LS6427

iTrader: (2)

So I put a new PCM in and I needed to do a crank relearn. I have P1336. Te engine is missing/stumbling a little bit all through the rpm range..but sometimes its gone and the engine runs perfect.

A guy tried to do a crank relearn today but it kept "not passing". It would except it and start the process but it wouldn't do it.

Any idea why it won't? Or what I do next?

ALSO, by not doing a crank relearn to clear the code.....can that cause misfires?

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jay_lt4

iTrader: (4)

that code has nothing to do with the way the engine runs,, it is only there for engine misfire diagnostics

LS6427

iTrader: (2)

OK, thanks.

So I'm safe to start looking for other causes of misfires? Its wierd because it'll run perfect for a day, then the next day on/off it'll misfire and stumble.

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joecar

When you initiate the relearn, you have to steadily raise the RPM to above 4000 (within a 10 second period)... are you doing this...?

As soon as the RPM is high enough you will get a sharp stumble for a moment... immediately release the throttle and let the engine spin down to idle, turn key off and wait at least 15 seconds.

edcmat-l1

iTrader: (10)

Exactly. P1336 is the most misunderstood code, diagnostic test out there.



Alot of times, if the car is cammed, it won't do the crank relearn. Also, if there's additional misfire stuff going on, it won't run the test either.

Turn the code off in the tune.

jimmyblue

iTrader: (11)

I've had a couple of different scan tools, and they have
been kind of squirrely about getting the relearn to go.
After the cam swap I had to try maybe a dozen times
going through the drill before it finally caught. But some
software versions simply didn't function, in the past.

There are certain sensor faults which will inhibit the
relearn; I had one fuel tank sensor code that didn't show
on anything but a Tech-II, dealership fixed that under
warranty.

If you can't find any codes (might check the shop
manuals, I remember seeing the list there) then I'd
give it several tries before giving up entirely. I don't
think I've ever seen it go the first time out the chute.

LS6427

iTrader: (2)

Cool, I'll tell him to try this. All he was diong was getting the GO light on the Tech II...and he would mash the pedal to the floor and the fuel injectors would cut out around 4000rpm. Then it said "FAIL". He tried that like 8 times and gave up.

.

LS6427

iTrader: (2)

My tuner said it shouldn't have any trouble doing the relearn....this same engine and tune did it back in 2002 when the engine was new. I just put a brand new PCM in and that same exact tune from 2002 was downloaded into it.

.

oddyls1

i also got a p1336 code out of nowhere, the car still seems to be running fine..so is the code harmless in a cammed car or what?

popethe5th

iTrader: (2)

any suggestions on where to find out more on the p1336 code not causing drivebility concerns. if the PCM cant learn cam to crank how does it know when to fire the plugs, or injectors?

jay_lt4

iTrader: (4)

you have a crank and cam sensor, the ecm always knows how to fire the injectors and plugs if these sensors are working correctly

the only thing the re-learn is used for is misfire monitoring, it will not effect how the engine runs, you can turn the dtc off and dont worry about it

smooth01

Should you do a CASE relearn if you have a forged motor, different balancer, flywheel, clutch, etc....,

jay_lt4

iTrader: (4)

yes if you are concerned about the misfire monitor,, the case learn has no effect on engine running or performance

joecar

When you change any of the rotating assembly internally (crank, rods, pistons) or externally (damper, flywheel/flexplate, clutch/stall), or the crank sensor, you should do a crank relearn.

The crank relearn procedure tells the PCM to induce a misfire and measure the rate of deceleration of the the crank; the PCM stores this info for later use in misfire detection.

More info: http://www.gearchatter.com/viewtopic9333.php

smooth01

I wasnt sure if it could be done cammed car. I thought that the rocking idle of a cammed engine would cause the pcm to throught miss fire codes at idle conditions

LS6427

iTrader: (2)

Whats up. So my thread pop up from the dead.

I still have that code, its been there for more than a year now and the SES light is still on.

I has a guy with a scanner try to get it to go out by doing that procedure where you hit the gas and it cuts out, etc...... He tried 10 times and it wouldn't go out. When my new 427ci engine went in back in 2002 the tuner was able to get the light out and the code never came back till I put a new PCM in about 1 year ago which caused the light to be back on and the code.

Any ideas on how to get it the "relearn procedure" to take.......?

Not a real big deal, but my SES light is on and I won't know if I get another code while I'm driving because its on all the time.

Thanks.

.

gectek

iTrader: (2)

You will have to have a tuner turn it off in the programming. Just unchecking the box does not always work.

I personally tried to do the relearn on 2 vehicles. One time it kept timing out (not with hpt scan tool) and the other time it kept showing a MPH reading above 3k but the truck was in park and def NOT moving and kept aborting the process. I said forget it and had no problems with either.

Find someone who can get it turned off if you do not have access to a tuner to do so.

adrynalinjunkie

iTrader: (4)

If your using hp tunners you need to punch the gas pedal quickly to about half throttle. That raising it steadily will just bounce you off the limiter

Midnite Magic

This need to be done with the Tech II or other high end scanners

joecar

Can be done with EFILive and HPTuners... and others like AutoEnginuity.