E30 M50B25nv Swap problems

[Rousan_e30]

Hello all,

I finished my M50nv Swap "e36 engine, 1991 was written on the back of the head" a couple of days Ago, been having problems since then.

the engine fired up pretty quick actually, but, the car or the engine for the matter of fact has been running like shit, excuse me for that.

it had like a symptoms of a misfire, the RPM was bouncing, car backfiring, and engine choking, in addition to a very big loss of power, considering going from an M20B20 to an M50B25nv.

what i changed actually was the spark plugs and the coilpack was working 100%.

i changed those and the car still had the problem.

The main symptoms are, Stuttering, engine choking, bouncing RPM, Engine hesitation" it doesn't sound rested" , Loss of power, too much gas consumption.

The RPM stays up at 2500rpms after revving up the engine, then after 5 seconds it starts to go down and settles at 1000rpms, RPM also goes up and settles at 2500rpms when the car is moving even if am not pressing gas "cruising in neutral" .

what i have done is "in addition to the spark plugs change", i went to a bmw electrician and he did an OBD scan on it, which the first time showed a fault of a Crankshaft positioning sensor and high rpm at idle which was due to a stuck throttle body which i have changed with a new one with its TPS.

No scanning faults other than the CPS fault.

the problem is i changed the CPS with another one and it still throws the CPS fault when OBD scanning it.

i have tested a couple ECUs also, i have a 405 green label, a 403 green label, and a 402 Red label "not the original one that came with the engine but its the one that made the engine feel a little more rested"

what i have in hand right now is, 3 ECUs 402,403,405, my Old TPS, my old CPS, another Crankshaft pulley, another ICV.

Help me guys am super confused.

Thanks : )

[drakesmith]

Check the timing and vanos ,Sounds like its jumped, but rare on the m50/52 family.

Pray you have no bent valves.

[DanThe]

The Bosch ECU's are rubbish for fault codes, MAF can be faulty and not display a code, cam sensor can be unplugged and the engine will still run ok on the non vanos so try that

[Rousan_e30]

Check the timing and vanos ,Sounds like its jumped, but rare on the m50/52 family.

Pray you have no bent valves.

It's not a timing issue i guess, and its a non vanos engine so...

[Rousan_e30]

The Bosch ECU's are rubbish for fault codes, MAF can be faulty and not display a code, cam sensor can be unplugged and the engine will still run ok on the non vanos so try that

Will check that, Thanks !