Start No Idle Code 1215

[bmwdirtracer]

I recommend testing fuel pressure

[pbonsalb]

At least on my obd2 E36 M3, the TPS and IAC harness ends will fit either device. I almost crossed them once. The IAC connector does not have a boot on my car and the TPS one does.

Fuel pressure is also something I would be looking at, especially since you recently changed rails and regulators.

[NolliM3]

I recommend testing fuel pressure

See below...

[NolliM3]

At least on my obd2 E36 M3, the TPS and IAC harness ends will fit either device. I almost crossed them once. The IAC connector does not have a boot on my car and the TPS one does.

Fuel pressure is also something I would be looking at, especially since you recently changed rails and regulators.

I did not bother with that fuel rail and stayed with stock rail (your 650HP) which I had blocked off with the monkey block, then used that aftermarket knock-off of AEM adjustable fuel pressure regulator. But as you know, I was experiencing fuel fumes that seems to indicate internal leaking; however, I had a reliable fuel pressure of 48-55psi.
The fumes though was making me nervous so I went back with a new stock fuel pressure just prior to the Thanksgiving holiday. That's why I said about that fuel pressure was known. I need to get a fuel pressure tester as the one I have gone kaput...that was the whole reason of going with that aftermarket one until I am ready to get the real AEM one. Since the car was working upon till that cold morning start described in the first post, I am assuming fuel pressure is good...but you know what happens when one used the word assume.

I had also removed all the fancy fuel line fittings (-AN) and went with high pressure (500psi) braided nylon lines.

[pbonsalb]

The obd2 rail has a schrader valve that makes testing easier. Maybe if you have your original lines you could borrow a free autozone tester and cut the rail feed and insert the tee from the test kit if it fits. This could be chasing a possibility that does not turn out to be the problem. Whenever I have issues after recently doing work I always first suspect my work.

I did have a cracked ICV hose years ago that opened up only under vacuum or boost so it took a while to find. Same with a cracked TB boot.

[NolliM3]

The obd2 rail has a schrader valve that makes testing easier. Maybe if you have your original lines you could borrow a free autozone tester and cut the rail feed and insert the tee from the test kit if it fits. This could be chasing a possibility that does not turn out to be the problem. Whenever I have issues after recently doing work I always first suspect my work.

I did have a cracked ICV hose years ago that opened up only under vacuum or boost so it took a while to find. Same with a cracked TB boot.

Great idea on checking Autozone...never thought of it. It's most likely tomorrow before I can and report back. Also, it will be a week from today before I receive the TPS.

[NolliM3]

Can anyone confirm that this is the correct method for testing the throttle position sensor per the Bentley BMW manual capture below? I asked because mine (original to the car), a used BMW one I bought, three BMW ones at the junkyard, as well as a new Chinese one I bought all tested no continuity between pin one and pin three. It's not reasonable that all would test exactly the same, unless the test method the manual is incorrect.

[bmwdirtracer]

Are you absolutely sure that your multimeter's Ohm function still works ? If, just once, you tested a powered circuit, it's toast. See if you get full continuity by touching the two leads of the multimeter together.

EDIT: As for the test procedure, I'm not sure whether 1 and 3 are the correct pins; but only two of the pins will have any continuity/resistance, and there are only 3 options - 1,3, 1,2, and 2,3. Again, this is tested with the TPS unplugged - if you test the harness side of the plug for continuity, you blow your multimeter.

No, the listed procedure is wrong.

[pbonsalb]

Sometimes the pins aren’t 123 in a row. Could be 213. But I have not studied the TPS in a long time. I tend to doubt TPS is the problem. Are you sure you did not cross IAC and TPS?

[NolliM3]

Are you absolutely sure that your multimeter's Ohm function still works ? If, just once, you tested a powered circuit, it's toast. See if you get full continuity by touching the two leads of the multimeter together.

EDIT: As for the test procedure, I'm not sure whether 1 and 3 are the correct pins; but only two of the pins will have any continuity/resistance, and there are only 3 options - 1,3, 1,2, and 2,3. Again, this is tested with the TPS unplugged - if you test the harness side of the plug for continuity, you blow your multimeter.

No, the listed procedure is wrong.

Thanks Chris, that's what I thought...yes, I had double checked by touching the prongs of the multimeter to make sure I had continuity. See below for the repair result.

[NolliM3]

Sometimes the pins aren’t 123 in a row. Could be 213. But I have not studied the TPS in a long time. I tend to doubt TPS is the problem. Are you sure you did not cross IAC and TPS?

Well, it did turn out it was the TPS. I replaced with the new one, and she starts right up and idle. It took a little time to find the sweet spot as if I blip the gas pedal, the idle would go up and down until it settles. After a drive and back now she stops doing that and if I blip the gas pedal, it settles at it usual spot.

I did not bother to do a fuel pressure test because I went to Autozone as well as Orielly's and they both wanted $150 to rent the fuel pressure tester which comes with stuff I did not need. Then, I concluded that, since I would most likely use a credit card, they're collecting info, and I did not want to participate in their surveillance capitalism. So I bought one from China for $26 and it will be here next Tuesday (it's in the U.S and cleared customs).

So, it seems that when the TPS is bad, the car will not idle with the harness disconnected from the MAF, only with a good working TPS.

[pbonsalb]

You found it! So does it run fine throughout the rpm range now?

[NolliM3]

You found it! So does it run fine throughout the rpm range now?

I would say fair in the lower rpm range and great over 3000-4000rpm...I don't know whether I am having an issue with one my coil pack...I'll monitor and create a new separate thread...something is slightly off. I had to change my rear shock mount today as I had a little drumming after hitting a huge pothole in New Orleans two months ago. Merry Christmas.