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#31
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Re: My car is mad at me! Random stalling, rough idle
Hi again.
I have more advice. I don't Know what you do for a living or where you work or what you have access to. Infra red thermography is a booming field. I have a level II certification. Here where I work, I do all the thermal imaging of our switchgear and electrical distribution, therefore I am allowed to use the IR camera and the company has let me take it home for personal use. If you have access to an IR camera or have a friend/relative that does, you can use the camera to find the cylinder(s) that are misfiring. The misfiring cylinders will have correspondingly lower exhaust manifold temperatures, and since your car misses at idle you could quickly determine which ones. After that, you would still not know why those particular cylinders are misfiring, but it would be a way to narrow the field a bit. For example. If the exhaust temperatures are consistent on each manifold, but one manifold is significantly different from the other, it may indicate a vacuum leak or out of spec O2 sensor for one bank. On the other hand if one port into one of the manifolds is cooler (or hotter) then it is narrowed down much further. If you don't have access to an IR camera then all this info is just a waste of time, but on the off chance that you do have access I highly recommend the IR camera as a very powerful troubleshooting tool. Chip. |
#32
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Re: My car is mad at me! Random stalling, rough idle
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Unless these tap-on connectors are applied to the exact cable they are designed for, i.e. Insulation thickness, material, wire gauge, number of strands, in respect of both cables, the conductor is very liable to damage and the damage is not obvious. Without standing in a cow pat, I have many times witnessed the evidence.
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Trevor, New Zealand. As a child, on cold mornings I gladly stood in cowpats to warm my bare feet, but I detest bull$hit! |
#33
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Re: My car is mad at me! Random stalling, rough idle
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The random stalling at low speed and power loss on freeway also happened to me, but the idle was always perfect. That was a MAF, but no codes. Any luck with this?
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#34
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Re: My car is mad at me! Random stalling, rough idle
Hi, I had a similar problem once and found that the soldered connecting wire inside the MAF had come loose. It's an easy thing to try.
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#35
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Re: My car is mad at me! Random stalling, rough idle
I hope that works for us, we will re-solder the failed MAF to see what happens
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Special Thanks to Our Friends and Sponsors: * http://www.alcyone.org.uk/ssm http://www.PhenixWheels.com http://www.dba.com.au/ http://www.ClassicSoftTrim.com http://ToyoTires.com/tire/pattern/versado-lx Gillman Subaru of Houston "QuickChange" http://www.TransGo.com/ http://www.PlanetSVX.com Bontrager Works, '92 Subaru SVX LS-L Claret ORIGINAL OWNER '92 LS-L Pearl~ '92 LS Pearl~ '92 LS-L Teal~ '92 LS-L Silver~ '95 LSi Polo~ '92 JDM Alcyone SVX Version-L 4WS Pearl~ http://www.subaru-svx.net/forum/showthread.php?t=54143 '92 JDM Alcyone SVX Version-L 4WS Ebony~ http://www.subaru-svx.net/forum/showthread.php?t=54117 |
#36
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Re: My car is mad at me! Random stalling, rough idle
I have a spare MAF now, so today I will try the resoldering how-to and hopefully find something.
Would one or more dying/carbon tracked coils cause this issue? Clogged cat cause this? The car builds power through the entire rev range so this may not be associated. Or a bad O2 sensor? Man, there are soooo many things to check. I plan to check and clean crank sensors and cam sensor today as well. The cam sensor is coated in oil and grime from the oil-fill neck gasket being bad. Will also pull and clean the TPS. No change=back to dealer. Thanks again for all the helpful suggestions.
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Mac __________________________________ 1995 SVX-L AWD, green, 98,xxx miles, ECUtune 1.5, mazda RX-8 wheels with subie center caps, stebro muffler, resonator delete, koni inserts, perrin crank pulley, hella 500 off-road lights, power-slot rotors and ..... 1993 968 Coupe 6-speed, 80,xxx miles black, H&R springs |
#37
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Re: My car is mad at me! Random stalling, rough idle
So,
Back to dealer for another round.
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Mac __________________________________ 1995 SVX-L AWD, green, 98,xxx miles, ECUtune 1.5, mazda RX-8 wheels with subie center caps, stebro muffler, resonator delete, koni inserts, perrin crank pulley, hella 500 off-road lights, power-slot rotors and ..... 1993 968 Coupe 6-speed, 80,xxx miles black, H&R springs |
#38
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Re: My car is mad at me! Random stalling, rough idle
Since they didnt fix the problem, the next round should be on THEM. Just be nice about it and any self-respecting shop shouldnt charge you again for a failed previous diag.
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#39
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Re: My car is mad at me! Random stalling, rough idle
They claim to have diagnosed the issue. They say that the voltage is dropping and causing the ECU to shut down or run incorrectly.
Just replaced the alternator a couple of months ago with a new reman one. Evidently the voltage regulator is bad in the new one. The alternator is being replaced under its own warranty. Or could it still be something else related to the alternator wiring to rest of car? I see that there is a wiring mod post. They have been fair so far and have not asked for more money as of yet. They were also kind enough to give me a loaner car this time. Mac
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Mac __________________________________ 1995 SVX-L AWD, green, 98,xxx miles, ECUtune 1.5, mazda RX-8 wheels with subie center caps, stebro muffler, resonator delete, koni inserts, perrin crank pulley, hella 500 off-road lights, power-slot rotors and ..... 1993 968 Coupe 6-speed, 80,xxx miles black, H&R springs |
#40
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Re: My car is mad at me! Random stalling, rough idle
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Even if the alternator stopped working, the battery would keep the voltage up, and the ECU would not notice it, it will operate down to a very low voltage. If the regulator was faulty, the voltage would either drop to 12.5V or go up to higher than 14.7. If the voltage was going up, you would notice the lights getting brighter, turn indicators would work faster. There have been a few cases of the regulator letting the voltage go up, the car has keep going, till the fusible link blows. Harvey.
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One Arm Bloke. Tell it like it is! 95 Lsi. Bordeaux Pearl, Aust. RHD.149,000Kls Subaru BBS wheels. 97 Liberty GX Auto sedan. 320,000Kls. 04 Liberty 30R Auto Premium. 92.000kls. |
#41
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Re: My car is mad at me! Random stalling, rough idle
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The alternator could have a regulator fault which involves a partial short circuit to ground, but is not passing the heavy current required to open the main, high rated fusible link. As a result there could very well be a considerable drop in line voltage and that delivered to the ECU. It would appear that the alternator has not been operating correctly for some time. Therefore it is very likely and it is logical to assume, that the battery is not fully charged and certainly will not deliver 12.5 volts. Whatever, goodwill appears to have been established, therefore you must give those involved the benefit of the doubt. Even so remain vigilant. Best of luck in securing a fix, Trevor. P.S. The ECU incorporates two distinct functions. One involves the computation of signals. In this instance a nominal regulated five volts is utilised. Provided that an input voltage which does not fall below say six or so volts is reliably on tap, this section is likely to function unabated. The second section involves the switching of external items, which require full battery voltage and relatively high currents, in order to operate. This section is absolutely voltage dependent.
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Trevor, New Zealand. As a child, on cold mornings I gladly stood in cowpats to warm my bare feet, but I detest bull$hit! Last edited by Trevor; 02-19-2010 at 07:29 PM. Reason: P.S. Added. |
#42
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Re: My car is mad at me! Random stalling, rough idle
So,
Picked up from dealer today. They replaced the alternator and said that the car had stopped stalling for them. They were not able to cure the poor running condition, hesitation/miss condition, which is actually worse now. They say they noticed that the wire to one of the crank sensors was cracked exposing the shielded core. Possibly causing interference. Could this be? Makes me think to check the wires to the MAF and other sensors too. Their suggestion was to replace the engine wiring harness. That is a very big dollar job. They claim to have tested all the sensors and even tested cylinder compression. They did not charge for the 2nd round, but time will tell if the car will stall again. If I had a warm garage to work in, I'd try lot's of things. For now its just throwing some more fuel system cleaner in it for s**ts and giggles. The bad thing is that the car is missing/hesitating worse than before. Thinking of other ways to isolate this damn thing, will the engine run with a knock sensor unplugged? Or an 02 sensor unplugged? I know that it won't with the MAF disconnected. I have always run 92 octane or 93 when I can find it and run fuel system cleaner every couple of months, so I wonder if it would be worth a trying to see if the problem gets worse with lower octane gas or the opposite and running an octane boost additive??? Thanks.
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Mac __________________________________ 1995 SVX-L AWD, green, 98,xxx miles, ECUtune 1.5, mazda RX-8 wheels with subie center caps, stebro muffler, resonator delete, koni inserts, perrin crank pulley, hella 500 off-road lights, power-slot rotors and ..... 1993 968 Coupe 6-speed, 80,xxx miles black, H&R springs |
#43
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Re: My car is mad at me! Random stalling, rough idle
My suggestion is to take it somewhere else for service.
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1992 LSL ebony pearl 170k - Thank you Ron Mummert Reading Box of Wine Car ----------------------------------- 1992 SVX LSL 5-Speed Sold at 180K 2019 1995 SVX Lsi Polo Sold at 118K 2007 |
#44
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Re: My car is mad at me! Random stalling, rough idle
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#45
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Re: My car is mad at me! Random stalling, rough idle
Yes, I have tried pulling injector wires at idle, and did not find one that made a "no change" condition. So, I ruled out the fact that one injector was bad. Maybe still partially clogged/dirty but not bad.
Tonight I tried a couple things: -Adjusting position of TPS and noticed that I would get a fast idle unless I shut down the car completely after the change. Basically I found no change. -Running car with open airbox=no change -Sprayed starting fluid on all known vacuum areas including manifold gaskets=no change in idle speed. -Disconnected Battery and will let it sit overnight to clear ECU. -Took video of tachometer while hesitation was occuring. Where to post? Youtube? I see that there are lines and a plastic valve to the emissions canister. Could there be a potential problem with that area? On the bottom of the canister, there is a hose that returns into the fender well under the airbox with a nipple that does not seat well, (often found dangling.) Still wonder what would happen if I disconnected the knock sensors or 02 sensors one at a time (like the fuel injector test.) Somewhere in the back of my head (a very scary place) I keep hearing this little voice saying "Put the ECU, and everything else back to stock." Thing is, the only mods I could see effecting such a condition would be the ECU tune and the Stebro muffler. I feel like I cannot rule out a clogged cat either, as it rattles, but with only 83,000 miles I'd find that hard to believe, plus the engine runs smoothly and builds power as the rpms climb. Wow, this is crazy!
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Mac __________________________________ 1995 SVX-L AWD, green, 98,xxx miles, ECUtune 1.5, mazda RX-8 wheels with subie center caps, stebro muffler, resonator delete, koni inserts, perrin crank pulley, hella 500 off-road lights, power-slot rotors and ..... 1993 968 Coupe 6-speed, 80,xxx miles black, H&R springs |
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