E30 m52tub28 terrible gas mileage

[cro_xt]

Greetings, its been a while since i have swapped this motor to my e30, but ever since, i have really bad gas mileage. I am talking about 20 liters per 100km now in winter...at summer ot was 16/100... what is weird also is that i had near same fuel consumption with m20b20 in it...
I am out of ideas really and i would like some advices...

What i have done so far is:
Check engine compression
New spark plugs ngk bkr6equp
New fuel filter, fuel pump
New cone air filter
New original front o2 sensors, rear are deleted
New thermostat
New summer and new winter tires, had the pressure right..
Didnt check injectors nor fuel pressure regulator

Mods so far
Homemade exhaust manifold, no cats.
I am in proces of getting complete e46 330i exhaust with rear o2 sensors as well, which i will be fittng to my e30
Currently i have m54b25 intake manifold, it was the same with original manifold... i had m54b30 manifold as well, same thing.
Cold air intake
I have 2 ecus, one i got with the engine i have no idea if it was remmaped or not, funny it had "m power" written on it... another ecu i bought from ebay, which stated remap to 207hp, but on dyno i have proof that atleast with mods i have, it had 195hp amd same power curve as previous ecu... then i went to remap it and the best the guy could achieve was 207hp... redline 7100
Performance wise its not bad, i went vs e46 330ci, rolling start 2nd gear, and i could overtake it... not all that great difference, 2nd and 3rd gear to limit and i am a car lenght ahead...
Idles fine, pulls fine... it consumes oil a bit tho... about 1l per 1500km
Any ideas?
Sorry for my long post... btw this forum has helped me a whole lot for the swap i did :)
Thank you so much!

[cro_xt]

Well, heres another question...
If i were to get m54b30 engine, just bare engine, would it work with ms42 ecu? I would use m54b25 intake manifold which i have already mounted on m52tub28 engine, along with m52tub28 throttle body? This, along with injectors and maf would choke the engine...
What i would end up with would be bigger displacement with a bit more agressive cams... now altho that does have its flaws, id always have the option to put ms43 + gas pedal and complete intake.
Any thoughts?

[nando]

pretty sure MS42 can run the M54B30, there should be tunes available for it at least.

I think later '328i' used the M54B30 but with the restrictive manifold, but that may have only been with MS43.

[cro_xt]

I do understand this is not great thing to do, but since I do everything myself, I wont be wasting anything more then time... Also I can always make it complete m54b30 with ease, afterwards...
So it would probably work with ms42...Thanks
A friend of mine already has a complete m54b30 head, renewed, completely assembled... if I could find a good block for cheap and put new bearings and rings in it, it would be awesome
Being on a cheap is the main point here. But I doubt its gonna happen.

Heres a pic of my e30

https://scontent-vie1-1.xx.fbcdn.net/v/t1.0-9/49185127_10216884603403223_818660142877769728_o.jpg?_nc_cat=106&_nc_ht=scontent-vie1-1.xx&oh=d17990b6ef2369aa8fb15ca3e614b09e&oe=5CD583DC

A lots of time and effort there. Everything that has been done on it, I did it myself. From tearing it apart, to horrible rust removal, welding, donor roof, made rear pockets myself, new sideskirts... bodywork, paintjob, and on and on :)
Putting m52tub28 was an easy part hehe, thanks to you guys, this forum, and other informations i found online...
but I am so sad that I did not go with m54b30 from start :)

[dude8383]

We'll be running a B30 with MS42 real soon :up:

[cro_xt]

Keep us posted!
I guess you guys are doing the same thing I want...

[cro_xt]

Any updates?
Back to my topic about bad gas mileage... 22 liters per 100 kilometers lately...

I have tested injectors, they were fine but had them cleaned anyway.

I tried to drive without maf sensor, the gas mileage stayed the same, car runs the same... when i disconnect it or connect it while the engine is running, engine nearly stalls. No effect on performance or gas mileage whatsoever.

I disconnected the purge valve, same thing. I have also tried to block the hose at the engine end and leave the purge valve connected, same thing. The end towards the gas tank is disconnected at the moment. No effect.

The emissions test is a disaster. I suspect it might be the map the engine is running on, since its not the stock one...

I will be putting on stock exhaust manifolds with cats on, and rear o2 sensors. Il put original map on the second ecu i have... If that does not help, i have no clue what to do next... I did not test the fuel pressure yet, not the fuel pressure regulator.

Id really like some help, or advices.

[cro_xt]

Small update
Fuel pressure regulator tested, works fine.
Injectors not leaking as i said before.

[cro_xt]

Tested fuel pressure regulator, its working properly.
Tested if there is any pressure after the fuel pressure regulator, there is not.

I have just installed e46 330i complete exhaust system with catalysts, took me few days.
Rear o2 sensors are still not connected.
These days il put new map, il see if that helps.

[dude8383]

You dont mention anything about checking your MAF... have you tested another good used one by chance?

[cro_xt]

No, I did not try another maf yet...
The only thing I did with it is that I have cleaned it, and tried to disconnect it or connect it while the engine is running, it did nearly stall the engine but I guess that is not a valid test for it...
No1 around has this engine... a friend of mine has e46 330i but its not the same maf... I will focus on maf now.

[dude8383]

Yeh definitely check it. Look at live data, how fast does it react to throttle inputs and voltage.

Oftentimes even if things appear to be okay they can be faulty. I've had so many cars come in with the strangest issues due to a faulty MAF.

[sebe20]

No, I did not try another maf yet...
The only thing I did with it is that I have cleaned it, and tried to disconnect it or connect it while the engine is running, it did nearly stall the engine but I guess that is not a valid test for it...
No1 around has this engine... a friend of mine has e46 330i but its not the same maf... I will focus on maf now.

Don't buy cheap ones, atleast get a Bosch, Siemens/VDO one. I got 5 MAF's on hand and every single one of them behaves different. Currently mine runs fine with the original Siemens MAF. Also most MAF's dont like cleaning, i tried it on all 5 MAF's and one died on the spot.

[cro_xt]

Huh, thanks for the advice!
Ive heard already that being on a cheap with sensors is not wise...