Dieseling / Decarbonisation help wanted.
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Rennlist Member
Rennlist Member
Joined: Nov 2003
Posts: 3,530
Likes: 4
From: Kauai, Hawaii
Gabi,
Is air mass meter the same as the MAF sensor? If so, it may have something to do with the K&N filter you have on the car.
https://rennlist.com/forums/showthre...light=air+mass
Glad to hear it's running better.
Is air mass meter the same as the MAF sensor? If so, it may have something to do with the K&N filter you have on the car.
https://rennlist.com/forums/showthre...light=air+mass
Glad to hear it's running better.
Thread Starter
Burning Brakes
Joined: Mar 2004
Posts: 993
Likes: 5
From: United Kingdom
kkim: You may well be right, the car always behaves badly after a service, so it could be to do with excess oil on the K&N filter causing problems with the MAF sensor. I am going to have it replaced to be on the safe side. Since it was cleaned it has made a huge difference.
Thread Starter
Burning Brakes
Joined: Mar 2004
Posts: 993
Likes: 5
From: United Kingdom
Well, I have made some progress. After a great deal of investigatory work with my mechanic, we decided to try a different air mass meter, having eliminated vacum leaks, broken distributer drive belt, bad gas, O2 sensor and a few others.
The air mass meter off another car was used in mine and the air filter was left off during the test drives, sure enough there was a marked improovement. Putting my sensor back on again without the filter made a pinking noise though not as pronounced as before. Deciding to test it for a day or two with the other cars sensor he puts the filter on for me to take the car away, and then..... "clatter, clatter clatter" the pinking noise returns, so he removes the K&N cone filter and assembally and puts on a stock air box with a motorsound cover, so far no pinking so fingers crossed, but the car still runs on from time to time
still progress is progress.
The air mass meter off another car was used in mine and the air filter was left off during the test drives, sure enough there was a marked improovement. Putting my sensor back on again without the filter made a pinking noise though not as pronounced as before. Deciding to test it for a day or two with the other cars sensor he puts the filter on for me to take the car away, and then..... "clatter, clatter clatter" the pinking noise returns, so he removes the K&N cone filter and assembally and puts on a stock air box with a motorsound cover, so far no pinking so fingers crossed, but the car still runs on from time to time
still progress is progress.
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Joined: Nov 2003
Posts: 3,530
Likes: 4
From: Kauai, Hawaii
Gabi,
I don't know if this will help or not, but might be worth a try... disconnect the battery for a few minutes, then reconnect. In my previous cars, this was done to reset the ECU or in our cars the DME. The DME might still have some memory of the past driving parameters with the K&N installed. By clearing it, you'll start off with the stock map and the car will relearn with the new filter/housing in place.
Good luck... HTH.
I don't know if this will help or not, but might be worth a try... disconnect the battery for a few minutes, then reconnect. In my previous cars, this was done to reset the ECU or in our cars the DME. The DME might still have some memory of the past driving parameters with the K&N installed. By clearing it, you'll start off with the stock map and the car will relearn with the new filter/housing in place.
Good luck... HTH.
RL Technical Advisor
Joined: May 2001
Posts: 11,870
Likes: 75
From: Portland Oregon
Hi Gabriel:
I'm very pleased to hear that you & your mechanic apparently fixed the problem.
I must tell you that we NEVER use those damned cone-style air filters in leiu of the Porsche factory airbox. Power losses and running issues, as well as less than effective filtering (for street cars) are the reasons.
Porsche A.G. did a superb job of designing and building an airbox for these single throttle intake systems and the majority of the aftermarket offerings make more noise, not more HP. I sincerely hope that others refrain from spending their hard-earned dollars on things like these and save those resources for upgrades that actually help.
Please keep me posted.
I'm very pleased to hear that you & your mechanic apparently fixed the problem.
I must tell you that we NEVER use those damned cone-style air filters in leiu of the Porsche factory airbox. Power losses and running issues, as well as less than effective filtering (for street cars) are the reasons.
Porsche A.G. did a superb job of designing and building an airbox for these single throttle intake systems and the majority of the aftermarket offerings make more noise, not more HP. I sincerely hope that others refrain from spending their hard-earned dollars on things like these and save those resources for upgrades that actually help.
Please keep me posted.
Thread Starter
Burning Brakes
Joined: Mar 2004
Posts: 993
Likes: 5
From: United Kingdom
I have to say that the car now absolutely flys, the difference an air intake can make is incredible, I would strongly urge anyone thinking of using a cone filter not to, it has caused me headaches ever since I bought the car with the cone filter installed. It seems that the filter layer itself actually contracted restricting the air flow, no matter how often it was cleaned out the same problem would always come back. I actually find the motor sound air box louder than the cone filter I had on the car.
Thread Starter
Burning Brakes
Joined: Mar 2004
Posts: 993
Likes: 5
From: United Kingdom
Ok now that the detonation issue is solved, it seems that the "run-on" issue may just be the flywheel noise that others have quite often 
Thaks to everyone for their input on this, I am now a happy camper. Rennist truely is a great source of information!
Thaks to everyone for their input on this, I am now a happy camper. Rennist truely is a great source of information!
