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When I turn on the AC at idle, the rpm's don't raise to offset the load on the engine. Does the ECU or Klima relay control the rpm's?
Also, turning on the AC seems to drain the Horsepower considerably.
OVP is good. ABS light is on, on the dash- missing the relay inside the cover of the pump. I don't know if any of this is related to the AC but I thought I would mention it.
190E 2.6L 1989, 190E 2.6L 1988, BMW 535dXdrive 2014, BMW 428i 2015
Hi Dave, I sent you a PM on this not noticing it was posted here. The idle change on 2.6 is very little, mostly goes unnoticed. There is more load on the engine so the idle controller automatically seems to compensate for that since it is in a closed loop. I believe the AC compressor clutch signal appears to go back to the ECU idle controller because the only thing I notice is that when the AC is on, the fuel cut off (rpms > 1800 with throttle plate closed) accomplished forcing -64mA on the EHA is disabled. This is to make sure the car is less jerky with the AC on in my opinion because the fuel cut-off is not needed with the AC load. Also if the two coincide the car would jerk even more, so it is disabled.
I would say, if you can feel the fuel cut off, in the automatic car, that is one sure way of telling if the ECU is aware of the AC being turned on. So if Fuel cut-off is still present, with AC on, I'm pretty sure something is wrong and your ECU-idle controller is not responding properly. I can tell this because I have an EHA current meter on my dash as you know, it maybe harder to detect without it but I can even tell in a manual transmission car because the drive train is direct coupled to the engine.
Last thought on this is that the fuel enrichment is not effected at all with AC. So the apparent sluggishness would be from the extra 5HP or so load.
I found this flow chart on mixture control. Looks like the ECU gets a signal from the AC compressor to adjust the mixture. So, Ill check the wiring from the AC clutch to ECU pin #19. (I have a pin out of my ECU). I also have a spare ECU I can swap. Ill try to monitor the EHA (mA) while turning on the AC as well as the voltage to the ICV.
Does anyone with a 2.3 8v experience this sluggishness when they turn on the AC?
GK+ & GK- are the compressor speed signal inputs. The circuit 15 is key on battery power. Circuit 31 is always ground.
KL is the command signal that comes from the pushbutton control that turns the compressor on. That is a GROUND signal!
T is the signal that the engine is overheating, that also is a ground signal form a switch in the waterpump. Ground on T will shut the compressor off.
87 is the power to turn the compressor ON.
87Z is a command signal to the fuel computer to raise the idle.
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GK+ & GK- are the compressor speed signal inputs. The circuit 15 is key on battery power. Circuit 31 is always ground.
KL is the command signal that comes from the pushbutton control that turns the compressor on. That is a GROUND signal!
T is the signal that the engine is overheating, that also is a ground signal form a switch in the waterpump. Ground on T will shut the compressor off.
87 is the power to turn the compressor ON.
87Z is a command signal to the fuel computer to raise the idle.
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190E 2.6L 1989, 190E 2.6L 1988, BMW 535dXdrive 2014, BMW 428i 2015
Valuable information Dave as always. I have read here and there that there is a fuel enrichment and idle speed increase with AC on. I have not witnessed this at all on the 2.6 manual transmission. I think some of the information may not be 100% accurate or only valid for certain models although the documentation does not mention this.
If you look at the first diagram fuel enrichment is not mentioned as one of the outcomes at all. And if you think about it, the fuel enrichment should not be effected by engine load much. Temperature, altitude, etc. of course but not engine load unless there is a WOT condition in which a quick burst is needed because the lambda system is not fast enough to react to something like that.
Most likely the 2.3 and diesel models have the compressor cutoff coming from the KLIMA relay under certain load conditions to make the car behave like the AC is not on during acceleration. We already know that the AC is shut down if there is a slippage in the serpentine belt by the KLIMA (By the way this is permanent until the car is re-started) so the temporary shutoff under certain engine speeds and acceleration make logical sense. I'm thinking that function is not working on your 2.3 I still do not know if the same feature exists for a 2.6 model since the KLIMA part numbers are different.
There is still a debate on whether the rpm's should increase with the 2.3 Engine with AC. That would be the idle controller's function. Even my Haynes model claims it should by 200rpm but my 2.6 does not so again even if true, the statement would be partially accurate.
Perhaps someone with a 2.3L engine can shed a light on this.
I have a 2.3 and I don't notice any sluggishness once I turn the A/C on. I do notice somewhat of an acknowledgement of the A/C when I first turn it on but there's no sluggishness.
190E 2.6L 1989, 190E 2.6L 1988, BMW 535dXdrive 2014, BMW 428i 2015
Originally Posted by 190Efan
I have a 2.3 and I don't notice any sluggishness once I turn the A/C on. I do notice somewhat of an acknowledgement of the A/C when I first turn it on but there's no sluggishness.
Good to hear 190Efan. What about the idle rpm's? Does it increase with AC on? I'm very curious to know even though I do not own a 2.3.
It specifically says 87Z of the Klima relay, sends a signal to the ecu to increase the rpms.
When I turn on my AC, it feels like a dropped a boat anchor. So, that circuit in my ECU could be bad or Klima relay could be bad or the wiring could be bad. Ill swap out the ECU check the wiring tomorrow. I don't have a spare Klima.
190E 2.6L 1989, 190E 2.6L 1988, BMW 535dXdrive 2014, BMW 428i 2015
Originally Posted by Dave Kost
It specifically says 87Z of the Klima relay, sends a signal to the ecu to increase the rpms.
When I turn on my AC, it feels like a dropped a boat anchor. So, that circuit in my ECU could be bad or Klima relay could be bad or the wiring could be bad. Ill swap out the ECU check the wiring tomorrow. I don't have a spare Klima.
I'm thinking if you have the two issues, it is more likely that it is your Klima because it is also not shutting off the compressor and making your car sluggish under acceleration.
Do let us know how this turns out Dave.
The only think that I can say when I first put my A/C on is that my A/C will cycle but that's all I notice. I just drive off and don't notice it until I get cold and need to dial up the temperature.
AC on from a standstill, if I drop the shifter down a gear, it seems to have more pick up and is more responsive.
Yesterday, I had a cold and warm start issues, smell of gas. The fuel line from the fuel filter to the hard fuel line that goes to the engine bay has a leak. This one-
Not available from MB, so I got one from FCP Euro coming. Maybe, this is part of the sluggishness.....??
AC on from a standstill, if I drop the shifter down a gear, it seems to have more pick up and is more responsive.
Yesterday, I had a cold and warm start issues, smell of gas. The fuel line from the fuel filter to the hard fuel line that goes to the engine bay has a leak. This one-
Not available from MB, so I got one from FCP Euro coming. Maybe, this is part of the sluggishness.....??
Maybe. See how the replacement of this fuel hose effects your car before you do anything more is my suggestion to you.
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