1995 Integra fine when cold, runs bad when warm?: Grassroots Motorsports forum: Grassroots Motorsports Magazine

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May 4, 2009 12:55 p.m. TreoWayne New Reader

I am trying to troubleshoot my brother's 1995 Acura Integra SE (non-VTEC motor, 5-speed, 180k miles). The car runs fine when it is cold, idles at about 1500 rpm.

Once the car is fully warmed up the idle drops to about 500 rpm and the car runs poorly. The idles but it dies if you give it a bunch of throttle all at once. Once you get moving the engine will kind of surge and it will run fine again.

My first thought is throttle position sensor. I don't want to buy a new sensor since it only comes as a whole throttle body assembly ($$$). I don't want to throw parts at this car without knowing what is really wrong.

Help?
May 4, 2009 1:11 p.m. Strizzo Dork

sounds like it could be o2 sensor. if its a non-heated sensor, then the ecu won't use it until a certain coolant temp, or something. a single wire replacement should run around $20 and even if its not the problem, if its never been changed its not a bad idea.
May 4, 2009 1:15 p.m. TreoWayne New Reader

The CEL is not on btw.
May 4, 2009 1:17 p.m. warpedredneck New Reader

could also be the coolant temp sensor, check resistance cold then hot a manual would be helpfull it will tell you what reistance you should have at what temps. hth's
May 4, 2009 1:21 p.m. 4cylndrfury HalfDork

Idle air control valve...do hondas have those?
May 4, 2009 1:57 p.m. 93celicaGT2 Dork

4cylndrfury wrote:

Idle air control valve...do hondas have those?

Yes. They always break. Always. No exceptions.
May 4, 2009 2:54 p.m. alfadriver Reader

93celicaGT2 wrote:

4cylndrfury wrote:

Idle air control valve...do hondas have those?

Yes. They always break. Always. No exceptions.

Good to know Honda makes only quality parts...

I'd also vote for O2 sensor (outside of the POS idle valve), since they change state from hot to cold. If the heater is bad, it will try to go closed loop early, and very, very badly.

And OBD 1 cars may not light a light depending on the O2 sensor failure- say if the heater dies, it may not light that light (that's what I'm actually suspecting).

Eric
May 4, 2009 2:57 p.m. John Brown SuperDork

Coolant temp sensor then O2 sensor are my votes.
May 4, 2009 3:08 p.m. mad_machine SuperDork

does honda have a cold start valve?
May 4, 2009 7:38 p.m. Jrodsvt None

Well do you know anybody with a scanner for Honda's? Like an OTC, snap on, or any generic OBD scanner. Something that can get you values from the TPS, Coolant, O2, Idle air control, and MAP sensors.

Otherwise I can see if I can find ways for you to test the sensors your self. do you have a Digital Volt and Ohm Meter? This could help you a lot.
May 4, 2009 8:02 p.m. mad_machine SuperDork

hang on....

could this a vacuum leak. When cold the computer will give it more fuel.. when hot, it cuts back to normal, which makes it run too lean and it then stalls
May 5, 2009 8:56 a.m. 93celicaGT2 Dork

Have you or he messed around with anything on the car lately?
May 5, 2009 9:55 a.m. TreoWayne New Reader

It turned out to be a lot simpler than all of that. I finally got some tools around the car so I pulled the spark plugs out. Three plugs looked fine, one plug was covered with black soot. I inspected the ignition wires and the wire for the black spark plug had a hole burned through the boot.

I bought new plugs and wires and the car runs like a champ now. Problem solved. Thanks for the replies.

I think the high idle when cold was partially masking the symptoms of the bad plug wire.
May 5, 2009 11:10 a.m. psychic_mechanic Dork

Had a similair problem this weekend with an engine swap. After a lot of head scratching it turned out the original 113k mile platinum plugs and wires were marginal and the engine would run fine cold, but sputter to a stop when it warmed up.

Don't forget the simple stuff, we were sure it was a sensor or wiring problem putting an OBD-II engine in a pre-WWII car.
May 8, 2009 11:49 a.m. CivicSiRacer Reader

My problem sounds like yours and Honda diagnosed mine as IACV (Idle Air Control Valve). This valve is responsible for the correct idle at a stop. When the throttle body is closed it opens a loop to keep the air going into the engine to prevent it from stalling. It's coolant actuated if I remember right, since there is a coolant line going into it.

I get the same problem when warm, surging idle at stop, there's a dead spot for me from 2500-3000 and the car finally goes.

The one tech said the valve is sticking because of age. Really easy to replace, just to lazy to buy and do it :)
May 13, 2009 1:55 p.m. TreoWayne New Reader

Well the spark plug wires were bad and putting in new plugs and wires made the car idle and run great.

Last Saturday I was driving the Integra over to my mom's house to change the oil and replace the stuck-open thermostat. I was about six blocks from home when I heard a weird noise and the car lost power.

I pulled into a Burger King parking lot and checked under the hood. There was a hole in the valve cover where the timing belt was. Inside the hole I could see that the belt was starting to come apart.

I had the car towed to my mom's house, pulled the valve cover off and took a look. It looked like the cams stayed in time.

I tore the side of the engine down for a t-belt swap. Everything was going well until I took the cam pulleys off for better access to the water pump. When I put one of the cam pulley bolts back on I overtorqued it and broke the bolt off inside the cam.

I was able to get the bolt extracted with a reverse drill bit. My brother and I found an identical replacement bolt in a junkyard 1990 Accord.

We put the water pump, t-belt and crank pulley back on and gave the car a test start. It started right up and went into a nice smooth idle.

It has been raining the last couple days so I still have to replace the timing covers and accessory belts and give the car back to my little brother.
May 18, 2009 4:31 p.m. TreoWayne New Reader

After replacing the belt the car now runs great.

I am putting a timing belt in my wife's 2000 Accord EX 4cyl and the mother-effin crank pulley bolt won't come loose with my air impact gun or my friend's megapower Snap-On electric impact.

I ordered the special Honda crank pulley holder tool so hopefully that will allow me to do the job on this Accord.
May 29, 2009 12:02 p.m. TreoWayne New Reader

I got the special Honda crank pulley holding tool and put it to use.

I had an 18" 1/2" breaker bar connected to the crank holder and a really big 1/2" ratchet with an 18" handle on the bolt. That wasn't enough torque so I had a 4-way tire iron hanging on the end of the ratchet for more length.

I thought the tire iron or the ratchet were going to explode from stress, but they held on and got the bolt loose.

2000 Honda Accord won't need another timing belt until 2015.