Running rich or lean?

[jlevie]

I watched the guy do the smoke test, and he did it as you describe. That's how I found the bitch tube leak. No other leaks exist.

Then it would seem reasonable to drop the possibility of intake leaks from the scan.

I have a spare ECU, but I'm not sure of its working condition. I bought it for the performance chip it contained. I'll give it a try to see if it runs any differently and report back.

Forget that DME for the moment. Get a known good stock DME for the test, or borrow one.

[mrgraphics]

I put another DME in with a whole new chip - it acted exactly the same as the other DME. With the coolant temp sensor unplugged it runs great, plugged in it wants to die or runs badly. I've tried 3 different sensors too. I wonder if I need to test the plug itself? I have no idea how I'd do that . . .

[Earendil]

I put another DME in with a whole new chip - it acted exactly the same as the other DME. With the coolant temp sensor unplugged it runs great, plugged in it wants to die or runs badly. I've tried 3 different sensors too. I wonder if I need to test the plug itself? I have no idea how I'd do that . . .

The plug for the DME. Find a Pinout for it, there is one in the Bentley. That'll test all the wires and you can verify it all the way to the DME.

[MJCRO]

I literally have the same problem as you with my 86' eta. I have all new sensors on the motor except the MAF (which I cleaned, and tried different ones) and no vacuum leaks. When I start the car cold, it will start up perfect, idle perfect but when harsh throttle is given, it will either lean out or dump fuel depending on temp of the engine. I think it's the FPR but I checked out my ECU and on the internals there is all this gooey brown shit over the PCB. So right now, I'm thinking it's either a fuel problem, MAF or ECU.

sub'd.

[mrgraphics]

Curious - where did you buy your new sensors from? Because I happened to come across my original coolant temp sensor. I put it back in (making it 4 sensors I tried) and the car ran much better. Not perfect, but better - than even with the new Bosch and FAE.

[MJCRO]

I got my coolant temp sensor off eBay, it's a genuine BMW replacement and made no change when I installed it. But when I swapped out my thermo time switch sensor with a new one, now my car now starts up perfect from a cold start and idles great cold or warm (before it would start rich all the time). Right now I'm stuck between the MAF or ECU. Have you looked at the insides of your ECU? Mine has all this gooey brown shit on it and a few melted capacitors leaking all over the place. But right now I'm debating whether I should just gut the car and do an M50 motor swap and get rid of all this shit.

[mrgraphics]

My ECU's were fine. (I have two.) I also have a normal chip and a performance chip, so they both were opened and all combinations of chip/ECU were attempted.

Right now mine is running ok, but I still have to enrich things at the MAF (which I don't recommend unless you are certain you can get the needle back EXACTLY where is should be.) I'd consider mine patched, but not 100% solved.

BTW - with my other sensors in there, it would idle great cold or hot. But pressing the gas is where the problem happens. I'd suggest checking the OHMs when the sensor is warm and make sure it is sending the right signal. I am going to do that as well. Only then will I start looking elsewhere for issues (such as the wiring to the ECU.)

[MJCRO]

My ECU's were fine. (I have two.) I also have a normal chip and a performance chip, so they both were opened and all combinations of chip/ECU were attempted.

Right now mine is running ok, but I still have to enrich things at the MAF (which I don't recommend unless you are certain you can get the needle back EXACTLY where is should be.) I'd consider mine patched, but not 100% solved.

BTW - with my other sensors in there, it would idle great cold or hot. But pressing the gas is where the problem happens. I'd suggest checking the OHMs when the sensor is warm and make sure it is sending the right signal. I am going to do that as well. Only then will I start looking elsewhere for issues (such as the wiring to the ECU.)

Same! When I throttle up lightly, the motor doesn't sputter. But when I start to push it a little harder, it'll begin to do the sputter. Yeah I don't think it's my ECU now since it sounds like we have the same exact problem. Checked my FPR and it's getting the 2.5 bar needed so I can rule that out too. I am really leaning towards my MAF since it's the only thing that I haven't changed and they are known to give this exact issue.

Did you test your car with a new/rebuilt MAF or just another used one? Because that's what I did and got no change.

[mrgraphics]

FYI - I ran into a guy at Pick n Pull who's car was doing the exact same thing as mine. I told him that it was probably the temp sensor (he had a 90 325i). I happened to have one of the sensors that made mine run like crap, gave it to him and said give it a try. He just text'ed me and said it was working great. So it seems like I was sent an "i" sensor instead of an "e". So even though it's new, it might not be right.

[MJCRO]

FYI - I ran into a guy at Pick n Pull who's car was doing the exact same thing as mine. I told him that it was probably the temp sensor (he had a 90 325i). I happened to have one of the sensors that made mine run like crap, gave it to him and said give it a try. He just text'ed me and said it was working great. So it seems like I was sent an "i" sensor instead of an "e". So even though it's new, it might not be right.

Damn, I need to check into that for mine as well. I ordered mine off eBay via part # and it was "genuine" according to them. So I might just look into finding a different one and see if it has any affect. Let me know if anything changes on your end.

[mrgraphics]

Found this on another site. I wonder if this ohm difference could make the car run badly? Would some experts on these sensors weigh in?

Model: 325, 325e, 325es
Connector color: white
Temperature Resistance
14+-4 F (-10+-1 C) 7000-11600 ohms
68+-2 F (20+-1 C) 2100-2900 ohms
176+-2 F (80+-1 C) 270-400 ohms

Model: 325i, 325is
Connector color: blue
Temperature Resistance
14+-4 F (-10+-1 C) 8200-10500 ohms
68+-2 F (20+-1 C) 2200-2700 ohms
176+-2 F (80+-1 C) 300-360ohms

[mrgraphics]

I am now thinking that it may be the O2 sensor. Even though it is new, they are known to fail.

I noticed that the O2 relay was the wrong part number. Luckily I had two in my bag that were right. It is definitely starting and running more stable, but it still has some issues. Without the right relay, it was not heating the O2 sensor and the values were all over the place.

Add to that, when I put the car together, I forgot to put new gaskets on the exhaust manifold to catalytic converter pipes (exhaust manifold to block do have gaskets.) I probably have an air leak there, introducing more oxygen into the system, and throwing the O2 readings off. Since I kept running it so rich, I'm sure I fried the O2 sensor. Hopefully my cat is still ok.

Going to try disconnecting the O2 sensor and installing my old one (this is why I keep old but still working parts.)

[Earendil]

AFAIK, The O2 Sensor if malfunctioning will make the car run poor, but will not cause sudden lack of power and stuttering. In addition, the ECU ignores the O2 Sensor when the engine is cold.

On a properly running car, you can unplug an O2 Sensor and most people would not notice any immediate difference in performance. Is that a better way of explaining it?

[MJCRO]

Now that I'm done with classes, I'm gonna go an check my FPR this weekend since I noticed when I fire up the car cold and r3v it a bit, the fuel gauge goes crazy. A bit odd since I replaced my cluster gauge board with a brand new one, so I doubt it's an electrical problem.

[Baxter Auburn]

Ive been having the same issues as described by the two of you since i installed an maf, ive contemplated switching back to the afm until i find out the issue. My car doesnt have any issues that fluctuate with the temp or on inclines but under moderate throttle it will sputter, best of luck Kory B