robertbartsch

OK so I was getting random misfire codes.


I did the following;

1. changed plugs
2. Changed crank shaft sensor
3. checked valve springs
4. checked cam walk

No codes have been thrown for several days - so I'm assuing it is OK.

TAQuickness

iTrader: (28)

I'm glad it's working out for you! FWIW, since you changed the crank sensor, you really should get a CASE relearn done now. The relearn will insure the PCM has the crank reluctor mapped properly.

robertbartsch

OK thanks....

Can you comment on why a case relearn is not necessary when ever a cam sensor is changed? I'm on my third cam sensor so far!

oange ss

iTrader: (50)

crank sensor not cam sensor

robertbartsch

Oh yeah, I forgot. I also got new rear SIMMS from Thunder --->.

I'm not sure this was a source of my PO300 issue but I did get a SES code indicating there was no 02 signal for Bank 2 Sensor 2:

So I deleted the 02 diagnostic tests using LS1Edit for the rear 02s immediately after the dealer replaced my PCM and gave me the factory flash. I still got misfires, however

Then I changed the PCM setting back to the factory flash until I figured out the misfire problem....


SO anyway after all the bull - I replaced the following:

1. plugs
2. Rear SIMMS
3. Cam sensor
4. Crank Sensor
5. Wires


I also checked the cam walk (none), timing chain, valve springs and rockers for busted hard parts (none).

No codes for several days of driving so I hope I have this puppy licked!

Josh McGrath

iTrader: (4)

do you have a cam installed>?

SUPRYZE

The PCM uses a high resolution 24X Crank signal for engine speed, cylinder identification and misfire diagnostics. The Cam signal, is a low resolution 1X signal used only to identify Intake or Exhaust stroke for cylinder #1. Since the 24X so critical, it must be measured accuratly, and therefore, any "variations" due to manufacturing tolerances, intallations, etc... need to be "compensated" for. The 1X cam signal is either pulled low for #1 intake stroke, or remains high for #1 exhaust stroke. Slight variations with this signal are not detrimental to engine operation.

robertbartsch

Surprize:
Thanks - that was informative.

The last time my cam sensor went the car had a very tough time starting when warm .....the GM dealer said the PCM can't find #1 and therfore, starting is touphF....

dummer

I thought random misfires codes, p0300
was normal for an engine with aftermarket cam?
I get that code every few days since my cam went in.
I just disabled it through LS1Edit

SmokingWS6

iTrader: (1)

It is normal with a cam, torque converter ect.

Disable misfire detection, 142* enable 143* disable

magnanpi

hmm cam sensor ehh? can anyone diagnose this

Got a cam sensor code....and a hard start... replaced it by a shady guy

Still had code still had start....replaced by a good guy (Noyzee)

Still have code still have hard start (P0342)

What do i do?

SmokingWS6

iTrader: (1)

He probably didn't do a case lean to calibrate the sensor

magnanpi

I thought you only needed a case learn for the crank sensor and not the cam sensor?

SmokingWS6

iTrader: (1)

Whoops I can't read.

2000 M6 PEWTER SS

iTrader: (2)

i had to 0300 mutli misfire code, i cleared and drove it about 10-15 miles
it is definately missing it *** off when under load, or up in the upper rpms but the light has not returned. I this possibly a crank sensor causing my problems as well? I have relatively new tr55 plugs w/ gm performance wires...the car has had a intermittent off and on misfire for a while now usually when the car
sits i dont drive it much...For example last time i drive it, it ran great, parked it for two weeks started up and biotch is misfiring!!!!! PLEASE HELP W/ INPUT AND ADVISE

Noyzee

iTrader: (37)

I didnt do a relearn, i think its the cranck sensor that needs that.
i think the issue with your car may be in the wiring. the shady guy probably f'ed somthing up, like the PCV hose he left broken behind the intake.
if anyone has any ideas, i will be more then happy to help you figure it out. let me know