Hey All,
99 M3 with Stage 2 Technique Tuning.
I'm looking to solution a problem I've been experiencing with the car. I just haven't taken any time to look into it or research much, the issue: At idle the car runs extremely rich the smell of un-burnt fuel can be smelt quite a bit, however when giving it any bit of gas it goes lean quickly. Would this be caused by a vacuum leak? Bad O2 sensor? Bad MAF?
I'm open to any feedback to get my car back to being enjoyable before I upgrade in the near future.
thanks in advance, Justin
Mod list - M50 manifold; TechniqueTuning Stg2, Apex Arc-8, ZKW euro, clear corners Mike R diffbrace, Koni Yell with HR race
X-brace UCC tranny mounts -BLK/with enforcers, powerflex rtabs,lcabs, AAfanclutch, mishimoto rad, UCC Ultra-cerametallic Clutch.
You will go through days of joy and days of sadness as the pursuit for power leads to madness...
Hey Justin,
Are you running a stock fuel pressure regulator? A boost leak would usually slow Lean at idle and Rich in boost, but you have the opposite. Assuming your fuel pump is OK (which I assume by it being rich at idle and overfueling), I think your pressure just may be too high (bad FPR). Do you have a stock FPR, or aftermarket? Any gauge on it?
Mike
IG: @mikevanshellenbeck
Hey Mike,
Thanks for the quick reply. I am running the stock FPR. No gauge. It has never been replaced. I was about to add that to a list of possible culprits. If this is indeed the issue what paths for replacement would take? I plan of upgrading my setup in the future and would want something capable of supporting 600whp.
Last edited by JuCo; 04-08-2015 at 12:02 AM.
Mod list - M50 manifold; TechniqueTuning Stg2, Apex Arc-8, ZKW euro, clear corners Mike R diffbrace, Koni Yell with HR race
X-brace UCC tranny mounts -BLK/with enforcers, powerflex rtabs,lcabs, AAfanclutch, mishimoto rad, UCC Ultra-cerametallic Clutch.
You will go through days of joy and days of sadness as the pursuit for power leads to madness...
The stock FPR is capable of supporting 600whp no problem, but with a high volume fuel pump, they tend to "overpressurize" the system at idle due to the factory FPR orifice not being large enough to bypass sufficient fuel and keep pressure in check. This can result in a slightly rich idle, but can be tuned around by your tuner, and usually is. The *ideal* setup is an aftermarket FPR that can keep fuel pressure perfect at idle, even with a large fuel pump like a walbro 400lph. If you are OBD1, it will require you chopping off the end of the fuel rail and welding it shut, then running your return line to the aftermarket FPR, then out to the stock hardline. If you are OBD2, you will be bypassing your stock proportioning valve underneath the driver side frame rail near the fuel filter with the same scenario (but no chopping of fuel rail - return line will go through the aftermarket FPR, then to the return hardline).
Hope that helps!
Mike
IG: @mikevanshellenbeck
Good to know. I am OBD2. Being that the FPR isn't an expensive fix this seems like it could be replaced, however the upgrade sounds like it would be worth it. Thanks for the details on the setup Mike.
What are the majority of members here making 400-600whp running? Anyone got any photos of their current setup they wouldn't mind sharing? I'm a visual person.
Mod list - M50 manifold; TechniqueTuning Stg2, Apex Arc-8, ZKW euro, clear corners Mike R diffbrace, Koni Yell with HR race
X-brace UCC tranny mounts -BLK/with enforcers, powerflex rtabs,lcabs, AAfanclutch, mishimoto rad, UCC Ultra-cerametallic Clutch.
You will go through days of joy and days of sadness as the pursuit for power leads to madness...
Here is the install I did on my dad's 1997 M3/4/6 GT35R car. Previously was a TTS2 setup, and had constant off-idle and stomp AFR problems where it would stumble all over the place. After going to the aeromotive, driveability has never been better. Off idle torque and response is dramatically better.
I don't have any pics of bypassing the stock piece, but I can get some in the AM.
Mike
IG: @mikevanshellenbeck
If the vacuum line to the FPR falls off or has a leak you will be rich at idle and lean at WOT.
Sent from my GTX3582R
'97 M3, Estoril blue, 2 dr, euro 6-spd, EFR 9180 divided T4 .92 IWG, RK tuning, CP 8.5:1 pistons, Eagle rods, Schrick cams, L19 11 mm ARP studs, O-ringed block, Supertech stainless/inconel valves, Supertech springs & Ti retainers, ported head, S54 oil pump/pan, 80 lb. injectors, OBD1 intake manifold, Steedspeed twin scroll T4, 3.5" SS exhaust, eBoost2 EBC, HFS-4 W/M injection, AEM Failsafe, Zeitronix data logger, Racelogic TC, OpenOBC w. ethanol %, Ireland Eng. engine mounts, UUC black tranny mounts w. enforcers, UUC twin disc feramic, ARC-8's, MCS 2-ways, Z3 rack, Rallyroad strut bar, X brace, Eibach sway bars, Ground Control LCAB bushings, Bimmerworld RTAB's, Powerflex subframe bushings, 210 4-clutch LSD, Stoptech BBK, titainium shims, steel braided lines, brake cooling ducts.
F
What do your AFRs look like at idle and WOT. You do have a wideband, right?
Mod list - M50 manifold; TechniqueTuning Stg2, Apex Arc-8, ZKW euro, clear corners Mike R diffbrace, Koni Yell with HR race
X-brace UCC tranny mounts -BLK/with enforcers, powerflex rtabs,lcabs, AAfanclutch, mishimoto rad, UCC Ultra-cerametallic Clutch.
You will go through days of joy and days of sadness as the pursuit for power leads to madness...
Aeromotive #13109
1996 332IS
Built 3.2
CES/Steed TS Precision 6466, spraying a "$π!℅" load of meth.
Technique Tuning 80# tune.
1/4 mile 10.84 @ 136.72
Your 1 and only stop for all your BMW performance needs
WWW.CESMOTORSPORT.COM
I just had the same exact thing happen, super rich at idle which slopes up to 14 at WOT. My tuner told me to look for boost leaks and check the line to the FPR. I had the FPR line going to the small barb on the side of the turkey neck adaptor that snaps into the bottom of the OBD1 manifold. I have been since told that that barb doesnt receive full vac or pressure, although I dont know why, you can blow right through it?? I Teed the FPR line into the bypass valve line but have not yet been able to test the car yet. But I have also heard its not good to Tee these lines together, is this true. If not where do you get the vac sources from, tap more barbs into manifold?
96 328i ITR Racecar
95 M3 blk/blk - hillclimb project - http://forums.bimmerforums.com/forum....php?t=1798796 - Retired to street duty after two awesome seasons!
2002 325XiT - daily
Mod list - M50 manifold; TechniqueTuning Stg2, Apex Arc-8, ZKW euro, clear corners Mike R diffbrace, Koni Yell with HR race
X-brace UCC tranny mounts -BLK/with enforcers, powerflex rtabs,lcabs, AAfanclutch, mishimoto rad, UCC Ultra-cerametallic Clutch.
You will go through days of joy and days of sadness as the pursuit for power leads to madness...
Has this been resolved? I installed an aeromotive fpr and it still does the same exact thing, rich at idle and slopes up lean at WOT on dyno. I will be starting my own thread. Hope you get yours resolved, keep us posted!
96 328i ITR Racecar
95 M3 blk/blk - hillclimb project - http://forums.bimmerforums.com/forum....php?t=1798796 - Retired to street duty after two awesome seasons!
2002 325XiT - daily
No not resolved yet, I looked over the car, the lines seemed to be ok. Since you replaced your FPR unit and it didn't resolve the issue I'm a bit worried it might not resolve mine. I'm also on a upgrade path and will most likely replace the walbro unit with the larger 450lph model however I'd like to sort the car out before I make too many changes. I'll let you know as I go along. Do you think you could share some photos either here or in a PM of your FPR setup and how you ran the lines, placed the unit etc..
Mod list - M50 manifold; TechniqueTuning Stg2, Apex Arc-8, ZKW euro, clear corners Mike R diffbrace, Koni Yell with HR race
X-brace UCC tranny mounts -BLK/with enforcers, powerflex rtabs,lcabs, AAfanclutch, mishimoto rad, UCC Ultra-cerametallic Clutch.
You will go through days of joy and days of sadness as the pursuit for power leads to madness...
Did you ever get this sorted out? My TT Stage 2 is running pig rich at idle.
was there any fix to this issue? I am having this same problem since a week or so ago after I fixed some vaccume leaks using my smoke machine. And now I get 10 - 11 idle and around 17 - 22 WOT!
Fuel Pressure Regulator?
Fuel Pump?
Injectors?
Spark Plugs?
Coils?
MAF?
"So we've come to the conclusion that BMW just has parts laying around they decide to throw on cars for no reason."
Interest on a Very Budget Supercharger Build??
I experienced something similar when I had a torn line going from ICV to throttle elbow. Car ran pig rich at idle and when I gave it gas I'd be in the 15-17afrs. Currently car runs great outside of boost but I'm still a little rich at WOT cuz of my fpr. From what I hear, your fuel pressure should be 44psi at idle so I'd put a gauge to the rail.
1996 332IS
Built 3.2
CES/Steed TS Precision 6466, spraying a "$π!℅" load of meth.
Technique Tuning 80# tune.
1/4 mile 10.84 @ 136.72
Your 1 and only stop for all your BMW performance needs
WWW.CESMOTORSPORT.COM
Hi
I recently started spoting same issue. Checked the vaccum with Torque bluetooth OBD 2 scanner. Vaccum/Boost showing at -29.92 in hg. From start to end its steady at -29.92. Is that bad reading. Pls help if any issue that fig pointing to.
From the grave.. is there any answers to this common problem?
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