hi guys i jus did a rebuild of a 96 420a engine to put into my 99gs .
ive searched around n found no answer to why my car wont start.
Mech says something grounding out cam sensor from goin to ecu. im still using the 99 ecu is that the problem?.
when he unplugs the cam sensor wire and odometer wire from ecu it starts but has the weird running like its gonna die. Mech says cus it cant find the cam sensor any help or insight would be appreciated thanks

you need the 96 ecu, i beleive.

No, you're fine with the 99 ECU. Did you use the sensors on the 96 motor, or did you take the sensors fromthe 99 motorand use them? They're all the same sensors, just different plugs on the later models.

yeh it still has the 96 sensor in the engine.
what should i do get a new sensor or wiring harness or plug?

The plugs for the cam and crank angle sensors are different between 96 and 99 i believe, you may want to verify that they're properly connected.

Originally posted by DarkOne
The plugs for the cam and crank angle sensors are different between 96 and 99 i believe, you may want to verify that they're properly connected.

Or you might want to just get the CPS off the original, 99 engine and install that one. If the connectors are different, he would have had to change them. Unless his mechanic is a moron and just mashed the two together.

Irregardless, I was always of the impression that the engine would not run at all without a CPS signal. :wary First thing we suggest to people when they say the car "just died" while making a turn is that their CPS (or the CAS on that harness section) has shorted out on the EGR or back of the block somewhere.

well the 96 engine is in my 99 body .. and the 99 engine is in the 96 body .
so how come the 99 engine works fine with all the sensors and the 96 ecu?
so im thinkin could be a dead ecu thats paired with my 96 engine

all the sensors are the same between all years of the 2G NT .. only difference is the harness plug used to connect to the sensors. If the mechanic cut and spliced the connectors to the sensors in order to complete the swap, the problem could be wiring. It's real easy to get the wires crossed or get the clors on the pigtails confused.

Did e cut and splice anything on the harness? If he did, i can guarantee you he got the wiring wrong and thats what is causing the problrm.

he didnt splice any wires. but as i said if the engines have diffrent plugs how come the 99 in the 96 body works fine but my current car doesnt with the 96 engine.
he did show me the wire from the cam sensor to the ecu .
was a yellow wire he cut to show me .
when he attached the wire back while car started it jus dies.
have any ideas new ecu. or diff wire harness .
i told him wat u guys told me here but he still says the ecu is done up

my car wouldnt start unless I primed it. Turns out it was the MFI and Fuel Pump relays. You could check those out (close to the battery). When mine were going out, if someone tapped on them with something while I tried to start the car it would fire up.

well thanks to u guys input .
a friend lent me his 99 ecu n i pluged it in it works..
just my speedo doesnt worknomore. weird .
well ill continue fixin my POS
thanks all