miss again
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Joined: Jan 2003
Posts: 156
miss again
Ok, on my way to work today, I noticed a very definite point in time that a miss started under the hood. There was a loss in power, and I could feel the rythmic miss. I just replaced the optispark this past weekend. I swung by a garage, and they were closing, but one guy looked at it. He unplugged one of the fuel injectors after feeling them all, and it didn't change the idle. However, all the others when unclipped did. So I'm thinking I either didn't plug one of the opti wires in all the way, and it just came off today, or I have a bad fuel injector. Any other ideas? Thanks.
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Joined: May 2003
Posts: 2,275
DO NOT DRIVE THIS CAR MUCH UNTIL YOU FIX THE PROBLEM. If it turns out the cylinder has got a spark problem but the injector is firing, serious cylinder/ring/piston damage could result. Better safe than sorry.
I am not one to believe in coinsidence and since you just replaced your opti recently I would think you have a mis-placed wire that may have shorted or burned through since that is common. However if he was feeling for the clicking of the injectors and found one that was not clicking, I would have to say the injector was not firing. Since spark has nothing to do with injectors firing. At least you know which cylinder you are dealing with. That's sometimes the major part of the battle.
You could approach it a couple of ways. I would confirm or deny spark first since that is the easiest. Pull the plug and connect it to the wire and lay it on the block and have someone crank it over. By using the original plug you can confirm the plug is good at the same time.
You could then move to the injector a couple of ways. There is a tester that uses magnetic fields like an inductive timing light. When it gets near an injector firing, it flickers. There are also small neon bulb like testers that back probe the injector plug. You could also swap that injector with another one. If you do find the injector is not firing there is a good chance that it is only a wiring problem. Look for the signal, all the way back to the PCM if necessary. At that point, it becomes merely a matter of checking continuity of the wires and connections from the PCM to the injector. Obviously if the signal is absent at the PCM then that means the PCM is defective.
I am not one to believe in coinsidence and since you just replaced your opti recently I would think you have a mis-placed wire that may have shorted or burned through since that is common. However if he was feeling for the clicking of the injectors and found one that was not clicking, I would have to say the injector was not firing. Since spark has nothing to do with injectors firing. At least you know which cylinder you are dealing with. That's sometimes the major part of the battle.
You could approach it a couple of ways. I would confirm or deny spark first since that is the easiest. Pull the plug and connect it to the wire and lay it on the block and have someone crank it over. By using the original plug you can confirm the plug is good at the same time.
You could then move to the injector a couple of ways. There is a tester that uses magnetic fields like an inductive timing light. When it gets near an injector firing, it flickers. There are also small neon bulb like testers that back probe the injector plug. You could also swap that injector with another one. If you do find the injector is not firing there is a good chance that it is only a wiring problem. Look for the signal, all the way back to the PCM if necessary. At that point, it becomes merely a matter of checking continuity of the wires and connections from the PCM to the injector. Obviously if the signal is absent at the PCM then that means the PCM is defective.
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tommalcolm
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Sep 11, 2015 03:39 PM