Help me out please? underpower... :(

[MT325is]

Hey guys, so in the past few months i have done a lot of work to my car.. did a gasket seal overhaul, new starter, o2 sensor, coolant hoses, distributer, plugs, wires, fuel filter, just pretty much a refresh... didi a smoke test an replaced the leaking places already..
well 2 weeks ago my o2 went thats why i replaced that. and this past weekend, im driving my car and out of no where it dies... so i start it back up, put it in gear and start driving from a rolling start.. well then decides not to rev past 2.5k and throttle response is very slow.. i pull over make sure everything plugged in(the usual visual check) turn around and drive home. I unplugged the o2 sensor and it decided to rev up to about 5.5 6ish a couple times an then back at 2.5:(

So i was thinking its proly the cat right? took off my exhaust today and took it for a little spin around the blocK(that was LOUD). ;) and still underpower.. i hit the gas, throttle response it slow.. it also used to stumble at when the engine was cold before all this happened...
So im stuck.. any experience with something like this??
oh and its just the m20..

[FLG]

Clean and inspect your grounds, check the c101 injector connector under the intake, check the cps sensor with a multi meter and make sure its at about 540ish ohms on 2 of the pins (forgot which ones but youll only get a reading on 2 of em, its the middle and one of the end ones)

[MT325is]

Ok so on CPS the sensor I'm getting 123.2 n 0... The wiring harness 504 n 0. On the same pins...
Injector connections are good.. An so are the ground.

[FLG]

504 is within range, cps at least appears to be ok.

Also check the gap on the cps, should be about 1mm

Check fuel pressure, make sure the cap and rotor are on correctly (i see you changed them, possible you didnt tighten enough and something got knocked loose)

Also check the tps sensor, and the coolant sensor.

[MT325is]

Ok, i disconnected the cps and the car died right away.
Then i disconnected the one that goes from the spark plug wires, no change at all?

But i will check all of those tomorrow after work. Thanks!

[jlevie]

Data from the Cylinder ID sensor attached to the #6 plug wire is used to time bank sequential injection. Disconnecting it will have no apparent affect on engine operation, though performance and fuel mileage will suffer.

[MT325is]

Alright. Thanks! I couldn't figure out what that was for!
Ohh one more thing I should add that I forgot to.. I put a colder thermostat in there.. 5 degrees colder.. That's all I remember. So I think 70?

[fronton]

It sounds like your AFM may be sticking if it won't let you rev pass a certain point and response is slow.

[MT325is]

I did retrack my afm also a while back.. But it doesn't hurt to open it back up and check again. Will do. Thanks for the responses guys.

[MT325is]

i have a question, well i didnt get to much like i planned today mainly because i was reading up on electrical stuff.. But i tested the coolant temp sensor and its reading 314.4 ohms... (i touched the two pins on the sensor with the multimeter.. i think thats how its done.. dont see any other way.

Bentley States that at operating temp it should be 270-400 ohms... the car hasnt been started in 24 hours.. The coolant temp is the about 65 ish right now.. which bentley states should be 2100-2900 ohms..

I do have a new temp sensor actually two.. and checked both of them with the outside weather which was 67.. both reading 297.2 ohms..

So the question is is that sensor that is in the car good? or am i probing it (reading it) wrong some how.

[Dj Buttchug]

do you have a CEL?

[MT325is]

not ever since it is running like this, but last time i checked i had the lambda code, ive had it ever since i got the car.

[RobertC]

From what I am reading I see a couple problems.

You said you got 123 Ohms from the CPS sensor itself, then said it read 504 Ohms.

Ok so on CPS the sensor I'm getting 123.2 n 0.

If you have 123 at the CPS sensor its bad. If you have 504 its marginal.

You mentioned that dead cold the Coolant sensor was reading in the 300 Ohm range. That is not good either. It should be 250+-300+ Ohms at full operating temperature.

Basically the hotter it gets, the lower the resistance. The lower the Ohms, the leaner the mixture.

I recommend using only Genuine BMW Coolant and Crank Position Sensors.

We (and others) have had problems with aftermarket brands, specifically Facet, and even Bosch.

On the coolant temp sensor the for the 2.5i, the part number will be 13 62 1 709 966, if your running a 325e the part number should be
13 62 1 357 414

Also as a note of how much a CPS can make a difference. Just recently our sponsored Enduro E30 was qualified a 2.17. That is slower then a Spec E30 on the same track. (BW) The CPS measured 600. (It was a plastic 'Facet' brand). It was replaced with a Genuine BMW CPS and measured 539 Ohms.

Next lap time was 2.13. That is 4 seconds per lap faster. The M20 in the enduro E30 lays down about 195HP at the wheels.

So if your CPS is reading 123 Ohms, that is your problem. I would also check the Coolant Sensor with the engine at full operating temperature to verify.

Good Luck

[FLG]

I took it as 504 at the sensor. But I'll wait for op to confirm. And yes stay away from non oem sensors. I've also had nothing but problems.

Sent from my Galaxy Nexus using Tapatalk 2

[MT325is]

the 503 ohms was wrong, i am completly new to this electrical stuff. I am learning as i go.. and trying to read up on it. Its tricky. The 503 ohms was testing the sensor plug on the engine harness.. not the sensor. (which i have no clue why i even decided to test the harness connector?)
I did unplug the CPS and the car died instantly.
I just went out again, and tested the CPS i am getting a steady 118 ohms.. you say it should be in the 540's? then mine i would assume is bad!:(