Project E30 / Ep. 15 / Fixing the Rough Engine Idle

Let's see if we can't knock out these rough idle issues.
Here's the OEM BMW part number for the pulse sensor: 12121722570
If you're missing it, first figure out if your year/version of E30 should even have it. If it should, Google that part number and you'll find OEM and aftermarket versions of the part to purchase.

[@wheelsdeal]

Excellent work .You really brought this car to life.Most people wouldnt deal with all these issues.

[@WelcomeToTheMadness]

Pulse sensor wire...simpler solution now back to being 100%

[@petescarport]

God I love videos like this. I'm always doing stuff like this. Finding ways around what they engineered to make it easier. Thanks for this awesome video

[@LucasGSousa]

Man I purchased my 1st e30 and I am trying to do most of the work myself and watching your videos definitely helps a lot

[@philbrutsche8928]

I am coming into this 5 years late, but there is a reason for that sensor. ALL inline 6 engines from ALL manufacturers - Ford, GM, Chrysler, Honda (CBX 1000 motorcycle), Toyota, AMC, ALL OF THEM - have several things in common; one of them is cylinder 1 and cylinder 6 are TDC at the same time. That sensor is how it knows the difference between cylinder 1 and cylinder 6 being TDC. An E30 3-series (and BMWs of the same vintage in the 5 series, 6 series, and 7 series) use one of the first computer controlled digital fuel injection systems: Motronic 1.x. It was designed in the mid-late 1970s and put into production in the late '70s with the E23 7-series. I'm fairly certain that the (extremely limited) compute power of the time dictated how certain things work - Motronic 1.x used the Intel 8008 8-bit microprocessor.

[@bombakdik]

The sensor is there so that the DME can determine when and which injector needs to inject fuel. On startup, all 6 injectors fire evenly, up til the moment where the pulse is sensed by the sensor.

[@becomematrix]

If the number 6 wire is still in working order just chuck it in.

[@jbaroli]

It definetely runs better because you fixed your vacuum leaks. The CID sensor aids mostly in fuel economy, switching between all injectors firing at the same time to semi sequentially (by banks).

[@xsduprwd3937]

Its weird it made any difference, if I unplug mine nothing happens. The sensor is just for economy like you say. Batch firing 3 injectors instead of all 6.

[@chasetiemeyer1056]

Sweet Bong.

[@robsfooty]

Can’t wait to see it drive again! Enjoying all the videos man. Keep em coming.

[@donalishop]

that smoke machine is soo easy to make, my next diy proyect. thanks!

[@rodrigoandrescepedaperez7877]

Hello dear friend. By chance you have the vehicle manual where it specifies the tests that can be carried out in the ICV. I'm having idle instability issues on my 1990 e30 320i. I came across a magazine article that said between the center pin (+) of the ICV connector and ground, you need to measure the battery voltage. And between the center pin (2) and pins 1 and 3, it should measure 10 VDC. In my case, pin 2 and pin 3 measure 4.1 VDC. I measured it at the output of the ECU (positive battery and pin 4 ECU) and the value is the same. I changed the ECU and the output voltage value between positive battery and pin 4 ECU is 4.1 VDC. Some help ?. Greetings from Chile, South America.

[@PracticalEnthusiast]

Hi Rodrigo, sorry, I don't have the manual for the car anymore. However I remember that when testing the ICV, you are testing the resistance (ohms) between the pins, not voltage. Take a look at this article for more information: www.pelicanparts.com/BMW/techarticles/JF-Tech/BMW_E30_3_Series_Idle_speed_troubleshooting.htm

[@technicianx4816]

Took me a while to figure out why my e30 316i had it, turns out its how the ECU determines the camshaft position. I'm sure yours is for the same purpose. I guess it runs how it does when this is disconnected because its in a worse case scenario/limp mode as it doesn't know some information. Not sure why it delays throttle response and nothing else but at-least you fixed it. keep up with the videos as there amazing and helping me out a lot!.

[@helenaschober3970]

Hey quick question. Got myself a 316i two weeks ago and found this cable loose. It has 4 spark plugs, obviously. On wich of on do i put it?

[@othmanreparaturen4151]

You are enteligent bro i like the smoke test .. you are the king

[@roberthayden-ck6sh]

I have one now idk if you will reply but idk where I’m suppose to connect the sensor part that’s on the 6th spark plug

[@franciscocosta2734]

I have a 1987 325 and I don't have that canecter it's normal?

[@PhyteByte]

Damn I moved that pulse sensor down away from the radiator water hoses and my car idled better Jesus 😂

[@CookRacingUK]

Love the smoke test home brew kit! :D

[@robi6713]

I just bought a set of NGK plug wires and they dont have that sensor like the old ones

[@S1ckbg]

Im supriced you didnt paint in gun metal gray the intake and cams cover )

[@W3b195]

hi do all e30 have this ? my is a 87 bmw 325i i dont think mines came with it or i forgot to installing it while putting the engine back together :( please spare some tips.

[@PracticalEnthusiast]

No, not all E30s had this. Yours may not have had it.

[@bnosrati]

I have same issue. I have replace most or all hoses, and Idle Valve control. The problem is still exists. I have not seen that spark plug sensor ever in my car. I have a 1987 325es.

[@trevor557]

Son of a bitch I've been trying to address the irregular idle for months in my e30 and after watching this video I remember seeing that very same loose plug on the left side of the engine... Freaking pulse sensor. Great catch, saved me one hell of a headache.

[@charleshenry2280]

You are a genius! My 1987 325 has the same problem you described. Replaced two ECUs with no luck. Thank you very much for the video. Awesome!!!

[@ruivalentedasilva6532]

I bought an e30 and this cable is cut. it is not normal and i did not know where it is from now i understand . the car works, but it's not economical and I think it affects the relati

[@ruivalentedasilva6532]

thank you very much for your video. helped me a lot. I'm going to check if I can find the sensor because the cable was cut at the top.

[@cristianmillacura7483]

Hello friend, I have a BMW E34 m20b25 engine does not turn on, and it does not have the sensor on the spark plug wire that affects, it only has the crankshaft sensor. I would greatly appreciate your help

[@samk.8687]

Great vid! But I can’t find that wire in the beginning where that spark plug leads into, the one by the thermostat housing? Might know why?

[@wackydriver]

I have the same issue on my m40b16 after being with mechanic... my pulse sensor is missing, thanks bro gonna check it

[@maxyboy350z]

Help me! The bit at 5:00, where the connector comes off the wire, I cannot do! It will not budge. It spins but won't come off. Any ideas?

[@erichague]

What are you putting on at 9:44? Electrical tape? I was replacing the intake elbow on my e30 and I noticed that that juncture was extremely loose and can't be making much of a seal, but wasn't sure if I should try to hit it with some permatex or what.

[@johnwillison]

Hey guys how's it going ? What are the 3 square female connectors under the obd port ? I have one not connected.

[@bmw-e30]

Its a CID--cylinder identification sensor which tells the car's computer which cylinder is firing. Present on all 4 cylinder and 6 cylinder cars. New plug leads should have it.

[@bigilworth]

Can you put the name of the company making those smoke machines in your video description. I definitely need to purchase that for some vacuum leaks in my e30

[@kobes1925]

Love the vids! Quick question though What is that blowing sound when you rev at 7:48? Mine does the same and I’ve never been able to find answer

[@victorhuang1114]

Nice smoke machine!

[@josemario1606]

I can't find where to connect it haha.

[@bimmerbruh2874]

Any one know what year of e30's apply to this? I have a 1987 m20b27 eta.

[@craig_ramjet990]

Thank you for posting this. I'm so close to buying an e30 and diving in. Just a few more paychecks and I'm there. Anybody looking for a 2006 Yamaha FJR1300 for Christmas? Low miles. Cheap and in perfect condition! Seriously thanks for your videos.

[@ThefearFoo]

Craig Thomas definitely get one man it was my dream are when i was 15 talk about achievable goals lol

[@PracticalEnthusiast]

Thanks for watching. As for the FJR...how cheap are we talking? :)

[@gettingitdone1015]

I got an an 1984 e30, manual transmission, clean in and out. No rust at all. But not run. Just a few issues. I'm selling it coz I'm just so broke.

[@davej8746]

Excellent vid!! Smoke diag! Thanks!

[@RayRayLitFam]

Same issue here on my 87 325 is. Looks like ill have to give this a shot, thanks for the informative video!!

[@gettingitdone1015]

I got an 1984 e30 for sale super clean no rust. I'm just broke. I need the money.

[@randeepdhillon9607]

Is there a pulse sensor on 325e?

[@treedeblue]

Great work but nothing about this method is practical

[@nathanielmervis5616]

I like how practical you think bro. If it dont fit, make it fit 👏👏👏👏

[@chawenhalo0089]

From the noise I'd say it also needs tappets and valve adjusment.

[@fhdz22]

He did a valve adjustment already I believe

[@chawenhalo0089]

@@fhdz22 Given how much of a keen and thorough mechanic he is, I thought so too as I wrote it lol.

[@bvd2551]

oils been sitting for a long minute

[@thesneak281]

M20 engines have loud valve trains. Also the bosch injectors click very loudly.

[@e30cu70]

what do you use and how do you do smoke test? Edit: oops entered comment too early!

[@mrnick8171]

I had the same problem with mine after doing valve adjustment

[@Eeeeste]

Hey man!! great videos!! I have a 325i 86' myself and have learn a lot about it with you, so keep on it!! I have the same issue with the idle and I have just realized XD. I cannot believe how underviewed is this series. Cheers from Uruguay!

[@theagam97]

By the way i had a 1989 bmw e30 318i with m40 engine, does the 4 cylinder m40 engine also have a pulse sensor like the 6 cylinder m20 engine? Because I have also been dealing with this rough idle issues. Changed the Air Flow Meter and still no luck. The next culprit might be the idle regulator valve but i dont know if that might fix the problem 😅

[@Iceeeen]

Yes they have it

[@finnpanziera5749]

Do you have a rough estimate on the amout of hours you have put into this project so far?

[@PracticalEnthusiast]

I've been afraid to add it up. But since you ask, I'd estimate it's been 375-400 hours so far. But that includes video recording and editing as well.

[@masjidilharam]

@@PracticalEnthusiast ... wow... thanks for sharing the video. regard from Indonesia.

[@alanhirayama4592]

Road test soon! Yay!

[@bayareabimmer7818]

Quick question, I have the same sensor on my spark plug wires but the place it is apost to plug in to I have an Intake Atmosphere Pressure sensor.... can I unplug it and plug the pulse sensor in or is there a separate plug I have to fine.

[@PracticalEnthusiast]

I'm not sure to be honest. If you have a Barometric Pressure Sensor, I have to assume it's supposed to be there and is likely plugged into the right spot. I would keep looking for another connector. Mine was right below the circular diagnostic port that's near the thermostat housing. But, knowing BMW, they probably put it in a different spot depending on your model year.

[@stefanrosu]

Thank you, I have the same problem, only now I know the solution!

[@rexu.3571]

jump cut jump cut jump cut

[@athromt]

A great illustration of why you should hang onto your old parts until the project is completely finished - even obvious throw-aways like old plug wires.

[@ابراهيمالاسدي-خ7ذ]

thanks

[@egbertgroot2737]

Brilliant way to detect vacuum leak!

[@bartucelebi]

Thanks a lot my friend it helped me a lot!

[@usalbert]

Thank you for posting this great video. I just got the pulse sensor today I will install it sometimes next week. My e30 325i, all of the sudden won't start, I found out that the pulse sensor was busted. I hope when I finally replace it my car starts.

[@matejcindric9249]

And will it start?

[@usalbert]

@@matejcindric9249 It was a bad computer. I replaced and started right up.

[@funkyed985]

Interesting, does the car have a cam position sensor? If not that may be the reason for that inductive clamp.

[@PracticalEnthusiast]

No cam position sensor that I'm aware of, but it does have a crank position sensor.

[@xsduprwd3937]

That pulse sensor is essential the cam sensor

[@Barthoization]

Is there a reason why the footage is cut up every 5 words ?

[@PracticalEnthusiast]

To connect things I say correctly with other things I say correctly, while at the same time eliminating pauses. Nothing is scripted in these videos and I'm certainly not perfect nor have infinite time to make the video so, so hopefully you can enjoy the videos as they are. Thanks.

[@theagam97]

Wow that smoke test is brilliant. Thanks mate

[@christianparaoan7438]

Can’t wait to see this E30 finished!

[@buzzzer3]

Amazing content

[@richardporter7981]

Were are you located?

[@PracticalEnthusiast]

I'm in Overland Park, KS.

[@monkeywentbananas]

Wow. Glad I found your channel ! I own several old BMW's. E46 and E90.

[@markusspeicher4648]

Great vid. Your ingenuity is remarkable.

[@zaccannon5572]

Do you intend to keep it m20?

[@PracticalEnthusiast]

Yep! No plans to change it out as of now.

[@beevahkronickz6219]

Practical Enthusiast I need some help my e30 sputters or shall I say gets stuck and loses power at 3-4000 could you know what it could be?

[@ActionM]

Good job!! Well done!!

[@naughtyponyracing]

Wow just did a swap and found that wire tucked away in the harness , Im on this this morning , My 2.5 will finally Purr, I knew it was simple , Someone else tried to hide it LOL, Greatr video! Cheers