Hi all just a quick question. I got my S2 PTU in the post tonight so about to put it in. Was wondering if there are some specific wires in the loom that i can test to make sure that it is earthing out properly cos i want to be really sure that i'm not going to blow the ass out of this one! I've triple checked all my earthing points on the whole harness but i want to be 100%. Can i check some of the connector pins to see if it is earthed right?
Would assume that a simple method would be using a multi-meter set to OHMS scale. With the PTU disconnected from the harness (as to ascertain alternate earthing points) perform an earthing continuity test to various points in your plenum. Take into consideration the earth resistance between your 2 test probes (touch them together, take note of the reading and ensure that you subtract that from your future readings. Shouldn't be any more than 0.02 ohms) Test Earth Continuity between Negative Terminal of Battery and various points throughout your plenum. ie- Coilpack mounting bolts. Im not overly familiar with the internal wiring of a PTU, but considering the most likely cause of frying the unit is lack of reconnecting the earthing points post Plenum Pull, can only assume that the coilpacks are using the PTU earth, rather than the earth tails, to ground, hence overloading the unit. Perform a visual check to ensure that earth tails are in tact. From memory, they are on the passenger side, located near the EGR piping. There should be tails connected to the rear of the engine, gearbox and the plenum. If in doubt, run an additional earth to 1 of your plenum bolts. Braided earth tails with lugs at either end are readily available at Supercheap, Repco etc. Just ensure that the surface that you are bolting it to is clean.
Ok great, thanks for that! i'll try those multimeter tests. I've already installed an extra earthing kit too, with earthing points all over the plenum, block and engine bay
Oh actually that makes me think... if i have connected an extra earthing wire from the plenum to the point where the PTU earths, could that cause an over load? even though all my earths are connected in series? (ie. from plenum to car body, to battery earth.)
doubt it highly. Why not relcate the PTU while you're at it. Remove it from the heat source at the front of the engine. Wiring is long enough in the loom to relocate it to under the nose panel for example. Just a bit of time and some with a stanley knife (unless you want to unwind all of the existing loom tape) and some electrical tape. Tidies up the front of the engine nicely, especially if you then re-route the Temperature sensor cables to come out from underneath the throttle cover.
