Possibly a bad maf - 986 Forum - The Community for Porsche Boxster & Cayman Owners

ohioboxster · 09-15-2006, 10:54 AM

Im surprised no one suggested that I may have a bad maf sensor. My car is stumbling on cold starts and after doing a little research on this site it appears this may be my problem. Im debating on spending $250.00 on a scan tool, $250.00 on a maf sensor or taking it to a shop to read my code. Anyway I go is going to be kind of pricey I guess. If I buy the tool I will always have it and be able to reset and read codes on many different vehicles but I've noticed the tools seem to point you in the wrong direction.

blinkwatt · 09-15-2006, 11:22 AM

I bought my Actron Pocketscan off eBay new for $50 shipped. $250,that better come with everything Durametric does and them some. Worthy invest for EVERY car(97 and up) not just your Boxster.

I had to deal with a bad MAF not tool long ago,it was caused by a K & N air filter. Does your car seem to "jam up" sometimes when you are accelerating? By that I mean does it pause while you try to accelerate? My idle was kinda of funky during the times this occured. Is it your original MAF?

ohioboxster · 09-15-2006, 11:34 AM

Its probably the original maf. No my car doesnt seem to have any trouble accelerating. That tool you bought, will it reset cel and give you trouble codes? Heres the one I was looking at...http://www.pelicanparts.com/catalog/shopcart/996M/POR_996M_TOLtol_pg2.htm#item11

Go to that link and check out
AutoEnginuity ScanTool Kit for PC - Windows 95/98/ME/NT/2000/XP (Plug-n-Play USB 2.0 interface) [Photo] [Photo]

Is this something like you have? Im still not sure if Im dealing with a MAF or bad 02's. I just called the shop and they want 150.00 to scan for codes.

I just looked up the pocket scanner you wrote about. When it gives you a code what do you use for a reference from that point? Is there a book or something with it?

Norminhouston · 09-15-2006, 11:38 AM

Quote:

Originally Posted by ohioboxster

Its probably the original maf. No my car doesnt seem to have any trouble accelerating. That tool you bought, will it reset cel and give you trouble codes? Heres the one I was looking at...http://www.pelicanparts.com/catalog/shopcart/996M/POR_996M_TOLtol_pg2.htm#item11

Go to that link and check out
AutoEnginuity ScanTool Kit for PC - Windows 95/98/ME/NT/2000/XP (Plug-n-Play USB 2.0 interface) [Photo] [Photo]

Is this something like you have? Im still not sure if Im dealing with a MAF or bad 02's. I just called the shop and they want 150.00 to scan for codes.

Go to an AutoZone store. They will scan for free.

blinkwatt · 09-15-2006, 11:39 AM

My tools reads me the codes and clear them. I will have to check out your link a little later,its currently not working.

$150 to scan codes? Bull,I can send you mine and you can barrow it,just pay shipping to your house and back.

CJ_Boxster · 09-15-2006, 11:40 AM

OR you can goto autozone and use there ODBII scanner they have for free, They can tell you what your codes are, Have you gotten a CEL yet?

Quote:

Originally Posted by ohioboxster

Im surprised no one suggested that I may have a bad maf sensor. My car is stumbling on cold starts and after doing a little research on this site it appears this may be my problem. Im debating on spending $250.00 on a scan tool, $250.00 on a maf sensor or taking it to a shop to read my code. Anyway I go is going to be kind of pricey I guess. If I buy the tool I will always have it and be able to reset and read codes on many different vehicles but I've noticed the tools seem to point you in the wrong direction.

ohioboxster · 09-15-2006, 11:40 AM

Quote:

Originally Posted by Norminhouston

Go to an AutoZone store. They will scan for free.

Really? Wow thats awsome I didnt know that!

ohioboxster · 09-15-2006, 11:42 AM

Yeah the cel just came on the other day thats why I dont think its the supercharger. Its a new problem.
So I just got back from Autozone and my car had ten codes as follows,

p0300, p0306, p0304, p0305, p1121, p0150,p1313, p1314,p1317,p1117

Well, cylinders 4,5,6 mis-fired, 02 sensor bank 2 sensor 1 (pre cat) and a maf code. Im thinking I must have screwed something up on 3 cylinders when I changed the plugs, all the codes seem to be related to three cylinders. I hope 4,5,6 are on the drivers side or Im going to have to pull the SC unit out if the issue is with the coils. I cant think of what in the world I could have done, unless its just the 02 sensors. This is one of those times when I dont want to just start replacing parts. Any thoughts?

MNBoxster · 09-15-2006, 12:28 PM

Quote:

Originally Posted by blinkwatt

My tools reads me the codes and clear them. I will have to check out your link a little later,its currently not working.

$150 to scan codes? Bull,I can send you mine and you can barrow it,just pay shipping to your house and back.

Hi,

Which Actron do you have the 9125 or the 9135?...

Happy Motoring!... Jim'99

MNBoxster · 09-15-2006, 12:30 PM

Quote:

Originally Posted by ohioboxster

Yeah the cel just came on the other day thats why I dont think its the supercharger. Its a new problem.

Hi,

I think it's the MAF, but possibly exacerbated by the increased flow from the supercharger.

I wouldn't be surprised to see a shortened lifespan on supercharger installations because they're the Hot Film type and a little less rugged than the Hot Wire type, it'll be interesting to see. Good Luck!...

Happy Motoring!... Jim'99

blinkwatt · 09-15-2006, 12:54 PM

Quote:

Originally Posted by MNBoxster

Hi,

Which Actron do you have the 9125 or the 9135?...

Happy Motoring!... Jim'99

The P125,I bought it back when I was having MAF trouble with codes,P1123 and P1125 if you remember.

http://www.autobarn.net/cp9125.html

ohioboxster · 09-15-2006, 12:57 PM

Quote:

Originally Posted by blinkwatt

The P125,I bought it back when I was having MAF trouble with codes,P1123 and P1125 if you remember.

http://www.autobarn.net/cp9125.html

Was the scanner correct? Did you end up having a maf issue?

CJ_Boxster · 09-15-2006, 01:25 PM

When i got my MAS code on the Scanner, it was accurate, However i do not think the misfire is related to the MAS code, I think maybe that misfire could have been a result of your boost leak you had OR maybe the mixture is getting too hot and your getting detonation and in that case i would recommend a colder spark plug...denso iriduims are awesome and autozone usually keeps them in stock.

If you pulling an o2 sensor code i think they were just about on there way out and the added heat exhaust gases from the supercharger may have helped in them failing. You may need all 3 things replaced.

blinkwatt · 09-15-2006, 01:25 PM

Quote:

Originally Posted by ohioboxster

Was the scanner correct? Did you end up having a maf issue?

1. The scanner gave me the codes indicated what was wrong. It read to me P1123 and P1125.

2. I found the meaning to those codes,I beleive it was;
"P1123=( Oxygen Sensing Adaptation Area 1 (Cylinders 1 - 3) - Lean Threshold)"
"P1125=( Oxygen Sensing Adaptation Area 2 (Cyclinger 4 - 6) - Lean Threshold)"

3. Time to troubleshoot. Searched every archive I could,talked to MNBoxster(he was dead on),called around some indie Porsche shops. As soon I let people know I had a K & N air filter from the previous owner they said to change the MAF.

4. Bought a new MAF and walla! All was good again!

The codes only point to whats rich,lean,misfiring etc. They don't say specifically what is causing the issues. Thats what the search and archives are for. Good luck with all those codes.

MNBoxster · 09-15-2006, 02:03 PM

Hi,

Pull the MAF and try cleaning it before spending $$$. If it works, at least you've bought some time.

You might be getting some detonation, use only the best gas. Going to a colder plug is OK if you can find one in the proper range. Too cold and you'll foul the plugs. Forget the irridiums, they're a marketing gimmick at a premium price, stick with OEM Bosch or Beru...

Happy Motoring!... Jim'99

Frank · 09-15-2006, 03:17 PM

Hi,
I recently had my MAF go bad.The car ran real bad on startup in the morning. It accelerated horribly and was just slow.I got the codes read at autozone and it said oxygen sensors,well it was the MAF and not the oxygen sensors to make a long story short. To figure out if that is your problem,just disconnect the wire for the MAF and it will put the computer into default mode,your car will run great if that's the problem.By the way,don't buy the bosch universal oxygen sensors if you ever need to replace any of them,they don't work

.
Frank

ohioboxster · 09-15-2006, 06:05 PM

Quote:

Originally Posted by Frank

Hi,
I recently had my MAF go bad.The car ran real bad on startup in the morning. It accelerated horribly and was just slow.I got the codes read at autozone and it said oxygen sensors,well it was the MAF and not the oxygen sensors to make a long story short. To figure out if that is your problem,just disconnect the wire for the MAF and it will put the computer into default mode,your car will run great if that's the problem.By the way,don't buy the bosch universal oxygen sensors if you ever need to replace any of them,they don't work

.
Frank

I wondered anbout those cheap universal 02 sensors. I have a couple of good 02 sensors from another car and dont see why they couldnt be used if I could figure out the wires.

Frank · 09-16-2006, 06:21 AM

Yes,I thought they would work great. I bought them off the internet for a good price and looked at the diagrams in my porsche service book and figured out the wires.(2 whites,1black,and a grey).After hooking them up,the car ran MUCH worse.I then spoke with a mechanic friend of mine and he said that most of the universal sensors will not work correctly on high end cars.Well,atleast I tried...

Gary Gaukler · 09-16-2006, 08:43 AM

Quote:

Originally Posted by ohioboxster

Yeah the cel just came on the other day thats why I dont think its the supercharger. Its a new problem.
So I just got back from Autozone and my car had ten codes as follows,

p0300, p0306, p0304, p0305, p1121, p0150,p1313, p1314,p1317,p1117

Well, cylinders 4,5,6 mis-fired, 02 sensor bank 2 sensor 1 (pre cat) and a maf code. Im thinking I must have screwed something up on 3 cylinders when I changed the plugs, all the codes seem to be related to three cylinders. I hope 4,5,6 are on the drivers side or Im going to have to pull the SC unit out if the issue is with the coils. I cant think of what in the world I could have done, unless its just the 02 sensors. This is one of those times when I dont want to just start replacing parts. Any thoughts?

Your codes are interesting. I looked them up in the Bentley manual. According to the manual, p1313-1317 do not exist for the 5.2.2 DME in your car, but they refer to cylinder 1,2,5 misfires with DME 7.2. That would mean you misfire on almost all cylinders, not just one bank... P1121 is the TPS, not a MAF code.

My thoughts: I don't see very much here that would point to a MAF fault. Also I don't think it is likely that you screwed up the coils / plugs. However, all codes can be related to fueling issues. You may be running severely rich / lean. Have you had the car on the dyno after the sc install to verify your A/F ratios?

Gary

Gary Gaukler · 09-16-2006, 08:53 AM

One other thought: You said it stumbles at idle for a while, and then it goes away. That could be another indicator that your fueling is off. The first couple of seconds at idle the car is in open loop: the o2 sensors won't correct the A/F ratio until they have warmed up. Hence you are running off some standard fuel maps. Once the car is idleing in closed loop, the o2 sensors correct the mixture.