Do you have a pocket logger. Check to see if the throttle is open any. There is an adjustment for the cable on the intake mani. Also have you checked your BISS?(base idle set screw)

 

I do not have a logger.

Throttle is not stuck open. Cranked in the BISS. I pulled the ISC, but I am not certain how this thing works. I assume I should be able to turn it with my hand, but I cannot do anything to it. Can anyone tell me if I should be able to turn this moto?

 

Here are more symptoms (by the way, this is a 93 Eclipse 2.0 Non-Turbo)

The idle has gone up to 5000. If I let it run for awhile, it will stay at 5,000 but occassionally dip down to about 3 for half a second. Then it shoots back up.

I disconnected the ISC Motor, and it seems to dip a little more frequently. If it was the ISC, shouldn't disconnecting it completely take away the high idle? I hate spending $250 "guessing" it is the ISC...

 

Here are more symptoms (by the way, this is a 93 Eclipse 2.0 Non-Turbo)

The idle has gone up to 5000. If I let it run for awhile, it will stay at 5,000 but occassionally dip down to about 3 for half a second. Then it shoots back up.

I disconnected the ISC Motor, and it seems to dip a little more frequently. If it was the ISC, shouldn't disconnecting it completely take away the high idle? I hate spending $250 "guessing" it is the ISC...

To determine if the IAC is bad, remove it from the intake, plug the connector back into it, lay it on top of the engine, turn the ignition to the 'on' position (don't start the car). If the IAC rattles, shakes and clicks, it's bad. If you see the brown colored tip rotate and move in and out smoothly, it's good.

I don't think that this is your problem, though. take the intake pipe off at the throttle body and check to see that the throttle plate is completely closed. Simple stuff first.

 

To determine if the IAC is bad, remove it from the intake, plug the connector back into it, lay it on top of the engine, turn the ignition to the 'on' position (don't start the car). If the IAC rattles, shakes and clicks, it's bad. If you see the brown colored tip rotate and move in and out smoothly, it's good.

I don't think that this is your problem, though. take the intake pipe off at the throttle body and check to see that the throttle plate is completely closed. Simple stuff first.

When I turn the ignition on, it clicks and wants to move. But it doesn't. I have to turn the ignition on/off 10 times to even see this motion. Is it fried?


Let me recap other stuff too:

1. ISC Motor - was not turning. I pulled and turned by hand. Now rotates. Resistance between 1-2 and 2-3 is abt 30 ohms. 4-5 and 5-6 I get NOTHING.
2. TPS Resistance across 1-4 is 5200 ohms. 2-4 varies as throttle moves.
3. Throttle is not stuck open. Throttle plate is closed.
4. IPS - continuity with ground is good. Swapped with VR4 and it made no difference.
5. Disconnect Intake Air Tempare sensor. No difference. Disconnect ISC Motor, and idle drops more frequently (down to 3,000 for about half second approx every 20-40 seconds

 

Sounds like the IAC is junk. That, or the ecu is whacked. From what I've seen, they usually replace the ecu along with the IAC. I got lucky, I only replaced the IAC. My motor wasn't idling at 3k+, though.

Go here: http://www.foreignecurepair.com/iscmotors.asp

Is the 'Check Engine' light on?

 

The check engine light comes on when it is up around the 5,000 rpm mark. When it dips momentarily, the light goes out. You can smell the exhaust so I am certain it is functioning appropriately.

How can I tell if the entire computer is dead?

And, how can I read "codes" about what the computer thinks is wrong?

 

The check engine light comes on when it is up around the 5,000 rpm mark. When it dips momentarily, the light goes out. You can smell the exhaust so I am certain it is functioning appropriately.

How can I tell if the entire computer is dead?

And, how can I read "codes" about what the computer thinks is wrong?

Go buy a 12v buzzer from radio shack and hook it up to the mpi diagnostic port. Here is the link for how to do it.

http://www.myzero.com/electrical/code.html;)

 

Well, we know the ISC isn't working. A new ISC is cheaper than a rebuilt ECU so I'd go that route first. If the caps haven't been replaced in the ECU it is possible that it is toast.

Still, to have a 4000 to 5000 rpm idle means a lot of air is getting into the engine. I suspect maybe the BISS is missing its o-ring or maybe the throttle stop (IPS) is set to hold the throttle too far open. This kinda sounds like a car that has been tinkered on some and is now all out of adjustment.

See the VFAQ for instruction on how to set the idle.

 

There is no way that a defective ISC valve would cause an idle as high as 5000 rpm. I'm guessing his throttle plate isn't closing all the way, as stated earlier by someone.

 

I agree with barney. It sounds a lot to me like a leak around the BISS. Correct me if I'm wrong, but doesn't the biss have to be backed OUT to lower the idle? You said it was turned all the way in. It could be in addition to a dead ISC, but I've never seen an idle go that high from one dying.

 

I agree with barney. It sounds a lot to me like a leak around the BISS. Correct me if I'm wrong, but doesn't the biss have to be backed OUT to lower the idle? You said it was turned all the way in. It could be in addition to a dead ISC, but I've never seen an idle go that high from one dying.

nope. you turn it in to lower it. but, even if you take it completely out, there is NO WAY that sucker can rev to 5000. that's a LOT of air, esp with a n/a. i agree with the throttle plate being stuck open.

 

The throttle is NOT stuck open. Although the sensor readings were okay, I took the throttle body off and scrubbed everything with a toothbrush. I disconnected the idle position sensor, and completely pulled the ISC. I was able to get it to "idle" around 2800 rpms (even with all the air sucking through the ISC hole).

I know of an ISC I can get at a junkyard on Monday, so I will replace it then.

In the meantime, I am going to go back in and pull the timing belt. I put it on a little looser this time (I have been eating through them with as tight as I have been putting them), and I forgot to turn the motor over by hand a few times after installing it. So it is possible that it slipped a tooth. With this high of an idle, I have been unable to test the timing...

Thanks for the tip about the buzzer for the computer. If I can get the check engine light to come back on, I will get a buzzer!

Any other ideas?

 

As for getting the timing belt too tight, that shouldn't be possible if you are measuring for the correct rod protrusion at the hydraulic tensioner.

 

Another thing to check is the idle switch. The switch should be screwed in until the switch makes (you need a multimeter - buy one with a meter and you can use it for ECU codes too) and then 15/16ths turns more in.

 

Update:

After ripping apart the car and checking the timing belt tension, I replaced the tensioner, and put it together. It was idling about 2500 RPMs without the idle sensor or ISC motor connected.

While driving to the junkyard, the water pump went out (I did not have a clue it was in bad shape as it seemed to turn normally and was not leaking). The pump was maybe 2 years old...

I did pick up an ISC at the junkyard for $10 (much better than the $250 the dealer wants). As soon as I have a minute, I will rip the thing apart again, put in a new water pump, redo the timing belt, reassemble, and see what happens.

The idle sensor is definitely my next place to attack if the idle does not come down more.