Guest Roel Posted August 25, 2010 Share Posted August 25, 2010 I've got this strange (?) problem.. Really would appreciate some help here.. What I've checked: - Coils all get 12v (IGN ON) - Injectors all get about 9v (IGN ON) - Did the spark test - Compression was OK - Changed coils - Changed spark plugs I know the injector is working because the sparkplug is soaked. When I then fit my old sparkplug, this one also gets soaked... Lots of fuel out of the exhaust too.... Btw I know I'm not getting a combustion on cyl #3, because the manifold runner stays cold. Could this be a faulty injector? Or is the spark too weak? TIA! Quote Link to comment Share on other sites More sharing options...
pistonbroke Posted August 25, 2010 Share Posted August 25, 2010 I'd do some simple methodical checks first. Change the plug in number 3 to a different cylinder and see if the problem chamber changes. If not, you know it's not the plug. Then I'd swap the coil packs around to see if one of your coils is weak. Quote Link to comment Share on other sites More sharing options...
Guest Roel Posted August 25, 2010 Share Posted August 25, 2010 Yep did all of that Thanks Quote Link to comment Share on other sites More sharing options...
Little Matt Posted August 25, 2010 Share Posted August 25, 2010 try bump starting it...simple idea I know but it may well just be flooded. Quote Link to comment Share on other sites More sharing options...
David Reid Posted August 25, 2010 Share Posted August 25, 2010 Just swap between 3 and 4, starting with plug, then coil then injector and find the component the missfire follows then replace it Quote Link to comment Share on other sites More sharing options...
pistonbroke Posted August 25, 2010 Share Posted August 25, 2010 You say you've done a compression check, but have you done a leakdown test? It may be that one of your valves is knackered. Quote Link to comment Share on other sites More sharing options...
nigelboyne Posted August 26, 2010 Share Posted August 26, 2010 faulty immobilioser maybe or no siginal going to injectors Quote Link to comment Share on other sites More sharing options...
Nodalmighty Posted August 26, 2010 Share Posted August 26, 2010 Sounds like Number 3 injector is stuck fully open. Swap injectors 3 and 4 and see if the problem moves. Quote Link to comment Share on other sites More sharing options...
Guest Roel Posted August 27, 2010 Share Posted August 27, 2010 Tried some things today.. Problem is still there.. Things we've tried; - changed all the coilpacks - changed the complete fuel rail with other injectors - checked compression on all cylinders (OK) - checked the loom at the ecu side, looks good. - double checked for spark at cyl #3 @ Nodalmighty: I 'm thinking the same thing, within seconds gasoline is pouring out at the exhaust if we connect the connector of the injector #3 I think the ecu is defective or maybe the loom somewhere? Quote Link to comment Share on other sites More sharing options...
Andy Blyth Posted August 27, 2010 Share Posted August 27, 2010 Try unplugging the #3 injector and the ECU and test for a short circuit to ground (chassis) on each of the wires in the #3 injector plug. If there is a short circuit, this points to a fault in the harness. If there is no short circuit I would suspect a faulty ECU. Quote Link to comment Share on other sites More sharing options...
pistonbroke Posted August 27, 2010 Share Posted August 27, 2010 if you swap the injector out, does the problem cylinder change? Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted August 27, 2010 Share Posted August 27, 2010 I agree, faulty ecu or wiring loom from injector grounds to ecu sounds likely. Quote Link to comment Share on other sites More sharing options...
Ian C Posted August 28, 2010 Share Posted August 28, 2010 The injectors work via a switched ground, so if there is a short it will energise the injector all the time and cause it to lock open. So it does seem to point to this Quote Link to comment Share on other sites More sharing options...
Digital Posted August 28, 2010 Share Posted August 28, 2010 Thanks for the help guys! Yesterday I tried to help Roel on this problem, I brought coilpacks, injectors and a igniter. We know for sure now that injector 3 stays open when we start the engine. The red/green wire from injector 3's connecter to the ECU is ok. The injectors are controlled/switched via ground indeed, but how can I check if the ground-wire on that injector is short circuiting or faulty? The J-spec ECU pinout doens't show a "injector ground" pin, and I can't find a J-spec wiring diagram for the injector ground. Where does the ground wire from the injector 3go to, can anyone help us? Quote Link to comment Share on other sites More sharing options...
Andy Blyth Posted August 28, 2010 Share Posted August 28, 2010 The injector has one wire that connects to a 12V source (that's live when the ignition is on - could be black/orange or red) and a switched ground wire (the red/green one). You need to see if the red/green wire is connected to ground when it shouldn't be i.e. when the ECU is commanding the injector closed. You need to start by disconnecting injector #3 and the ECU. Use a multimeter set to either the continuity or resistance range. Check to see if there is an electrical path between the red/green wire and the chassis (the - terminal on the battery will be fine). If the resistance is high (e.g. more than 1000 Ohms) your harness will be fine and the ECU is suspect. Quote Link to comment Share on other sites More sharing options...
Guest Roel Posted August 30, 2010 Share Posted August 30, 2010 Thank you very very much guys!! I'll try this today Quote Link to comment Share on other sites More sharing options...
Ian C Posted August 30, 2010 Share Posted August 30, 2010 There isn't a specific "injector ground" pin, each injector has its own pin on the ECU and the ECU internally switches these to a ground when it wants them to open. Injector number 3 is controlled by pin B18 on the ECU, but I doubt this is at fault. more likely is the wire going from the injector to the ECU is damaged and shorting out to the car body, causing a permanent earth switch. Take the plug off the injector and check for continuity between pin 1 on the injector plug and the battery negative. There should be infinite resistance until the injector fires - if there is low or no resistance, you've got a short on that wire somewhere and that's causing your problem The injectors are controlled/switched via ground indeed, but how can I check if the ground-wire on that injector is short circuiting or faulty? The J-spec ECU pinout doens't show a "injector ground" pin, and I can't find a J-spec wiring diagram for the injector ground. Where does the ground wire from the injector 3go to, can anyone help us? Quote Link to comment Share on other sites More sharing options...
Guest Roel Posted September 1, 2010 Share Posted September 1, 2010 Okay guys.. I've tried a couple of things yesterday.. But I'm kind of stuck at the moment... I've first cut the wire at the ecu (red/green b18) and at the injector #3 (also red/green). Then soldered a fresh new wire between the two. No result.. My friend Digital sent me his spare ecu, and I tried this one yesterday. Engine is still running on 5 cylinders. And at cyl3 is still no combustion (runner stays cold). Here the strange part of the story: So I removed the spark plugs. There was NO fuel on the spark plug #3. I also noticed that the fuel isn't pouring out of the exhaust while the engine is running with this ecu. Plugging in and out the connector of injector 3 while the engine is running makes no difference. In other words.. I think the injector isn't opening at all now! Then Soldered the original red/green wire at the injector and ecu connector again. No result.. Decided to try my own ecu again, and the injector #3 was stuck open and fuel pouring out of the exhaust again. What to do next... Think I'm getting crazy haha.... Must have done something wrong I guess.. Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted September 1, 2010 Share Posted September 1, 2010 What happens if you connect injector 3 plug to injector 2 and vice versa? Although the injector firing order is wrong it will still run, you can then see if the problem moves to cylinder 2. You may need to extend the loom a bit. Quote Link to comment Share on other sites More sharing options...
Guest Roel Posted September 1, 2010 Share Posted September 1, 2010 Chris, I haven't tried that. I'll try tonight! Thanks! Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted September 1, 2010 Share Posted September 1, 2010 You should also measure the resistance of the injectors in case No3 has shorted windings. It will show as a lower resistance than the others if that's the case. Do not ignore the possibility of having replaced one bad part with another bad part, coincidences DO happen. Quote Link to comment Share on other sites More sharing options...
Digital Posted September 1, 2010 Share Posted September 1, 2010 @Chris: sure somtimes it could happen, but the injectors and ECU that we switched came of my car which ran normal. Quote Link to comment Share on other sites More sharing options...
Guest Roel Posted September 2, 2010 Share Posted September 2, 2010 Somehow (without changing anything!) cylinder 3 works like it should do! But.. The problem has moved. Now the runner of cylinder 6 stays cold When I unplug/plug the connector of cyl 6 while it's running, the engine doesn't sound/run different. Strange eh...??? Quote Link to comment Share on other sites More sharing options...
Guest Roel Posted September 4, 2010 Share Posted September 4, 2010 I got it running on six cilinders now! But it is misfiring pretty badly.. Lots of smoke out of the exhaust and it stalls if I don't keep the revs up... Quote Link to comment Share on other sites More sharing options...
Andy Blyth Posted September 4, 2010 Share Posted September 4, 2010 Try checking the crank position sensor and the two cam position sensors. There's a manual on here somewhere with the expected resistance values. If you have access to an oscilloscope, try looking at each of the three waveforms with the engine running. You may have a weak signal from one of the sensors. It might be a pain to do but it's worth a try. Quote Link to comment Share on other sites More sharing options...
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