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Author Topic: Idle Issues  (Read 12984 times)

powow66

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Idle Issues
« on: January 08, 2016, 08:44:53 PM »

Hey guys!

New to the forums, but have been reading through lots of threads and you guys have helped me a lot with my build!
I've spoken on the phone with Brody, and first of all I'd like to say I'm very happy with the m50/s50 turbo tuning kit. The WAR chip software is an amazing platform that has extended my knowledge of cars tenfold. So far on the base tune my car pulls great at 9psi, and I've been successfully playing around with the tune to get the AFRs around 12.5 at WOT. Part throttle the car is settling nicely around 14.7 at cruising speeds.

HOWEVER here's my current issue which is related to this thread ( http://forums.millerperformancecars.com/index.php?topic=65.msg241#msg241 ):

-When I cold start the car, I need to pump the throttle right afterwards because it seems like the car has fuel starvation and wants to stall out. The car will then idle fine and start to warm up, but I notice that my AFR's slowly drop from ~14.7 all the way down to about 10.9, which is way to rich I think.

-Additionally, the idle tends to lean out intermittently and the car stalls once its warm. Doesn't matter if I drove it around or not, I need to feather the gas so that the idle will hold. From what I've been told by the admins at MP and from what I've read, I do think that the O2 sensor is overshooting the fuel corrections to bring the AFRs to 14.7, and that by changing the idle fuel values, I can minimize how much correction is needed to smooth out my idle. The AFRs once the motor is warmed up hovers at about 11. My current issue lies here, because so far I've tried changing the idle fuel values on the base tune from 100 down to 70, but once rewritten I see no change in the AFR's, it even drops a bit down to 10.8 occasionally. Turning the O2 sensor off hasn't made any noticeable affect, but I will continue playing with the fuel map and O2 sensor tab tomorrow to see if I make any progress!

Here is a list of the major components of my build:

0.120" MLS Head Gasket
ARP Head studs kit
Precision 5858 turbo
Miller WAR chip
60 lb siemens injectors
Miller MAF
CXracing intercooler
CXracing tubular T3 manifold
Tial WG and
Tial BOV (Currently open vent at idle, good/bad?)
3" plumbing
IE Oil cooler cap + oil cooler
AEM wideband O2 sensor + gauge

Replaced components:

O2 sensor
Knock sensors
Camshaft + Crankshaft position sensors
fuel pump
copper plugs (gapped to 0.025")
Ignition coils +boots
Cylinder head temp sensors
Oil pressure sensor
Both timing chain tensioners

Addionally:

-ecu scanned with no codes
-O2 sensors are about 5" from the exhaust turbine of the turbo
-cleaned ICV (strong buzz when key is in the ON position)
-inspected for boost leaks (car idles at about 22 mmHg of vacuum pressure)
-inspected FPR
-fuel pressure will be inspected, because I'm not sure how recent my fuel filter was replaced

Are there any other fuel maps I can modify to further diagnose the issue(I.e CT idle fuel maps, acceleration enrichment) and/or anything I should check mechanically? Any advice/suggestions/input would help me a lot! I'm very enthusiastic about finishing my build, and this is the final thing that needs to be resolved to get my car to the dyno! My apologies for the dense post! I appreciate all the help!

Cheers to a new year!
« Last Edit: January 08, 2016, 09:24:15 PM by powow66 »
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bulletholez

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Re: Idle Issues
« Reply #1 on: January 31, 2016, 06:54:43 PM »

Hey man! Glad your car is running great! I have literally this EXACT same issue that I've had 0 luck solving. Still trying to troubleshoot it to this day. I'm pulling about 20in of vacuum at idle and it loses it as it leans out, until a quick feather and back to rich idle. BOV being open as it's still metered air as it's pre-MAF shouldn't cause issue, unless it's causing turbulence. Random question, but was your car equipped with ASC from factory? This may sound weird, but my car ran GREAT when I first put it together, but I actually had my TPS plugged into the ASC "TPS" plug but obviously forever had a CEL for no TPS. Once I realized I had it in the wrong plug I corrected that, and my CEL went away, but that's when my problems started. I actually slowly started getting more lean conditions over the course of driving it. this may sound stupid but I'm out of options, I'm going to try and splice the ASC and TPS cables so the ECU sees response from "both". I'm really out of options unless my brand new MAF is bad or some other sensor that controls idle circuit that I don't know about went out... but even O2 sensors on/off still nothing. I'll check back every once in a while to see if you make any leway and if I find anything I'll post it up here. We can't be the only two with this problem! My build is very similar to yours also, could small differences that wouldn't do anything. I've changed the FPR on my car as well as flow tested my injectors to no avail.
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powow66

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Re: Idle Issues
« Reply #2 on: February 03, 2016, 12:04:29 PM »

Thanks for your input bulletholez!

In regards to my BOV, I've tried clamping down the vacuum supply so that it would stay closed at idle just to further diagnose my issues with no luck. I do agree though that turbulence could be an issues, which is why I'm in search of a stiffer spring for it. To answer your ASC question: Yes, my car came with it from the factory, but I don't think I switched the plugs between the TPS and the ASC (since there's no check engine light whatsoever). I doubt any of the WAR chip/turbo kit hardware is faulty, but rather we have some mechanical issue we're overlooking  :-\.

Unfortunately I'm not gonna be able to further diagnose my issues until early March (my spring break from college), BUT the things that I am planning to do are:
-Replace the TPS sensor (I took resistance values and didn't get exactly a variable 1-4kohm upon opening the throttle, but more like variable 1.45-4kohm. Not sure if that's enough of a difference to need replacement, but I thought I'd do so to rule it out as being part of the issue).
-Check for Vacuum leaks (I'm gonna start by doing the old brake cleaner trick, spray around intake plumbing and observe for idle surge to find a leak)
-Unplugging the ASC (if that does anything)
-Check compression values
-Check Fuel Pressure/change fuel filter
-Trying different Crankcase vent methods (I'm not sure if I'm pulling enough of a vacuum from the crankcase, nor am I sure if that could contribute to the overall idling issue)

Regardless, I'll also stay active for any updates you may have (forgive me for delayed responses, for I am overloaded with schoolwork/work/etc.) and will post further any headway I make as well! We got this!
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powow66

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Re: Idle Issues
« Reply #3 on: February 08, 2016, 08:46:04 PM »

Quick random thought/update: upon doing some research of the VANOS system (for my engineering research paper ;D), I realized that the vanos system retards the intake camshafts at idle. Getting to the point, I've never turned vanos ON, or set it at any of the VANOS control tab functions since I got the car running. Could selecting the "5300 (stock)" tab help with the issue or not at all? Cheers
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bulletholez

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Re: Idle Issues
« Reply #4 on: February 18, 2016, 05:12:30 AM »

I've tried it on, off, everything. No change. Understood on the lack of time! The cold New England weather with no garage to currently use plus work and my family are slowing my wrench time. I've tried emailing and calling Miller with no response, slowly losing faith in this setup especially when a compression and boost/vacuum test both check out okay on my motor and my entire fuel system is new, injectors have been flow tested and have new filters, TPS is new, ICV is functioning properly, crank and cam sensors are new, MAF is clean and only has 1000 miles on it, the only things left are the air metering and ECU/tune. I'm actually on a silver label DME, I may bite the bullet and buy a red label to try (I hate spending money on shots in the dark), but after that this car is either getting a standalone/some other tuning setup or parted out. I'm very much over this at this point all last year it sat as I tried troubleshooting it, and have had other certified mechanic and BMW mechanic and insane gear head friends all get baffled by it still having issues. I don't want to band aid it, I want to fix it.
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Chris91e30

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Re: Idle Issues
« Reply #5 on: February 29, 2016, 05:39:44 PM »

hey there guys, ive had the turbo tunning kit in my m50 swapped e30 and have had the exact same issues. ive swapped the dme and that didnt change , o2 on and off made no difference either. ive even turned the fuel in the idle tables to zero and can still start the car without issue and t still idles anywhere from 10.6 to 11afr with a little surging once its warmed up. ive tried different gaps on the plugs and even crazy timing changes just to see wat would happen and have had zero luck. i work for bmw and even im baffled. i also swapped the tps sensor for another one out of a another car in the shop and no change. i even put e85 in the car so it would lean out but only did so in part throttle the idle still drops into the 10s with e85! driving me crazy
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powow66

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Re: Idle Issues
« Reply #6 on: March 03, 2016, 04:25:29 PM »

I'm sorry to hear that Chris91e30! I might change my tps sensor as well and maybe mess with some timing because that's where I'm at so far. Ill post of any headway I make once I go home for spring break this weekend. Is there any way to tag Brody or MillerP to this thread? I've been trying to contact them over the phone and email with no luck  :-\.
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bulletholez

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Re: Idle Issues
« Reply #7 on: March 06, 2016, 01:37:27 AM »

I've had and been working on this issue since last spring with no avail, and also can't get ahold of them now. About to dump this kit and go RK. Happy to know it's not just my car being a freak.
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powow66

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Re: Idle Issues
« Reply #8 on: March 09, 2016, 03:03:53 PM »

MIGHT HAVE FIGURED IT OUT. Don't hold me to this being the only solution, but it turns out despite my vaccum reading -22mmhg, I changed my injector seals with oem ones and lubed them up with Vaseline. Popped them back in and despite the fuel rail being empty of fuel the car started quickly and didnt stall out!! The car now idles pretty good with the o2 sensors on, fluctuating between 13.9-15.7 AFRs at 13.5 degrees of timing advance. Maybe I'm having good luck with the warm weather in Massachussetts, but I'll update in a few days to see if anything changes! I hope this helps guys!
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millerperformance

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Re: Idle Issues
« Reply #9 on: March 17, 2016, 02:24:26 PM »

I've had and been working on this issue since last spring with no avail, and also can't get ahold of them now. About to dump this kit and go RK. Happy to know it's not just my car being a freak.

Have you tried grounding your ECU directly? Take a wire and wrap it around one of the ECU cover bolts and fasten the other end to a chassis ground directly. We have seen this problem lots, especially in swap cars.

Also, what is the MAF output voltage at idle? Should be around 0.7v
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bulletholez

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Re: Idle Issues
« Reply #10 on: March 22, 2016, 10:04:25 AM »

ECU is and has been grounded as you described, I'll get a MAF reading tonight when I get home, maybe the other guys with this issue can post up their results also.
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powow66

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Re: Idle Issues
« Reply #11 on: March 23, 2016, 09:19:59 AM »

I will also try grounding the ecu once I get back from school in May. As for another update, before I left for break my "new" pump decided to quit on the car...time to order a Walboro 255!
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bulletholez

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Re: Idle Issues
« Reply #12 on: April 11, 2016, 10:06:22 AM »

ECU grounded, MAF reads .76-.79v at idle. just replaced vanos seals, rest of the motor relatively solid. no vacuum or boost leaks. Still confused. Hoping this is on my end. Going to try tuning it out some more. I still don't understand why the idle tuning tables don't affect idle at all.
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bulletholez

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Re: Idle Issues
« Reply #13 on: April 12, 2016, 03:56:26 PM »

Got some work done today, vanos seals replaced, started tuning some... got it driving OKAY... the turbo base tune Miller supplied basically doesn't nothing at this point, but it used to run great. knowing my MAF is in spec was a good start, but i ran across this today. may be the solution for a couple of us? a weird solution tho, I've never ever ever touched my idle screw.

http://cars.forumsee.com/a/m/s/p12-15951-01827408--miller-war-chip-413-and-506-p1216-1216-tps-sensor-error.html
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bulletholez

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Re: Idle Issues
« Reply #14 on: April 13, 2016, 05:05:11 AM »

I'll just keep posting here until someone figures it out. I just got a great deal on another ECU, also, my car is a silver label, anyone running a red label? any difference, I know it SHOULDNT matter seeing as the EWS is the only difference.

On another note, while messing around yesterday, I got the car to pop a 1216 and a 1282 code, TPS Potentiometer and Fault Memory Error, which is what prompted me to pick up another ECU. TPS is brand new (third one, because I kept thinking the car wasn't using the idle circuit if the TPS wasn't reading right because I wasn't able to change idle fuel in the tune). Hell if I know. I guess I'll try the cam sensor next. I thought I got a 1244 code (cam sensor) but I went thru all the codes again and I only got the 1282 and 1216... hell I have no clue. I should just replace every sensor on the car and see what happens at this point.
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