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John
12-18-1998, 05:44 PM
Here's a wierd one to contemplate (93 525i, 68K):<p>Over the past couple of weeks, my idle speed crept up to 1000 rpm in gear, 1200 rpm out of gear (automatic).<p>Then, when stopped at a traffic light, the transmission shutdown, givng me a TRANS PROG message from the OBC.<p>I drove a block further home, shut it off, tried it again an hour later and it ran fine, although still at high idle.<p>The following day, I was advised to check the battery. Theory was that low battery was calling for more charge, and the idle speed automatically increases to turn the alternator faster to charge faster. Fine, a new battery seemed like a better way to go than some of the alternatives I had imagined.<p>Went to a battery shop and had a new battery installed. They plugged a voltage source into the cigarette lighter while changing the battery, presumably so the radio, etc. would not have to be reset.<p>Following the battery replacement, the idle came right down to around 500 rpm. However, a new problem has cropped up. After the car is at temp, and after slowing to a stop, the engine hunts for the right idle speed and bounces between 400 and 600 rpm. Eventually the vascillation gets severe enough that the engine stalls.<p>At this point, I resign it to the dealer - who tries the old swap it out till it works routine. They installed a new throttle position sensor switch - and the car behaved in exactly the same way as it did when I took it in.<p>They next want to try an idle valve, and if that does not work, they want to try a new computer (ouch!)<p>Thanks for your patience in reading through this. Any ideas?

WillO
12-18-1998, 08:33 PM
<i>: Here's a wierd one to contemplate (93 525i, 68K):<p>: Over the past couple of weeks, my idle speed crept up to 1000 rpm in gear, 1200 rpm out of gear (automatic).<p>: Then, when stopped at a traffic light, the transmission shutdown, givng me a TRANS PROG message from the OBC.<p>: I drove a block further home, shut it off, tried it again an hour later and it ran fine, although still at high idle.<p>: The following day, I was advised to check the battery. Theory was that low battery was calling for more charge, and the idle speed automatically increases to turn the alternator faster to charge faster. Fine, a new battery seemed like a better way to go than some of the alternatives I had imagined.<p>: Went to a battery shop and had a new battery installed. They plugged a voltage source into the cigarette lighter while changing the battery, presumably so the radio, etc. would not have to be reset.<p>: Following the battery replacement, the idle came right down to around 500 rpm. However, a new problem has cropped up. After the car is at temp, and after slowing to a stop, the engine hunts for the right idle speed and bounces between 400 and 600 rpm. Eventually the vascillation gets severe enough that the engine stalls.<p>: At this point, I resign it to the dealer - who tries the old swap it out till it works routine. They installed a new throttle position sensor switch - and the car behaved in exactly the same way as it did when I took it in.<p>: They next want to try an idle valve, and if that does not work, they want to try a new computer (ouch!)<p>: Thanks for your patience in reading through this. Any ideas?<p></i>A BMW dealer should have a way to read the trouble codes stored in the processor and trained staff to operate this equipment. Trouble shooting should not be a swap till you drop affair. If they replaced the TPS then they should have had a trouble code related to the throttle position switch, and then checked the TPS to see if it was defective BEFORE replacing it. If you have the impression they are in a swap till you drop mode then get a better shop. You and your car are not a test bed where they expeiment and you pay no matter the outcome. Ask the next "dealer" do you pay if they can't fix it? Find one that is confident enough to say " We fix it or there is no charge". Did your shop indicate what they did and how they solved the problem on you bill? No? Find a shop that does this including reporting the diagnostic codes they found while trouble shooting.<br> Perhaps the dealer is capable and competent, but from what you described I give a thumbs down.<p>Will<br>88 325ix<br>91 525i

john
12-19-1998, 08:38 PM
Thanks for the follow up. I don't know what the specific trouble code was, but they told me they did go through the diagnosis and did get an indication that the TPS was at fault. Incidentally, I did not pay for the TPS. I left the car there, told them I wasn't going to accept it or pay for it, until it's right.<p>I wish I had some other shops to choose from - I haven't had any luck finding one within reasonable driving distance.<p>If you're interested, I'll let you know how this plays out. Monday, they plan to try an idle valve.<p>John<br>'93 525i

Phil Coppin
12-20-1998, 12:45 PM
The symptoms appear to be the Idle Control Vavle. Idle control valve problem is a typical, and easily solved, problem on your car.<p>Phil C.<br>95 525i 5spd. Sharked

WillO
12-20-1998, 01:04 PM
<i>: Thanks for the follow up. I don't know what the specific trouble code was, but they told me they did go through the diagnosis and did get an indication that the TPS was at fault. Incidentally, I did not pay for the TPS. I left the car there, told them I wasn't going to accept it or pay for it, until it's right.<p>: I wish I had some other shops to choose from - I haven't had any luck finding one within reasonable driving distance.<p>: If you're interested, I'll let you know how this plays out. Monday, they plan to try an idle valve.<p>: John<br>: '93 525i<p></i>

John
12-21-1998, 07:30 PM
Phil,<p>Thanks for the reply. The dealer replaced the idle control valve, and although it has improved to the point where it does not stall, it's still not right.<p>The idle oscillates, and when the lights are on, they oscillate with the engine between bright and dim.<p>I'm taking it back to the dealer tomorrow. I did not pay for the throttle position sensor they put in the first time they looked at it, and it does not seem that the idle control valve completely fixed the problem.<p>Any other ideas?<p>Thanks,<p>John '93 525i


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