"Guv Bob" wrote in message m...
"gregz" wrote in message ...
"Guv Bob" wrote:
"gregz" wrote in message
...
"Guv Bob" wrote:
"Guv Bob" wrote in message
m...
I know this sounds stupid........ but I can't find this thing to save my life.

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

= 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.

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

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?

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

Greg

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.

===

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