Code P1124, P1126, P0446

[logray]

"Although, I've seen a few posts where the valve wasn't replaced and didn't cause any issues. However, I don't want to take any chances with fuel + hot engines."

You can reuse the test port cap a few times. I would replace it maybe after 4 or 5 times. But if you want to be meticulous about it, replace it.

"From the links above, fuel pressure should be 43.5 to 58 psi when pump is activated by Durametric?"

3.3 bar with engine idling. 3.7 bar ignition on engine off, activated by durametric. Then with the pump running, engine off, count off 30 seconds or less the pump should fill a 1 quart container.

"How about intake manifold vacuum? How many inches of vaccum am I looking for?"

Good question! This varies greatly depending on you altitude. If you are near sea level I would guess a normal reading is between 17 and 18 inches of mercury. If your reading is drastically lower than that, it could indicate a vacuum leak. Reading the gauge can tell you other things about the health of the car too.

Also can you please post your fuel trims (FRA and TRA) from Durametric (you don't need to turn the car on to get this)

[logray]

And I just want to note this is sort of ironic because I'm troubleshooting a lean running issue myself, but I think I might have it resolved. My solution probably won't be anything like yours though.

Here's are some good PDFs for troubleshooting P1124 and P1126:

http://www.renntech.org/forums/index.php?app=forums&module=forums&section=attach&tid=20397

http://www.google.com/url?sa=t&rct=j&q=porsche%209103%2F2%20.6%20bar&source=web&cd=8&ved=0CGAQFjAH&url=http%3A%2F%2Fwww.renntech.org%2Fforums%2Findex.php%3Fapp%3Dcore%26module%3Dattach%26section%3Dattach%26attach_id%3D3722&ei=ZU9BT4LPFezXiALe86SyAQ&usg=AFQjCNE1hV_uxNLV9-ZcquKHPRwtSnXE-Q&cad=rja

[bar10dah]

3.3 bar with engine idling. 3.7 bar ignition on engine off, activated by durametric. Then with the pump running, engine off, count off 30 seconds or less the pump should fill a 1 quart container.

48 psi (3.3 bar) - engine idling

56 psi (3.9 bar) - ignition on, engine off, pump activated w/ Durametric

52 psi (3.6 bar) - ignition on/off, engine off, pump off

If you are near sea level I would guess a normal reading is between 17 and 18 inches of mercury.

16 in/hg at idle, 171 MSL

Also can you please post your fuel trims (FRA and TRA) from Durametric (you don't need to turn the car on to get this)

1.02 Range 2 Cylinder 1-3 (FRA)

1.02 Range 2 Cylinder 4-6 (FRA2)

0.32 Range 1 Cylinder 1-3 (TRA)

0.34 Range 1 Cylinder 4-6 (TRA2)

Edited March 12, 2012 by bar10dah

[logray]

The lower than normal vacuum reading could indicate a vacuum leak, air is entering the intake somewhere besides where you are measuring.

Your short term fuel trims are nearly three times the limit indicating lean running near idle range.

More than likely there is an intake leak, because the DME is enrichening the mixture due to the unmetered air entering the intake.

I know we sound like a broken record, but...

[logray]

Also, can you check that your idle air control valve is clean and ohms out properly?

Maybe because the long term trims are farily normal, your IACV is opening wider than it should due to a failed or failing open winding...

Here's how to test it with a multimeter (last several posts):

[bar10dah]

It's worth testing. I did remove it and cleaned it a couple months ago. I'll pull it out again and ohm it out.

[logray]

What really made mine smoother, even though it is bad, was to remove the little brass pin, then twist the unit apart.

At that point you can really clean it, inside and out. Then twist the magnet back onto the solenoid and then put the pin back in place.

But if it doesn't pass the electrical tests, I would probably replace it (fyi, best price currently is autohausaz.com). NO affiliation.

Edited March 11, 2012 by logray

[bar10dah]

Wow, that IS pretty cheap!

[catmanluge]

I suffer with these codes all the time! Once a year during mandatory inspection time I get my car to keep the CEL off for about 400 miles and then get it inspected. Frustrating!

[bar10dah]

Also, can you check that your idle air control valve is clean and ohms out properly?

Maybe because the long term trims are farily normal, your IACV is opening wider than it should due to a failed or failing open winding...

Here's how to test it with a multimeter (last several posts):

http://www.renntech....7-new-cel-codes

at 22.8 degrees celsius:

19.1 ohms Pin 1-2 (from the link above, should be 14-17 ohms at 20C)

17.5 ohms Pin 2-3 (from the link above, should be 16-19 ohms at 20C)

How do I check pin 2 to ground? Since I have the part out, I tested it from pin 2 to the sleeve where the bolts fit, as that would be where the sensor gets it's ground reference from, but it shows as open.

Just to note, when activating the IACV with Durametric, I can hear it clicking every second or so.

Edited March 17, 2012 by bar10dah

[logray]

Those numbers look normal.

There is a ground point right near the sensor, a bunch of brown wires going into a ring terminal bolted into the side of the head.

[bar10dah]

Those numbers look normal.

Really? Pins 1-2 shows 19.1 and the link you provided said a normal reading is between 14-17. Since I'm 2.8C above the normal testing temp, could it be that far off and still be good?

There is a ground point right near the sensor, a bunch of brown wires going into a ring terminal bolted into the side of the head.

Is there a way to test the ground of pin 2 when the sensor is off the car? I know ideally the ground needs to be made with the car, but where on the sensor does the ground "ground" to the car? Or, am I checking the ground of pin 2 on the wiring harness? If so, then I'm getting ~73 ohms.

What really made mine smoother, even though it is bad, was to remove the little brass pin, then twist the unit apart.

At that point you can really clean it, inside and out. Then twist the magnet back onto the solenoid and then put the pin back in place.

But if it doesn't pass the electrical tests, I would probably replace it (fyi, best price currently is autohausaz.com). NO affiliation.

I tried to clean mine like you did yours. I wasn't able to get that brass pin out. So I just filled with throttle body cleaner, shook it up, let it sit for about 3-5 mins, drained, repeated two more times.

I then took readings again across pins 1-2 and got 16.4 this time. Then I took a reading across pins 2-3 and got 18.2. Now, within the tolerances from the link you provided. But, just barely.

What's the torque value for the IACV security hexs? Want to make sure I torque this thing down right so it's not a possible cause of air leaks, since I'm still trying to find my main source of air leaks.

And since I'm already in the engine bay, I tested my crank position sensor because of an occasional hard starting problem I've been having. I wasn't able to get at the crank position sensor. I just can't seem to get a hex w/ extension to line up properly on what I'm guessing is 5 mm? So I went at it from the other end, the connector. Got that out and free. Please correct me if I'm wrong, but I should be able to test this thing while it's still in the car?

0.961 ohms between pins 1-2 (from another thread, should be between 0.8-1 ohms at 20C)

open between pins 1-3 (from another thread, should be infinite ohms, which means short, right?)

So, appears my crank position sensor is faulty. Unless, I'm getting an erroneous reading since the sensor is still in the car.

Edited March 17, 2012 by bar10dah

[bar10dah]

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Edited March 17, 2012 by bar10dah

[bar10dah]

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Edited March 17, 2012 by bar10dah

[bar10dah]

Since cleaning my IACV, and driving 45 miles, I haven't had a CEL. Checked w/ Durametric and no pending codes. Also checked my Range 1 fuel trims. A lot better than before, but still too much air.

0.11 Range 1 Cylinder 1-3 (TRA)

0.18 Range 1 Cylinder 4-6 (TRA2)

[logray]

That looks better, but maybe still some intake leaks. Have you had the car on a smoke machine?

To really clean the IACV well you need to get the pin out.

I hope to post a DIY in the upcoming days.

[bar10dah]

No, no smoke machine. The only one I could find locally was at the Porsche dealer. When I took it in, the tech said, without hooking up the machine, he could hear a hissing sound under the passenger side intake manifold. From the diagram in post 12 of this thread, the tech said it could either be #10 or #15. Swapped both out. #15 appeared okay. But #10, a one way check valve, was corroded and blew air both ways. Post 15 shows that valve. I haven't taken the car back since replacing it.

I wasn't able to remove that brass pin in the IACV. I think I'll just order it from that place you recommended and see how it does.

In troubleshooting my issue, discovered my passenger side radiator fan's resistor is possibly bad. Ordered one from Sunset Imports today. Sheesh, if it's not one thing, it's another. ;)

[bar10dah]

Replaced the IACV. No change. Replaced the two rubber intake manifold boots and upper AOS tube. We'll see.

Radiator fan resistor came in, but haven't had time to install it. Appears it must be soldered into place? Two bare wires has solder on them.

Also, went to replace the crank position sensor. The 5 mm bolt was stripped. Sheesh... Tried to use an easy-out, but it wouldn't catch. Ran out of light, so I'll try to finish this some other day.

Edited April 9, 2012 by bar10dah

[logray]

Yes some people just solder the resistor leads either because they are too lazy to remove the cowling or the new resistor doesn't come with an electrical connector.

[bar10dah]

The resistor must be soldered in. On one end is the connector, on the other end was the resistor, and in the middle, two leads came off and goes into the back of the fan and must be soldered into position. And in saying such, the old resistor must be desoldered out. Kinda hard to explain, I should have taken pictures...

My fans all work now! :)

[Car Cro]

Hi there

I am new to this forum, but have been on different forums with different cars.

Well I just got a 2001 Porsche Boxster. We drove the car up from Florida to Montreal last June and looked to sell it.

The car basically sat in a friends driveway since then and only started driving it last week.

Well I decided to buy the car outright from the other 2 people involved since it was not selling.

When I picked up the car, it was running well but low on gas so I filled it with 91 oct which other than Petro-Canada/Shell no one sells above 91, but in reading that is not a problem.

Well within 10 km of filling up I get a CEL, I get the oil changed and get the code P1126

After reading many many posts, I decide to clean the MAF.

Well after spend $$$ on a tamperproof tork set and MAF cleaner, I removed the MAF and cleaned it.

Drove the car for 2 days then filled up. Drove a day without problems, then today on my way to work I get a CEL P1126 (I also bought a code reader)

I found a more detailed description of cleaning the MAF and will try cleaning it again.

Most posts people get multiple codes, but the threee time I got it, it is only P1126. Leading me to think it might be oxygen sensor or...

But I have read a few posts where people experience this after filling up, could this be EVAC (I think that was what someone had mentioned) should I blow out the hoses?

bar10dah, I give you koodos as I do not have the time or knowledge to change all the things you did. Plus since the previous owner changed the top to a glass back, it is hard to get to the engine bay. (unless I am doing something wrong)

Anyways if there is something I should be looking at with my situation, please let me know, as I am new to Porsches

Thanks

[bar10dah]

Since you're only getting one code, it could mean your problem is only on one side of your engine. So more than likely, it's an air leak somewhere after the air diverter (splitter that leads into the intake manifolds) and before the O2 sensor. That code is telling you the O2 sensor is reading a very lean condition, and your DME has enrichened your mixture at it's maximum limit, while the car is at idle.

P1126 Oxygen Sensing Range 1 (cyls 4-6), range 1 means "at an idle state" and cyls 4-6 are on the driver's side of the engine.

I'll drive 700 miles on the highway and not get my CELs. But I'll drive 15 miles in the city, and get my CELs. Appears your code, P1126, only gets set when you do any prolonged idling.

[Car Cro]

I have no clue how to do a leak test, guess I will have to bring it to a stealership to check it out?

Removing and cleaning the MAF was simple but not sure I want to try to find a leak.

[bar10dah]

Doubt Montreal has an emissions requirement, so independent shops up there may not have a smoke machine, but that's what you need. Call around to a few shops that do emissions type work and ask if they have a smoke machine.

Down here in Alabama, where we don't have an emissions inspection, I went around looking for a smoke machine, and most shops told me they've been working on cars for over 40 years and never needed a smoke machine. Not sure that answered my question, but I said thanks and I left...

My local Porsche dealer does have one. And when I get around to it, I'll be bringing my car to them to help me find my leak. I've been all over this car, replaced all the suspected parts, and I still get P1124 and P1126 codes.

[bar10dah]

Another thought, you can try to find any loose bolts on your exhaust system. I've done an awful lot of reading through threads about my problem and see that sometimes a loose exhaust component can cause air to leak into the exhaust stream and throw off the O2 sensor. Just a thought.