ECU sensor ground probs, Pin 92

[manrightchea]

Sup guys, I recently had an issue with the TPS reading 100 percent constantly on my SAFC2. I noticed that if this connection is interrupted a number of important sensors will fail to function and the car will likely not start. Well on my harness I notice that the wire from this pin does not run anywhere. The previous owner did a hack job on a number of items. Where can i run this ground to? Just to the chassis? Where does it run stock? I know that trace can get burnt and lead to my issues. I can solder a bridge if I need to, just wanted to try this first. I'm just trying to alleviate the issue for now until I can change the entire harness.

Currently my car is pulling very low vac and it didn't began until I did some work on the harness today, which is why I think this is the issue. I've swapped with two other TPS sensors and have tried another ECU as well. I just need to know how to properly run this wire. Any help would be great.

 

[luv2rallye]

Read "important note" here: http://www.dsmtuners.com/forums/articles-electrical-wiring/244376-oxygen-sensor-wiring.html

 

[TALONTRAX]

Read this . . .

 

[manrightchea]

Thanks for the responses guys. So the wire just hangs there stock? It doesn't connect to another wire on the harness? This is basically what I wanted to know. I guess its time to pull out the multi-meter and pull some codes.

 

[manrightchea]

Found it. Down by the ECU plugs on the main engine harness there are two large bundles wrapped in a grey tape of some sort (you will notice 2 large green wires leading to it) . At first I thought this was something installed, but the bundles run into the main engine wiring harness itself. It happens to be a bundle of about 4 wires connected with a stock wire tap. This tap feeds the coolant temp, throttle position, barometric (maf) and IAT (maf) sensors. It is a grounding point for all of those sensors. They tap from 4 into 1 wire, and ground to the wire leading to pin 92. It seems the wire was old and became seperated from the group. Once I resoldered it all of my sensors were back in order.

BTW as stated earlier, this pin is mislabeled on the 2G ECU pin out diagram. It is actually pin 81 (a black wire with white dots) and it is very important!

 

[97ebaygst]

Read this . . .

i tried to do a similar repair instead I used a defroster repair kit that came with copper colored liquid. my question is how can I be sure it took? Once I fixed it i thought to check the resistance and got some but I don't know if it should have any. Can anyone help me out with this?

 

[luv2rallye]

Some resistance resulting from a defroster repair kit on defroster window foil paths is ok but on an ECU ground it can be disasterous! The slightest resistance can cause a voltage drop which will change all sensor and internal ECU voltages.
Solder a wire across any blown sensor ground in the ECU now!!!

 

[97ebaygst]

Some resistance resulting from a defroster repair kit on defroster window foil paths is ok but on an ECU ground it can be disasterous! The slightest resistance can cause a voltage drop which will change all sensor and internal ECU voltages.
Solder a wire across any blown sensor ground in the ECU now!!!

what kinda wire do I use and where could I find it? It looks like a solid copper wire. I work at a parts store and we don't sell anything solid that thick. Plus I want to make sure I don't fry my ecu, any advice on how its done? I'm gonna try the defroster liquid again but I don't completely trust that for a long lasting repair, so if anybody has a walk thru on the wire repair I would be indebted forever!!!

 

[luv2rallye]

For blown sensor ground in ECU any copper solid wire 20 gauge or larger will work.
http://www.dsmtuners.com/forums/art...585-troubleshooting-fried-ecu-components.html
blownsensorground [ECMTuning - wiki]