Newbie with a single engine code problem

[Phil Mead]

Before I start I'd like to thank you folks in advance for having this forum. Streetrods, cobras, british, porsche, etc..... its great to see others that do their own work. Car lovers of all types a great people!!

Here is my issue. 2001 Boxster (non-S), 49,000 miles, Check engine Code 1128. I have no drivability issues. The car is running great. I have checked the fuel cap, reset light and it came back after 50 miles (same code) I have checked for excessive vacuum at oil fill, it is normal. When I did a search for 1128 everyone had multiple codes, I have only the one. I was thinking MAF but I would think that would trigger both sides for the engine???? (Bently says P1128 is 1-3 bank) Could it be as simple as an 02 sensor? How do I know which one?

[mikefocke]

Causes:

– Incorrect signal from MAF sensor

– Intake air system leaking

– Fuel pressure too low

– Volume supply of fuel pump too low

– Fuel injectors fouled

– Exhaust system leaking

[infocusf8]

I have a similar issue but with more codes.

CEL on, car running about 10 deg. hotter.

Codes 1126-1130-030-050

Codes cleared, MAF sensor cleaned and reinstalled, K&N filter removed and OEM filter installed, engine liquid and smoke tested for intake leaks non found, fuel filter changed 6K mi. ago, no rough idle, no loss of acceleration, no smoke, gas cap sealed.

CEL back on around 250 miles later car still running fine but about 10 deg. hotter again.

[Phil Mead]

Thanks Mike, I will check intake for leaks with starting fluid, run some injection cleaner through it, clean my MAF sensor, is there a shrader valve to hook up a fuel pressure guage? and what should the pressure be? I cant hear or see an exhaust leak. I will also put a stock air filter back on. I replaced it with a KN.

[mikefocke]

I notice both had K&Ns and neither mentioned cleaning the throttle body.

http://www.pedrosgarage.com/Site_3/Clean_the_Throttle_Body.html

Allow oil into the intake and you can get oil into the MAF and onto the O2 sensors. So cleaning the intake makes sense and, if that was all it was, will hasten getting things back to normal.

Infocus8, it's important to mention the model year when describing your problems as the codes can be different due to different DME firmware revisions. Don't know what to make of your running hotter. Nor the -030-040 codes you cite as there are none of them in the 5.2 or 7.2 DME manuals.

[infocusf8]

I notice both had K&Ns and neither mentioned cleaning the throttle body.

http://www.pedrosgar...ottle_Body.html

Allow oil into the intake and you can get oil into the MAF and onto the O2 sensors. So cleaning the intake makes sense and, if that was all it was, will hasten getting things back to normal.

Infocus8, it's important to mention the model year when describing your problems as the codes can be different due to different DME firmware revisions. Don't know what to make of your running hotter. Nor the -030-040 codes you cite as there are none of them in the 5.2 or 7.2 DME manuals.

Hi Mike, it's a '99 Boxster and I erred on the codes they are PO 130 & 150, P1126 & 1130.

Edited March 9, 2010 by infocusf8

[Phil Mead]

I will get a chance to clean MAF and TB this weekend I will post the results!!!

[Loren]

I will get a chance to clean MAF and TB this weekend I will post the results!!!

Use only MAF sensor cleaner - some folks have had worse problems with "other" cleaners.

[mikefocke]

You said " it's a '99 Boxster and I erred on the codes they are PO 130 & 150, P1126 & 1130."

I suspect you meant P0130 and P0150 (second place being a zero and not an O).

P0150 relates to a short or limited voltage increase in the O2 sensor or wiring in the sensor nearest the engine on the drivers side of a LHD US spec car. P0130 to same problem other side.

Did your ECM get shorted due to water? Critters get into the wiring and start gnawing? Bad ground? Bad ECM?

Or are the sensors both just covered in excess oil that didn't get burned off in combustion?

[infocusf8]

You said " it's a '99 Boxster and I erred on the codes they are PO 130 & 150, P1126 & 1130."

I suspect you meant P0130 and P0150 (second place being a zero and not an O).

P0150 relates to a short or limited voltage increase in the O2 sensor or wiring in the sensor nearest the engine on the drivers side of a LHD US spec car. P0130 to same problem other side.

Did your ECM get shorted due to water? Critters get into the wiring and start gnawing? Bad ground? Bad ECM?

Or are the sensors both just covered in excess oil that didn't get burned off in combustion?

Interesting that out of three "Porsche Specialist" mechanics that I've talked to none of them has mentioned the ECM. They all want me to spend $150 on a diagnosis or replace the MAF or the O2 sensors. I will check the ECM tomorrow to see if there are any connections that are loose. I just paid a "Porsche Specialist" $250 to reconnect a wire to the immobilizer unit under the seat that had come unconnected and completely immobilized the car. Thanks for the tip and yes of course I meant "0" and not "O." How would the sensors get covered with oil? Occasionally I get the puff of smoke at startup from oil that accumulates from sitting, is that what you are referring to?