1995 E-36 Temp Sensor

[bmwdirtracer]

I remember finding more than a few AFMs that had failed intake air temp sensors. Hell, perhaps the plug for the AFM has a bad pin....which causes an intermittent open circuit for intake air temp? (I know that you just swapped AFMs with no change.) I sure wish you could talk to the DME.....can you talk to any other modules?

Just looking at the US version: do you have continuity between pin 74 of the DME plug, and pin 1 of the diag connector? (I have no way to see wiring for the Euro car) (I would think that you MUST have continuity, because you can use the stomp test, but, well, I try not to assume.)

[WadiM3]

If I'm not mistaken, Darin's car is a US model.

[dworthy]

I remember finding more than a few AFMs that had failed intake air temp sensors. Hell, perhaps the plug for the AFM has a bad pin....which causes an intermittent open circuit for intake air temp? (I know that you just swapped AFMs with no change.) I sure wish you could talk to the DME.....can you talk to any other modules?

Just looking at the US version: do you have continuity between pin 74 of the DME plug, and pin 1 of the diag connector? (I have no way to see wiring for the Euro car) (I would think that you MUST have continuity, because you can use the stomp test, but, well, I try not to assume.)

Yes it is a U.S. spec car so the Bentley appies. I did clean the Air Intake sensor in the AFM just to make sure, and funny you should mention it. I also had the hunch that there might be a problem with diagnostic head to the DME, so I checked all 4 connectors to the DME, with all of them at .1-.2 resistance, so nothing out of order there either.

The only good thing about the Motronics 1.7 is it pretty much uses all the same stuff on the Euro cars too, which the yard is full of them.

[dworthy]

So I cruised over to the M42 club website to see if they had some tips. One of the threads that talked about the 1226 fault code pointed to the oxygen sensor. So I thought why not unhook it to see what happens. Now I know that it will go into closed loop and is suppose to turn on the check engine light. Well no check engine light and no odd ball running. So that is telling me 2 things: Somebody messed with the DME, and perhaps the problem has been the oxygen sensor this whole time. The trouble I have is that the oxygen sensor has about 47k miles on it and 6 years old.

[bmwdirtracer]

"Messed with the DME" ? Hmmmm, maybe you just need a stock DME, with EWS aligned?

[dworthy]

It doesn't look like it have been opened up, but you never know. I am thinking that since the M-43's here use the same DME, I would have to swap the chip over to make it work. I am not a DME expert, so I will drop Able a line and ask if he knows.

[dworthy]

So this is what I got from the Snap-on brick today.

[dworthy]

So after working with Abel over the weekend, I finally got the ADS to work and talk to the DME! Many props to Abel for taking the time to help me out, and having the patience to walk me thru the ADS mess.

So what I did find out once connected was #2 Knock sensor and AFM code. I cleared them out, and drove 250 miles home. Tomorrow I will give it a try to see if those two codes came back and hopefully will be able to do some driving around and looking at the live data, which isn't much, and try to narrow it down. I can understand that the AFM could cause this issue as a "No Throttle Response" and would clear when going WOT. But for me to have 2 bad AFM's doesn't really make sense.

[shadowpuck]

glad you were able to connect!! ADS setup can be a bit tricky, but once working it's great. i keep a brick (Snap On MT2500) around just for my e36 track car. although, surprisingly, the smartphone based app carly talks to my e36 with a 20-pin adapter.

[dworthy]

So after attempting to get the problem to occur while I have INPA connected, it just doesn't want to. This seems to be very sporadic, but the only thing that is showing outside of normal parameters is the Adaptation Values for the TEV or Evap system. I have reset the Adaptation Values several times, and with the Evap system plugged off from the motor, it doesn't run any different.

So I decided to try and pressurize the Evap system by pulling a vacuum on the line that goes to the throttle body. It will pull fumes all day long, but when I open the gas cap, I feel no suction what so ever. So I am thinking that I have a gross leak, but that shouldn't be causing my issue.

The only code that seems to stick is the Knock Sensor #2 which it too seems to be sporadic. I have problems thinking that would be an issue, while it would cause the ignition timing to retard a bit, it shouldn't cause a no throttle response for 20-30 seconds.

So that leads me to the oxygen sensor. The DME turns from Closed loop to Open loop when I go WOT, and ignores the Oxygen sensor. If I do this for about 3-5 seconds, the problem will go away. If I just throw in the clutch and let it idle, it will be very erratic for about 5-10 seconds, and then clear itself out. My thinking is the Oxygen sensor is getting heat soaked or just not working properly during those first 30 seconds of running.

Now if anybody else may have an idea, and think I am full of it, let me know your thoughts.

[dworthy]

So I am going to update this thread.

I replaced the Oxygen sensor, as there was the Check Engine light coming on, but no codes. As I watched the live data, limited that it is, I could see the "Oxygen Sensor Control" turning on/off. When it had an episode of low power with the Check engine light, the Oxygen sensor control went into Off mode.

Also on a side note, it isn't good to zip-tie the excess cable to the exhaust support bracket. I think that is what weakened the wires and started to cause the problems of no throttle until WOT. But it was 6 years old and had about 60k on it, so this time I zip-tied the extra to the transmission support bar.

Next will be the Knock sensor as it is currently messing with the timing while running.

[bmwdirtracer]

Hi Darin,

I don't think an O2 sensor can cause no throttle response. I'd tend to believe, on this car, that the only thing which could cause no throttle response would be the throttle body....or the AFM, not opening. Surely, if a large amount of air suddenly enters the engine, the engine is going to rev?

What have I missed?

[dworthy]

Nope, nothing that I can see. However it would rough idle for the first minute or two if I didn't take off right away. What I mean by no throttle response is you still have WOT and it would take off. The AFM and TPS both passed with flying colors, and I even swapped in a known good ones and it still did the same thing. So that lead me to believe the Oxygen sensor as it is the only other item that can move the fuel map around.

It would only do this under very specific conditions:
Drive to work, park the car for 3-4 hrs.
Start car, drive about 5-7 minutes
Park car, go inside store, shop ect for 5-10 minutes.
Start car, then it has a 50% chance of rough idle after a minute or no throttle response after you take off within driving 100 yards. Even then it would only do this once after you go WOT for 5-10 seconds.

OBD-I is very sketchy at best for some of this stuff. When the TPS was bad, it did kick up a code. Even with the Check Engine light coming on/off, and staying on for several minutes, no code was stored. That is what pointed me to the oxygen sensor not operating properly, as the temp change under the car would cause good contact when cold to heat soaking after driving for a couple of minutes.

[bmwdirtracer]

Thanks for updating....I'll try to remember this lesson for the future. It's working correctly now, I take it?

(Here's a lesson I learned today: If changing rear brakes on a 2013 + Touareg or Audi Q7 with electric parking brake, do NOT use a scan tool to open the parking brake motor to service position !!! Sure, it's how we all change brakes on the rear of all newer cars, that have electric parking brakes.....but NOT this car -- EVEN IF PRO RESOURCES AND THE SCAN TOOL TELL YOU TO ! It's the end of the world, if you do. Unlike all other electric parking brakes, this car's work on drum brakes! You'll end up having to adjust air gaps with the computer, then recode the damned car, then drive from 60 to zero umpteen times for the "grinding procedure". )

[dworthy]

Yes, going on 3 days, and attempting to get it to do the miss/stall/ect has not happened yet. Also no check engine light while driving. What I did notice upon inspecting the cable for the oxygen sensor is that where I zip-tied it to the exhaust support bracket, it has worn thru the protective lining a bit. I don't recall there being a clip or clamp to hold the excess cable out of the way, and there is like 8 inches of extra wires you have to tie up. I had tried to just loop it around the transmission support, but it was about a inch too short, so I just zipped the loop to the front side of the support bracket to keep the excess out of the way.

Now I am waiting on the knock sensor. I do not know how long it has been bad, but it was replaced 6 years ago with a Bosch OE part, and I really haven't looked into the DME until this past winter.

On the positive side, I was able to get the EWS installed with the help of Abel, after 5 years of it sitting in the garage.

Well it is time to sell the car anyway, so I am trying to get all the little bugs worked out of it. Most of the bugs don't bother me, but I have to finish the project I started and not pass it onto the new owner.

And it is always the hardest lesson to learn, Ops, did I just push that button?!?! Hahahaha

[dworthy]

Looking at the last update for this thread as on Thursday the car will be on it's way to a new owner.

So I replaced the #2 Knock Sensor, and that put back a couple of ponies it seems. The car does run a bit smoother and has a little more pep in it's step. I think that with a bad Knock Sensor, it was retarding the timing a bit more than needed. While the Premium fuel helped to smooth this out, with two working knock sensors, I can take full advantage of it on the fuel map.

[WadiM3]

What's the beaters new replacement !?