first e30 w/ m50 swap IDLES ROUGH

[nwe30]

i just bought my first e30 last week wednesday and it was running perfectly fine up until today.

i was teaching my sister how to drive stick because im going to the same college she is next year and we'd be sharing the car (i know, i was extremely unhappy when my parents told me this)

she stalled maybe 5 or 6 times for the half hour i was teaching her and she rode the clutch quite a bit.

i drove it the rest of the way home and parked it in the garage. 30 minutes later i had to take a trip to the grocery store so i turn the car on and the engine turns right on. i sit there in neutral with the handbrake up and the engine starts to rev to about 1500-2000 rpms by itself and then drops immediately down to 500 and keeps doing that a few times until it stalls.
i put it into gear and tried driving and it drove fine when i was in gear, but when i came to a stop with my clutch depressed, the car continued to rev between 1500 and 2000 rpms and eventually stalled.

what's going on? im going to upload a video on youtube soon.
i need the car by monday for sure and i only have time tomorrow to fix what needs to be fixed.

this is extremely stressful especially because this is my first car and i don't know much about the technicality of these cars. engine was swapped out of a 1992 325i m50b25

also, i was low on fuel the entire time but the gas light didn't turn on so i didn't think low fuel would be a problem.



CAR IDLING FROM INSIDE:

http://www.youtube.com/watch?v=xERR7xilEHs

REV TEST:

http://www.youtube.com/watch?v=G5hCjePvDig

CAR IDLING WITH POPPED HOOD:

http://www.youtube.com/watch?v=M0zQx1X1Y7c

[e30BMart]

It's def not low fuel. I'm not familiar with the m50b25 but if you have an airflow meter and you have the tinniest of rips in your intake boot it will cause your symptoms. Happened to me, the previous owner thought it was an engine problem and sold it for cheap because of that, changed the intake boot for 30$ and no more problems hehe ^^'.

PS: refuel before it gets too low, mine shows there is more fuel then there is in reality, and once it just cut off almost No warning at all, at least I did it on purpose and had spare gas in the trunk..

But check the intake boot for sure. if you see a rip don't worry about driving it its not gonna damage anything, just change it as soon as possible....

[MR E30 325is]

You have a vacuum leak, or a bad ICV.

You need to check your intake system for air leaks. Check the rubber hoses for cracks, and check for tightness where they connect to the engine and the intake boot.

You can use carb cleaner and spray it in areas to see if the idle kicks up. If it does, there is your leak.

[nwe30]

so the problem is somewhere in my intake system?

i can't find any tears in the intake boot....it's difficult to look under the boot.
is it okay for me to drive? i might take it to a shop but i don't want to if there's any risk in damaging the car

[Dirtsquirt]

Grab a can of starting fluid...

Spray around the intake boots/MAF/etc. If the car starts to rev then you've found a leak.

[ck_taft325is]

That's most definitely a vacuum leak by the looks of it. Check all of your vacuum lines very, very closely.

[nwe30]

if the car eventually just dies by itself, how is this test going to work?

how high should the car rev when i spray the starting fluid?
the car leaps from 500rpms to 2000..so you can imagine what it sounds like when the hood is open and the engine is running. if there is in fact a leak, will the starting fluid make the engine rev past 2000rpms?

[nwe30]

does this look like something?



By nwe30 at 2011-03-19

[Reckless_Havoc]

does this look like something?

That looks like the hose from the coolant reservoir.

[416stroker]

if the car eventually just dies by itself, how is this test going to work?



how high should the car rev when i spray the starting fluid?

the car leaps from 500rpms to 2000..so you can imagine what it sounds like when the hood is open and the engine is running. if there is in fact a leak, will the starting fluid make the engine rev past 2000rpms?

The car doesnt always rev it can bog down also depending on the size of the leak.



Im not so sure it is one though.



is there a cell ?

[e30rapidic]

I'm leaning towards idle control....try cleaning it and see what happens

[nwe30]

i did a little rev test.

http://www.youtube.com/watch?v=G5hCjePvDig

in the beginning of the video when i first turned the car on, you notice that the revs are really rough and they're not clean. the revs also aren't passing the 2k mark.

i kept stomping and towards the end of the video the revs were cleaner and reach 3k. what's that mean?

[blackhawkimpact]

Like mention above. It's either your ICV or you have a vacuum leak. I leaning towards a vacuum leak somewhere.

[nwe30]

i texted the PO and he thinks that the fuel pump is friend.

is this also a possibility?

[blackhawkimpact]

I don't think the fuel pump will cause it to idle like that?

Did you check for leaks? or cleaned the ICV?