90 Mitsubishi Eclipse - Idle Air Valve Motor

May 09, 2012 5 Replies

When I turn the ignition 'on' there is clearly a solenoid chattering in = the middle of the engine, between the engine and firewall. Best I can = tell it's coming from about 6-12 inches down from the top of the engine. = Normally I can use a tube to find these things but this time can't = locate the sucker.



A problem I have this time is I'm just learning this car and can't find = any diagrams showing solenoids. Haynes and Chiltons aren't much help = this time.



I know it's not coming from near the starter solenoid. Anyone know what = other solenoids would be in that area?


1990 Mitsubishi Eclipse.

Thanks in advance.



Bob



=3D=3D=3D



Found it - the idle speed stepper motor was chattering. Had to drill = out 3 screws to get it apart. Cleaned it off and seems to work but not = sure. The shop manual says to apply 6vdc to some of the connector pins = and see if it if moves or vibrates. I can barely feel it move every = time I hit a pin with 6v, but no vibration or continuous movement. Same = when terminals swithed. Does this right? I'm guessing that one 6v = pulse from the control unit causes one step in the motor - can't find = that out anywhere and the Mitsubishi place here won't say anything = except "bring it in and we'll test everything for $150".



It would also be nice to know how many steps there are in the motor. No = info from anywhere I could find about this.


sucker.

time.

I checked one on truck by operating off engine still connected. Just see if it has resistance on all leads, assuming the same ohms. Lubricate.

Greg

save my life. =20

in

can

engine.=20

locate the sucker.

find

help this time.

what

drill

not

pins

time

when

from

"bring

No

see if

Thanks Greg. Coil resistance is 30 ohms, which is within spec. I need = a refresher on stepper motors..... Does it turn once step with each 6v = pulse?

life.

the sucker.

time.

That's what happens, but voltage or ground occurs on all leads, not open.

Greg

save my life. =20

chattering in

can

engine.=20

locate the sucker.

find

help this time.

know what

Had to drill

but not

connector pins

every time

Same when

pulse from

out

"bring

motor. No

Just see if

need a

6v pulse?

open.

OK, after spending Sat & Sun under the hood, I'm officially a shade tree = semi-expert of some of this stuff.

I cleaned and lubricated and shoved as many parts around as I could. = Got the stepper motor back running again. Fixed some vacuum leaks, loose = electrical connectors. Checked every sensor in the book and all were = OK.

Engine starts up fine and runs a lot better, but still has a miss. Will = start again next weekend.

save my life. =20

chattering in

can

engine.=20

locate the sucker.

find

help this time.

know what

Had to drill

but not

connector pins

every time

Same when

pulse from

out

"bring

motor. No

Just see if

need a

6v pulse?

open.

OK, after spending Sat & Sun under the hood, I'm officially a shade tree = semi-expert of some of this stuff.

I cleaned and lubricated and shoved as many parts around as I could. = Got the stepper motor back running again. Fixed some vacuum leaks, loose = electrical connectors. Checked every sensor in the book and all were = OK.

Engine starts up fine and runs a lot better, but still has a miss. Will = start again next weekend.

=3D=3D=3D

Next weekend update....

Took the ECU apart and saw corrosion around 2 capacitors. Scrubbed the = board and other board connections looked OK. Replaced the caps with = same only 105 deg instead of 85 deg. All symptoms gone at engine cold = start. Fine when hot, except when in neutral idle speed cycles between =

1300 & 1500 rpm with about 1/2-second cycle time. This is only when up = to temp.

TS guides say that's likely in the intake air flow -- mass air flow = temp, press or flow sensors, idle speed air sensor, motor, etc.

I'm so jazzed that the main problems are solved that I'm going to call = it a day and go have a BURGER!! LOL!!!

Bob

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