any ecu wisemen out there?

[missouri_dsm]

Ok, I replaced my knock sensor a couple days ago and also I readjusted my tps(it was off a bit). I took my car for a test drive and it ran 10 times better. Well I started back home and when I tried to give it gas it would hardly move like an ic pipe blew off. I checked my scanmaster 3 and there was like 5 different cel codes. coolant temp. sensor read -25, barometric was around 355, air temp was around 200's, tps read 100 and knock was everywhere also o2 was 5.02. So I take my ecu out and replace it. The car ran pretty good other than it wanted to idle high(around 3000) so I turn the idle down on my maft. This got the idle down but then vacuum was at like 10. So I disconnected the battery to reset everything and put knobs at basic settings. I then connect the battery and start the car and multiple sensors are reading all whacko again. Has anyone ever had this problem. Any help would be greatly appreciated.

 

[missouri_dsm]

Just in case anyone else has this problem with multiple cel's. I know that a lot of times sensors share the same ground so I checked to make sure all the wires were all connected
to each other with an ohm meter. They were all connected so I tested one of the wires off a sensor(tps,coolant temp sensor and mas share ground wire).It was a green/black wire. Turns out the wire wasnt grounded, I still dont know where it lost ground, so I tapped into it and grounded it. Problem fixed.

 

[steve]

Sensor ground is generated inside the ECU. Time to open up the case on both those ECUs and start checking to see why/where it's blown.

I've seen a few sensor ground failures but I don't have enough background data to identify specific causes. Usually one of the circuit traces is blown and I suspect it's from 12v being applied to sensor ground but the only place it looks like it could accidentally happen is at the CAS connector where pin 4 has 12v and pin 3 is sensor ground. If it gets wet the pins could short. Otherwise it has to be from a harness short or user error.

Steve

 

[missouri_dsm]

Thanks for the info Steve. I needed you a little more last night. I couldnt hardly sleep knowing my car was down. Anyway, better late than never.