O2 sensor relay?

[e3091318is]

I tried looking around online and couldn't find which relay it is.  I know it is under the firewall area and it is one of the three relays, but which one!?

[keflaman]

I presume you've removed the wiring cover and you're looking at three relays; they are (inboard to outboard): #1-Master relay, #2-Fuel Pump relay, #3 O2 Sensor relay.

[e3091318is]

I presume you've removed the wiring cover and you're looking at three relays; they are (inboard to outboard): #1-Master relay, #2-Fuel Pump relay, #3 O2 Sensor relay.

ok so the one closest to the fuse box if the O2 sensor relay. Thanks!

[e3091318is]

I presume you've removed the wiring cover and you're looking at three relays; they are (inboard to outboard): #1-Master relay, #2-Fuel Pump relay, #3 O2 Sensor relay.

ok so the one closest to the fuse box if the O2 sensor relay. Thanks!

I might as well replace all three.  Does 0332014456 work for all three?  The Orange Bosch relays?

[keflaman]

I presume you've removed the wiring cover and you're looking at three relays; they are (inboard to outboard): #1-Master relay, #2-Fuel Pump relay, #3 O2 Sensor relay.

ok so the one closest to the fuse box if the O2 sensor relay. Thanks!

I might as well replace all three.  Does 0332014456 work for all three?  The Orange Bosch relays?

Not according to BMWfans.info:

61368373700 is for the Lambda and fuel; 61361729004 is for the Motronic.
http://bmwfans.info/parts-catalog/E30-2-doors/USA/318is-M42/L-M/jul1990/browse/engine_electrical_system/relay_motor/

[DesktopDave]

There's a whole bunch of relays you can use - the orange plastic 4-pin "456" can be used for most locations on the E30, including the fuel pump and O2 heater. The white case main relay is definitely different - it has to be a 5-pin with two switched power outputs. If it has two "87" terminals you can use it. If it has both an 87 and an 87a you can't - it's a 'flip-flop' toggle relay like the E30 high beam uses (some of those are purple plastic, some have a purple mark on a metal case). Some 5-pin relays will even work as a quick substitute for a 4-pin relay.

Most relays also have a wiring diagram on the side. Those will note resistors and diodes as well.

I'd also consider using diode/relay protection in the main relay to preserve the ignition switch. Bosch makes a huge family of relays that can fit. I'll see if I can dig up some part numbers.

[e3091318is]

Thank you very much for all the help.  I am trying to do everything I can to get rid of this ridiculous 1222 code.  I have all new hoses, a leak down test done, idle is fine but it still will stick sometimes at 1000 when I get off the freeway.  The CEL comes on only when I am idling after I drive for a bit but as soon as I give it a little gas it goes away.  I am hoping I have all my hoses hooked up correctly.  The o2 sensor has not been changed and I am unaware of the condition of it, same with the relay so I am going to try and swap those out.  If that doesn't get rid of it, I don't know what else it would be other than the fuel injectors being faulty.

[colin86325]

When you say the idle will stick, have you verified that the throttle cable isn't binding and that the TPS is working properly?

Just a couple of things to check.

[e3091318is]

When you say the idle will stick, have you verified that the throttle cable isn't binding and that the TPS is working properly?

That is something I was checking a few days ago.  The cable seems to be ok but sometimes doesn't always go back and will barely stick.  Would the TPS send a code?

[colin86325]

I'm not sure what sort of error condition (if any) would result from a stuck throttle cable. But I would definitely replace the cable if it is sticking.  Your problem might just go away!

[DesktopDave]

BMW had a recall about cracked throttle cable ferrules. Many M42s I've seen have a cracked ferrule at the throttle cable mounting plate. Sometimes they twist out of alignment and can bind.

BMW has a little spring clip that your local dealer's parts counter should know about. It's an OEM band-aid for the M42 & M50 motors. I couldn't find a part number or TSB to back it up though.

[e3091318is]

BMW had a recall about cracked throttle cable ferrules. Many M42s I've seen have a cracked ferrule at the throttle cable mounting plate. Sometimes they twist out of alignment and can bind.

BMW has a little spring clip that your local dealer's parts counter should know about. It's an OEM band-aid for the M42 & M50 motors. I couldn't find a part number or TSB to back it up though.

I will have to check it out.  I replaced the O2 sensor but the light still comes on.  I think I need to put more than 2 miles on it though.

[colin86325]

Here's the info for the throttle cable clips (part 35-40-1-165-394) to prevent the cable from binding:

http://www.s14.net/forums/forum/hacked-by-zey/general-e30-m3-discussion/59987-throttle-cable-clips?58780-Throttle-Cable-Clips=&p=553071

[DesktopDave]

Thank you very much for all the help.  I am trying to do everything I can to get rid of this ridiculous 1222 code.  I have all new hoses, a leak down test done, idle is fine but it still will stick sometimes at 1000 when I get off the freeway.  The CEL comes on only when I am idling after I drive for a bit but as soon as I give it a little gas it goes away.  I am hoping I have all my hoses hooked up correctly.  The o2 sensor has not been changed and I am unaware of the condition of it, same with the relay so I am going to try and swap those out.  If that doesn't get rid of it, I don't know what else it would be other than the fuel injectors being faulty.

Now that you mention it...I have seen occasional CELs during long downhill drives. I always figured the DME cut fuel on overrun. If that's true, I'd suspect the O2 sensor was just getting too cold. At any temp under ~300 degrees, the O2 sensor won't give a sensible reading to the DME. O2 sensors also tend to age, and the wiring is vulnerable to damage. You can splice any late-model 4-wire pre-cat O2 sensor into the car (mid-'90s Bosch sensors for the Ford V8 are popular).

Your symptoms are similar - an M42 at idle normally keeps the exhaust gas hot enough for the O2 sensor, but if not you'll be seeing CELs. To make this more complicated, I'm also fairly sure that the O2 heater only runs when the car is in cold start (open-loop) mode.

Unfortunately, idle is also when vacuum is highest - worst time for vac leaks.

[e3091318is]

Thank you very much for all the help.  I am trying to do everything I can to get rid of this ridiculous 1222 code.  I have all new hoses, a leak down test done, idle is fine but it still will stick sometimes at 1000 when I get off the freeway.  The CEL comes on only when I am idling after I drive for a bit but as soon as I give it a little gas it goes away.  I am hoping I have all my hoses hooked up correctly.  The o2 sensor has not been changed and I am unaware of the condition of it, same with the relay so I am going to try and swap those out.  If that doesn't get rid of it, I don't know what else it would be other than the fuel injectors being faulty.

Now that you mention it...I have seen occasional CELs during long downhill drives. I always figured the DME cut fuel on overrun. If that's true, I'd suspect the O2 sensor was just getting too cold. At any temp under ~300 degrees, the O2 sensor won't give a sensible reading to the DME. O2 sensors also tend to age, and the wiring is vulnerable to damage. You can splice any late-model 4-wire pre-cat O2 sensor into the car (mid-'90s Bosch sensors for the Ford V8 are popular).

Your symptoms are similar - an M42 at idle normally keeps the exhaust gas hot enough for the O2 sensor, but if not you'll be seeing CELs. To make this more complicated, I'm also fairly sure that the O2 heater only runs when the car is in cold start (open-loop) mode.

Unfortunately, idle is also when vacuum is highest - worst time for vac leaks.

I don't know what else it could really be.  I had a smoke test done, relay and sensor changed, it's a rebuilt engine with 3,000 miles, new fuel filter and fuel pressure test done.  I don't know what else it could even be.