Looks close enough

Specific conversations and info for the BMW E28 M5 and M535i.
Post Reply
bigwave
Posts: 178
Joined: Apr 03, 2013 10:43 PM
Location: Buffalo

Looks close enough

Post by bigwave »

But it is not the correct part! I researched a bunch of threads here and tested my TPS only to find that it is not giving correct continuity across the 2 and 18 pins and etc. So, I now know it is in need of replacement. Only thing is that the one that is currently on the engine is not the part # 13621273277 that Real OEM has or the more common Bosch #0280120301 that shows up online at many retailers like AutohausAZ.

Instead it is #0280120319, which has the same housing aside from the last 3 digits, and could explain many of the running issues that originally had me cleaning the ICV and looking for vacuum leaks. According to Pelican, that number is the one for the M10, some M20, and various M30 engine iterations, though mine is an S38. While it looks original or at least old, I'm going to assume some ass hat switched it in much earlier in the car's life OR, possibly there are others out there that have found this discrepancy installed in their own cars. My car is one of the later M5 build dates at 11/87, though unless any of you have found this, I will stick with the moron mechanic theory. I ordered a new one and my mission here was to hopefully find that I was alone in this TPS wrong boat. The engine is enough of an adventure before people start guessing on part cross references.

Image
tschultz
Posts: 4059
Joined: Mar 01, 2009 7:58 PM
Location: Denver, Colorado
Contact:

Post by tschultz »

Was your car having running issues? Hopefully that solves it!
ahab
Posts: 6174
Joined: Jun 11, 2006 9:12 AM
Location: Chalfont, PA

Post by ahab »

My 11/87 car had a 319 on it which was testing WOT at idle so I called my local parts guy for a replacement and this is what showed up. Works great. M20 and M30 are different rotation. This one is suitable for M20 or S38. As an aside, Murfinator was selling a 301 for $60 a few weeks ago.

Image
bigwave
Posts: 178
Joined: Apr 03, 2013 10:43 PM
Location: Buffalo

Post by bigwave »

My 11/87 car had a 319 on it which was testing WOT at idle
Thanks for the response and while it only deepens the mystery, glad I'm not the only one. Still would like to know how they got on there to start with? My car was running and driving, though was occasionally stalling when you came to a stop (especially if a/c was on) and felt like it was holding back a bit at WOT with some hesitation at times coming up off idle. From that description it sounds terrible, hence the need for multiple actions. My first thought was clean the ICV (for the occasional stalling issue) and replace the cracked hose from it to the plenum. While there I also replaced the intake boots, a couple more hoses, the two fuel lines on the back of the rail, drained the rail, and had the injectors refurbished by OKinjectors (highly recommend them). Two of those were stuck open and one was badly clogged. All of this made for major and immediate improvements, so nothing was wasted aside from cleaning the ICV since the valve was not getting the proper signal to start with.
New TPS is in the mail, so hope this is the magic final piece of the puzzle for now. I had noticed the one Murfinator was selling in my original search, though still wasn't sure it was even the right one until I got on the phone with a parts guy $70 included shipping.
buzby
Posts: 466
Joined: Feb 10, 2009 8:21 PM
Location: Auburn, CA

Re: Looks close enough

Post by buzby »

Just fitted new Bosch 0280120301 TPS which solved a number of problems, to name a few:

No no bucking on the overrun-I was getting a lot of bucking when coasting with foot off accelerator
Constant 700 rpm idle (according to tach)-no wavering at all-used to "wander" at will 100-150 rpm
Even warm up and solid back to idle speed once temp sensor cuts in-no lumpiness in between
Fast starts-as soon as starter operarates
Nicer to drive-seems smoother in all respects

The original part number was 0280120319 which is the only weird part. I assume mine had the original TPS on it? It did bench test out OK but seemed noisy when the microswitch engaged unlike the new one which is more silent but audible.
tn535i
Posts: 5585
Joined: Jul 14, 2006 1:30 PM
Location: Middle Tennessee

Re: Looks close enough

Post by tn535i »

Weird issue. Someone was trying to fix one thing and thought this looks like the same part only to create a new an unusual to find problem? I think a basic electrical test (5v to 0v) of the idle control input would have shown you couldn't adjust the closed throttle idle input to go on/off with the microswitch as it should. I do that rather than rely on the click. Does the micro switch click on that one at WOT then.

I've had trouble with every TPS on every BMW I've owned except my M6 and found cracked contacts in all of them which is what I was going to guess could be wrong. Somewhere I learned there was a counterclockwise and a clockwise switch I thought but would not have guessed you had the wrong one.

This part may be good for someone else as I doubt you wore out the WOT, I mean idle, contact. Or maybe you have :)
buzby
Posts: 466
Joined: Feb 10, 2009 8:21 PM
Location: Auburn, CA

Re: Looks close enough

Post by buzby »

Hi, my M5 still running great with new TPS. Tested out again with test harness as easier that way. Hard to get tips of meter onto the terminals when in place. Continuity at idle and full throttle.

tn535i-The old TPS is toast with intermittent idle continuity and nothing at full throttle. No one would want this one....

I have placed a 650 MB video of the test process in my DropBox if any one interested in viewing it. Also pics of test harness. Shows engine running with smooth idle as well at end.

Video (will be there for a while then I will remove it)

https://www.dropbox.com/s/go5nq6y2liiml ... 7.MOV?dl=0

Test Harness photos

https://www.dropbox.com/s/l0j93ikq0a401 ... M.jpg?dl=0

https://www.dropbox.com/s/a8beqev6g3rri ... M.jpg?dl=0

Enjoy!
buzby
Posts: 466
Joined: Feb 10, 2009 8:21 PM
Location: Auburn, CA

Re: Looks close enough

Post by buzby »

I have posted on YouTube now, link to dropbox will be removed.

https://youtu.be/k7bSmUWDIcI
Post Reply