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DIY: Do It Yourself
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Old 05-17-2015, 07:29 PM   #1
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Join Date: Jan 2015
Location: DFW, TX
Posts: 6
My Ride: 02 330c/11 X5d/97 M3
I'm stumped, rough idle, car stalling when coming to a stop

I have an E46 330 5-speed with 140k miles that I've had for a few months.

I didn't get a service history with it, so I don't know much about it's past.

It started off stalling a few times on me and would go into limp mode. I noticed a leaking oil separator, so that was my initial replacement along with a coolant overhaul due to the mileage.

1. Replaced oil separator and hoses along with some other PM items: belts, pulleys and tensioners. Also did a coolant overhaul: new radiator, water pump, thermostat, sensors, and coolant hoses.
2. Found 2 more leaks in the oil dipstick o-ring and OFHG, so I replaced those.
3. The previous owner had the throttle body both the male and female connectors broken and just left them connected with a blob of glue to hold it in place, so I replaced the throttle body with a used one that I bought off another car and rebuilt the connector housing with a new one, including having to splice a wire that broke off on me while removing the glue.
4. As some more preventative maintenance, I also replaced the throttle body gasket, disa o-ring, lower intake boot.

Got it all put together, coolant system working great, but still having a rough idle and stalling. CEL, EML, yellow Brake light, and DSC off lights came on and cruise control is disabled.

5. I searched around and some people reported the brake reservoir causing the yellow brake light, so I went ahead and put new fluid in while bleeding the brakes.
6. Replaced the fuel filter and replaced the line going from the intake boot f-connector to the fuel filter regulator since the old was crumbling. I really thought finding this line this was the cause. But it didn't have any effect.

Pulled codes and was getting lean bank codes along with throttle position sensor.

7. So I started with a new MAF, then went on to put new spark plugs, new ignition coils, and precat o2 sensors (I think the o2 sensor was the real culprit on the lean codes only).

Now I'm no longer getting lean codes, but I'm still getting these codes:
P0340 - intake camshaft sensor
P0222 - throttle position sensor
P0122 - throttle position sensor
P0121 - throttle position sensor

8. Replaced both the intake camshaft sensor as well as bought a brand new VDO throttle body since the TPS is built into the unit. Tried my best to check for a bad splice on the connector I replaced. I couldn't find the exact pinouts to ohm out the connector to where it goes. I tried my best to ohm out the wires from my rebuilt connector. It goes from the Throttle body-wiring box-DME. No apparent shorts with neighboring pins or open circuits from connector-to-DME that I could find ohming it out matching up colored wires and assuming it's just a straight pass through from the wiring box.
9. Thought the stalling was from a stuck ICV, so I cleaned it up, reinstalled, then ultimately replaced with a new one as well.

Car will work fine when it's cold and in open loop mode. Once it warms up and gets into closed loop, if I'm driving and coming to a stop or slowing down to change gears, the rpm's will drop all the way down and just stall the car. When I restart it, it is in limp mode. I can turn it off and on again and it will at least drive normally. I can finesse it and slow down and then wait until shifting very carefully below ~1000rpms to prevent it from stalling just to get by for now. Works beatifully at normal driving speeds, just that rough idle and stalling.

I'm completely stumped at this point and don't just want to blindly replace parts.

Unfortunately, I don't have a bmw code reader and have replaced just about every reasonable part on the intake side except the DISA. I did the little finger over the hole check on the DISA and the flap will move slightly then hold - which seems normal.

Very plausible if I did make a mistake when rebuilding the throttle body connector and not making contact with the throttle body itself? Any suggestions to test this? I can ohm out from the connector to the DME if I had the proper pinout, but once it's mated to the corresponding connector on the throttle body, I have no clue how to test continuity. Do I try again? Do I just bite the bullet and replace the whole wiring harness?

Any ideas on something else? Fuel pump? Disa? Somehow got a dud on the intake camshaft position sensor? I have manual trans, but any neutral gear position or clutch pedal sensors causing problems?
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Old 05-18-2015, 11:22 AM   #2
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Join Date: Feb 2015
Location: Saint Paul, MN
Posts: 97
My Ride: 2002 330ci vert
Year: 2002
Model: 330 CiC
Transmission: 5 speed manual
I don't have any advice for you, but I suspect I am about to get a repair estimate from my indy shop that bears an eerie similarity to your list of rememdies. My 02 330ci just stopped running in the middle of traffic over the weekend and I had it towed to the shop. They are preparing to email me the butcher's bill right now. I'm hoping for a number lower than a Yankees signing bonus.
Model description: 330CI
VIN: EV88139
Market: USA
Type: BS53
E-Code: E46 (C)
Chassis: Cabriolet
Engine: M54 - 3,00l (170kW)
Drive: Heckantrieb
Transmission: manuell
Body Color: Titansilber Metallic (354)
Upholstery: Standardleder/hellbeige 2 (arbeitsn (N6HC)
Production date: 31.08.2001
Assembled in: Regensburg

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Old 05-18-2015, 01:04 PM   #3
Registered User
Join Date: Jan 2015
Location: DFW, TX
Posts: 6
My Ride: 02 330c/11 X5d/97 M3
If anyone has a loose wiring harness and could give me the pin and wire colors for the 6-pin socket going to the throttle body connector, I'd greatly appreciate it.

I have the bentley, but it shows it being DME MS 42.0 with a 10-pin connector, and I believe my car is MS 43.0 and it certainly has a 6-pin connector.
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