I tried out a second CAS on the weekend and I think it helped a little bit, but more when driving it seemed a little smoother. The idle issue still seems to be there. I checked the earths and they seem ok. Would using a bling bolt be a potential issue? I have one of the hex head bolts in place, maybe I should try a normal bolt just to see. Cheers, Simon
Also doing the power balance test still shows #6 as only a very small drop in rpm compared to 1-5. jamersss. Can you elaborate on how you identified your issue? Did you connect the injector connector from no 4 to no 2 and vice versa and the issue moved? I would have thought that would cause all sorts of problems with firing order?
That is how I did it. Cylinder fired right up. I guess when you have spark, fuel and compression the cylinder will tend to do that It worked well in my situation, because I had a completely dead cylinder. However you have half an operational one so it makes troubleshooting a pain. You mentioned you did a compression test though. What were the full figures? Cylinder 6 is distant from the cooling system and so I've been told it can operate lean due to its location on the fuel rail.
Have you checked for vacuum leaks in the clutch or brake booster?? Number 6 on RHD cars would be closest to those correct? If there is a leak in one of them, #6 is going to show it the most.
Would hooking up a smoke machine in place of the intake expose leaks in the clutch or booster? I assume it would??? With the smoke machine we found a very small leak out of the passenger inlet hardpipe and that was due to a faulty clamp. The other was an even smaller leak out of the press fit pipe that connects to one of the cam covers.
You cant see vacuum leaks in a clutch booster or brake booster with a pressure test. The check valves close under pressure so it doesn't blow boost in to the brake or clutch system. It is easiest to just unhook the hoses and blow into them with your mouth. IF it holds pressure, it is probably fine, if not then investigate further.
Finally some progress!! I figured I might as well try swapping the injector leads around to see if I could move the issue. I swapped #4 and #6 and ran the power balance test. #6 had a noticeable drop in rpm and #4 only a very small change. So it looks like it an electrical gremlin. I've tried a second ecu, so i'm hoping it's the injector subharness (have a wiring specialties loom). Can someone explain why you are able to swap injector leads? Wouldn't that cause the injectors to open at an incorrect time? Or am I missing (pardon the pun) something? Cheers, Simon
You shouldn't be able to do that... and have it run right. The CAS basically determines when each injector will fire, just like it determines when each coil fires. I would have thought you would have had some big backfires swapping leads from one injector to another.
You may want to do a dynamic compression test... Basically, when you are doing a static test (all plugs out, turning the starter) you are checking compression sealing. When you do a dynamic (engine running) compression test, you are checking how well the cylinder is taking in air, and emptying air. Check it out here: http://www.imperialclub.com/Repair/Engine/dynamic.htm This could tell you if you have a weak valve spring, a lifter not pumping up all the way, or a lobe partially rounded off on a cam.
Hi everyone, Forgive the long post but i'm running out of ideas and thought I would describe everything in the hope that you might be able to help!! Late last year I had a spare engine rebuilt. Nothing to crazy, standard internals with ball bearing turbos and larger injectors. When we swapped the engines over I took the opportunity to replace the wiring loom. I ran the engine in and the car was running great, but there was a loud ticking noise which we identified was a lifter issue. We pulled the plenum and replaced 3 of the lifters we thought looked questionable. Unfortunately when we put it all back together the tick was still there. A couple weeks later we pulled the plenum off again and just replaced all of lifters with new ones. When we put things back together the ticking was gone, but the idle seemed lumpy. Using my nProbe/datascan we did a power balance test. It showed that #6 wasn't dropping the same as the other cylinders. When we pulled the #6 coilpack connector it barely dropped the RPM. The issue with idle and vibration is worse when the car is cold. After it is up to running temperature it's not as obvious. The car also pulls well when you accelerate and if it's missing slightly when driving it's not noticeable. We have done the following to try and diagnose what the problem might be. - We swapped coilpacks around, the issue stayed with #6 - Checked timing, timing at 15 degree - Inspected the #6 spark plug, had a little bit more carbon build up - Replaced the #6 spark plug with a new one, the issue stayed with #6 - Removed the injectors and cleaned them all - Swapped the #2 and #6 injectors, the issue stayed with #6 - Tried 3 different ECUs, issue stayed with #6 - Compression test, all 6 cylinders were within 5psi of each other - Connected noid tester to #6, bulb flashed, was difficult to tell if the intensity was different between connectors - Checked continuity between injector connector and ECU connector, all 6 had continuity - Checked voltage of each injector connector, all had voltage that hovered between 11.3 and 11.8V - Replaced the injector subharness (wiring specialties loom), the issue stayed with #6 - Swapped the #5 and #6 injector connectors over, issue moved to #5! We thought that perhaps there might have been an issue with either the #6 wire inside the loom or the subharness connector due to us pulling the plenum a bunch of times. We took two wires and spliced them into the loom behind the ECU connector and ran them directly to the #6 injector to bypass the loom and subharness connector. We re-ran the power balance test and the issue was still with #6. We checked the voltage and continuity of our spliced in wires and got the same 11.3 - 11.8V We depinned the number 6 cylinder connection from the ECU plug to see if maybe the crimp was lose, but it looked fine. While the wire was out we slid it on to the ECU pins just to check that there was some resistance when it meets the pin, it seemed the same as other connections. To check once and for all if there was an issue with the wire or connector we swapped the position of #5 and #6 wires in the ECU connector. So swapped the blue wire with the white/blue wire. We swapped the injector connectors around at the engine so the wires were going to the correct injector. When we re-ran the power balance test the issue was still with #6. When we switched the #5 and #6 injector connectors, the issue moved to #5. Based on that it would seem to indicate that the issue was with the ECU and the #6 injector pin. However I have tried 3 different ecus now and there has been no difference. The ECUs I have used have all had adjusted k values to allow for the larger (550CC) injectors. and they've varied from a standard map to a hitec map that is about 15% leaner than standard. Can you think of anything that might be causing the issue? The fact that it moves when we swap injector connectors would seem to point to an electrical problem, but we have run out of ideas Would appreciate any ideas you might have. Again, sorry for the long post and thanks if you have managed to make it this far! Simon
Might be a long shot, but do you have anything else wired into the ECU? I had an issue with mine where the traction control had a loose/corroded wire and because the injectors go through it, caused a misfire.
Hi grantd, No I purposefully didn't wire in my AVCR because I wanted to run it in and take things easy for a while so there is nothing else wired in Simon
When you ran the wire from the ecu to injector 6, did you try run a different earth? Considering when you swapped 5 & 6 connector over the problem moved to 5, i think it would have to be the wire to injector 6 or the earth. No other ideas come to mind sorry.
Check the coilpack harness connectors. When you say you changed the injector connectors 5 & 6 and the issue moved does that mean that you also changed the pins at the ECU. Also just check the COIL PACK harness connectors for any green corrosion. It may be that the connector is the issue as you have swapped the packs over. Tricky one but In my experience the tricky ones are caused by a simple and sometimes obvious fault that is never suspected. MichaelZ
All the earths for the injectors bunch together from memory, What you want to do is check the resistance between the ecu plug injector 6 pin and the injector plug signal wire. Everything should come up the same but i bet you have an earth leak somewhere on that lead, does the plug come up hot/lean? if nothing else works, try a noid light and see if it blinks as brightly...
Is the Timing belt on properly ??? Not a tooth out ?? Is it throwing error codes? Have you swapped the det sensor harness with the passenger VTC connector by accident? They are the same connector and it will run like crap if swapped. Will have bad idle and poor response. BTW, check your fuel pressure.............
Voltage measurements.... You have specified voltage tested between 11.3 & 11.8VDC. That is a difference of 0.5VDC. A lower voltage reading may be caused by resistance in that circuit. The available voltage at the injectors or coil packs should be almost identical to the battery voltage. Recommend performing voltage drop tests.
Isn't the battery voltage too low. After reading the last post I went out started my Zed and measured my battery (charging) voltage at 14.1V. I would be checking the battery voltage and the alternator. Early cars developed idling issues and funny electrical issues with low ECU power voltages. MichaelZ
