Done! High flow intake install 99 6 speed 540i

[Iforgetalot]

So yes I installed a 1996 7 series intake manifold on my 6speed 99 540i. Found the intake sitting in the trunk of a 540i at the Charlotte Pull a Part. The install was very easy and straight forward. Before the install I have been greeted every day by a check engine light for high LTFT for bank 1. Did several smoke tests and found a leak around bank one intake gasket and the TB. I needed to get in there to replace the gaskets so why not, right? After I was done I cranked the car, it started right away and settled beautifully... huge grin. Didn't drive it because I had to sit down for dinner with the wife and kids but I will be driving it this weekend. The car already had a Dinan CAI, MAF, TB and stage 4 tune. I also modded the factory resonator so that it now has pipes running out of both lungs, it still has the factory cats to dual pipes out the rear with muffler delete. And no it is not loud at all, trust me I'm old and I don't like loud angry exhausts.

Should I satay with Dinan and get their stage 5 tune or go with DUDMD tune or similar?

[RuskiE39]

The DUDMD tune is is specific for M60 mani swaps, so I would go with that one.

[zarboz]

DUDMD has developed a tune on a dyno for the manifold swap but I wanna say it is in tandem with a 4 inch MAF

That being said DUDMD is skilled enough to just tune for your manifold ;-)

he might even be able to put it on top of your existing dinan stuff he is a great guy and VERY skilled

[Iforgetalot]

Thanks for the info guys. I messaged DUDMD and they promptly replied with the requested information. I drove the car quite a few times since and it does feel as if it pulls harder from 3500+ RPMs to redline. For those that find this swap worth it just for the sound, then yes, the note coming from the intake is very aggressive and pleasing to my ears.

On the other hand...

I still have a CEL P0170 (Fuel Trim Bank 1) but OBD shows both banks with very high LTFT hovering at 21.9, YIKES!!!, even after replacing gaskets for intake, TB, and CCV. Will be checking fuel pressure this weekend and vacuum line connection at the FPR. Wish me luck!

*EDIT*

Also, I noticed that when I disconnected the fuel line to the fuel rail there was no pressure, nothing spewed or came out under pressure, just a few drops trickling onto the rag. Is this normal? I was under the impression that the rail remains pressurized. If so could this be part of the LTFT mystery?

[JimLev]

Reset the adaptations, drive it for a few days then check it.
How old are the O2's?

[mattmar1]

whats the fuel pressure when/right after the engine is running? how quickly does it drop off? theres a one way check valve in the fuel pump, that may be bad causing the pressure to drop off after turning off.

[Iforgetalot]

I don’t have the means to reset adaptations. Might have to take it to the shop for that. I will be checking fuel pressure tomorrow.

O2 sensors are probably original but no real way of knowing.

[Iforgetalot]

Checked fuel pressure at idle, 50psi. Shut it down and very slowly, like 10+ minutes, went down to 30psi and stayed there.

Sprayed carb cleaner around every conceivable place where I could find a leak, nothing, all good and clear. Then did a smoke test and found a leak at the TB gasket. Re-seated and retightened the gasket and no more leaks, anywhere.

Next morning, went ahead and did the “adaptations reset” for the TB per YouTube “experts” instructions just cause I figured it wouldn’t hurt. Some people stated fuel trim adaptations can only be cleared using INPA or similar. Cranked the car up and the LTFT were right at 0. Looks like it did reset fuel trims, idk, your thoughts?

Drove it for about 15 minutes of back roads around the neighborhood and it climbed up to 10% and stayed there.

Found another small leak under ABS pump. Still have trifecta. Front suspension starting to show signs of aging. And for some reason I still love this car.

[mattmar1]

thats just a tad hi of a fp dropoff, but not bad seeing that it stayed at 30 psi. i wonder what the difference was that when you pulled the rail and it had no pressure at that point?

[JimLev]

Pretty sure the spec on fuel pressure drop is 7 PSI or less in 20 min.

[ninetyseven1]

Checked fuel pressure at idle, 50psi. Shut it down and very slowly, like 10+ minutes, went down to 30psi and stayed there.

Sprayed carb cleaner around every conceivable place where I could find a leak, nothing, all good and clear. Then did a smoke test and found a leak at the TB gasket. Re-seated and retightened the gasket and no more leaks, anywhere.

Next morning, went ahead and did the “adaptations reset” for the TB per YouTube “experts” instructions just cause I figured it wouldn’t hurt. Some people stated fuel trim adaptations can only be cleared using INPA or similar. Cranked the car up and the LTFT were right at 0. Looks like it did reset fuel trims, idk, your thoughts?

Drove it for about 15 minutes of back roads around the neighborhood and it climbed up to 10% and stayed there.

Found another small leak under ABS pump. Still have trifecta. Front suspension starting to show signs of aging. And for some reason I still love this car.

10 percent is way too high, way too lean. You want to be at 0 or even in the slight negative on these cars. You will see a HUGE torque increase. Do you have any codes? try disconnecting the fuel pressure regulator vacuum hose from the regulator and plugging it with a screw and then drive it. Look at the LTFT afterwards and see what you have. I wonder if your fuel pressure regulator is bad.

[Iforgetalot]

Cleared adaptations with OBD scanner. LTFT still the same (very high). Will update as I slowly move along.

*EDIT*
After clearing the adaptations I took it for a 30 minute ride. LTFT for both banks jumped to 10% after a few minutes of driving and continued to slowly creep to up 15% where it seemed to settle, for now. Both banks read the same trim level and if the do vary it’s only by a few tenths. Seeing as they read almost identical I am leaning to believe this may be a fuel delivery issue. Replaced FPR and filter last week so I’m going to try a new fuel pump soon.