CM code: 41 October 21, 2009, 09:57:17 PM Hey guys! I'm having a bit of trouble with my Turbo Coupe, and I'm hoping someone might have some ideas...I have an '88 Turbo Coupe with a 5-speed that frequently idles quite roughly, and tries to stall when you push the clutch in. It will also break up at speed. The exhaust seems rich to me, though it seems to burn your eyes a bit, so maybe it really is a bit lean. Nonetheless, the CEL comes on quite a bit after it has warmed up. This happens mostly at speed, though when it is running its worst, it will also come on at idle.So far I have;Adjusted base idle (900 rpm)Adjusted base timing (13* w/spout unhooked)Adjusted fuel pressure (40 at idle w/vacuum unhooked)Replaced the O2 sensorSwapped out the VAMSprayed carb cleaner everywhere I can think of in search of a vacuum leakBlocked the EGR passages to ensure it wasn't leaking.It sets an KOEO code 41No KOER codesAny ideas as to where to go next? I'm leaning towards the ACT or ECT.I do have a bypass valve. It picks up from the inter-cooler and dumps in between the VAM and turbo inlet. Is it possible that this is messing me up?Argh! You know, the nice thing about GM computers is that you can see data-stream. Anyone know of a scan tool that will show EEC-IV data-stream?Shiny Side Up!Bill Quote Selected
CM code: 41 Reply #1 – October 22, 2009, 06:46:56 PM Ok guys... I may have found the solution.I found a .2-.3 volt voltage drop between the negative battery terminal and the engine block. I ran a ground wire directly from the negative terminal to the block, and reduced that to .015, after which I have driven 50-some miles with no more problems. I am not 100% convinced that this is it, but so far... Shiny Side Up!Bill Quote Selected
CM code: 41 Reply #2 – October 22, 2009, 07:02:57 PM Code 41. Did you get this KOEO, or KOER? Either way, it's pointing at the O2 sensor (HEGO or EGO, whichever you may have) If you lose the O2 sensor, yes, it will run rich because it has no way to know when to trim the fuel mixture. No switching normally indicates LEAN condition, which will make the EEC turn on the injectors more for "limp mode" operation. Mine never ran rough when the O2 went south, but it sure did run rich. This was on my F-150, and that thing DRANK fuel. Popped a new HEGO in, bingo, ran like a top. Here's a good site to interpret your favorite codes. www.fordfuelinjection.com Loads of good info on that site. Quote Selected
CM code: 41 Reply #3 – October 22, 2009, 08:27:45 PM It was a KOEO Constant Memory code. I replaced the O2, but to no avail. On the other hand, the ground problem seems to have done the trick. I'll know for sure tomorrow when I take my wife to work. An hour in traffic is sure to make it act up if it is going to do so. Her car, a Mercedes SLK230 is in the shop for a seized supercharger. Thank goodness for an extended warranty! $2500 for the repairs! Thanks for the website info. I'll definitely bookmark it! Shiny Side Up!BillQuote from: Old_Paint;295998Code 41. Did you get this KOEO, or KOER? Either way, it's pointing at the O2 sensor (HEGO or EGO, whichever you may have) If you lose the O2 sensor, yes, it will run rich because it has no way to know when to trim the fuel mixture. No switching normally indicates LEAN condition, which will make the EEC turn on the injectors more for "limp mode" operation. Mine never ran rough when the O2 went south, but it sure did run rich. This was on my F-150, and that thing DRANK fuel. Popped a new HEGO in, bingo, ran like a top. Here's a good site to interpret your favorite codes. www.fordfuelinjection.com Loads of good info on that site. Quote Selected
CM code: 41 Reply #4 – October 23, 2009, 09:26:32 PM Ok, if CM, that means you'll possibly have to clear it. Easy to do. Start the KOEO test. When it starts flashing the CM codes, pop out the jumper on STI, and it will reset any stored codes. Plan B, disconnect the negative lead on the battery for 10-20 minutes. That will make it learn all new habits in the fuel tables. Not a bad idea any time you replace a sensor. Quote Selected
CM code: 41 Reply #5 – October 23, 2009, 10:11:00 PM Quote from: Old_Paint;296150Ok, if CM, that means you'll possibly have to clear it. Easy to do. Start the KOEO test. When it starts flashing the CM codes, pop out the jumper on STI, and it will reset any stored codes. Plan B, disconnect the negative lead on the battery for 10-20 minutes. That will make it learn all new habits in the fuel tables. Not a bad idea any time you replace a sensor.Thanks! Actually though, I have an OTC Genesys, so I can just clear the codes that way. And so far, still no CEL or related problems.... I'm thinking more and more that it really was the voltage drop! Shiny Side Up!Bill Quote Selected
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