rich condition and fuel pressure help

[cpandrewschmidt]

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

[mcgnms]

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.

I started the car and turned it all the way off and pressure holds, doesn't drop off.

Wait a minute, so simply shutting the car off and it holds pressure, but energize the pump with ignition (no start) and it drops? Just want to make sure I got that correctly.

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.

This doesn't add up. It sounds like you have a ~51 PSI regulator that is manifold referenced. At idle with about the ~10 PSI of vac as you'd expect it brings it back down to 41 PSI. When the car is off however, the regulator has no vacuum so it doesn't matter if its plugged in or not. Pressure should be 51 PSI.

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.

Okay so it does shoot up to 51 PSI first. Hmm.

This really doesn't sound like a leaky injector or a fuel check valve. Its also unlikely to be the regulator since running fuel pressure looks fine and a rich condition implies it would be stuck at a higher pressure, not a low pressure like you're getting when the pump is primed.

It could be multiple things but since you said it worked fine prior to installing the kit, I would start looking elsewhere.

You did remote tuning right? They're in GA and it says you're in WI. My next step would be confirm that TRM knows exactly what injectors you have. Are you sure your injectors are the ones that came with the kit originally? Are you sure the PO didn't install or provide larger injectors which would certainly cause a rich condition if the tune assumes smaller ones?

Can you get BMW specific codes?

[cpandrewschmidt]

"Wait a minute, so simply shutting the car off and it holds pressure, but energize the pump with ignition (no start) and it drops? Just want to make sure I got that correctly." - yes, that's correct, strange I thought too.

"It could be multiple things but since you said it worked fine prior to installing the kit, I would start looking elsewhere." - the kit was installed prior to my owning it. It was installed at approximately 90K miles, has 113K miles on the car now. When I first got the car it didn't have this problem. All I know from the previous owner was the kit was installed by TRM in GA. They have confirmed they did work on the car, but they state their target fuel trims would be around 0%. I have to assume the injectors are the ones that came with the kit. The previous owner didn't seem like the type of car person that would have changed that after they did the work.

Unfortunately I can't get bmw specific codes. I took to a local shop and they claim the car runs within bmw specs except the supercharger is throwing things off.

Is it possible my routine maintenance items could have "tightened" up the car? If it was originally tuned and isn't mechanically as sound as it is now is it realistic it could run richer?

Things I've done again: valve cover (previous one was leaking bad), vanos re-seal, spark plugs, new boots on coil packs (haven't changed coil packs), coolant flush, cleaned MAF and ICV, fuel filter, Supercharger oil change, fixed small vacuum leak. I have a new FPR on order just to confirm it's not that. Probably original anyway so might as well replace it.

Thanks

[mcgnms]

Your setup is a standard MAF->Supercharger->Throttle? In other words, its a normal draw-through with a pre-throttle blower? A leak post-throttle (a vacuum leak) will cause a lean condition, meaning this isn't your problem. A leak between the MAF and the supercharger can also cause a lean condition, so that probably isn't the problem either. However, if there is an air leak somewhere after the supercharger, but before the throttle plate then in your case, that would cause the MAF to measure flow that ends up pushed out before it gets behind the throttle and that can cause a rich condition (negative trims). Check very carefully in this region.

It sounds like fuel pressure is pretty normal while its running so lets start with the above. There can always be multiple unrelated issues. If your SC is a TS mounted post-throttle then ignore the above.

[mcgnms]

Check also to make sure your MAF isn't installed backwards by accident. It is somewhat possible that the MAF is on its way out as well.

[cpandrewschmidt]

This is a picture of the Supercharger set up. MAF is on correctly as I checked this twice MAF is the 803 version that was replaced 20k miles ago when the supercharger went on so that should be good.

SC.jpg

I'll pressurize system again to check for leaks. Haven't been able to find any and have had another set of ears listen as well. Would a leak between engine and exhaust pipes cause a rich condition? I don't think i have a leak there but i'm also not sure if my pressurized air is reaching that far.

[95AWM3]

Is the 803 wired in properly? I know some tuners require either bridging the grounds or a resistor to fix the scaling of that MAF.

[cpandrewschmidt]

Is the 803 wired in properly? I know some tuners require either bridging the grounds or a resistor to fix the scaling of that MAF.

I'm not sure how to check, but since this problem didn't exist before i assume that was done correctly initially.

[95AWM3]

I'm not sure how to check, but since this problem didn't exist before i assume that was done correctly initially.

yes after I hit submit I read the part about having it in for 20k, so have you been driving it this whole time with these issues? or did they only just come up?

[cpandrewschmidt]

CELs only started coming up a few weeks ago. If my timing was messed up from my vanos seal could that cause rich condition? That's the only other thing I can even remotely really think of. I used a homemade tool to lock CAMs. They did slip slightly when taking vanos off. I re-flattened CAM to head upon installation and everything stayed locked tight. Checked timing on flywheel notch several times through and it always lined up. Check engine light didn't come on till a couple weeks after the vanos job so I don't think it's that either. Plus everything idles perfectly. I think that's a long shot, but how can i confirm that?

I'm going to try to look into trying to download this software and see if I can get it to work http://forum.e46fanatics.com/showthread.php?t=925533

[cpandrewschmidt]

Hi all,
I'm still trying to plug away at this one. I replace FPR to no avail. I downloaded the free version of http://bimmersoftware.com/bmwlogger and messed around with it a bit today. Pulled the codes and got the following attached. Definitely different the the Carly App pulls. Anyone have any clue what these could mean? Thanks!

codes4.25.jpg