My 1990 Mitsubishi Eclipse (DSM 1G 2L non-turbo) is starts and idles cold fine, and runs fine warmed up. When warm and I put it in neutral (AT) the idle oscillates between 1800 and 2200 with about 1/2 second cycle time.

MAS was the first guess -- so I put a rebuilt mass airflow sensor assy in and same problem. Checked all the connections and vacuum - all OK.

Also took the throttle assy apart and cleaned all - helped the running but still oscillating. Cleaned Idle air motor, checked voltages and resistance for all sensors and also voltages coming from the computer, and all OK.

About out of ideas -- anyone have some thoughts on how to start troubleshooting this?

Thanks in advance.

Bob

Guv Bob wrote:
My 1990 Mitsubishi Eclipse (DSM 1G 2L non-turbo) is starts and idles cold fine, and runs fine warmed up. When warm and I put it in neutral (AT) the idle oscillates between 1800 and 2200 with about 1/2 second cycle time.

MAS was the first guess -- so I put a rebuilt mass airflow sensor assy in and same problem. Checked all the connections and vacuum - all OK.

Also took the throttle assy apart and cleaned all - helped the running but still oscillating. Cleaned Idle air motor, checked voltages and resistance for all sensors and also voltages coming from the computer, and all OK.

About out of ideas -- anyone have some thoughts on how to start troubleshooting this?

Thanks in advance.

Bob

Hi,
Checked fuel pressure, filter, pump?

On Sat, 02 Jun 2012 15:48:29 -0600, Tony Hwang
wrote:


About out of ideas -- anyone have some thoughts on how to start troubleshooting this?

Thanks in advance.

Bob

Hi,
Checked fuel pressure, filter, pump?

I don't work on cars much anymore.

Fuel, air filters or a bad gas cap? A bad spark plug?

something is wrong :-\

OP how many miles on the automobile?

On Sat, 02 Jun 2012 16:34:32 -0700, Oren wrote:

On Sat, 02 Jun 2012 15:48:29 -0600, Tony Hwang
wrote:


About out of ideas -- anyone have some thoughts on how to start troubleshooting this?

Thanks in advance.

Bob

Hi,
Checked fuel pressure, filter, pump?

I don't work on cars much anymore.

Fuel, air filters or a bad gas cap? A bad spark plug?

something is wrong :-\

OP how many miles on the automobile?
None of the above would be likely to cause the reported symptoms -
and most would affect normal and high speed operation.

In article ,
Tony Hwang wrote:

Guv Bob wrote:
My 1990 Mitsubishi Eclipse (DSM 1G 2L non-turbo) is starts and idles cold
fine, and runs fine warmed up. When warm and I put it in neutral (AT) the
idle oscillates between 1800 and 2200 with about 1/2 second cycle time.

MAS was the first guess -- so I put a rebuilt mass airflow sensor assy in
and same problem. Checked all the connections and vacuum - all OK.

Also took the throttle assy apart and cleaned all - helped the running but
still oscillating. Cleaned Idle air motor, checked voltages and
resistance for all sensors and also voltages coming from the computer, and
all OK.

About out of ideas -- anyone have some thoughts on how to start
troubleshooting this?

Thanks in advance.

Bob

Hi,
Checked fuel pressure, filter, pump?

Only have a couple of seconds... but try Googling:

"idle speed hunting 90 Eclipse" (sans quotes)

Good Luck!

Erik

"Guv Bob" wrote:
My 1990 Mitsubishi Eclipse (DSM 1G 2L non-turbo) is starts and idles cold
fine, and runs fine warmed up. When warm and I put it in neutral (AT)
the idle oscillates between 1800 and 2200 with about 1/2 second cycle time.

MAS was the first guess -- so I put a rebuilt mass airflow sensor assy in
and same problem. Checked all the connections and vacuum - all OK.

Also took the throttle assy apart and cleaned all - helped the running
but still oscillating. Cleaned Idle air motor, checked voltages and
resistance for all sensors and also voltages coming from the computer, and all OK.

About out of ideas -- anyone have some thoughts on how to start troubleshooting this?

Thanks in advance.

Bob

I don't know the car. Is it possible to read computer, if it has one. I'm
thinking of idle motors, oxygen sensor, manifold leak, ....

Greg

On 6/2/2012 4:48 PM, Tony Hwang wrote:


Guv Bob wrote:
My 1990 Mitsubishi Eclipse (DSM 1G 2L non-turbo) is starts and idles
cold fine, and runs fine warmed up. When warm and I put it in neutral
(AT) the idle oscillates between 1800 and 2200 with about 1/2 second
cycle time.

MAS was the first guess -- so I put a rebuilt mass airflow sensor assy
in and same problem. Checked all the connections and vacuum - all OK.

Also took the throttle assy apart and cleaned all - helped the running
but still oscillating. Cleaned Idle air motor, checked voltages and
resistance for all sensors and also voltages coming from the computer,
and all OK.

About out of ideas -- anyone have some thoughts on how to start
troubleshooting this?

Thanks in advance.

Bob

Hi,
Checked fuel pressure, filter, pump?

i missed the original post, but i'd be looking for a vacuum leak.
Probably on a gas deteriorated pcv line.

--
Steve Barker
remove the "not" from my address to email

"Tony Hwang" wrote in message ...


Guv Bob wrote:
My 1990 Mitsubishi Eclipse (DSM 1G 2L non-turbo) is starts and idles cold fine, and runs fine warmed up. When warm and I put it in neutral (AT) the idle oscillates between 1800 and 2200 with about 1/2 second cycle time.

MAS was the first guess -- so I put a rebuilt mass airflow sensor assy in and same problem. Checked all the connections and vacuum - all OK.

Also took the throttle assy apart and cleaned all - helped the running but still oscillating. Cleaned Idle air motor, checked voltages and resistance for all sensors and also voltages coming from the computer, and all OK.

About out of ideas -- anyone have some thoughts on how to start troubleshooting this?

Thanks in advance.

Bob

Hi,
Checked fuel pressure, filter, pump?

Hey Tony, yes - both OK.

"Oren" wrote in message ...
On Sat, 02 Jun 2012 15:48:29 -0600, Tony Hwang
wrote:


About out of ideas -- anyone have some thoughts on how to start troubleshooting this?

Thanks in advance.

Bob

Hi,
Checked fuel pressure, filter, pump?

I don't work on cars much anymore.

Fuel, air filters or a bad gas cap? A bad spark plug?

something is wrong :-\

OP how many miles on the automobile?

125K

"gregz" wrote in message ...
"Guv Bob" wrote:
My 1990 Mitsubishi Eclipse (DSM 1G 2L non-turbo) is starts and idles cold
fine, and runs fine warmed up. When warm and I put it in neutral (AT)
the idle oscillates between 1800 and 2200 with about 1/2 second cycle time.

MAS was the first guess -- so I put a rebuilt mass airflow sensor assy in
and same problem. Checked all the connections and vacuum - all OK.

Also took the throttle assy apart and cleaned all - helped the running
but still oscillating. Cleaned Idle air motor, checked voltages and
resistance for all sensors and also voltages coming from the computer, and all OK.

About out of ideas -- anyone have some thoughts on how to start troubleshooting this?

Thanks in advance.

Bob

I don't know the car. Is it possible to read computer, if it has one. I'm
thinking of idle motors, oxygen sensor, manifold leak, ....

Greg

Yes, computer codes shows all sensors being monitored are OK. Also checked O2 and others with meters and so far all OK.

"Steve Barker" wrote in message ...
On 6/2/2012 4:48 PM, Tony Hwang wrote:


Guv Bob wrote:
My 1990 Mitsubishi Eclipse (DSM 1G 2L non-turbo) is starts and idles
cold fine, and runs fine warmed up. When warm and I put it in neutral
(AT) the idle oscillates between 1800 and 2200 with about 1/2 second
cycle time.

MAS was the first guess -- so I put a rebuilt mass airflow sensor assy
in and same problem. Checked all the connections and vacuum - all OK.

Also took the throttle assy apart and cleaned all - helped the running
but still oscillating. Cleaned Idle air motor, checked voltages and
resistance for all sensors and also voltages coming from the computer,
and all OK.

About out of ideas -- anyone have some thoughts on how to start
troubleshooting this?

Thanks in advance.

Bob

Hi,
Checked fuel pressure, filter, pump?

i missed the original post, but i'd be looking for a vacuum leak.
Probably on a gas deteriorated pcv line.

--
Steve Barker
remove the "not" from my address to email

Thanks Steve. Will check this out.

I'd post in auto repair group, unless you live in your Mitsubishi.

Christopher A. Young
Learn more about Jesus
www.lds.org
..

"Guv Bob" wrote in message
m...
My 1990 Mitsubishi Eclipse (DSM 1G 2L non-turbo)

On Jun 2, 10:46*pm, gregz wrote:
"Guv Bob" wrote:
My 1990 Mitsubishi Eclipse (DSM 1G 2L non-turbo) is starts and idles cold
fine, and runs fine warmed up. *When warm and I put it in neutral (AT)
the idle oscillates between 1800 and 2200 with about 1/2 second cycle time.

MAS was the first guess -- so I put a rebuilt mass airflow sensor assy in
and same problem. *Checked all the connections and vacuum - all OK.

Also took the throttle assy apart and cleaned all - helped the running
but still oscillating. * Cleaned Idle air motor, checked voltages and
resistance for all sensors and also voltages coming from the computer, and all OK.

About out of ideas -- anyone have some thoughts on how to start troubleshooting this?

Thanks in advance.

Bob

I don't know the car. Is it possible to read computer, if it has one. I'm
thinking of idle motors, oxygen sensor, manifold leak, ....

Greg- Hide quoted text -

- Show quoted text -

Another question, aside from the varying idle speed, is why it's
idling between
1800 and 2200 to begin with. That is 1000 RPM too high. Perhaps
going down
that diagnosis path will be more fruitfull. Reading the computer out
would be an
excellent idea. Some of the auto parts stores, like Advance,
AutoZone etc will
do that for free. But I figured out a long time ago it pays to have
an OBD II reader
if you intend to do work on the car yourself and to keep stealership/
repair shops
honest even if you're not.

Also, with some things, paying a mechanic $90 for an hour's labor to
diagnose
it may be worth it.

Thanks folks for the help. It's running much better but still checking more sensors, etc.

Any idea what this part is? It has 4 leads that feed into the wiring harness and can't trace it any farther. Looks like a solenoid but can't find it in Haynes or other manuals I have.
Not sure if the first photo took, so uploaded it again...

http://imageshack.us/photo/my-images/833/dsm1g20.jpg/
http://img593.imageshack.us/img593/8655/dsm1g20.jpg

Sorry for posting in the alt.home. repair group, but it's the about the best repair newsgroup I've found - alt.autos, and mitsubishi are dead.

Thanks again.

Bob


"gregz" wrote in message ...
"Guv Bob" wrote:
My 1990 Mitsubishi Eclipse (DSM 1G 2L non-turbo) is starts and idles cold
fine, and runs fine warmed up. When warm and I put it in neutral (AT)
the idle oscillates between 1800 and 2200 with about 1/2 second cycle time.

MAS was the first guess -- so I put a rebuilt mass airflow sensor assy in
and same problem. Checked all the connections and vacuum - all OK.

Also took the throttle assy apart and cleaned all - helped the running
but still oscillating. Cleaned Idle air motor, checked voltages and
resistance for all sensors and also voltages coming from the computer, and all OK.

About out of ideas -- anyone have some thoughts on how to start troubleshooting this?

Thanks in advance.

Bob

I don't know the car. Is it possible to read computer, if it has one. I'm
thinking of idle motors, oxygen sensor, manifold leak, ....

Greg

I'm glad to say this is my last post on this topic. Made the last few adjustments and it's idling and running stable and like new again. Here's an excellent procedure on how to set the idle. Much easier to follow and better illustrations than most shop manuals.... http://www.vfaq.com/mods/BISS-1G.html

"Guv Bob" wrote in message m...
Thanks folks for the help. It's running much better but still checking more sensors, etc.

Any idea what this part is? It has 4 leads that feed into the wiring harness and can't trace it any farther. Looks like a solenoid but can't find it in Haynes or other manuals I have.
Not sure if the first photo took, so uploaded it again...

http://imageshack.us/photo/my-images/833/dsm1g20.jpg/
http://img593.imageshack.us/img593/8655/dsm1g20.jpg

Sorry for posting in the alt.home. repair group, but it's the about the best repair newsgroup I've found - alt.autos, and mitsubishi are dead.

Thanks again.

Bob


"gregz" wrote in message ...
"Guv Bob" wrote:
My 1990 Mitsubishi Eclipse (DSM 1G 2L non-turbo) is starts and idles cold
fine, and runs fine warmed up. When warm and I put it in neutral (AT)
the idle oscillates between 1800 and 2200 with about 1/2 second cycle time.

MAS was the first guess -- so I put a rebuilt mass airflow sensor assy in
and same problem. Checked all the connections and vacuum - all OK.

Also took the throttle assy apart and cleaned all - helped the running
but still oscillating. Cleaned Idle air motor, checked voltages and
resistance for all sensors and also voltages coming from the computer, and all OK.

About out of ideas -- anyone have some thoughts on how to start troubleshooting this?

Thanks in advance.

Bob

I don't know the car. Is it possible to read computer, if it has one. I'm
thinking of idle motors, oxygen sensor, manifold leak, ....

Greg