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| High/Odd Idle...; I didn't mess with anything!! | |
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| Tweet Topic Started: Jan 4 2013, 05:32 PM (2,187 Views) | |
| sarguy01 | Jan 25 2013, 07:10 AM Post #16 |
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I am starting to think that the stripped wire in my previous pics is factory. It would be hidden under the wire harness tape. It looks to be some sort of shielding wire, which would make sense as it is next to the camshaft position sensor's wires and the O2 sensor. Going to go back through the FSM and see if I missed a step. If I didn't, since I read it several times last night, I am going to get a new ECM today, unless someone happens to know why the FSM is telling me to replace it when it doesn't need to be?? |
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| sarguy01 | Jan 25 2013, 12:07 PM Post #17 |
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Yep, I was right. That braided wire in the pic is in fact a shield wire. I need to solder it back together. I doubt it is causing these problems, but the factory wanted it that way. I went ahead and got another ECM. I think it is the right one, though the sticker is hard to read. It was only $35 and I can return it. Yes, I checked my grounds. I looked through the FSM wiring diagrams and traced the grounds. I may run another ground from the battery negative to the junction block ground, just in case. I may also replace the batt negative cable as there is corrosion in the crimp where the wires meet the terminal on the battery post. I hate changing stuff as a guess, but with grounds it is hard to determine if they are doing their job completely in a DIY setting. Besides, a negative battery cable is cheap. I really cannot think why one sensor is throwing codes if there is a grounding problem. I don't know what other grounds need to be checked. |
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| sarguy01 | Jan 26 2013, 02:54 PM Post #18 |
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Put new ground wire from battery to body/trans. Check voltage on ECM Lt Grn/Wht wire. 1.97 volts. Okay, changed the ECM. Didn't even turn the car on, checked voltage, 1.97 volts. FML. |
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| sarguy01 | Jan 26 2013, 06:21 PM Post #19 |
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Ran another ground to junction box. 1.97 volts. Tore tape off of harness from TPS to ECM. Wire is good and not rubbed through. 1.97 volts. When am I going to fix this??? |
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| clarkdw | Jan 26 2013, 06:39 PM Post #20 |
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Not ignoring you. This is my three 15hr workday weekend so not much available time. What you are going through is very similar to the process I went through with my hatch. I have a suggestion. Remove the ISC from the throttle body to be sure the plunger does not touch the throttle spindle. Now check the adjustment of the "screw that must not be touched". That is the throttle stop screw. It is meant to barely hold the throttle plate from closing tight, no more. When you move the stop screw make sure you know exactly how much you move it so you can return it to the same position if you determine that it has not been messed with. Loosen the stop screw off till the throttle plate is fully closed. Let it snap shut a couple of times by hand and then tighten up the stop screw till it barely moves the throttle plate. Lock it up and then proceed to the process of adjusting the TPS. You don't need the ISC reinstalled for this adjustment. Follow the FSM for the TPS setting and then install the ISC. Try it out for a number of drive cycles after resetting the ECM by removing the tailight fuse. It seems to take a few drive cycles for the idle to settle down after any adjustments. I'm still working with you. Good luck.
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| sarguy01 | Jan 26 2013, 08:09 PM Post #21 |
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Thanks for staying with me. I don't want to touch those screws. The fact is, the voltage to that should be in the lt grn/wht wire is wrong. No screw adjustments are going to change that. When I adjusted the throttle body, I did remove the ISC so the plunger would not get in the way of the feeler gauges doing their job. Again, thanks for the help. Do you have a 3 wire TPS? If so, would be willing to unhook yours, turn the key to on and tell me how many volts you get at your lt grn/wht wire? I know you said you were busy, but if you got a chance I would appreciate it. |
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| clarkdw | Jan 26 2013, 10:49 PM Post #22 |
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The TPS on my 94 hatch is exactly the same as yours. I will check the voltage as soon as I can. I may not be able to till Monday am. These Weekend night shifts take a toll. From Fri afternoon till Mon morning I am away from home 45 hrs.
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| sarguy01 | Jan 27 2013, 08:46 PM Post #23 |
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Tonight I held the test wires on the TPS so they wouldn't move. I grabbed the wires going into the dash and the voltage started jumping around. I think on of those wires in the harness is causing it to do this. Which one? No clue. I have no idea what else can cause the voltage to change in that wire. Ugghhh! Anyone want to buy a mostly running Geo Metro in Virginia Beach? I'll make you a deal!
Edited by sarguy01, Jan 27 2013, 08:47 PM.
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| sarguy01 | Jan 28 2013, 08:29 AM Post #24 |
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Tonight I am heading out into the garage to try and figure this out. Before I tear into the harness any more, I am going to play with the grounds on the back of the intake. It would not surprise me if one of the ground wires has some corrosion inside the terminal end, where I am not able to clean. I have most of the harness untaped and don't see any wires that are damaged, but that is not to say that there isn't a broken wire inside the insulation. The only other thing I can think of is some other sensor is acting up and causing the ECM to put out less than 5 volts to the lt grn/wht wire. I am going to try unhooking other sensors, one at a time, to see if the voltage goes to the 5 as it should be. Any thoughts?? |
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| clarkdw | Jan 28 2013, 08:39 AM Post #25 |
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Ok, don't give up now. You will get this thing worked out. As requested I pulled the TPS connector and checked the voltages. GRN 4.99 v, GRN/WH 4.7 v key on engine off. Strange that you get 1.97 from both ECM's. That would suggest that the problem is in the harness or another sensor. I am wondering if a short to ground in another sensor would drag down the voltage to the TPS. Edit: You beat to the post. I was typing when you suggested another sensor. Edited by clarkdw, Jan 28 2013, 08:40 AM.
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| clarkdw | Jan 28 2013, 08:43 AM Post #26 |
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The grounds is another great suggestion. I was getting all kinds of niggly little problems and DTC triggers till I cleaned all the grounds thoroughly. |
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| sarguy01 | Jan 28 2013, 08:46 AM Post #27 |
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Thank you so much! PM me your Paypal address...if you don't have one, PM me your address so I can send you a little compensation! Now I feel better about chasing this 5V issue, knowing that a running car should have 5V. Yes, if I can't find a bad wire/ground I am going to start checking other sensors. Again, thanks for taking the time to check for me. |
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| clarkdw | Jan 28 2013, 08:52 AM Post #28 |
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Hey. You are very welcome. I really like to be able to return some of the benefits that I have gained from this great forum. Other than doing a cylinder head I am off till Wed evening now so if you have any other questions or requests go for it.I am going to have a peek at the schematics and see if anything clicks. Keep after it.
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| sarguy01 | Jan 28 2013, 01:26 PM Post #29 |
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Apparently, one should not troubleshoot wiring after having a few drinks...hehe...I went home for lunch today and hooked up the meter again. This time, there was no change in voltage by shaking the wiring harness. I also unplugged the MAP and ISC with no change in voltage. I guess a good harness is not bad news, but it also means I don't know where else to look. So, we are back to checking grounds, again. But wait, I type this as I read my FSM schematics. Could this be an issue related to cutting/splicing the headlight wire? Is there some chance that some previous owner did their own headlight fix? I see the diode module (where is that??) is fed from the combo switch, rear defogger (don't have one) and blower speed selector. It then feeds the ECM's Electrical Load-Up Idle signal. Could it be that the ECM is trying to tell the TPS to compensate a screwed up signal from the diode module? I am going to cut that headlight wire/unplug the diode module and see what happens. My head hurts! |
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| sarguy01 | Jan 28 2013, 05:31 PM Post #30 |
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Breakthrough, sort of! I found that lt grn/black sensor ground wire is at .87 volts. Not good, it should be at .5 or less. The TPS is also at 2.2 volts when ground to battery negative. So this is one of two things: One, the ECM is not grounded enough, so I needed to quadruple check the grounds on the back of the intake. Two, there could be a broken wire inside the harness somewhere. I checked the ground wire at all sensors that use it: TPS, MAP, O2, IAT and ECT. With all sensors unhooked, the wire still shows .87 volts so I can assume the ECM is providing this voltage or there is a break in the wire. I don't think any of those sensors or bad. Going back out there.... |
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2:29 PM Jul 11