I recently bought 05 MCS with a Dinan stage 5, claimed 208 hp. Lotsa fun to drive until very recently...

Now, mostly when accelerateing and random other times the car will lurch, and sometimes go into limp mode and require a restart to return to life. SES light is now permanent

My local mechanic got error / fault codes of P1688 and P1237. He said that indicates that the upstream or MAP sensor is bad and that there is a leak in the leading air intake. Apparently there is a process to go through to find the leak.

While I really trust my mechanic ( plan on dropping the car off in a few days) I was just wondering if anyone has had similar problems / solutions.

Thanks!

 

P1688 - Level 2/3 Mass Air Flow Calculation.
P1237 : Secondary Upstream Manifold Air Pressure Sensor Low Input.

If you have the time before having your MINI checked by the mechanic, I would just do a quick check of your thottle body and make sure it's not staying open more than it should be. Somtimes gook can build up keeping the plate open some.

I have also seen where the oil from aftermarket hi-flo foam air filters can eventaully work their way down stream and coat the MAF wire also causing similar issues.

 

Not sure if it would help, but take a quick look at your intercooler boots...see if you see any oil seeping out around them...perhaps if they are loose or dried out enough it could cause a problem...not sure if it would result in the codes you have though. Then again it might just be a bad sensor...if the car still has the Dininan filter, and not an aftermarket air filter, it should be ok... They are disposable, cost $70 ish, but if it is oily...someone might have tried to clean it and re-oil it....not recommended, but a few folks here on NAM have done it....

 

This is remeniscent of my problem. Even though the codes are for the MAP system, don't even bother changing them. Inchanged mine and it helped, for a while, but it still started doing the limp mode routine. The front MAP was dirty, but not bad and the rear MAP, well let's just say it looked brand new. My supervisor told me a while back to start looking for a leak somewhere. I going to check out the throttlebody area. Afterall, I have added a DT bypass valve. Zippy is right, could be a leak somewhere.

 

Have an assistant start and stop the car. As the car shuts down you may hear a sucking sound from the source of the leak. It will last less than a second, so you will probably have to do it several times. Take a piece of rubber hose, hold one end to your ear, and probe around the intake tract with the other until you identify where the sucking sound is coming from. You may have to put the hose down between the motor and radiator fan, and under the intercooler, to get to all of the usual suspects.

 

Thanks. Great advice!

 

You could also look for a shop that has a smoker. It is a device that they hook up to the boost and vacuum lines that emits smoke with low pressure. If you have a leak, smoke will come out of it.

 

Problem not yet fixed. At first he thought it was the Dinan rubber boots that were not installed exactly right going in and out of the super charger. Unfortunately , that did not fix it. There appears to be no air leaks. However the serpintine belt was 50% worn and replaced. Then- the new one started to wear quickly too. They found about 1/2 inch of wobble in the pulley. I think that pulley is attached to a shaft that goes to the cylinders. It is an original MC pulley.

Should the original pulley been upgraded when the other Dinan upgrades done? My mechanic has some calls out to Dinan and another BMW tech before he just starts replacing more parts.

Has anyone ever seen this serpetine belt pulley problem?

I miss my car. Its been about 2 weeks : (

 

have the ati damper put on . i think it's ati anyway . i had a later model stock damper i got 2nd hand and put it on and it's doing the clicking bit now too . so just get the better ati and seems no problems yet reported .

 

Scuse my mechanical ignorance, but what is an ati damper and how does it help my problem?

 

just sayin' if your damper is wobbling it more than likely needs replacing ,. so rather than go with stock; i'd recommend one from ati i think it's called super damper or something . they have a very good racing history .

 

http://www.atiracing.com/ your damper is wobbling so rather than get another stock; i suggest what many have done and get ati's damper .

 

i had this exact same problem a year ago on my R53, it ended up being the bypass valve. went ahead and got the detroit tuned one off of outmotoring.com. Never had the problem again since.

EDIT
To be more specific, it was the diaphragm on the bypass valve that failed and would not open the valve.
P1688 - Level 2/3 Mass Air Flow Calculation.
You can check the valve by hand at home to see if it is opening correctly by simply moving the arm that controls it by hand, if it doesn't move smoothly or gets stuck, you have a bad bypass valve. attached is a pic of the old bpv and im holding the arm that should move smoothly

 

Juanfe, Great advice! Im having a few of the same symptoms as some of the others here! Very informational! Thank you!

 

the ati dampener is a crank pulley (dampener is another name for the crank pulley, or the pulley that is attacked to the crank shaft (bottom on the cylinders) My pulley actually fell completely off (the stock one) and i had it replaced by Way Motor Works with an ATI Super Damper crank pulley. Ati is a big name in the drag industry, and has a great rep for making parts that will hold up to the harsh conditions of extreme drag racing (making them especially great for street durability)

https://www.northamericanmotoring.co...ct/397/cat/112

http://www.waymotorworks.com/super-d...ulley-r53.html

 

We found that Dinan rubber boots around the turbo were not originally fitted correctly, seemed loose and were replaced. However, that didn't fix the problem. Then the pulley was wobbling and replaced with the upgraded OEM, but that was not the cause of my problem. Just lucky it was caught before the belt snapped.

A new bypass valve was ordered, but tested the same as the old one, so was returned

That left the MAP sensors. At least one was tested bad, so both were replaced. Now, at long last I'm back on the road : )

However, considering that the parts alone cost over $800, I suppose that I can't complain about a bill of $1,325.00. It also included a new battery.

The car is 6 yrs old with 65,000 mi on it. I think my mechanic spent more hours on trying each unsuccessful solution that I was billed for.

 

Good to hear you are back on the road....It is a sad fact of life when you push a card hard with performance mods, things tend to fail faster...but I'm sure the car must be an absolute blast to drive now that it is running right!!
Sounds like a good honest mechanic....Good to hear he gave you a bit of a deal!