Hey guys,

I know there are several discussions about all of the lights coming on like a Christmas tree, but I have not found what is wrong with my car yet.

So the backstory is, I was driving one afternoon and as I sped up, the lights came on and car went in to limp mode.

It did it a couple more times, but I ended up being able to drive about 5 miles to get the code looked at.

I dont remember the code, but it was about a bad fuel pump.

I decided to drive it a mile down the road to my mechanic. They looked at it and said it was my supercharger was bad and causing it. (It has sounded horrible the past couple months, getting worse.)

So I decided to replace the supercharger myself today. Got a rebuilt one from WMW with a 17% pulley, new belts, new spark plugs, new valve cover, thermostat, water pump, and all the gaskests and orings.

After putting everything back on, new oil and coolant, I turned the car on and it sounded great. No more rattles, just sounded smooth.

However, I pull out of the driveway and try to give it a little extra gas, and it trips them EML light again. After a few tries, and resetting the ECU, it keeps happening. Also, everytime I turn the car off and on, the ECU resets again?

So, any ideas what it may be? Not sure I can make it to get codes checked again with towing it. Dont want to buy a couple hundred dollar fuel pump if thats not it. And I dont know why the ECU resets every time I restart the car.

Thanks!

 

If it were me, I'd get a test kit like this (at my distance this is much cheaper than a tow truck). If pressure is low, then I'd try to rule out other things, like poor electric connection at the pump, bad relay, or clogged filter. But I think if you want to know if its the fuel pump or not, that's how to find out. Any strange noises from the fuel pump?

There may be other sources for a tool, but this was the first one google turned up for me http://promini.bmpdesign.coresense.c...arch_model/100

Part Number: 115210
Fuel Pressure Test Kit

This is a professional quality fuel pressure gauge that will be need to test the fuel system on all the late model BMW's and Mini's. These are vehicles that have the quick connect (Schrader valve) located at the engine fuel rail. (see photo)

The kit features a large 4 inch diameter gauge with a range of 5 to 145 P.S.I. which is divided into one P.S.I. increments. Kit also includes rubber gauge protector, 24 inch high pressure hose, fuel bleed off valve with clear collection hose, and a 90 degree angled connector.

This is the same tools our technicians use daily in our service department.

MSRP $71.35
Your Price: $61.15

 

It would really help knowing the codes or codes rather then trying to guess IMO.

 

I was thinking the same thing too....

 

Just a hunch....did you look at the crank damper while the sc was off?
My other suggestion...buy or borrow a genaric odb2 reader....and post the code.
It might help lots!!

 

So I just ran the code and it is p1688.

I have looked around a lot and it looks to be the BPV or Harmonic Balancer/tensioner.

I looked at the BPV and the spring is nice and tight, moves in and springs back quickly when the car is off. Turn it on and it opens, turn it off and it closes.

I'm guessing I need to replace my Harmonic Balancer then. I glanced at it when replacing the supercharger and it seemed ok, but I know that doesn't mean much.

Any suggestions on anything else I could do or try?

Thanks again.

 

Since a harmonic damper is a $400+ item, don't just do it cause....
If you need it diagnosed, tow it...
bad bpv will not result in a code unless the vac diafram in it has tottaly failed...but car should still run..
Will look up the code later....maybe somebody will beat me to it!!

 

Thanks for the reply.

I plan on throwing the car on the lift tonight or tomorrow to take a look at the pulley.

I plan on getting the RMW fluid dampener if I need one. It seems like the way to go.

Anyone have any experience with it?

Thanks,

 

Could not find p1688...will look around!

 

Question...is the car running a tune?
The codes in that range TEND to pop up on tuned cars if the tune goes "bad" due to an issue or having additional mods.....the pulley you took off...was it an OEM?

 

Nope.

Before I replaced the SC last night, the car was bone stock. The only thing I had done was NGK spark plugs, and I removed my air filter box and added a cone filter. It threw the same code a couple weeks ago before replacing everything.

My mechanic told me it was because of my SC, so instead of their $2,700 I did it myself. But it is throwing the same code.

Though my old SC was going bad, rattling really badly. The car sounds a million times better, but doesnt go over 20 mph. :(

 

P1688- Electronic throttle control monitor level 2/3 mass air flow calculation

Most likely with a car of that the crank pulley is going bad.

 

You should also clean your throttle body. Do you run an OIL style air filter?

 

Ok will do. Yes I do.

Is there anyway the throttle body could be causing it?

 

Yes, if the oil from the filter gummed it up.

 

Well another p1688 code was because of the harmonic balancer.

My local Mini had one and sold it to me for $300. So being impatient, I bought it and replaced it tonight.

The old balancer was split in two when I pulled it off. Ill try and post pics tomorrow of it.

Car is running wonderfully now! Nothing like the whine from the new 17% pulley.

 

Good to hear it was (kinda of) an easy fix!! Congrats on getting back on the road in a reasonable amount of time for a decent $$!

 

 

Well there's my problem!

 

Well then, now you can get back to motoring.

 

Glad you got it diagnosed. I had the same problem with my 2005 mcs. Same code also (p1688). Harmonic balancer for me as well. Got the ATI one from Way. Had my mechanic install it (it took a little over an hour - he's great) and all is good.

 

Seems like this harmonic balancer issue is becoming more common lately...Happened to me a month ago.

 

I hadn't seen this thread before today. My question is about the ECU resetting each time the OP started the car. What's up with that?

 

When a car is in "limp mode"...it runs at reduced power and rpm.
Shutting off the car...then restarting it allows the computer to return to normal mode...till the issue reoccurs.

 

OK, that makes sense. Thank you!