Multiple error codes '99 996

[steve 996]

I'm guilty of accidently running a tank of lesser quality gas through my 996 and I'm wondering if that's what led me to see multiple error codes (P1124, P1126, P1128, P1130 and pending codes P0130, P0150). I've checked all the easy vacuum leak sources, like gas cap, oil filler cap, air filter hose (there was a slight leak there the first time the code showed up) without success. The idle's rough, but there's no smoke of any sort. Is there something else I should try before I try the PITA aos change or the expensive MAF change?

Help?

[RFM]

P0130 - P0150 refers to O² sensors ahead of cat. cylinder banks 1 - 3 and 4 - 6 inter core short circuit or limited.

P1124/26/28/30 refers to oxygen sensing adaption area 1 and 2 on cylinder bank 1 - 3 and 4 - 6 RICH threshold which means LEAN running engine.

I would try, in first place, with a full tank of fresh premium fuel mixed with a fuel cleaning product, after the error codes are deleted. Parts replacement can always be done later on.

[steve 996]

P0130 - P0150 refers to O² sensors ahead of cat. cylinder banks 1 - 3 and 4 - 6 inter core short circuit or limited.

P1124/26/28/30 refers to oxygen sensing adaption area 1 and 2 on cylinder bank 1 - 3 and 4 - 6 RICH threshold which means LEAN running engine.

I would try, in first place, with a full tank of fresh premium fuel mixed with a fuel cleaning product, after the error codes are deleted. Parts replacement can always be done later on.

Thanks, I'll give that a try. I'd like to add that a few minutes ago, after the car was well warmed up from a 25 minute round trip, I tried to block the intake with a clean cloth. I found it didn't effect the engine one bit. That's pretty convincing evidence of a large vacuum leak, isn't it? If so, where should I start looking for it?

[RFM]

Oil filler pipes, OAS, vacuum pipes, etc. are all known for leaks, the shortest and best way to find an air leak is to contact someone with a "smoke machine", your air leak can be found in 10 minutes than.

[SteveBreen]

I changed the OAS this weekend, what a PITA. It actually looked to be in good shape. In the process of swapping the OAS, I found that the dealership, when they changed the starter a couple of year ago, incorrectly installed one of the rubber sleeves the joins the plenum and the upper intake. They clamped it hard without seating it properly first, leaving a large cut which turned into my vacuum leak.

I had to take break from the job,and two minor issues surfaced. I have an electric plug and a vacuum line I can’t seem to place. I’m sure when I have a chance to go at it again the plug will jump up and bite me in embarrassment, but the j-tube vacuum line has me puzzled.

Help?

[logray]

Hose on left goes to the rear of the plenum that is behind the y-plenum that is behind the throttle body. You have to do that one by feel unless you want to start ripping into things.

Electric plug looks like it goes to either idle air control valve or throttle body position sensor area circled in red. (doesn't look like it goes to a change over valve above or near the circle on the left.

Edited May 31, 2011 by logray

[logray]

Note that depending on how that rear plenum tube is rotated, the connection for that hose could vary (only one inlet on that plenum though for that particular tube). Mine happens to be in the back of the plenum (in red).

As pictured in green here:

[SteveBreen]

The j-tube vacuum line goes to item #21 in the diagram? I thought #21 connected right next to the j-tube just above the alternator.

As to the plug, it comes from a bundle containing three plugs and two of them are already hooked to the throttle body position sensor. How can I locate the alternative location you mentioned?

Thanks for the help.

Edited May 31, 2011 by SteveBreen

[SteveBreen]

So the J-tube connects to the complication inside the green circle?

[logray]

So the J-tube connects to the complication inside the green circle?

Yep! (or where the red circle is) Whether that's on the front or back or top or bottom of the rear plenum (depending on how it's rotated). There's just one inlet on that plenum where the hose connects.

You might have to remove the throttle body (and sometimes y plenum behind the throttle body to reach it).

Or perhaps the hose leading to that inlet is just laying down on the top of the engine, just underneath the center of the whole intake assembly and you need to "pluck it out" and connect it to that j tube..

Edited May 31, 2011 by logray

[logray]

The j-tube vacuum line goes to item #21 in the diagram? I thought #21 connected right next to the j-tube just above the alternator.

Not #21, but into the round tube side (middle) of the plenum #13 into a small inlet

As to the plug, it comes from a bundle containing three plugs and two of them are already hooked to the throttle body position sensor. How can I locate the alternative location you mentioned?

It goes to a change over valve then if you've already connected the two leads going to the IACV and throttle position sensor. Check above the j tube on the left for a connector (front top of engine) - above that j tube.

Edited May 31, 2011 by logray

[SteveBreen]

Thanks, I'll give your suggestions a try tomorrow and will report back.

[SteveBreen]

You were right about the plg. A refreshed mind and your advice about where it might go solved the issue quickly. The J-tube, otoh, resisted my efforts. I simply couldn't find a a place within its length where it should be inserted. I left that for a visit to my local indy. The car started quickly, idled smoothly and the CEL light was out. Everything was great, until the cooling reservoir started the purge process. I guess I'll just keep refilling the tank until it's burped itself out.

Thanks for the assistance.

[logray]

Great work.

Yes that stupid hose goes to the resonance flap IIRC and it's a pain in the *** to connect with the engine in car. Some people actually cut it in half on purpose. The car will run fine without it, but to ensure no vacuum leaks or other problems, have it connected to that rear plenum at some point.

Be sure to run with the coolant bleeder valve in the up/locked position and be religious about keeping it full (in fact, stop on the side of the road the check it every so often and carry the appropriate mixture of coolant in your boot).