Originally Posted by blong4life
Got my motor back together, went to fire her up and she keeps dying on idle. If you run her past 1200 rpm the thing runs the **** if you go below that you hear the IAC starting to suck in and it dies off.
On my scantool,it's not showing a Crank Reference signal,could this be a problem. Obviously,it's working because of the fact that the RPMs,etc show.
It has had a new TPS,IAC,Crank Sensor,pickup coil, and map sensor.
Only other thing it could be my dad was saying is,since i changed the timing chain,etc there is some anti-freeze in the oil and it was running rich for awhile,could the oil be to thing causing a shutoff to be initiated from not enough oil pressure at low RPMs?
Thanks for the help,
To answer that question regarding coolant / lack of oil pressure, the answer is: NO.
That is not what's going on here.
Under normal circumstances, IF there's no CKPS signal (crank reference) it will not run- AT ALL.
The CKPS is the master clock for the entire EFI system. The entire system is timed, based around that one sensor so, if it's not working, the PCM is programmed to execute the AUTO SHUTDOWN command thus NO PWR to anything. This cuts power via the ASD relay in the PDC.
Now, here's what I think 'MAY' be the root cause based on the information that was provided:
WE know that you put the motor back together and:
A. It runs fine at higher RPMs so long as your foot is on the gas. Is this correct?
B. When it idles it dies right out / does not stay running. Is this correct?
IF the answer to the above two questions are YES, then, there's a very good chance that there's a SYNC issue here and, what that is, is a large offset between the crank and the cam sensors at the PCM program level in which case, you will have to take it to a dealer to have your CAM re-timed to your CKPS values along with resetting the SYNC offset value in the PCM to fine tune the timing of the EFI / fuel delivery system.
At certain RPMs this can lead to what your seeing on your scan tool as well. It will LOSE sync.
What I don't know is:
Scratch my earlier comments, I just found out what you did by re-reading it two more times.
Ok, if you put back in the OEM CKPS and CPS - it will run fine and, that error will go away.
The reason why your having issues is, the NEW CKPS and CPS are NOT putting out exactly the same waveform as the OEM ones and, if your going with aftermarket sensors, this can be a PITA to remedy. I recommend to use ONLY OEM for those two sensors. There's some history here that I have posted on in regards to what I am saying but, I don't have time to re-state it now.
Moving on: you will most certainly have to have your PCM adjusted for those two sensors because, both are out of sync with what's programmed into the program at the PCM level. You can not change this without using a DRBIII or DART tool to reprogram the values.
While some of the more expensive tools such as the 9K snap on tools will allow you to change / program the value however, you will have no way of knowing what is the best value without running it on a scope / rack rig.
The dealers have this tool and, they can tune it precise to the best value to ensure the timing is on and that the sync will not lose lock.
PS: Brandon: do this simple test first: place the OEM sensors back in and re-test. If the issue subsides, LOSS OF SYNC was the issue.
That air sound, that's an indication there but, for now, just start with those two and see what we got.