Lots of weird stuff to do.. May be better off with an interpreter while your jumping through the hoops. https://www.g6performance.c...ndex.php/t-4830.html Spoon

I have read about this before, may have to do this, if I can not find another way.

Like cmechmann said : You need to borrow a decent scanner that has capability to read misfire data and see if the counts are rising on any pair. 1/4 3/6 2/4. A flacky coil can cause misfire counts on 2 cylinders. Being a waste spark type system.
Also I have had on occasion lean conditions cause misfire counts.

Or your spark plug wirings is no good change it.
Or if you do not have a misfire on any pair of cylinder as explained by cmechmann but the missfire are randomly changed your ICM (ingnition control module)

The Sierra uses a magnetic crank sensor. Those and Silverados with LS series engines are the ones we have to do a throttle relearn on a lot.
Of course the expensive scanners like Snap, Mac, Matco would do it. But there are less expensive scanners out there that will also do it. Autel, Launch etc. A basic code reader won't normally work. Need to look for one that will bring up data stream. Most ODBII scanners that will bring up misfire data up to 2005 PCMs. After that it starts to get a little odd. When they brought in the CANs bus spec., some started to put in manufacture specific data.
Just worked on a 1997 Firebird with the same ignition for a similar problem. Ended up being a coil. Original coil with 182,000 miles on it. Would misfire and sometimes backfire into the intake. Misfire counts would come up on cylinders 3 and 6.
Don't see that many failure with the ICM on the secondary end unless a coil was let go long enough for it to short through the module. Have on some occasions had the ICM fail on the volt feed/regulated 10 volt supply to the crank sensor. But rare.

If you want to be able to do a crank variation relearn on a 3800 PCM in a Fiero swap that has a manual transmission, here is info on how to do that:

You may need to do some additional wiring so the PCM will allow a CASE Learn to be enabled. This is required for modern V6 swaps utilizing 1998-newer OBD2 PCMs that never came with manual transmission programming. You will need to “fool” the PCM into thinking the auto trans you don’t have is in PARK. To do this on 1998-05 FWD car PCMs, you will need to ground the following wires going to the PCM pins: C2-16 and C2-18 (clear connector). Make sure no wiring connections are made to PCM Pins C1-68 and C2-56 during the CASE Learn. You will also need to hook a brake switch feed up to the PCM pin C1-30 (blue connector). There should be a wire coming from the brake switch that has 12v + voltage on it with the key on and the brakes not applied. When you apply the brakes, the 12v + voltage should drop to 0 volts. Auto trans applications should already have these circuits wired up and ready to do the CASE Learn as described below…

1. Start the engine and make sure that the engine coolant temperature is at least 158 degrees F. (70 degrees C.)
2. Turn the engine off for at least 10 seconds.
3. Select the crankshaft position variation learn procedure (CASE Learn) on your scan tool.
4. Make sure that the auto transmission is in Park (manual trans in neutral). Start the engine.
5. Apply the brakes and hold the pedal firmly.
6. Follow the scan tool instructions.

Remember: That you are going to apply throttle and increase the engine speed to approximately 3000 RPM, 4000 RPM, or 5150 RPM. That’s the variation learn fuel cutoff RPM (depending upon the engine), and that it’s important to release the throttle when the engine RPM starts to decrease as a result of the fuel cutoff going into effect. Failure to do such will result in over revving of the engine, causing possible engine damage.

7. Once the engine has returned to idle, check the status of Diagnostic trouble code P1336. If the scan tool indicates that the CASE has been learned, the relearn procedure is now complete. If CASE has not been learned, check for the presence of other power train codes. If any exist, correct the problem, then repeat this procedure. If you have a manual transmission equipped vehicle, you should now disconnect the ground wires going to pins C2-16 and C2-18. The brake switch wiring can be left connected.

-ryan

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More is more. Less is not enough.

Custom GM OBD1 & OBD2 Tuning | Engine Conversions & more | www.gmtuners.com

Thank you Darth, but I may have found the issue. I am loosing a decent amount of oil. I am guessing the misfires are being caused by bad valve seals.