I guess the challenge is now to find it. Any tips Eric on the best way to do this? Should I just start peeling back insulation, and just look for a bare wire? Or is it something that should be left to an auto electrician or mechanic?
Think outside the 'box' man. Once you diagnose the fault with a multimeter, just wire it up accordingly outside of the loom. Snip the old wire, and route over the loom and re-tape it.
Update.... Airstyle (Greg) came over this morning and equiped with a multimeter we attacked the loom. First we started at the injector connector and peeled back a lot of tape following the injector wires back through the loom. After not finding anything remarkable we moved to the ECU and follow the wire back from there towards the injector......but found nothing there either . So next Greg isolated the wire from the loom by cutting at each end and running a new temporary wire outside of the loom (as per Mitch's suggestion). Would you believe it.......we still had 12V across the connector . So it would seem that my ECU swap was not diagnostic and that the ECU is in fact where the problem lies. From this I have to assume that when we did the ECU swap the car was not run for long enough to clear all of the fuel out of the system. I did note that the car did run better with the swap ECU but it was still rough and was sill blowing a lot of grey smoke. So at this stage I have to assume that the ECU is the problem. When possible I'll borrow another one and test again. This time I'll check the voltage across the connector with the other ECU in place to confirm that that issue has been resolved. If anyone has any other thoughts I'd be happy to hear them. Big thanks to Greg for generously giving up his time today to help out. Just being able to exclude that section of the loom was a massive help. Thanks mate:thumbup:
Next time you swap the ecu, put another spark plug in that cylinder. It will be definitely fouled from all the fuel pouring in. This is why it didn't run remarkably different last time you swapped ecu's. Cheers Eric.
Update.... Once again I swapped the ECU with one borrowed from another member (Dave Budden....thanks mate). This time I didn't worry about even running the car, just plugged it in and tested the voltage across that suspect injector and sure enough 0 Volts yayy!!!! So at last I've isolated the issue. Later I pulled apart my ECU and there was a nice little burn mark on the edge of the board and also black on the casing. There was also some corrosion along the board near the short. Looks a bit like there has been water getting into it at some point . Now I don't know if this has happened since I have owned the car or not, but I believe it probably happened long before I owned it. My question now is.........is it common for water to leak down onto the area on the firewall that the ECU is screwed to? I'm thinking of putting some sort of water proof cover over the ECU.....is this a bad idea? Does it need to breath? Would this make heat a problem?? I have never detected water in the floor wells or smelt rotting carpet or anything so not sure if this has actually occured.
well done, patience and application wins through ...... !!!! regarding the entry of water, coolant from a blown/ruptured heater core can end up in the passenger footwell in that area ... but for the water to pass through the carpet, then the shoddy plywood cutout and then into the ECU would be a heap of bad luck .... not sure about possible heating issues for the ECU if you do waterproof that area ....
Just above the ecu compartment there is the a/c drain. If you look behind the passenger side turbo dump pipe you will see a rubber elbow about 50mm long and 15mm diameter poking out of the firewall. These are often missing the rubber grommet or if it has had any work done behind the dash, they are not put back in. Or it may be missing a grommet inthe floor on that side.
Yeah, good thinking......didn't think of the heater core. May have been replaced before I got the car after a rupture.
Your ECU may have been remanufactured at some stage. I had such an ECU with a blown ignition circuit, on closer internal inspection, we discovered a small water mark on the ign circuit. Could have been a small drop of sweat from the forehead of the tech who did the refurbish. Unbelievable, the replacement ECu had the same problem (on the fuel pump circuit). A 3rd ECU was sourced and no further problems. If your ECu doesn't show any signs of water ingress on the outer case, this might be the same issue with yours. At least you have isolated the culprit! Don't forget to give that spark plug affected by the excess fuel a good clean/replacement. It will most likely be fuel fouled.
Phew, that's great news. If you need any more help mate I don't mind popping up your way, manly is awesome . Cheers Greg.
Thanks Mark. Yes I intend to give all the plugs an inspection and clean, then I'm going to drop the oil out and replace it as well. Airstyle was good enough to point out that there was a definite petrol smell to the oil, so I've bought some replacement and a new filter. Hopefully I get get her back to health soon.
Cheers Greg and thanks again for your help at getting to the bottom of this. If your looking for something to do your welcome to come over and help with the cleaning of plugs and oil change .
Update.... Well thanks to EVZ my replacement ECU arrived today and I managed to get some work done. ECU in, oil changed and removed all spark plugs and cleaned. The plugs were all black, all six of them. What should I expect to see? Put her all back together and she started immediately. Good news is there was no more clouds of grey smoke . Bad news is she was still running rough . I pulled the coil pack connectors off one at a time, and one made no difference . Interestingly its not the one that just had the issue with the injector short. It was the middle cylinder on the passenger side. So I guess I need to check my coil pack first and then expand my search from there. Happy to hear your ideas? Note to anyone reading this thread in the future. As per Eric's (A2ZED) suggestion, I checked the drain from the A/C through the firewall. Well the drain was present in the firewall, but was not connected to the A/C unit under the dash. The hole was directly above the ECU . I can only assume this was in fact where my water damaged ECU was getting its water from. Eric, I don't know how you do it, but so far with every issue I have described you have some how come up with right diagnosis. I think you might be sitting on a perfect 100% track record so far. So thanks again for all the help. Hopefully at some point I'll get this car running reliably and you can have a rest :rofl:.
Black plugs are nromal if it has been misfiring, the ecu is commanding more fuel to be dumped in to maintain idle speed and rpm. Fit 6 new plugs, the one that is nowmis firing will be the plug from the cylinder that was effected before, they are pretty cheap. NGK BCPR6ES-11. Leave them at that gap. How do I get the diagnosis right? I repair alot of zeds, you get to know them pretty well. Also after 8 years doing roadside breakdown for heavy transport, you get pretty good at decifering the complaint and determining the actual problem.
Also check your injector connector on that offending cyl. If it has been off or disturbed, the connection could be poor.
I've just cleaned all the injector connectors (not that I think they needed it). Pretty sure they are good but will double check.
New update Well I put a new set of plugs in today and rechecked all the injector connectors with no luck. Still have a miss on the same cylinder (middle passenger side). When I disconnect the coil pack connector it makes no difference to the revs . When I give it a rev there is a clear miss. The rest of the cylinders seem ok. What should be my next step??
Have you checked PTU and Coil Packs? Swap the coil pack from the problem cylinder with one from another and see if the problem moves to that cylinder. If it does then you've got a dodgy coil pack, if not I'd check the PTU.
