Faultless rough running cured by disconnecting MAF sensor.
03-23-2019, 07:44 PM
#1
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Faultless rough running cured by disconnecting MAF sensor.
I'm new here, have recently acquired a 2000 986, am fairly handy with a set of spanners, and have a problem.
I’ve Googled until insane and asked on FB pages but got no sensible info. I would be really grateful if someone here could give me some pointers. Here are symptoms -
One day last week the car did 150 faultless miles. Next morning we start and running rough at idle, and won’t rev past 2,000rpm.
No fault codes or lights.
Disconnected MAP sensor and runs fine.
Bought and fitted identical Bosch sensor. SAME PROBLEM!
(Incidentally while waiting for new sensor I changed AOS, cleaned TB & tubes, and checked all hose connections)
Today left MAF disconnected and did 120 miles below 4,000rpm - all fine and still no lights or codes.
Any ideas or comments?
TIA
I’ve Googled until insane and asked on FB pages but got no sensible info. I would be really grateful if someone here could give me some pointers. Here are symptoms -
One day last week the car did 150 faultless miles. Next morning we start and running rough at idle, and won’t rev past 2,000rpm.
No fault codes or lights.
Disconnected MAP sensor and runs fine.
Bought and fitted identical Bosch sensor. SAME PROBLEM!
(Incidentally while waiting for new sensor I changed AOS, cleaned TB & tubes, and checked all hose connections)
Today left MAF disconnected and did 120 miles below 4,000rpm - all fine and still no lights or codes.
Any ideas or comments?
TIA
03-25-2019, 12:33 AM
#2
This may have no bearing on it but my 4runner did the same thing but ran incredibly bad over 2000 unplugged maf and it cleared it up alot, changed maf 3 times and checked all wiring for the maf to find out i had a bad plug wire, check your coils etc you'd be surprised where some problems may lie and ignition is the easiest to go over when your out of options on your first guess
03-25-2019, 01:24 AM
#3
Racer
This is from a post I made on the 986forum a few years back. MY 2000 was a MAF changeover year so . . .
"You may want to make 100% sure you have the correct MAF. They all look pretty much the same but their sensor characteristics have to be matched to your particular car. The 2000 year is a cross over year.
This is from the Pelican DIY article. Link here Porsche Boxster Mass Air Flow Sensor (MAF) Replacement and Troubleshooting - 986 / 987 (1997-08) - Pelican Parts Technical Article
Porsche Part # BOSCH Part # Application Notes
996.606.123.00 0-280-217-007 1997-99 All Boxsters Sensor for use with cable throttle cars
996.606.124.00 0-280-218-009 Early 2000 Boxster / Boxster S Original sensor for E-gas cars
(thru Boxster 2.7L Chassis #98 6YS 62 0414 and #98 0YU 62 5099)
(thru Boxster S 3.2L Chassis #98 0YS 66 0257 and #98 3YU 66 2413)
986.606.125.00 Mid 2000-04 Boxster / Boxster S First updated sensor for E-gas cars
(discontinued and replaced with version 125.01 below)
986.606.125.01 0-280-218-055 Mid 2000-04 Boxster / Boxster S Latest updated sensor
987.606.125.00 0-280-218-145 2005- All Boxster / Cayman Integrated housing design"
"You may want to make 100% sure you have the correct MAF. They all look pretty much the same but their sensor characteristics have to be matched to your particular car. The 2000 year is a cross over year.
This is from the Pelican DIY article. Link here Porsche Boxster Mass Air Flow Sensor (MAF) Replacement and Troubleshooting - 986 / 987 (1997-08) - Pelican Parts Technical Article
Porsche Part # BOSCH Part # Application Notes
996.606.123.00 0-280-217-007 1997-99 All Boxsters Sensor for use with cable throttle cars
996.606.124.00 0-280-218-009 Early 2000 Boxster / Boxster S Original sensor for E-gas cars
(thru Boxster 2.7L Chassis #98 6YS 62 0414 and #98 0YU 62 5099)
(thru Boxster S 3.2L Chassis #98 0YS 66 0257 and #98 3YU 66 2413)
986.606.125.00 Mid 2000-04 Boxster / Boxster S First updated sensor for E-gas cars
(discontinued and replaced with version 125.01 below)
986.606.125.01 0-280-218-055 Mid 2000-04 Boxster / Boxster S Latest updated sensor
987.606.125.00 0-280-218-145 2005- All Boxster / Cayman Integrated housing design"
03-25-2019, 05:46 AM
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This may have no bearing on it but my 4runner did the same thing but ran incredibly bad over 2000 unplugged maf and it cleared it up alot, changed maf 3 times and checked all wiring for the maf to find out i had a bad plug wire, check your coils etc you'd be surprised where some problems may lie and ignition is the easiest to go over when your out of options on your first guess
03-25-2019, 05:55 AM
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This is from a post I made on the 986forum a few years back. MY 2000 was a MAF changeover year so . . .
"You may want to make 100% sure you have the correct MAF. They all look pretty much the same but their sensor characteristics have to be matched to your particular car. The 2000 year is a cross over year.
This is from the Pelican DIY article. Link here Porsche Boxster Mass Air Flow Sensor (MAF) Replacement and Troubleshooting - 986 / 987 (1997-08) - Pelican Parts Technical Article
Porsche Part # BOSCH Part # Application Notes
996.606.123.00 0-280-217-007 1997-99 All Boxsters Sensor for use with cable throttle cars
996.606.124.00 0-280-218-009 Early 2000 Boxster / Boxster S Original sensor for E-gas cars
(thru Boxster 2.7L Chassis #98 6YS 62 0414 and #98 0YU 62 5099)
(thru Boxster S 3.2L Chassis #98 0YS 66 0257 and #98 3YU 66 2413)
986.606.125.00 Mid 2000-04 Boxster / Boxster S First updated sensor for E-gas cars
(discontinued and replaced with version 125.01 below)
986.606.125.01 0-280-218-055 Mid 2000-04 Boxster / Boxster S Latest updated sensor
987.606.125.00 0-280-218-145 2005- All Boxster / Cayman Integrated housing design"
"You may want to make 100% sure you have the correct MAF. They all look pretty much the same but their sensor characteristics have to be matched to your particular car. The 2000 year is a cross over year.
This is from the Pelican DIY article. Link here Porsche Boxster Mass Air Flow Sensor (MAF) Replacement and Troubleshooting - 986 / 987 (1997-08) - Pelican Parts Technical Article
Porsche Part # BOSCH Part # Application Notes
996.606.123.00 0-280-217-007 1997-99 All Boxsters Sensor for use with cable throttle cars
996.606.124.00 0-280-218-009 Early 2000 Boxster / Boxster S Original sensor for E-gas cars
(thru Boxster 2.7L Chassis #98 6YS 62 0414 and #98 0YU 62 5099)
(thru Boxster S 3.2L Chassis #98 0YS 66 0257 and #98 3YU 66 2413)
986.606.125.00 Mid 2000-04 Boxster / Boxster S First updated sensor for E-gas cars
(discontinued and replaced with version 125.01 below)
986.606.125.01 0-280-218-055 Mid 2000-04 Boxster / Boxster S Latest updated sensor
987.606.125.00 0-280-218-145 2005- All Boxster / Cayman Integrated housing design"
I was scrupulous in getting the correct sensor (and so was the supplier). I sent him a photo of part number etched on original sensor. It was -
0-280-218-055 Mid 2000-04 Boxster / Boxster S Latest updated sensor.
Apparently some 2000 cars had updated sensors fitted after-market and reprogrammed.
Probably no-bad-thing replacing MAF in a 100k engine, but it ain’t cured it...
I can’t figure out why no codes thrown. For once I wish there WERE some!
03-27-2019, 01:27 AM
#7
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Some may remember I was having strange rough-running problems which seemed to disappear if MAF was disconnected. It finally threw fault codes - misfire on ALL cylinders! Even I couldn’t be unlucky enough to have all plugs or coils fail at once - it had to be more global. In desperation I cleaned connections of engine ground cable arrowed in photo. Misfire gone; pulls like a train to red line; another 20hp! Happy days.
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03-27-2019, 10:11 AM
#8
Racer
Some may remember I was having strange rough-running problems which seemed to disappear if MAF was disconnected. It finally threw fault codes - misfire on ALL cylinders! Even I couldn’t be unlucky enough to have all plugs or coils fail at once - it had to be more global. In desperation I cleaned connections of engine ground cable arrowed in photo. Misfire gone; pulls like a train to red line; another 20hp! Happy days.