BMW M3 Forum
BMW M3 Forum BMW M3 Gallery BMW M3 Reviews BMW M3 Social Groups BMW M3 Chat M3Forum Sponsors >>
Loading


Mobile M3forum
Go Back   BMW M3 Forum.com (E30 M3 | E36 M3 | E46 M3 | E92 M3 | F80/X) > BMW M3 Discussions > E36 M3 (1992-1999)
Tire Rack Buy Winter Tires Now!
Not a member? Register Now!
Register Gallery All Albums Garage Search Today's Posts Mark Forums Read Calendar FAQ

E36 M3 (1992-1999) {Euro - S50 B32 321hp @ 7400 rpm} {U.S. - S52 B32 240 hp @ 6000 rpm}
Total Produced: 71,212 - Years Produced: 1992 to 1999


Reply
 
Thread Tools Display Modes
Old Thu, Apr-13-2017, 04:55:03 PM   #1
cpandrewschmidt
Registered User
 
cpandrewschmidt's Avatar
 
Join Date: Mar 2003
Age: 35
Posts: 129
Reputation: 0 cpandrewschmidt is on a distinguished road
Location: Wisconsin





Default rich condition and fuel pressure help

Hi all,
I have a 98 M3 with a Eurosport supercharger recently acquired and I have been doing maintenance. I'm chasing the P1108, 1109 CELs. Done just about everything in the book I can think of, vacuum leaks, new o2 sensors, ICV cleaning, vanos kit, valve cover, fuel filter, CCV, clean MAF. I'm running rich with fuel trims of LTFT -8.6% and STFT -20% ish at 2500 RPM.

I checked fuel pressure. With ignition on car not running I get 41 psi with FPR vacuum line plugged in. However, its pressure starts to drop off quickly. Like 30 psi within a minute. With car running FRP vacuum line in I'm at 41 psi and 51 psi with it off. So, I believe that's OK. Appears FPR is working then? So, I think injectors might be leaking. Unplugged injectors, turned on fuel pump watched injectors, no leaking.....but pressure still drops. So, car runs steady at 51 psi with FRP unplugged, 41 psi with it plugged in. When I start the pump FPR plugged in (not starting the car) the gauge instantly goes to 51, but immediately drops to 41 psi then pressure bleeds off somewhat quickly.

I started the car and turned it all the way off and pressure holds, doesn't drop off. That tells me it doesn't appear to be siphoning back when car is off, I've never had a hard start problem so it's not a check valve. Pressure only drops when key is in AUX position. When I pinched the fuel lines at the back of the rail the pressure on the gauge would go up and down, doubt that means anything.

So, still maybe a partially functioning FPR if there's such a thing? Hate to throw $90 at one not truly knowing. Or maybe it is tune related, but this problem didn't exist when i first got the car. I'm out of ideas. I took to a shop who could dig deeper with their code reader and he claimed if it weren't for the supercharger the car is running within BMW stock specs. He claimed it's probably the tune. I checked with TRM tuning who did the car and they said their specs would have the fuel trims targeted at 0%. So, I still think it's mechanically related.

Thanks for any tips you might have!
Andrew
__________________
98 M3 Eurosport SC sedan
Jump to top cpandrewschmidt is online now   Reply With Quote
Sponsored Links
Register now and remove these ads
Old Thu, Apr-13-2017, 06:20:17 PM   #2
NolliM3
Registered User
 
NolliM3's Avatar
 
Join Date: Jun 2014
Posts: 675
Reputation: 0 NolliM3 is on a distinguished road
Location: Louisiana

United States




Default Re: rich condition and fuel pressure help

It seems that you're caught in he says she says. Your fuel pressure although acceptable seems a little weak...should be closer to 50psi. Mechanically related...well, you're still guessing. What size injectors you have...do you smell gas when you pop the hood? How did you determine that you're running rich? Is your FPR stock? Do you have a computer with INPA and the interface to put on the diagnostic port.
__________________

1995 Alpine White...X-Brace, Fan delete, Cold Air Intake
Jump to top NolliM3 is offline   Reply With Quote
Old Thu, Apr-13-2017, 06:45:32 PM   #3
cpandrewschmidt
Registered User
 
cpandrewschmidt's Avatar
 
Join Date: Mar 2003
Age: 35
Posts: 129
Reputation: 0 cpandrewschmidt is on a distinguished road
Location: Wisconsin





Default Re: rich condition and fuel pressure help

I believe the injectors are the 36 lb that supposedly come with the kit, they would only have 20k miles on them when the kit was installed:

http://www.eurosporthighperformance....ercharger.html

The FPR looks pretty old, so I assume it's stock. I have a scan tool to read live data and that's how i got my STFT and LTFT readings, which indicate the rich condition.

I thought 51 psi (3.5 bar) with vacuum line off FPR is where pressure is supposed to be, at least that's where it is with car running.

Unfortunately don't have INPA but could probably download it. Is there version or link out there recommended? My brother just bought a cable to code his 135i so I can probably use that.
__________________
98 M3 Eurosport SC sedan
Jump to top cpandrewschmidt is online now   Reply With Quote
Old Thu, Apr-13-2017, 10:07:02 PM   #4
NolliM3
Registered User
 
NolliM3's Avatar
 
Join Date: Jun 2014
Posts: 675
Reputation: 0 NolliM3 is on a distinguished road
Location: Louisiana

United States




Default Re: rich condition and fuel pressure help

So, I take it you didn't smell gas...I would take the fuel pressure right after the filter or before the FPR...also if you can get some data while you're driving that would clarify the tune is ok if all the vacuum line looks good (non dry rotting). The fuel pressure does take a while to return to normal when the car turned off (couple hours)...you'll find that out whenever you ever change the filter...you should get 51psi just on the fuel line.

Honestly, it does sound like your tune which data would confirm.
__________________

1995 Alpine White...X-Brace, Fan delete, Cold Air Intake
Jump to top NolliM3 is offline   Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump



All times are GMT. The time now is 09:04:37 PM.


Powered by vBulletin® Version 3.8.6
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
M3Forum.com and M3forum.net is in no way sponsored, endorsed or affiliated by or with BMW NA / BMW AG or any of it's subsidiaries or vendors.
BMW and M3 (E90 M3 | E92 M3 | E93 M3 | E46 M3 | E36 M3 | E30 M3) are registered trademarks of BMW AG.
M3Forum Terms of Service
Copyright 1999-2017 M3Forum.com
Discussing rich condition and fuel pressure help in the E36 M3 (1992-1999) Forum - {Euro - S50 B32 321hp @ 7400 rpm} {U.S. - S52 B32 240 hp @ 6000 rpm}
Total Produced: 71,212 - Years Produced: 1992 to 1999 at BMW M3 Forum.com (E30 M3 | E36 M3 | E46 M3 | E92 M3 | F80/X)