Sporadic rough running/cel

[parkerbink]

The idle goes crazy when the MAF is disconnected, I called the store and asked for a replacement, that was the last one they had in the state, it'll take until Tuesday to get from Ca.

What is a CTS?

[parkerbink]

Figured out coolant temp sensor, realoem shows two so I ordered both.

[cirrusblue]

Sorry about the Relay, at least it doesn't cost too much. It does feel electrical to me. My buddies car had a similar problem where it woudl run when it was cold, but once the engine warmed up it would die. Turned out it was rusty engine grounding cables - that when they got hot, did not conduct, but when cold conducted enough to run. It was a bi)ch for 3 months while we did all kinds of things that didn't fix it. Once we redid the rusty grounding cables, the car runs like champ for 2 years. That and the engine position sensors - check they aren't damaged or broken.

I know it sounds random, but cold rusty wires conduct and hot ones have too much resistance.

[hippiester]

Gad a dimilar issue, tested and tested cleanded everything andnit turned iut to need a new battery

[parkerbink]

Sorry about the Relay, at least it doesn't cost too much. It does feel electrical to me. My buddies car had a similar problem where it woudl run when it was cold, but once the engine warmed up it would die. Turned out it was rusty engine grounding cables - that when they got hot, did not conduct, but when cold conducted enough to run. It was a bi)ch for 3 months while we did all kinds of things that didn't fix it. Once we redid the rusty grounding cables, the car runs like champ for 2 years. That and the engine position sensors - check they aren't damaged or broken.

I know it sounds random, but cold rusty wires conduct and hot ones have too much resistance.

No worries, it was 20 bucks, now I have three spares because after I got the relay I met the seller to get an extra set of front seats and he had a box of parts including two of these relays.

lol

Gad a dimilar issue, tested and tested cleanded everything andnit turned iut to need a new battery

I have a trickle charger/battery conditioner that I ran on it at low/condition for 18 hours to 100% and it's sitting at 12.87 volts after sitting overnight.

I know from my e53 BMWs are super sketchy with slightly bad batteries. I found a tiny weird vacuum leak at the PVC outlet on the intake and now it idles and revs much better. I can't drive it because they are freaking paving the street in front of my driveway (wasn't thinking, drove up & down the street and got to remove tar from both sides of the car for 45 minutes. FUN.

[EyExR]

Figured out coolant temp sensor, realoem shows two so I ordered both.

The blue goes to the ECU the brown goes to the instrument cluster gauge.

If you can get the car smoke tested that would be great. It's a good thing to do regardless... These cars are very cranky when the vacuum pressure is not right.

Meanwhile, some free testing you could do on your own if you have a multimeter is to do the ECU pinout tests described in the Bentley Manual.
Also here: http://www.rtsauto.com/ecu-pinout-an...cal-tests-e30/

Also, here's a link to CORRECTLY test your AFM: https://web.archive.org/web/20120415...44.com/afm.htm

Be aware, I had a nightmare with a "new" (reburbished) AFM that essentially destroyed two new engines. Even though it tested out fine it was causing the car to run lean and rough. If you can get somebody to loan you a known working AFM that would be great. As far as getting a new or replacement AFM I would only trust Bavarian Restoration at this point.

And as far as your electrical system goes, you should test it at the battery terminals with the car running and under load. Voltage should then be between 13.5 to around 15 VDC. This will ensure the alternator is charging your system correctly. Typically when it's low your battery light will start illuminating on the dash.

[parkerbink]

Great info, I plan as soon as I can drive it (without fear of it dying) to take it to my shop to do all the tests it needs. It is running better than it has and my plan is to take it to get gas, if it makes it issue free I'll go a bit further (the shop is 14 miles away) if I can make it about 20 miles I'll take it tomorrow.

Thanks for al the great input.

[parkerbink]

I gave in & took the car to a mechanic today, the fuel pump relay socket was deemed defective so was bypassed and the crank position sensor was replaced. This made the car run but idle is still sketchy, another ICV is on order.

[cirrusblue]

I gave in & took the car to a mechanic today, the fuel pump relay socket was deemed defective so was bypassed and the crank position sensor was replaced. This made the car run but idle is still sketchy, another ICV is on order.

Good news. In order to reset the electronics stuff needs to be powered off avwhile. So hopefully after that and icv youll be good.


Sent from my iPhone using Tapatalk

[parkerbink]

The blue goes to the ECU the brown goes to the instrument cluster gauge.

Using the part numbers from realoem, using my vin I got two wrong sensors. The blue one is black & does not fit my connector, the brown has no color and is a single male spade connector. wheeeee

Good news. In order to reset the electronics stuff needs to be powered off avwhile. So hopefully after that and icv youll be good.


Sent from my iPhone using Tapatalk

I hope so, the ECU is currently disconnected to clear it.

Thanks

[parkerbink]

Replaced ICV, no change. The car runs perfectly for 5-10 minutes, then runs rough idles choppy and sometimes stalls.

Really confused.

[Kershaw]

Does it run smooth after every start, or after you disconnect the battery? You said there's no difference in operation between the 525 and 173?

[parkerbink]

Until it's warm it revs to 1000/100/wants to die. Once warm it runs great for 5-15 minutes, then cel that on my newly acquired peake is the MAF. I have had three all do this. I am getting another tomorrow, and am working on getting one from Bavarian Restoration.

Happens on both ECUs.

[parkerbink]

Got yet another afm (bosch manufactured, says Ford on it, oe part number coralates to 3.5 & M3

http://www.vehiclepartsdatabase.com/vehicles/allprivateroadvehicles/bmw/7saloon/735i/m30b35motronic101/360/airmassflowsensors/bosch/0280203027

Which makes no sense but it does run like sh!t.

Wasn't there a mod that allowed the use of the 027?

I'm confused.

So I wanted to move the car onto ramps but no afm, I figured what's the worst that can happen? No run? It runs better than with the afms I have had. wtf?

[parkerbink]

Finally mostly solved! The last piece of the puzzle was getting the right MAF. I also replaced the original FPR and junk coil at the same time. The car runs ok, but is a bit slow to rev from 3k-3500 or so. Above 4k it is great.

Any input greatly appreciated!