Unstable idle +frequent lost of power supply flow.

[theduke]

Greetings everyone,I have an e30 powered by the famous M20b25 powerplant which is the Motronic 1.1 version. It seems that everytime i switch on the A/C, as the compressor kicks in the RPM Lowers down to as low as to 500rpm from a normal 900-1000rpm(A/C off). The problem worsens when the headlights and radio are ON altogether. And as u start to drive, it feels like the engine isn't up to it's optimum potential....another word is - it drags..Which makes me prefer to drive it with the window down most of the time. This is the part where i do not understand why the engine runs much more smoother with the A/C off?PLus the radio shuts down on it's own everytime the signal lever is in use. Even the power window goes crazy too sometimes as if there's an insufficient power supllied.Are all these symptoms normal for an e30 like mine?thanx in advance.appreciate it.

 

[miepower]

check your ICV and get a proper wiremen to inspect your loom. Those symptomes are signed of scrued up and tempered wiring system.

 

[theduke]

check your ICV and get a proper wiremen to inspect your loom. Those symptomes are signed of scrued up and tempered wiring system.

Thanx alot for the heads-up Bro Mie, any good wireman around whom u can recommend me to?

thanx again.

 

[theduke]

hi guys,thanx for the heads-up..just got back from the mech this evening & had the alternator + battery checked via vlt/ampmetre.he said everything seems to be running fine..now da jalan buntu...adoi...any more ideas sifu2 sekalian??..

thanx..

 

[sk30]

had almost the same problem as to yours with my first UDM an E30m20b20.temporary solution done by a friend and fellow e30 owner,increased the idle rpm to 900 to 1000.seems like it solved my problem at the expense of slighty higher fuel consumption.(unstable idle and sudden die of engine).

get ur wiring checked for the player issue.mine was earthing issue.(no sufficient grounding for cd player).

as mentioned by fellow forumer its better for you to get the wiring checked by a PROPER WIREMAN familiar with BM.
at times this cars do 'act' wierd,a non familiar mechanic wont be able to troubleshoot the problem!!! gd luck

 

[cempaka]

There is a wire that tells the ecu when the aircon compressor is on, this tells the ecu to raise idle to compensate for the extra load. If it's not connected you will get the idle drop. I had the same problem after engine overhaul when they forgot to connect back the wire. Can talk to ah wai at bmworld about it, he will know about this.

I didn't have the other problems you describe with insufficient power, crazy electrics etc so that sounds like another issue, maybe some bad grounds or too many grounding locations. Also how many years old is your battery?

 

[theduke]

There is a wire that tells the ecu when the aircon compressor is on, this tells the ecu to raise idle to compensate for the extra load. If it's not connected you will get the idle drop. I had the same problem after engine overhaul when they forgot to connect back the wire. Can talk to ah wai at bmworld about it, he will know about this.

I didn't have the other problems you describe with insufficient power, crazy electrics etc so that sounds like another issue, maybe some bad grounds or too many grounding locations. Also how many years old is your battery?

Hi there Cempaka, appreciate & thanx for the tip. By any chance are we able to trouble-shoot this by DIY? If it's impossible, may i have either Ah Wai's contact number or Bimworld's location? Btw my batt is only half a year old.

cheers & thanx again.

 

[cempaka]

You could probably do it if you have experience with wiring and a diagram. Alll I remember seeing was a bunch of spaghetti so I can't offer any help beyond I think the wire was green lol.


Ah Wai 0122206387 / 0162206687

 

[theduke]

You could probably do it if you have experience with wiring and a diagram. Alll I remember seeing was a bunch of spaghetti so I can't offer any help beyond I think the wire was green lol.


Ah Wai 0122206387 / 0162206687

thanx a mill bro.Mind telling me the exact location of Bmworld?.thanx again.

 

[cempaka]

Sure, it's in Cheras. Desa Tun Razak, the small industrial area next to Bandar Tasik Selatan LRT.

The shop is directly opposite the water treatment fields.

 

[theduke]

There is a wire that tells the ecu when the aircon compressor is on, this tells the ecu to raise idle to compensate for the extra load. If it's not connected you will get the idle drop. I had the same problem after engine overhaul when they forgot to connect back the wire. Can talk to ah wai at bmworld about it, he will know about this.

I didn't have the other problems you describe with insufficient power, crazy electrics etc so that sounds like another issue, maybe some bad grounds or too many grounding locations. Also how many years old is your battery?

forgive me for askin but r u refering that this applies to the M20 engine?

cheers

 

[miepower]

forgive me for askin but r u refering that this applies to the M20 engine?

cheers

Yes, I'm very sure it is applicable to M20 :wink: