m42 to m44 swap issues
 

Hi people I hope someone can help me out a bit here i have done a complete swap from m42 to m44 in a 96 316i and the swap is all working execpt for one thing when its in gear the engine wont rev past approx 5200 when in netural it will rev to 7000 when it is cold it will rev to 7000 in gear but when at running temp she wont.when i did the engine swap i even had it taked to the dealer to allign the obdII. I am now stuck and dont know where else to look and the dealer in western australia just put his up in the air and said i dont know so please someone help!!!!

you need a plug speed signal to your dme.

are you using the correct dme to the motor?

the dme is from the same car as the engine so is the wiring harness and there are no plugs unplugged

abs located in yours car?

yes it has abs

bump bump

Try unplugging the maf sensor first and test.

Then replug that in and unplug the coolant temperature sensor and test.

Replug temperature sensor then unplug the o2 sensor and test.

All should be done at operating temperature. Id say its not the maf giving faulty reading as it should be the same whether hot or cold. Coolant temp sensor helps set up parameters for the fuel/air before and after the engine is ran and up to temperature but gives a rich parameter and leans out as it gets warmer and the o2 sensor helps monitor temps to provide a better "tune" while driving. Another issue could be the fuel pressure regulator. Make sure the hose isnt rotted nor is the T fitting for the vacuum system. You can pinch off the supply to richen the fuel mixture and see if it runs better or worse as cutting the vacuum supply should raise the fuel pressure to the rail providing it with adequate fuel for high rpms.

You can also get a 300ohm resistor and a 2k ohm resistor (or series of resistors to equate to the measures) and put them in place of the coolant temperature system. The engine management will "think" the engine is at operating temperature, based on a coolant temperature reading, when you install the 300ohm resistor, the 2k ohm is the complete opposite at ice cold. You can use this to help find answers or want the engine management to perform a bit differently.