325is surging idle?

[u3b3rg33k]

Had you posted the year of your car, you would have been able to tell what DME you had, and then see if yours was correct...but all of that is a moot point: the "173 idles better" is basically bullshit. I mean it is a tiny bit better, but the 153 DME most certainly does not have a surging idle...they came in $30,000 cars in 1987! They do not suck, believe me, at their worst BMW is still excellent.

Old electronics can start to show signs degradation (eg, caps fail). But what's more likely is that bosch changed the way the ecu handles changing states around idle.
The actual idle isn't different, it's when something happens near or at idle (like my a/c kicking on/off combined with mass of the barn door basically resulted in what seemed like hysteresis induced retardedness that would be highly unlikely to show up on a then new car), M1.3 seems to handle it much better.

[StereoInstaller1]

Yeah, but they don't crap out overnight.

It ain't the DME.

[u3b3rg33k]

I tend to agree.

[Atara]

Journalism major, huh? You write well, thank you for being descriptive. Had you posted the year of your car, you would have been able to tell what DME you had, and then see if yours was correct...but all of that is a moot point: the "173 idles better" is basically bullshit. I mean it is a tiny bit better, but the 153 DME most certainly does not have a surging idle...they came in $30,000 cars in 1987! They do not suck, believe me, at their worst BMW is still excellent.

So: let me make this clear: the fuse has nothing to do with the idle issue. They are unrelated.

Look in the ETM, which can be found under "MANUALS" and then AUTOMOTIVE at www.wedophones.com do not forget to save a copy.

The idle is likely either vacuum leaks or a crappy idle air control valve, or just an IAC that is all gunked up. They can be blasted out with carb cleaner, it usually helps. Vacuum leaks can be hard to find. There is a thing called a "smoke testing machine" that blows thick smoke into the intake just to help spot leaks. If a careful inspection of the hoses do not reveal a leak, and going as far as swapping your IAC, you may wanna take it a shop for smoke testing. (I have one to recommend, BTW)

Since you have a 173 DME, you likely have a late model car which has a slightly different harness. There is a connection for the fuel injector harness directly under the throttle body. They can get pretty corroded and can cause running issues too, but not generally a surging idle.

Welcome to R3V.

Luke

Whoops! It's a 1990. I don't see my car listed there, would another year/model work? What shop would you recommend in the area? I've seen broad stroke associates in Snohomish recommended quite a few times. Is there anything I could do myself before taking it in? Don't have much money left over after buying the car. I'm pretty technically proficient but don't have much more than the tool kit in the trunk and the garage in my apartment building to work with. I just looked through the bentley manual and didn't see anything mentioning an idle air control valve or IAC. Also, one of the fuses fell into the engine bay (direction in picture) and I was unable to find it. Could that have gotten stuck in something creating this issue? Thanks!

[87e30]

Fuse problem seems to be completely unrelated.

Also, I don't suspect a vacuum leak since it idles fine once it warms up.

Try googling "m20b25 IAC" or "m20 idle air control valve" and add DIY to one of those searches and poke around. You can probably find a write up with pictures as those are pretty common parts.

[Atara]

Thanks! An update as well, I just took it out for 20 minutes or so around my house. The car was still rough when idling and it would randomly lose power while I was driving. It was just like in the video but seemed to be more often. Every time that happened the check engine light would pop back on after it regained power. I'm going to go take a quick video.

[llll1l1ll]

Sounds like more of an electrical problem to me (i.e. something in the system electronics for the fuel injection). I would take a peek at your crankshaft position sensor, along with all the ICV stuffs.

[Atara]

That's what I was thinking. I just drove it around a little more and it happened less frequently but still had the problem (couldn't catch it on my camera while driving). Going to pick up some carb cleaner and clean out the ICV now. Where is the crankshaft position sensor and what would I be looking for?

[Atara]

I just pulled out the ICV and cleaned it out, waiting for it to dry now. Anything else I should look at/clean while I'm at it?

[Atara]

Just put it back in and tried starting it up, same problem. Starts and sounds fine for a few seconds then does what it did in the video. It stalled a few times after I switched it into gear and once just while idling. If I don't stall and start moving, even if I have my foot on the gas, the car is acting like it's not getting any gas and the acceleration is sporadic.

[u3b3rg33k]

Just put it back in and tried starting it up, same problem. Starts and sounds fine for a few seconds then does what it did in the video. It stalled a few times after I switched it into gear and once just while idling. If I don't stall and start moving, even if I have my foot on the gas, the car is acting like it's not getting any gas and the acceleration is sporadic.

This makes me want to lean in the not the ICV direction. After you check for vac leaks, pull a plug, look at it, and check the gap.

You also mentioned the check engine light was coming on (not the check light?). The 173 DME will store and release codes via a stomp test (search for it). That may point to what it thinks is the problem.

[Atara]

This makes me want to lean in the not the ICV direction. After you check for vac leaks, pull a plug, look at it, and check the gap.

You also mentioned the check engine light was coming on (not the check light?). The 173 DME will store and release codes via a stomp test (search for it). That may point to what it thinks is the problem.

It's the check engine light, it flashes on just like in the video I posted on the first page. What do you mean by the bolded part?

[Atara]

I just tried the stomp test but I must have done something wrong. I turned the key till just before ignition (when all the dash lights are solid) & pushed down on the gas pedal 5 times. After I did it the only change I saw was that the check engine light went from solid to flashing every 5 or so seconds. Where would the codes read out, I couldn't find that. These are the directions I used: http://www.bimmerboard.com/forums/posts/669551. It says the check engine light should blink once, but it keeps blinking.

[u3b3rg33k]

The check engine light is supposed to blink out the code. it'll keep repeating the code indefinitely as far as I can tell. 1-4-4-4 means no problems.
No matter what, it should give you a code, you just have to figure it out. It took me a few tries to figure out what was up.

[Atara]

Where does the code show up?

Edit: Is it the check engine light itself that blinks the code? If so it's 1-4-4-4 which means no errors?