Engine Puzzles m20b20

[bmcaz]

Hi guys;Just got myself a e30 m20b20 84' coupe as a second car. Got it fairly cheap at mudah, but of course lah... the rust is not that bad, i've seen worst. Will be sending for body works soon thanks to bro mizhans guide.Anyways, i got a small problem with the engine, now lets see if all of us can put our heads together and solve this;The Symptoms No 1;a) During cold start the engine revs all the way to 3000 RPM and screams her heart outb) When i on the aircond, the RPM drops to about 1000c) When im driving around, if i stop at a trafic light and engage the 'P' gear (without aircond), the engine revs up to 3000 RPMNow what may the problem be? i suspect its the idle control valve, or leaking at vacuum hose, or injectors are clogged. Any specific ideas anyONE? The Symptom No 2a) This is a very very minor issue, the aircond blower controller wont work at No 1,2,3 but will only work at No 4. And darnnnn its irritatingb) Went to aircond shop next to the place i got my tires fixed, and he said the priginal control switch tak boleh carik, and want to propose a new switch near the head lamp switch...no way!i suspect it might be one of the relays, but not very sure.... what do you guys think?Thanks guys!

 

[evilnickwong]

Symptom no. 2 is due to the aircon resistor, it's located right at the aircon blower under the front cowling/scuttle panel I believe.

 

[bmcaz]

Symptom no. 2 is due to the aircon resistor, it's located right at the aircon blower under the front cowling/scuttle panel I believe.

thanks mate, i am planning to dismantle the panel to replace some burned lamps , will have a go at it. Logically, if it is a regulator (speed selector) it is definitely a resistor unit. But i need to make an inspection to see if the resistor is built in the selector it self, being which, im sure its factory sealed, and any attempt to dismantle it may break the whole housing as it is almost 30 years old!

 

[evilnickwong]

Here you go:
http://e30.bmwdiy.info/blower-resistor/index.html

 

[bmcaz]

Thanks bro evilnickwong! Ur a darl!! Am gonna get workin on this 1st thing in the morning tmrw! As for the symptom 1: i got a PM that m20b20 doesnt have an idle control valve. Hmmmm... Gotta check on this.

Read in several forums tat injectors could get clogged for old cars. Just for FFS (for fu*ks sake) i got a STP fuel injector cleaner thingy tat u put in the the fuel, and wah!! It works like a charm! My 3 & 4th gear now are very smooth plus getting better acceleration.

 

[kura2]

Your m20b20 have an air slide valve. This link will explain to you on how to test it.

http://www.e30tech.com/forum/showthread.php?t=98014

 

[evilnickwong]

No prob.

I use a fuel injector cleaner every now and then too as I find it does help maintain good fuel consumption levels.

 

[bmcaz]

Hi guys;

Symptom 2 solution

I own a company tats into the maintenance business. Since the techy boys didnt have much to do, thanks to bro evilnickwong, i decided to give them some work to do.

All the fuses were good working order after through cleaning. The main culprit was the blower motor

As u can see, the motor aperature is in contact with the carbon brush. Thus gives a great friction. After taking it out, reservicing the motor, and replacing with new brushes, im gonna try to fit it in and hope it will work.

In a way, it does makes sense, at low speed, the motor is not producing enough power for the blower fins to spin. Thats why i can feel the extra "load" whenever i on the aircond. Orait guys, time to get back to work. Adios

 

[lightspeed]

Hi guys;

Symptom 2 solution

I own a company tats into the maintenance business. Since the techy boys didnt have much to do, thanks to bro evilnickwong, i decided to give them some work to do.

All the fuses were good working order after through cleaning. The main culprit was the blower motor

As u can see, the motor aperature is in contact with the carbon brush. Thus gives a great friction. After taking it out, reservicing the motor, and replacing with new brushes, im gonna try to fit it in and hope it will work.

In a way, it does makes sense, at low speed, the motor is not producing enough power for the blower fins to spin. Thats why i can feel the extra "load" whenever i on the aircond. Orait guys, time to get back to work. Adios

damn kao hairy chest...

 

[bmcaz]

Haha tats not me

 

[bmcaz]

Fixed back the blower after servicing. Cleaned the fuses and fixed them back in. Works like a charm thanks everyone!