Power lost & engine smoothness gone

[abeaujuin]

For over a year now, I have been trying to figure out why my car keeps loosing power. I have been to 3 BMW Dealers and 4 different shops. No one was able to help me out. Well I decided to get the car Dyno'd to see what the Air/Fuel ration was. I need some help trying to figure this out guys please help.

209500

[Nico3k]

Keeps loosing power? Can you be more specific?
Is it supercharged?
The dyno #'s look fine for a 323; not sure about your AFR

[Minnoe07]

I haven't worked with BMW's in tuning but I have worked with a couple others. Your A/F ratio is erratic. Are those 3 pull done right after another? You shouldn't have a 1 point spread. They should be bunched much closer together.

[abeaujuin]

Well, I have been loosing power and smoothness. I changed the o2 sensor power came back then disappeared after about 2 weeks.

I change the spark plugs power came back and disappeared after 2 weeks

I changed Spark Plug boots power came back and disappeared again after 2 weeks.

I changed out the MAF sensor and power disappeared after about 1 week.

I change Intake Cam sensor same thing power came back lasted about 1 week or so... same for the exhaust.

No check engine light, but it's clear to me that the power is gone.

The dyno now shows me that I am running rich which explains the why I am loosing power.

Just don't know why.

[photogenic]

hey you said it was running rich but you don't know why. Well have you thought about adjusting the ECu yourself or with a reputable tuner? I dunno. but i think tuning the stock ECU is possible.

[pei330ci]

hey you said it was running rich but you don't know why. Well have you thought about adjusting the ECu yourself or with a reputable tuner? I dunno. but i think tuning the stock ECU is possible.

photogenic,

Your logic is off.

There is something wrong with the engine, not the software.

If the timing is retarded, it could be the cause of the rich condition...which a lot of people focus on the AFR when it's only a side affect of a late burn cycle.

To the original poster:

Something that really bothers me is that you have items changed out, and it comes good, then goes bad. None of the items changed out have a lifespan of 1 to 2 weeks, so something else MUST HAVE BEEN DONE to the car. My guess is that the ECU adaptations were reset.

There are codes that are stored on the ECU that don't light up the CEL. The next time your car is running poorly, you want to have the fault codes read. Get these fault codes and post them here, people will be able to help you with these.

Regards,

Adam

[photogenic]

photogenic,

Your logic is off.

There is something wrong with the engine, not the software.

If the timing is retarded, it could be the cause of the rich caondition...which a lot of people focus on the AFR when it's only a side affect of a late burn cycle.

To the original poster:

Something that really bothers me is that you have items changed out, and it comes good, then goes bad. None of the items changed out have a lifespan of 1 to 2 weeks, so something else MUST HAVE BEEN DONE to the car. My guess is that the ECU adaptations were reset.

There are codes that are stored on the ECU that don't light up the CEL. The next time your car is running poorly, you want to have the fault codes read. Get these fault codes and post them here, people will be able to help you with these.

Regards,

Adam

ahh adamn my apologies. its jus the mentality i am in :-\ thanks for correcting me :0

[abeaujuin]

That's correct. I will take the car back to the shop that read them before and see what he gets this time. He uses an Autologic computer to read this stuff.

I just changed out the Fuel pressure regulator and nothing. The car still feels the same and I can still smell unburned fuel like its running rich.

I was also thinking about changing out the Water Temp Sensor. I have heard that this can cause the engine to run rich too. What do you think?

[Mike Benvo]

Are you consistently using the same grade gas? By the looks of your AFR, I would venture to say that higher octane gas was put in the car and then it was dynoed...Am I correct?

[redronin]

i may be confused because 1. i dont understand why the afr is changing so much, is this input by the dyno technician or is it just straying on its own?

2. does this not look like a perfectly fine dyno for a 323? i dont see any noted loss of power, curves look okay to me. 150 hp/tq.. thats fine isnt it?



i think id agree with pei its very strange that many unrelated replacements would have the same effect on the power that you feel. its gotta be the ecu.

[abeaujuin]

Ok Last night I changed the Fuel pressure regulator drove the car to work and nothing power still gone.

So this afternoon, I went and purchased a Water Temp Sensor. Power is back. The car feels alot stronger now. I will drive it home today and see how it does on the highway.

[BMW_DK]

Now that you feel that the power is back, go and get another Dyno run and see what the difference really is.

Did you reset the ECU after replacing, or did the power just come back instantly after putting the water temp sensor on? Disconnect the battery?

[abeaujuin]

The power came back instantly and it feels so good. I am going to get another dyno run maybe tomorrow. I will post the results then.

I knew it had to be a $2 dollar item causing me this grieve.

[abeaujuin]

Power is still back.

210337

[redronin]

looks exactly the same to me 3hp diff

[abeaujuin]

Power is now gone. Don't know what else to do. Maybe sell the car and get a Honda or Toyota.

[BMW_DK]

I know how you feel, but just remember your issue, whatever it is, could just as well happen on a Honda or Toyota, no need to go to another brand.

Could your problem be a loose / bad cable. Since the problem disappears whenever you change something, and then comes back, you should into what you are doing when changing stuff, instead of focussing on a defect component.

Also, do you have aftermarket stuff on the car?

[abeaujuin]

I know how you feel, but just remember your issue, whatever it is, could just as well happen on a Honda or Toyota, no need to go to another brand.

Could your problem be a loose / bad cable. Since the problem disappears whenever you change something, and then comes back, you should into what you are doing when changing stuff, instead of focussing on a defect component.

Also, do you have aftermarket stuff on the car?



That's what I thought. I have been looking and looking for anything that could have gotten disconnected or isn't making a good contact. I can't find anything. The last part I changed out was the water temp sensor I touch nothing but the sensor. It's right up front. can't mess that one up, the power and engine smoothness came right back, but after 1 week of driving about 600+ miles is slowly disappeared again and the engine doesn't feel smooth when accelerating.

It's clear that the DME is doing something, but not sure exactly what. It Feels like the timing is being retarded or something.

I once had a busted Secondary air pump hose and as soon as I changed it out, the car felt so much smoother and the power was there in every gear, but of course after one or two weeks of driving it disappeared. Could it be a vacuum leak causing this? Wouldn’t the CEL come on if there was a vacuum leak?

[redronin]

try putting better fuel sounds like dme thinks ur fuel sucks and is retarding the timing?

[abeaujuin]

I think I found the problem. It seems as if my boots on the coils are not making a good connection. I saw some sparks coming from 2 of my brand new coils that are Bremi replacement coils. My other original coils are Bosch and they seem fine, but the new boots I got from the dealer are not the same boots that came off the car originally. The original boots look a bit longer.

Well, I removed the boots and reseated them and took the car for a spin. My power and engine smoothness is now back. So, I went back in there again fooling around with the boots this time I pushed the boots all the way into the coils and connected them back. Took it for a spin and now power is gone and engine did not feel as smooth.

So again, I removed the coils this time I put some Dielectric grease on the inside of the boots that will connect to the spark plugs and too the car for a spin, my power and engine smoothness is back.

Why are the boots different? The new boots now have a gold looking connector inside and the original have a silver connector inside. Was I supposed to put the Dielectric grease on the boots to keep them working?

Well my power is now back and the engine feels really smooth 0-100 is so smooth and quick.

[668Ci]

did you ever pull a code?

[abeaujuin]

Never got a code that was the tricky part. Nothing stored. No ghost codes.

[travisbickle]

Yeah, that doesn't surpirse me. The DME won't throw some codes unless you're in closed loop mode and under certain operating conditions. The ECU is told to ignore misfires and ignore air fuel ratios above certain loads and RPMs such as running through the gears at WOT.

[abeaujuin]

I think I figured it out. It's the oil. I've been using Mobile 1 oil. I went from 5w30 to 10w30 too 0w40. Ow40 felt good for a week or so, but then car began to feel sluggish. Well this time I was using 5w30 and after 600 miles, I decided to change the oil to something else. I drained the oil and it looked like water coming out. It was very thin.

I went to AutoZone and they now carry 5w40 by Castrol specifically designed for BMW’s and Mercedes. The oil did appear thicker and as soon as I took off, I felt the difference. The engine was smoother and more powerful. I have put over 600miles on the car since I put this oil in and the car keeps feeling stronger.

I don’t know why I didn’t just go to BMW and buy the $4 per quart oil instead of this expensive Mobile 1 $6 bucks a quart. I guess I just did not want to believe that BMW oil is different. (Plus I hate going to the dealer.)