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Old 05-23-2011, 03:51 PM   #21
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I have over 4 years of tuning this beast under my belt with the same injectors and ecu. I know what it was capable of, this is why I know there's an under lying issue.
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Old 05-23-2011, 04:27 PM   #22
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my first guess is a componet in the MS took a hit and needs replaced, even if you still can't see any visible damage there maybe internal damage, I check everything out thats need for injectors, etc
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Old 05-23-2011, 04:55 PM   #23
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I have logs of a relatively steady idle at 17.5:1 AFR.

above that it started to bounce around and die. it never did really misfire audibly.
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Old 05-23-2011, 04:59 PM   #24
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yeah. I do too:




with the a/c running to boot.
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Old 05-23-2011, 05:02 PM   #25
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How's the EGTs for that lean of an idle? Any way to save gas is a good way in my book..
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Old 05-23-2011, 05:38 PM   #26
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Supply voltage: 11.33v
U5 Pin 1: 10.44v
U5 pin 2: 0v
U5 pin 3: 4.99v
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Old 05-23-2011, 05:43 PM   #27
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That's normal, what matters is what you would see on the scope, with the car running.
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Old 05-23-2011, 05:45 PM   #28
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gotcha. i knew that was normal, so why i posted. they look okay physically. no spares here, will take trip to store.
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Old 05-23-2011, 06:07 PM   #29
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ugh the shack doesn't have the TANT ones i need.

fooling around, I find that I have 14.5K of resistance through the c16 if measure from positive to neg, if I reverse the leads of my DMM its 514ohm.

if I do it to the C17 I get 608 and 336ohms respectively.


when i do the same to sleepinbaclkbeautys unit, it's look 105K through c16, everything else is similar.
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Old 05-24-2011, 09:40 AM   #30
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I wasn't able to source the proper c16 and c17. I threw in two 10uF caps in place of c16 and a 22uF aluminum cap for c17. Replaced c22 and c18 with the proper parts.

No change. after warmup the car was idling around 13.5:1 at 1.831ms of fuel at 900RPM. during my drive to work, the idle became richer, hitting closer to 12.5:1 at high 1.7XXms pulse widths and the vacuum pulled stronger reading 33kPa vs 35kPa during the first few idling sessions.

Once I got to work I started pulling fuel a little to bring it closer to 14.0:1. There's just a certain point were the car will suddenly miss and like skip a beat, then there is just no recovery, it gets into an endless oscillation. As soon as I add just enough fuel to bring it back to ~13.5:1, it smooths right up.

I mean, even if the car was happiest at 13.5:1 at idle, it still shouldn't go entire to **** when I lean it up, I don't ever remebering it behave in such a manner. It might get choppy and uneven, but it shouldn't freak the **** out. Unless my LC-1 has crapped its pants and isn't reporting the correct AFRs at low airflow speeds, but I don;t think the LC-1 can report false richness if properly calibrated, as it would have to increase the voltage when it sniffs gas.

Otherwise it drives like normal, and when I do idle richer, it idles perfectly. You wouldn't think there was an issue otherwise. I'll continue to monitor my overflow levels, if it starts to drop again, I'm going to have to consider the head gasket again.

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Old 05-24-2011, 09:46 AM   #31
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have you checked with pryometer the exhaust header to see if there is a big difference in temp between cylinders, maybe one injector or so is off enough compared to others. Just a thought.

Just a note on a wideband, I've seen one off by a whole point richer at idle but is only off by .1 at wot and cruise compared to another wideband we were testing with.
it would read like 12-13 and when we tried to lean it out it wouldn't take and start doing same crap yours would. AFter install of the SLC DIY wideband, we found out that it old one was reading a point richer at idle and we were near 14 at idle. Old injectors, old 12v inline 6 bmw engine
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Old 05-24-2011, 09:49 AM   #32
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Why would that happen on two sets of injectors?
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Old 05-24-2011, 10:43 AM   #33
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Quote:
Originally Posted by Braineack View Post
I wasn't able to source the proper c16 and c17. I threw in two 10uF caps in place of c16 and a 22uF aluminum cap for c17. Replaced c22 and c18 with the proper parts.

No change. after warmup the car was idling around 13.5:1 at 1.831ms of fuel at 900RPM. during my drive to work, the idle became richer, hitting closer to 12.5:1 at high 1.7XXms pulse widths and the vacuum pulled stronger reading 33kPa vs 35kPa during the first few idling sessions.

Once I got to work I started pulling fuel a little to bring it closer to 14.0:1. There's just a certain point were the car will suddenly miss and like skip a beat, then there is just no recovery, it gets into an endless oscillation. As soon as I add just enough fuel to bring it back to ~13.5:1, it smooths right up.

I mean, even if the car was happiest at 13.5:1 at idle, it still shouldn't go entire to **** when I lean it up, I don't ever remebering it behave in such a manner. It might get choppy and uneven, but it shouldn't freak the **** out. Unless my LC-1 has crapped its pants and isn't reporting the correct AFRs at low airflow speeds, but I don;t think the LC-1 can report false richness if properly calibrated, as it would have to increase the voltage when it sniffs gas.

Otherwise it drives like normal, and when I do idle richer, it idles perfectly. You wouldn't think there was an issue otherwise. I'll continue to monitor my overflow levels, if it starts to drop again, I'm going to have to consider the head gasket again.

I have the exact same problem. I thought I had a leaky head gasket. Every once in a while when I start the car in the morning I can see behind the car where it blew out a liquid spray. My coolant level never drops. My spark plugs don't indicate coolant.

I hope you find something that fixes this. I'll be right behind you doing it to my car to see if it solves my issues.

Have you played with the injector time at idle. degrees before tdc it injects the pulse?
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Old 05-24-2011, 10:53 AM   #34
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Yes, I've gone from 360 (lands fuel after valve has opened) to 10 (a long time before valve opens).

Nothing on my setup has changed. I take that back, I added a 255HP fuel pump and everything was fine with that, I did that before I swapped the alternator in an effort to reduce my pulse witdhs in boost (went from 95% to 80%).

It after the new alternator I started having the issue. and it was just one random day soon after loading new firmware I noticed my idle went to ****. I thought it needed tuning, but I couldn't tune it out. So I have been poking around the engine bay trying to solve it. This all happened within the last few weeks.


When I pull my plugs at idle they always are coated with a white and falkey "powder". I have no visable coolant leaks and can hold 20psi of pressure for 5 minutes when pressuring the radiator. If I start the car, the gauge doesn't move or flicker when running and revving the motor.
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Old 05-24-2011, 01:14 PM   #35
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Do you have COPs?
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Old 05-24-2011, 01:16 PM   #36
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yes.
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Old 05-24-2011, 01:19 PM   #37
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Try a different set.
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Old 05-24-2011, 01:20 PM   #38
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hmmm...I'm sure y8s loves me by now.
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Old 05-24-2011, 01:58 PM   #39
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he didn't say you had to try mine.
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Old 05-24-2011, 02:05 PM   #40
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lawlz.

I'm begining to think it's my LC1 controller.

I was looking at logs before I noticed problems, and found a few just after I installed my 255 pump and was trying to log my max duty cycle.

I was idling at 15.0:1 and my VE% was 28.x. I fattened it up to around 30% on a later map and was averaging 14.5:1.

today I was idling at an average of 26.1% and my AFRs are showing between 13.5-11.9:1. There is no consistency in my tune, this morning I never saw over 15.0:1 when cruising, on the way to the post office I was seeing 16.5:1 in places.

I'm going to see if I can't just load an older map and drive it with no EGO and see how it feels.
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