M52 a little down on power, any ideas ??

[jimbom30cab]

So I ran the M52'd e30 on the rolling road today and the peak BHP was 215. I'll get the graph up asap.

I was expecting 225bhp as this has been previously achieved with this set up.

The set up is:

M52B28 with M50 manifold and M50 BBTB.
Danthe re-map
Full BTB system.

I fitted a new BMW coolant temp sensor about 3 months ago.

The rolling road dudes said it was running rich and also went into "closed loop" on one of the runs, not entirely sure what this means.

I've been recommended to look at the fault codes but sadly I have absolutely no idea how to do this.

other people have recommended a new MAF, Temp sensor and oxygen sensors. Someone also said the 6 speed box would lead to greater mechanical losses.

Dan's advice sounds sensible, to get the fault codes read, how could I get this done?

Thanks

[jimbom30cab]

Apparently the wavy dotted line that drops down is bad...

[reggid]

too lean on the bottom end and then goes too rich uptop. around 13 or 12.8 should be ballpark. def needs sorting.

[Motorhole]

Deffo second a diagnostic. You could spend a small fortune blindly replacing various sensors on a wbim and be no better off at the end. I bought one of these:

http://m.ebay.co.uk/itm/190864760050?_mwBanner=1

It's not the best reader out there by any means and it feels a bit cheap (because it is!), but it will read & reset codes and you can even few response from various sensors in realtime. For less than an hours labour at most BMW specialists, can't complain. Worth writing to the seller to double check its the correct one for your motor. Also worth noting you will need a 22 pin to 16 pin BMW obd adapter.

[bss325i]

Who said about mechanical losses from a 6 speed box?!

[jimbom30cab]

I think Matt said the 6 speed was worse for losses than the 5 speed

[scoobydo]

Your wavy bit on the graph is the AFR, air fuel ratio, you are way to rich for a NA car. It does vary from car to car what target afr gives best power. Too much fuel will not only loose you fuel consumption but will also rob you of power. Below is a graph of my AFR ignore the figures as my car is FI M30 but will give you an idea of what is required. For FI extra fuel is used to help with det as it cools the combustion process.

Closed and open loop is just where the car uses the lamda sensor in the calcs to work out the AFR. If it isnt using lamda engine under moderate to high load, then it goes to pre defined values based on various other sensors but not the oxygen sensor.Note my car isnt using motronic.


Dont worry about the lost power, more of a concern is why so rich.

[bss325i]

The loss of power is a side effect of it being so rich though. Sort the richness which is most important then lost power will come back.

[jimbom30cab]

Thanks guys that is great info. I will get one of those diagnostic fault code readers and update on here.

[DanThe]

Got any pics of the MAF Jim?
Closed loop usually means the ECU is using the lambdas to calculate how much fuel to dump in, they should be in open loop when accelerating on pretty much any engine

[jimbom30cab]

Hi Dan, thanks for the tip mate

I will get a photo of the maf probably tomorrow now as it's locked away in the garage and blocked in also.

[rich318i]

whats your mpg on ave jim?

[jimbom30cab]

Only done a couple of tanks in since the re-build but the last tank averaged 30mpg

[rich318i]

same here with the M50 manifold and when i put the cams in was still the same MPG give or take 5mpg on how i drive it.

Wish i came yesterday now.

Get a standard 328 ecu and see what thats like. They are good ecu's and sort out the best for the car.

Thats what im running at the mo with all the mods and is ok.

Live remap is the key though!!!

Remapped to the car and not someone elses setup.

Going to try my mates ecu thats ment for the M50 plus mods and see what its like.

[jimbom30cab]

Dan,

here is the best photo i have at present