The 15 Y/O Turbo M42 Build Thread (Now Holley EFI Terminator X Controlled)

[MR E30 325is]

I will gladly take it off your hands buttchug, right before it goes off the cliff. Haha

You will figure it out.

[gearheadE30]

Yeah, I know the feeling. The first time I drove mine any distance it started running on 3 cylinders and belching smoke. Thought I killed the motor, so I rented a uhaul and towed it home. turned out that there was too much oil in the engine. Hopefully yours is something simple, but I'm sure you'll get it figured out.

[Dj Buttchug]

I spent all day trying to figure this out. I swear I cannot pin point the issue. The car idles fine. right when I jump on its starts cutting out. Even under full vacuum with maybe 30% throttle it still cuts out expecially when Im going up a hill or under some sort of load.

I found my #4 coil wire wasnt all the way plugged in, fixed that but it didnt change anything. Also spent some time trying to get an accurate coolant temp sensor resistance reading. All i could get was about 180 ohms at operating temp. Checked my fuel filter as well. Its not plugged as I could blow through it easily. Fuel pump seems strong. Had no isses with it before the build so thats out.

Funny thing is its completely non turbo related. Even before I had the charge pipes hooked up it still fell on its face at about 3k rev.

Its gotta be something stupid. Im gonna get a coolant temp sensor just because I know mine is old but im not sure its gonna fix my issue.

I also considered AFM problems... but again the afm worked fine before i built this thing.

Heres a question tho. Im running m50 green top injectors. I dont see how this could be an issue but you never kno....

any ideas guys???

[trackjunkie21]

I spent all day trying to figure this out. I swear I cannot pin point the issue. The car idles fine. right when I jump on its starts cutting out. Even under full vacuum with maybe 30% throttle it still cuts out expecially when Im going up a hill or under some sort of load.

I found my #4 coil wire wasnt all the way plugged in, fixed that but it didnt change anything. Also spent some time trying to get an accurate coolant temp sensor resistance reading. All i could get was about 180 ohms at operating temp. Checked my fuel filter as well. Its not plugged as I could blow through it easily. Fuel pump seems strong. Had no isses with it before the build so thats out.

Funny thing is its completely non turbo related. Even before I had the charge pipes hooked up it still fell on its face at about 3k rev.

Its gotta be something stupid. Im gonna get a coolant temp sensor just because I know mine is old but im not sure its gonna fix my issue.

I also considered AFM problems... but again the afm worked fine before i built this thing.

Heres a question tho. Im running m50 green top injectors. I dont see how this could be an issue but you never kno....

any ideas guys???

02 sensor?

[Dj Buttchug]

na i dont think so. shit who knows it could be. Also No check engine like at all.

it pisses me off too cause right when i hear the turbo start to spool it starts cutting. I cant even hold 5psi.

[trackjunkie21]

na i dont think so. shit who knows it could be. Also No check engine like at all.

it pisses me off too cause right when i hear the turbo start to spool it starts cutting. I cant even hold 5psi.

It sounds like an 02 to me.

[Dj Buttchug]

yea i just drove it some more. Its hunting for idle. bout 100 to 200 rpm intermittently. temp gauge is twitching all over and it smells pig rich. either o2 or temp sensor im thinkin

[Jesse30]

try someone elses AFM if you can. mine did the same thing when the AFM burned out. who knows, things choose weird times to go out. it might have been on its last leg when you were building the motor then after hitting boost a few times finally gave up.

[fiftytakedowns]

crank sensor, those are responsible for fuel AND spark cut if they receive erratic signals

[Dj Buttchug]

crank sensor, those are responsible for fuel AND spark cut if they receive erratic signals

what about cam sensor? shit i need to get on mitchell 1 right now but i cant log in FML

[Ryann]

You should plug in a fuel pressure gauge and strap it to the driver's side wiper arm, then drive it & check for fp drop during the cutouts. In my experience fuel pressure issues tend to fly under the CEL radar in most older EFI systems, and hey, you DID just add a blower. Things like CPS and AFM should throw codes.

[Dj Buttchug]

You should plug in a fuel pressure gauge and strap it to the driver's side wiper arm, then drive it & check for fp drop during the cutouts. In my experience fuel pressure issues tend to fly under the CEL radar in most older EFI systems, and hey, you DID just add a blower. Things like CPS and AFM should throw codes.

good point. I remember now that I had to tap the top of the fuel pump to get it to start once i finished the engine. Im really hoping for a weak pump because I need a 255lph anyways to feed bigger injectors.

[Dj Buttchug]

swapped the crank sensor out with a good working one. didnt change anything.

going to source all the resistance values and check every sensor on the engine and go from there

[trackjunkie21]

swapped the crank sensor out with a good working one. didnt change anything.

going to source all the resistance values and check every sensor on the engine and go from there

Check the voltage in the 02.

[Dj Buttchug]

checkin that soon. gonna have a few fittings made hopefully by the end of next week