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So I had a unusual problem recently(well I think its unusual not sure). Im hoping I can get a good explanation on this situation
engine 2jz rebuilt with factory components stock pickup and cam.
wiring wiringspecialties plug and play
Engine had a not start condition, with factory base map of supra 2jz in aem v2 software.
checked timing with timing gun while cranking with no fuel to confirm timing was within range set to 10 BTDC
while cranking with fuel pumps on, all syncs would go to ON Status and timing errors count would continue to error continuously.
After you left off the starter, the engine would back fire out of exhaust, 1 time loudly. (I knew this had to be timing issue but I was certain the timing was set to 10 BTDC). With the timing errors counting non-stop while cranking something was not right here...
AEM tech support told me to go to (ADV/Pickup tab) and change the ignition sync value in the cam/crank setup.
apparently the spark was occurring on the exhaust stroke.
So to my question
what in the world?
How would one go abouts figuring that out?
The base map had a good value for one engine but for this engine it was completely off... base map ignition sync 6.0 teeth. This engine runs at 17.6 teeth.
Is this common?
Thank you in advance for any info on this.
the non vvti 2jz engines have 2 sensors on the camshaft which are 180 degrees out. not sure on the AEM v2, but maybe it's trying to sync off the "wrong" sensor?
Are you firing on the exhaust stroke maybe?
Try adding or substract 360 degrees to your current timing offset number
thanks for the reply guys,
the engine is now running after adjusting the ignition sync to what the AEM tech support told me to put it at.
I have both sensors on the cam shaft connected, I have heard somewhere that the AEM is really only using the back camshaft position sensor. Im not sure how true that is. or what but maybe which ever one the AEM is reading it was off compared to a factory engine harness? im not sure.
I just want to know if this were to ever happen with another engine. is there a trick or some steps that can be taking to confirm where the ignition is occurring?
yes that is true, aem, and motec i know for sure only use the front cam sensor. there are a few other ecu's I believe dont use it also, but dont want to list them as i could be wrong.
As mentioned by others, most 2JZ non-VVTi engines have two cam sensors and the signals from those sensors are about 360 (crankshaft) degrees apart. The aftermarket harness may be connecting the rear cam sensor to the pin would be connected to the front cam sensor in an OEM harness, or you may have somehow connected the front sensor's harness plug to the rear sensor on the engine.
If the engine has visible cam gears, pointing the timing light at the cam gear can be helpful in seeing if the ignition coils are firing at TDC intake rather than TDC exhaust. Coil 1 should fire when the cam gear's timing mark is up (twelve o' clock).
@AEM_SB That is a fantastic idea of pointing the timing light at the cam gears! Thats a great tip. Will keep that noted down for any future start up problems.