Loss of Power on Takeoff/Cold start misfire

[Old-Skool-Kid]

Reasearch hasnt turned up much on this, but sometimes my car seems like it has really low power, especially on takeoff in 1st. Itll act like im starting off in 4th gear until ~2k and then it shoots off like a rocket and then 2nd gear, low rpms the same thing happens. At times, it seems to have plenty of power and get up and go, others it seems like no matter how much I put my foot down and make the rpms go up it doesnt go anywhere fast. And also whenever its cold (the colder it is outside the worse it is) It idles fine until takeoff, and then ~1500-2500 it sputters and misfires really bad. Then at a stop, idle fluctuates. At low rpm cruising (1500-2k cold) sometimes itll start bucking really bad. All is good when the thing warms up, runs like a champ except for the intermittant problem stated above.

My car is a 318, but it has a 2.7 running the i sensors and stuff with a MAF upgrade and an MSD coil, new fuel filter, full headers and no cats. Every so often between shifts and decel itll pop a little, but I assume thats from the headers. Any advice is always appreciated!

[paperplane94]

I was gonna suggest the AFM, but you don't have one anymore, I guess you retrofitted a MAF sensor.

Then I would check to see if your MAF is the problem if you have one.

[89 e30]

I'm guessing maf too. If you still have the normal one hook it up and see if it makes any difference

[Old-Skool-Kid]

I don't have the orig, it had already been done before I bought the car so I know nothing about it. What is the maf usually off of so I can get another?

[paperplane94]

I don't know what kind of setup you have now, but...

the e30 in its stock form has an Vane Air Flow meter, or AFM.
like this:



You are telling us you have a MAF, which does not have a vane inside of it
like this:


We are saying that you should get the old AFM back and restore the cars stock form so that that you can better troubleshoot whats going on.

The VAFM is found on 3251's with the M20 engine, and 1989-1990 525i's with the M20. It must be from an M20, preferably M20B25.

[Old-Skool-Kid]

This is what I have, its the MAF. The ECU has a sticker on it that says "For MAF Upgrade ONLY" I do have another Motronic ECU but what its for I have no clue. I would have to use this with the stock AFM, correct? I will try to hunt down an AFM tomorrow

[89 e30]

That might not be the problem if he changed the ecu too. If you wanna put a original maf back you have to find the right ecu for your car

[Old-Skool-Kid]

I think I figured out the problem, the connections at the MAF are very poorly protected and had a bunch of "blue fuzz" in them. I cleaned it up best I could and it seemed to run MUCH better but the problem is barely noticeable now. Rule no.1 is always check connections first!