S50 Runs like poop...

[bimmer630]

...My swap isnt competely done.. I have an S50 but my DME chip is still for the 2.5 m50, my exhaust isnt on yet.. and my 02 sensor is just zip tied to the trans xmember.

It will run and idle fine.. but driving it up and down the road with open headers, it starts to run rough and almost load up..

My question is, do you guys think this is just all related to having no exhaust back pressure, no 02 signal to the dme, and the incorrect chip? Im pretty confident that it will run fine once I get all this squared away.. but what if Im wrong

[AirplaneBuilder]

Your going to need to fix those issues you listed anyway so why not try to do that first and see how it runs... It's like saying my tire is flat so the car won't drive good, should I inflate it and try again or do I have a bad tire and need a new one... Fix the known issues first.

[Roysneon]

Without a clean o2 sensor signal it will run like shit.

[bimmer630]

I know the engine won't run right with these three problems but the point of the question was to make sure somebody else wasn't going to say " I ran mine like that and it was fine" because I want to drive the car next weekend and I'm just crossing my fingers that it'll be fine once the exhaust is on

[ForcedFirebird]

If you don't have the o2 installed, then unplug it and it should run better since the Motronic will resort to generic maps.

[brenE30]

If you don't have the o2 installed, then unplug it and it should run better since the Motronic will resort to generic maps.

This! I ran my old M50 for a year with the o2 unpluged

[bimmer630]

Unplug oxygen sensor still ran like poop...
unplug mass air flow sensor and runs smooth. Ordering a new MAF tomorrow

[EN318isPDX]

Unplug oxygen sensor still ran like poop...
unplug mass air flow sensor and runs smooth. Ordering a new MAF tomorrow

Really? Seems premature

[bimmer630]

Well I stole the maf from an insurance total car that was flooded during sandy and I didnt know the salt water went all the way up to the windows until today.. so that thing has gotta be shot

[bimmer630]

Oops dbl post

[EN318isPDX]

I would recommend testing it first

[bimmer630]

I might do that for shits n giggles.. or I can plug the car into the bmw gt1 we have at the shop, but obd1 doesn't seem to give you much to play with.. at least they should show me actual values

[ForcedFirebird]

Stomp test for OBD1. GT1 will tell you Jack.

[bimmer630]

Vague gt1>stomp test

I don't see how flashing codes is any better than using the factory scanner

[ForcedFirebird]

Vague gt1>stomp test

I don't see how flashing codes is any better than using the factory scanner

It's not, but can be done on the spot and he didn't have to wait to go to his shop.