$500 in parts- now have stumbling issue

[bimmerboy12]

Sorry for not responding, I was in Vegas for the last week for work. Back now and ready to dive into this again.
Concerning reference sensors, I believe only the E cars had them that referenced off the flywheel? I just have a crank position sensor on the front, which is brand new and one of the parts I replaced with the other 500 bucks worth of parts. I may be erroneous to assume that the problem is with the parts I have replaced- it could be that the parts replaced brought out the problem, like the new ignition components somehow revealed a weak link somewhere else.
Anyways, I am planning on doing the TPS check tonight as suggested by BritishBMW. I will let you know what happens... and the saga continues on.

[Philo]

Also test the reference sensor please. I've heard stories of people buying bad new parts. The test is simple and takes 30 seconds. G/L

[Hallen]

There is also a specific gap for the reference sensor to the vibration damper (if I remember correctly). Make sure that gap is correct. Just for giggles, and because it's easy, make sure there is no crud stuck to the teeth on the vibration damper and that no teeth are missing.

Sorry, it's a long shot, but should be easy to check and rule out.

PS, I do get that rhythmic idle after I have had the battery disconnected. I don't know why, but it always goes away and does not come back until I disconnect the battery again.

Good luck. I hope you find it.

[bimmerboy12]

OK- so I just ran the checks on the TPS; I got full resistance until about .020 then full continuity just like the Bentley manual said if it is good. However, I never got full continuity on the other lead when it was cracked wide open. I don't think that would do anything to the idle though.
For the reference sensor, the bentley said I should have 500-600 ohms of resistance. I read 900 ohms on the brand new sensor. I don't know what that means, and I hope my ohm meter is reading correctly (its only about a year old). I know my reference sensor gap is .060 which is correct. Any other ideas? Is this reference sensor bad? I will try to get my dad's ohm meter and double check it this weekend.

[Philo]

Wait. Does the car have the original engine in it? If the engine is from an e or es that reading would be right. Hmm. Well i'll talk to my mechanic buddies and see what they think.

[Hallen]

Wait. Does the car have the original engine in it? If the engine is from an e or es that reading would be right. Hmm. Well i'll talk to my mechanic buddies and see what they think.

And if it isn't an e or es, then you have the wrong part? It's still a long shot, but possible. Resistance goes up as things get hot. It might start missing more teeth as it gets hot.

[bimmerboy12]

Original engine, never pulled. Only 121,000 miles. I just checked the receipt and it says I purchased the correct part, but I have no way of verifying that they sent the right part as I don't have the original packaging. I will have a chat with my guy at bavarian and discuss, and will let you know what comes of it.
Keep in mind I performed this test with the engine somewhat hot... only been turned off for half an hour or so.

[bimmerboy12]

UPDATE TIME... I talked to my guy at Bavauto and he said the CPS is fine... 900 ohms is normal and this is a misprint in the Bentley manual. I believe him- he's had 17 E30s over the last couple decades. Anyways, I just went out and bought a vacuum gauge, and my car is reading 14.5 in Hg at idle. It wavers down 0.5 in Hg along with the idle. As soon as the car is turned off, the vacuum is gone.
Can anyone verify that this is normal?
Brian

ANOTHER UPDATE: I also just replaced the intake to throttle body breather hose and my pressure fuel line into the rail (it had some wetness around the clamp). No change, idle still sucks.

[bimmerboy12]

no input guys? Im gonna try a Vintel Sauber valve soak next.

[tallscott]

have you done a compression test? long shot but it may surprise you. my eta had the same problem needed rings no other symptoms but bad idle after new timing components were installed. also did you try swapping ecus with another car that idles well. just a thought

[bimmerboy12]

have you done a compression test? long shot but it may surprise you. my eta had the same problem needed rings no other symptoms but bad idle after new timing components were installed. also did you try swapping ecus with another car that idles well. just a thought

I will run a compression test, good idea. I have no access to any ECU's but will keep an eye out for a cheap one.


Any input on the vacuum readings I got?

[gtarwiz]

ok, this may sound kind of out there, because I to am having some idle problems, but different from yours, but another place to maybe check for a vacuum leak if you haven't already is the injectors themselves. From what I have read if the seals go bad on the injectors then it can give a really crappy idle. I dunno, just a thought.

-Griffin

[bimmerboy12]

another update: I did a compression test and got the following:
1 - 144
2 - 120
3 - 125
4 - 120
5 - 110
6 - 115

Not that great, but not bad and pretty consistant.

While the motor was running, I sprayed carb cleaner on all the injectors and didn't note any change in the idle.

On another note- it idled WAY better today... I don't know why, but it was 66 degrees today maybe that had something to do with it??

[Keanan]

another update: I did a compression test and got the following:
1 - 144
2 - 120
3 - 125
4 - 120
5 - 110
6 - 115

Not that great, but not bad and pretty consistant.

While the motor was running, I sprayed carb cleaner on all the injectors and didn't note any change in the idle.

On another note- it idled WAY better today... I don't know why, but it was 66 degrees today maybe that had something to do with it??

Have you been keeping records of what you have been testing and the results of those tests?
Your compression numbers are not really consistent. #1 has 144 psi and #5 has 110 psi? Redo your compression test just to make sure your numbers are accurate. I think they are supposed to be closer to 150, but check your Bentley for the exact spec.
In order to keep your sanity and and prevent ulcers I say you take it somewhere. Find a shop that has certified technicians that know a lot about older BMW's. Give them a list of what you have tested and the results of those tests. Then pay them for one hour of diagnosis. If your compression numbers are still low then have the shop do a leak down test.
In the end you should have to pay the shop for 1 hour of diagnosis and maybe 1 hour for leak down. If they don't find it then you can consider pay for another hour of diagnosis.

If you don't want to pay someone then I understand. It is usually easier to spend 7 months trying to figure out a problem than paying a shop for 2 or 3 hours of work.

[Hallen]

Yeah, those numbers are way low. Factory new is something like 150, but on older engines it isn't uncommon to see it up around 170. So either you have a problem there, or you didn't do the test right.

The Seafoam treatment might help... it certainly won't hurt. But you have something else going on there that, in my opinion, isn't right.