Honda Car Forum

When my 91 Integra is idling, the RPM's are going up and down from
1500-2200 RPM,....like it the car is breathing..... This started just
this weekend. Also noticed my temp gauge stopped working when this
weird idling began or maybe the weird idling started when the temp guage
stopped working. The temp needle stays on C, never raises to operating
temp. I also noticed the heater air temp, is not as warm/hot as it
normally is. The car runs fine other than the weird idling.

I suspect a faulty temp sensor/sending unit or a faulty thermostat,
causing the idle issue.

What do you think Tegger?....or anyone else.

THANKS!

B.Creech wrote:
> When my 91 Integra is idling, the RPM's are going up and down from
> 1500-2200 RPM,....like it the car is breathing..... This started just
> this weekend. Also noticed my temp gauge stopped working when this
> weird idling began or maybe the weird idling started when the temp guage
> stopped working. The temp needle stays on C, never raises to operating
> temp. I also noticed the heater air temp, is not as warm/hot as it
> normally is. The car runs fine other than the weird idling.
>
> I suspect a faulty temp sensor/sending unit or a faulty thermostat,
> causing the idle issue.
>
> What do you think Tegger?....or anyone else.
>
> THANKS!

------------------------------

As Groucho said: "Why, a four year-old boy could understand this".

Your reservoir and radiator are mostly empty. Don't drive it anywhere or
you might crack your head. Fill them both with Honda premix and then
keep topping up the reservoir to the MAX mark for a couple more mornings
until is stops 'sipping' coolant as the AIR is purged. It will solve
your immediate problems. There's more to purging air from a '91 Teg, but
this will get you out of the woods.

'Curly'

motsco_ wrote:
> B.Creech wrote:
>> When my 91 Integra is idling, the RPM's are going up and down from
>> 1500-2200 RPM,....like it the car is breathing..... This started
>> just this weekend. Also noticed my temp gauge stopped working when
>> this weird idling began or maybe the weird idling started when the
>> temp guage stopped working. The temp needle stays on C, never raises
>> to operating temp. I also noticed the heater air temp, is not as
>> warm/hot as it normally is. The car runs fine other than the weird
>> idling.
>>
>> I suspect a faulty temp sensor/sending unit or a faulty thermostat,
>> causing the idle issue.
>>
>> What do you think Tegger?....or anyone else.
>>
>> THANKS!
>
> ------------------------------
>
> As Groucho said: "Why, a four year-old boy could understand this".
>
> Your reservoir and radiator are mostly empty. Don't drive it anywhere or
> you might crack your head. Fill them both with Honda premix and then
> keep topping up the reservoir to the MAX mark for a couple more mornings
> until is stops 'sipping' coolant as the AIR is purged. It will solve
> your immediate problems. There's more to purging air from a '91 Teg, but
> this will get you out of the woods.
>
> 'Curly'

I guess I should have mentioned, I check the obvious Friday when the
symptoms started. The radiator and resevoir are full.

B.Creech wrote:
> I guess I should have mentioned, I check the obvious Friday when the
> symptoms started. The radiator and resevoir are full.

-----------------------

Then it must be just AIR, since the sensors have to be immersed or they
will give the symptoms you describe. Are you sure nobody has been
working on your cooling system recently ?

'Curly'

"B.Creech" <bcreech61@nc.rr.com> wrote in news:47f030c6$0$1110
$4c368faf@roadrunner.com:

> When my 91 Integra is idling, the RPM's are going up and down from
> 1500-2200 RPM,....like it the car is breathing.....



Only when hot, right?



> This started just
> this weekend. Also noticed my temp gauge stopped working when this
> weird idling began or maybe the weird idling started when the temp guage
> stopped working. The temp needle stays on C, never raises to operating
> temp. I also noticed the heater air temp, is not as warm/hot as it
> normally is. The car runs fine other than the weird idling.
>
> I suspect a faulty temp sensor/sending unit or a faulty thermostat,
> causing the idle issue.



I'd suspect a faulty thermostat before anything else.

The ECU and the dash gause use different sensors. It would be unlikely for
both to fail at teh same time.

Try replacing the thermostat with new OEM. Do not use aftermarket.

As for the dash gauge... the sender is a single-wire unit under the
distributor. Make sure that's hooked up and the wire isn't broken.

Fluctuating idle can also be caused by neglected coolant changes. The Fast
Idle valve sticks open, leading to excessive air when hot. There is a way
to test for that.



--
Tegger

The Unofficial Honda/Acura FAQ
www.tegger.com/hondafaq/

motsco_ <motsco_@interbaun.com> wrote in
news:13v0ger2vt0cm49@corp.supernews.com:


>
> Your reservoir and radiator are mostly empty.



This affects idle only on Accords and Preludes and other F-series engined
cars on account of the system's design.



--
Tegger

The Unofficial Honda/Acura FAQ
www.tegger.com/hondafaq/

No. I first dicovered the issue Friday when I went to lunch. Cranked
the car....cold... up and down idling. When car gets hot, no
difference. HOwever once, while driving the weekend, I noticed the temp
needle had started working and was registering normal operating temp.
When I stopped at stoplight, car idled normal.

This temp gauge starting to work only occurred once all weekend.

Tegger wrote:
> "B.Creech" <bcreech61@nc.rr.com> wrote in news:47f030c6$0$1110
> $4c368faf@roadrunner.com:
>
>> When my 91 Integra is idling, the RPM's are going up and down from
>> 1500-2200 RPM,....like it the car is breathing.....
>
>
>
> Only when hot, right?
>
>
>
>> This started just
>> this weekend. Also noticed my temp gauge stopped working when this
>> weird idling began or maybe the weird idling started when the temp guage
>> stopped working. The temp needle stays on C, never raises to operating
>> temp. I also noticed the heater air temp, is not as warm/hot as it
>> normally is. The car runs fine other than the weird idling.
>>
>> I suspect a faulty temp sensor/sending unit or a faulty thermostat,
>> causing the idle issue.
>
>
>
> I'd suspect a faulty thermostat before anything else.
>
> The ECU and the dash gause use different sensors. It would be unlikely for
> both to fail at teh same time.
>
> Try replacing the thermostat with new OEM. Do not use aftermarket.
>
> As for the dash gauge... the sender is a single-wire unit under the
> distributor. Make sure that's hooked up and the wire isn't broken.
>
> Fluctuating idle can also be caused by neglected coolant changes. The Fast
> Idle valve sticks open, leading to excessive air when hot. There is a way
> to test for that.
>
>
>

Tegger <tegger@tegger.c0m> wrote in
news:Xns9A7243DA29FC1tegger@207.14.116.130:

> "B.Creech" <bcreech61@nc.rr.com> wrote in news:47f030c6$0$1110
> $4c368faf@roadrunner.com:
>
>> When my 91 Integra is idling, the RPM's are going up and down from
>> 1500-2200 RPM,....like it the car is breathing.....
>
>
>
> Only when hot, right?
>
>
>
>> This started just
>> this weekend. Also noticed my temp gauge stopped working when this
>> weird idling began or maybe the weird idling started when the temp
>> guage stopped working. The temp needle stays on C, never raises to
>> operating temp. I also noticed the heater air temp, is not as
>> warm/hot as it normally is. The car runs fine other than the weird
>> idling.
>>
>> I suspect a faulty temp sensor/sending unit or a faulty thermostat,
>> causing the idle issue.
>
>
>
> I'd suspect a faulty thermostat before anything else.
>
> The ECU and the dash gause use different sensors. It would be unlikely
> for both to fail at teh same time.
>
> Try replacing the thermostat with new OEM. Do not use aftermarket.
>
> As for the dash gauge... the sender is a single-wire unit under the
> distributor. Make sure that's hooked up and the wire isn't broken.
>
> Fluctuating idle can also be caused by neglected coolant changes. The
> Fast Idle valve sticks open, leading to excessive air when hot. There
> is a way to test for that.
>
>
>

on my 94 Integra GS-R,I had to replace both thermostat and ECT;the temp
sensor(on the thermostat housing) ohmed out as open.
My dash temp gauge read fine.

--
Jim Yanik
jyanik
at
kua.net

Jim Yanik wrote:
> Tegger <tegger@tegger.c0m> wrote in
> news:Xns9A7243DA29FC1tegger@207.14.116.130:
>
>> "B.Creech" <bcreech61@nc.rr.com> wrote in news:47f030c6$0$1110
>> $4c368faf@roadrunner.com:
>>
>>> When my 91 Integra is idling, the RPM's are going up and down from
>>> 1500-2200 RPM,....like it the car is breathing.....
>>
>>
>> Only when hot, right?
>>
>>
>>
>>> This started just
>>> this weekend. Also noticed my temp gauge stopped working when this
>>> weird idling began or maybe the weird idling started when the temp
>>> guage stopped working. The temp needle stays on C, never raises to
>>> operating temp. I also noticed the heater air temp, is not as
>>> warm/hot as it normally is. The car runs fine other than the weird
>>> idling.
>>>
>>> I suspect a faulty temp sensor/sending unit or a faulty thermostat,
>>> causing the idle issue.
>>
>>
>> I'd suspect a faulty thermostat before anything else.
>>
>> The ECU and the dash gause use different sensors. It would be unlikely
>> for both to fail at teh same time.
>>
>> Try replacing the thermostat with new OEM. Do not use aftermarket.
>>
>> As for the dash gauge... the sender is a single-wire unit under the
>> distributor. Make sure that's hooked up and the wire isn't broken.
>>
>> Fluctuating idle can also be caused by neglected coolant changes. The
>> Fast Idle valve sticks open, leading to excessive air when hot. There
>> is a way to test for that.
>>
>>
>>
>
> on my 94 Integra GS-R,I had to replace both thermostat and ECT;the temp
> sensor(on the thermostat housing) ohmed out as open.
> My dash temp gauge read fine.
>

I was mistaken when I replied earlier the problem occurred when the
engine was cold also. Today I have found that the bouncing idle issue
only occurs after the engine gets warm a few minutes after starting, at
the same time the temp gauge is not working...reading C. Again today the
temp gauge started working while I was driving. When I came to a stop,
the car idled just fine. That is the second time I have seen this happen.

I am still inclined to believe the temp guage not working is related to
the bouncing idle issue. I guess I can start by replacing the
thermostat, probably the cheapest place to start

The coolant was changed in the vehicle about 6 months ago when I had the
timing belt and water pump replaced, so no coolant neglect.

Jim Yanik wrote:
> Tegger <tegger@tegger.c0m> wrote in
> news:Xns9A7243DA29FC1tegger@207.14.116.130:
>
>> "B.Creech" <bcreech61@nc.rr.com> wrote in news:47f030c6$0$1110
>> $4c368faf@roadrunner.com:
>>
>>> When my 91 Integra is idling, the RPM's are going up and down from
>>> 1500-2200 RPM,....like it the car is breathing.....
>>
>>
>> Only when hot, right?
>>
>>
>>
>>> This started just
>>> this weekend. Also noticed my temp gauge stopped working when this
>>> weird idling began or maybe the weird idling started when the temp
>>> guage stopped working. The temp needle stays on C, never raises to
>>> operating temp. I also noticed the heater air temp, is not as
>>> warm/hot as it normally is. The car runs fine other than the weird
>>> idling.
>>>
>>> I suspect a faulty temp sensor/sending unit or a faulty thermostat,
>>> causing the idle issue.
>>
>>
>> I'd suspect a faulty thermostat before anything else.
>>
>> The ECU and the dash gause use different sensors. It would be unlikely
>> for both to fail at teh same time.
>>
>> Try replacing the thermostat with new OEM. Do not use aftermarket.
>>
>> As for the dash gauge... the sender is a single-wire unit under the
>> distributor. Make sure that's hooked up and the wire isn't broken.
>>
>> Fluctuating idle can also be caused by neglected coolant changes. The
>> Fast Idle valve sticks open, leading to excessive air when hot. There
>> is a way to test for that.
>>
>>
>>
>
> on my 94 Integra GS-R,I had to replace both thermostat and ECT;the temp
> sensor(on the thermostat housing) ohmed out as open.
> My dash temp gauge read fine.
>
Hey guys, could it be bad or dirty IACV?