E21 m50 swap not running good

[jeds320i]

hmm.. i guess i havent tried disconnecting the maf while running... i will try this. i assume with it discconnected it'll idle even rougher?

[jeds320i]

just a quick update, i ordered a set of new ignition coils from bav auto and it did not fix the problem.. ive checked all the vac lines and its all good. im srsly stumped :(

[derrith]

Intake manifold gaskets? Did you try spraying carb cleaner at all the vacuum lines as previously suggested? I had a few vacuum leaks that kept my nvm50 from running quite right initially that were hard to track down.

[jeds320i]

yes i sprayed carb cleaner around everything.. couldnt seem to find a leak. i dont know why its running rough

[Fusion]

Tried the MAF test? Have you driven it, is it only idle that's messy?

[jeds320i]

i unplugged the maf while idling and it made it idle a lil rougher. i have driven it a couple times, up to 2k rpms it runs rough then it literally snaps out of it and seems to run great. like in first gear barely on the throttle it kinda jerks and doesnt run good then around 2k it snaps right out of it ya know.

[derrith]

Did you replace the spark plugs? O2 sensor operating correctly? Coolant temp sensor ohm out properly? Did it sit for a long time? How are the injectors? Is fuel pressure good? Recently had an m20e30 that idled like crap but drove fine, fuel pump wasn't putting out enough pressure at idle.

Do you have an e34 or e36 bentley? It would really behoove you to go through the fuel injection troubleshooting section instead of throwing parts at the problem.

[e46s54dr]

By no means am I trying to be an ass but just take it to someone who knows what they are doing. Sometimes asking for help without knowledge and expirience is like describing a picture to a blind man. With all the money you spent on throwing parts at it without a correct diagnosis or even valid one at that, you couldve got it fixed by now. Save yourself the further headache.

[328ijunkie]

Tps

[jeds320i]

Did you replace the spark plugs? O2 sensor operating correctly? Coolant temp sensor ohm out properly? Did it sit for a long time? How are the injectors? Is fuel pressure good? Recently had an m20e30 that idled like crap but drove fine, fuel pump wasn't putting out enough pressure at idle.

Do you have an e34 or e36 bentley? It would really behoove you to go through the fuel injection troubleshooting section instead of throwing parts at the problem.

im a little confused.. how can a fuel pump put out enough fuel at 6k rpms but not at idle? im pretty sure my fuel pressures good, i got a new fuel pump too. new plugs and new 02 sensor. how much of a factor is the coolant temp sensor? i repleced one of the coolant sensors with my m10 one so my temp guage would be accurate, if i switched the wrong one could this be makin the computer act funny and make it not run right?

also, how many ohms is the tps supposed to put out or w.e? i could check that to make sure

[jeds320i]

By no means am I trying to be an ass but just take it to someone who knows what they are doing. Sometimes asking for help without knowledge and expirience is like describing a picture to a blind man. With all the money you spent on throwing parts at it without a correct diagnosis or even valid one at that, you couldve got it fixed by now. Save yourself the further headache.

i really havent spent any uneccessary money.. the icv hoses were like $20 and needed to be replaced anyway really.. and the coils i had were mismatched and old lookin. i swapped in a m50/g260 into an e21 and had to custom do everything. so im not exactly a moron. i had no help with the project and did everything myself. im a diy kind of person and dont wana pay some shop $75 an hour for some easy fix ya know. thats why i come to u guys bc i know some of u are very knowledgeable

[derrith]

I'm trying to suggest things that may be the issue without complete knowledge of everything you've done. There are two coolant temperature sensors in the head. The coolant temp sensor sends coolant temperature information to the ecu. It plays a huge part in running the engine optimally. It is a two pin sensor that has a blue or clear connector. The coolant temp sender only sends coolant temp information to the gauge on your cluster.

EDIT:

Straight from the e34 bentley:

TPS Test:

Test terminal 1 at TPS harness, ignition on: 12vdc between terminal 1 and ground

Test at sensor, ignition off: terminal 1 and 3 approx 4.0k ohms

test at sensor, ignition off: terminal 1 and 2 between 1.0k ohm and 4.0k ohm smoothly while opening/closing throttle manually

Coolant Temperature Sensor and intake air temp sensor Values:

Around 70 degrees fahrenheit: 2.1-2.9 k ohms

[jeds320i]

hmm.. maybe i took out the wrong temp sensor.. theyre right next to each other. i have much work to do lol. do u know what sensor is for ecu and which is for the temp guage?(front one or rear one) i better test the tps when i get time too

[jeds320i]

i just checked a few things, my tps and air temp sensor are working good. and my coolant temp sensor i replaced was the rear one(closest to firewall)

[e46s54dr]

i really havent spent any uneccessary money.. the icv hoses were like $20 and needed to be replaced anyway really.. and the coils i had were mismatched and old lookin. i swapped in a m50/g260 into an e21 and had to custom do everything. so im not exactly a moron. i had no help with the project and did everything myself. im a diy kind of person and dont wana pay some shop $75 an hour for some easy fix ya know. thats why i come to u guys bc i know some of u are very knowledgeable

Im all for doing things myself to save money as long as its in your ability. The fact of the matter is that the symptoms you described can be caused by an array of things. Is there any check engine light? Like members before me stated, start with checking for vacuum leaks and move on from there. Be really meticulous when searching because they will pop up in the least expected areas. Good luck and let us know how it turns out.