99 Porsche boxster unstable idle! revs up constantly maf related?

mr.datskiy · mr.datskiy's Garage

I have a 99 porsche boxster, 5 speed manual, 48k miles. Its my daily driver and i need it fixed asap. It was running perfectly fine when i purchased it several months ago.

I bought it with full service records for mods/maintenance since about 18k miles so it was cared for. Other than an oil change and drive belt replaced, i didnt do much maintenance for the short period of time that i owned it.

When i started it up last monday afternoon, idle would stay at about 2500 than when car gets a little warmer it would just constantly bounced from 1200-2000 rpms like shown in the video below.

1999 Boxster Base Idle Problem - YouTube ( Not my car but does the same excact thing )

Engine check light also came on, Here are the codes:

P0102 - Maf low input
P1123 - fuel and air metering
P1125 - fuel and air metering

What could it be? I cleaned my maf with maf cleaner from a local auto zone and still no fix. Should i go ahead and purchase a new one?

If someone experienced a same or similar problem please help me out! still nube to pelican parts as this is my first porsche so help me out!

Thanks, Stan.

Drop a line/pm me, call/text at 2535613101. Thanks!

squireiii · 02-21-2012, 09:33 AM

As Wayne has advised in several previous posts, unplug the MAF and see if the car runs better, or at least different. This is a good way to isolate the MAF. I had problems similar to yours, and found that the MAF sensor installed in my car was a knock off. It had no writing on its side (there is a post on this issue here on Pelican). I ordered a Bosch unit from Pelican, and all issues ceased, 2,000 miles later, still running like a top. 99 Base as well. Hope this helps!

mikefocke · 02-21-2012, 10:37 AM

P0102

1. Check wiring from MAF Sensor to Engine
Control Module (ECM) for continuity.

2. Check wiring from MAF Sensor to ECM
for short to ground.

Around all the O2 related codes there are suggestions of lose air intake tubes, fuel pump/filter problems, etc.

rdb525i · 02-21-2012, 03:29 PM

Check the throttle position sensor and its attached wiring. you need to take the top engine cover off to see it. good luck

mr.datskiy · mr.datskiy's Garage

When i unplug my Maf car runs i would way great! it dont even miss a beat. From the looks of it i was pretty sure its just the maf.

Alright, so i went ahead and bought a maf sensor from a site called buy auto parts. It looked good and ran me about 94 bucks. Plugged it in and no difference!

It came with a one year warranty so im probably just going to return it. It had no writing on the side like my bosch one that i took out. Guessing like what squireiii said at it being a knock off. Should i just pick one up here a pelican? Do they come with some sort of warranty incase same thing happens?

newlife · newlife's Garage

Quote:

Originally Posted by mr.datskiy

When i unplug my Maf car runs i would way great! it dont even miss a beat. From the looks of it i was pretty sure its just the maf.

Alright, so i went ahead and bought a maf sensor from a site called buy auto parts. It looked good and ran me about 94 bucks. Plugged it in and no difference!

It came with a one year warranty so im probably just going to return it. It had no writing on the side like my bosch one that i took out. Guessing like what squireiii said at it being a knock off. Should i just pick one up here a pelican? Do they come with some sort of warranty incase same thing happens?

Yes ! would order from Pelican and make sure you have the correct serial number. Also, did you give it a good cleaning? MAF cleaner. I hope you work it out.

Rod

squireiii · 02-23-2012, 02:41 PM

I would recommend a Bosch part from Pelican. Sounds like the one you received was a knock off like the one I had prior to replacement. Cleaning did it no good. Once I put in the genuine article the car was transformed. I just drove it 600+ miles yesterday (Kentucky to Hilton Head, SC) and not a hiccup. Good luck, and keep us posted.

Harriet03 · 02-23-2012, 04:22 PM

Check wiring from MAF Sensor to Engine

mr.datskiy · mr.datskiy's Garage

Yes I gave oem Bosch one a good cleanig with maf cleaner as well as new knock of one. Going to return the maf I got from auto part store and get a new Bosch one here from pelican.

Gonna work on car today.

Will let you guys know! Thanks..

mr.datskiy · mr.datskiy's Garage

90% sure its the maf sensor so gonna order an OEM one here from pelican tonight and put it in as soon as it come(when i uplug the sensor car runs great!) As for the Bullsh** buy auto part store sensor gonna give those busters a hollar and hustle up my money back..

Would not recommend that place to anyone. They say on their website that their one sensor goes for 97-2004 models. According to wayne there is like 4 different ones during that time period. Pretty sure wayne cant be wrong when it comes to porsches

Ill let you guys know how it turns out when i get the oem bosch one.
Thanks for you help.

mr.datskiy · mr.datskiy's Garage

Quote:

Originally Posted by newlife

Yes ! would order from Pelican and make sure you have the correct serial number. Also, did you give it a good cleaning? MAF cleaner. I hope you work it out.

Rod

Replaced maf sensor with oem bosch one and still the same thing.. When i start up idle jumps around like in the video.

What else could it be?

squireiii · 03-01-2012, 08:55 AM

Did you "reset" your computer? I'm just repeating the steps I went through. Hope you figure it out soon!

mr.datskiy · mr.datskiy's Garage

Yes i reset the computer still nothing

Miss driving the car like crazy...

Dont think it could be anything else because when i unplug maf car transforms. It runs cleaner with no hunting idle...

Maybe the wiring to the maf? How can i check that?

Any help is greatly appreciated.

Thanks..

mr.datskiy · mr.datskiy's Garage

Checked the wiring to the maf by using ohmmeter(reading the 5 pins on maf cap) and it all checked out. Looked up reading online and it was what it was suppose to be. So wiring to the maf is out if the picture.

Anything else??

squireiii · 03-02-2012, 03:29 PM

Vacuum check? I've found vacuum leaks to cause all manner of idle problems, though not on my Boxster, yet...

mr.datskiy · mr.datskiy's Garage

Quote:

Vacuum check? I've found vacuum leaks to cause all manner of idle problems, though not on my Boxster, yet...

How do I check that? Like i said still a nube at Porsches..

Is there a tutorial here on pelican?

squireiii · 03-03-2012, 05:35 AM

Yes. There are a few things that you can do. Do a search and you will find more info. Also, if you already have one, I would recommend Wayne's 101 Projects book. It has been invaluable to me and many others here. And it has an article on vacuum. I feel your pain, but you will figure it out!

bala · 03-04-2012, 04:49 AM

I have the same revving idle issues. Though it happens more at cold and seems to be less once warmed up. It does come back mostly when stopped - cold or hot. Even threw a cylinder misfire once. It all started after i did the throttle body clean and aos replacement. So, i must have accidentally coused some hose to break or allow a leak somewhere. I am going to replace the oil fill tubes, and check the entire secondary air system. My air pump operates fine and the rest of the part are not that expensive so, it would be good to trash them and replace o think.

randy_k · randy_k's Garage

Bala, Just a suggestion. Check the cross over tube from the throttle body to the AOS. I accidentally left it off when I did mine and put things back together. It did all kinds of weird things when I started it with it off. You may have one end lose. Just a thought and easy enough to check.

Randy

bala · 03-04-2012, 07:08 AM

Randy,
that was snug. I just pulled the oil fill tubes, the ribbed one had cracks at 3 places. Of course I broke the one to the engine as well. The plastic must be the lowest quality ever. Anyway, I'd rather replace the whole line as well as the parts for the secondary air system and be done with it. Let's see how those fare.