Is This A Coincidence Or !

[RolfHarris]

Hi Guys

OK this is the story, purchased this car with 104,000 miles on it ... It's in very good condition and has had every service.

has been running great until about 2hrs ago.

I thought I would see if my Launch X431 Diagun could read / stream live engine data.

I first go in to engine codes section, click on fault codes and to my surprise I see 2 (I have not had the CEL on when driving does light up when ignition is cycled)

1. P1128 Oxygen Sensing adaption idle range Bank 1

2. P1130 Oxygen Sensing adaption idle range Bank 2

So I cleared the codes, started the car, ran rough when 1st started, then the idle settled down BUT major lack of power, feels as a misfire flat spots through out the whole rev range.

Drove to BP station about 3 miles filled up with 98 Premium fuel as I was low.

Drove back was a little better but still lack of power.

I have done a forum search and what I can gather is the MAF is a possible candidate.

Now this car has driven for 90 miles fine then I clear some codes and now this? Coincidence?

what you think?

I'll clean the MAF tomorrow and see what we get?

Also can you let me know what the readings for the MAF voltage should be when at Idle and say 2200 RPM?

I've experienced bad MAF's before and this does feel the same?

Cheers

Rolfy

[wvicary]

You could also have a vacuum leak. Clean the MAF,clear all codes and monitor.

[RolfHarris]

You could also have a vacuum leak. Clean the MAF,clear all codes and monitor.

OK New update:

Engine is misfiring bad now! More than a MAF problem..

Yesterday I had cleared the codes, and took on a drive this morning and when cold it would hardly run.. Check Engine light flashed then stayed solid.. new set of codes!

1. P0300 Misfire Detection

2. P0306 Misfire Cylinder 6

3. 04889 P1319 Knock Sensor (KS1) circuit G6 1:Short to ground

4. 0488 P1318 Cylinder 14 Ignition Circuit Limit attained

also found an invoice for the this car (I've just purchased the Boxster this last week) all 6 spark plugs and ignition coil packs were replaced on December 02 2008 but only 9,000 miles ago

All my running problems started AFTER I cleared some codes (P1128 and P1130) with the Launch X431 Diagun... Only hooked it up to see if it works with a Porsche Boxster 986

Have I deleted some adaption values or ruined an ECU, I managed to drive it to a Porsche Specialist that is 5 miles away, Told him all the info he said that Porsche have been known to change the pin configuration in the DLC3 connectors and may have damaged something... If I had fried an ecu then I wouldn't be able to drive it would I?

what's your thoughts?

Thanks

Rolfy

[Wayne R. Dempsey]

I would start with the basics: Check for vacuum leaks and then take a closer look at the MAF. Here are two tech articles I wrote that may help:

http://www.pelicanparts.com/techarticles/Boxster_Tech/21-FUEL-Vacuum_Leaks/21-FUEL-Vacuum_Leaks.htm

http://www.pelicanparts.com/techarticles/Boxster_Tech/27-FUEL-Mass_Air_Flow_Sensor/27-FUEL-Mass_Air_Flow_Sensor.htm

-Wayne

[RolfHarris]

I would start with the basics: Check for vacuum leaks and then take a closer look at the MAF. Here are two tech articles I wrote that may help:

http://www.pelicanparts.com/techarticles/Boxster_Tech/21-FUEL-Vacuum_Leaks/21-FUEL-Vacuum_Leaks.htm

http://www.pelicanparts.com/techarticles/Boxster_Tech/27-FUEL-Mass_Air_Flow_Sensor/27-FUEL-Mass_Air_Flow_Sensor.htm

-Wayne

Hi Wayne

"Great write up"

Had the Boxster checked out and they confirmed that the MAF is giving intermittent false readings BUT also said I may also have a problem with the fuel pump??

Recommends changing the MAF then re-test...

I will post the results after the replacement..

Also spoken with another specialist today and was told that once you clear codes, it's common for the car to run rough if theres a problem due to all the adaption values being deleted... makes sense due to after I deleted my trouble codes thats when I had the drive ability problems straight away. what you think?

thanks

Rolfy

[RolfHarris]

MAF fixed all running problems! Now runs perfect.

[Wayne R. Dempsey]

Problem with the fuel pump? I wonder where that came from. When the MAF goes screwy, it can cause lots of different error codes. I would just keep an eye on it - maybe recheck the codes in a month or so to see if anything came up. Off the top of my head, I can't think of a sensor that senses actual fuel pressure in the lines - I wonder why they thought there was a problem with the pump? Oh well, glad to hear the car is running well.

-Wayne