s2konroids

Okay I doubt anyone can help me, but to cut a long story short the car is turbo'd running a mase turbo and AEM ECU V2, the air filter resided close to the block so i decided to relocate it to where the horn and coolant expansion tank sit, this involved buying 4inch aluminium piping and having a feed from the faux vent.

The hardline air con pipe was bent out of the way as well as the others and was a real tight fit. Some wires ran down the side.

Now also another job to do was i had excess loom left over from the removal of the air pump, everything was removed but there were some annoying connectors on the loom, i snipped all the plugs off (x3) and came to snip the white one (which i think is 12v feed) and must of grounded it as heard a spark! - forget to disconnect the battery, didnt bother to start the car.

So i finished this off and the air filter relocation job, started the car and it sounded like shit and stalled - fearing the worse i thought i caused some major damage

I decided to get the PC and hook up to the ECU, i then noticed that the TPS value and MAP value was 30% (1.3V should be 0.3 ish) and MAP value 11PSI no wonder it would not idle i disconnected and altered the map the car run it did so proved these sensors were giving erroneous readings.

Done various fault finding on the sensors checking resistance and they seem fine, but couldn't get correct readings. I accidentally touched one of the snipped wires from the air pump loom (green) to a ground bolt and the TPS and MAP sensor started reading correctly - i thought about connecting this wire back to the connector but did nothing and checked all other wires on the snipped off loom to see if they were grounded no luck. I cleared AEM calibration and re did TPS calibration. Checked fuses but they look okay too.

Any ideas? i cant understand how the air pump loom has done something or actually what I've done?

shind3

Sounds like a grounding issue. An inadequate ground plane can cause the measured sensor voltage to shift around like that.

Sometimes a ground circuit can be run through various harnesses so maybe something was part of the air pump harness that loops a ground through it.

s2konroids

Thanks for the reply, i did a continuity check from the C102 connector and to the TPS wire (Green yellow) and got no continuity. I then grounded the original green wire mentioned above the ground which caused the sensors to read more or less as they should do but now the TPS, MAP and ECT fluctuate wildy by -/+ 2% TPS, -/+ 0.5 PSI and , -/+ 11F ECT.

I tried to find the ground on the diagram that says that pin is grounded but no idea where to find it.

Must be some shared ground or something?