Irradic idle.

[Gasolinebaptism]

These are the first few days the car has been running for 7 years.
It idled when I started it up the first time just fine, bt after I drove it around at all it would die when I pushed in the clutch, or stopped. Then yesterday morning I hopped in and it was just fine, there wasn't an issue, it idled 800-1000 rpm. then I drove it later in the day and it wouldn't idle again, after awhile of driving I got it to idle once again, I adjusted the screw on the throttle body for it to consistently idle, even if it's high. The next time I ran it, it idles around 2 grand, I was just thinking it was because I adjusted the TB, I drove it home last night with that idle. I started it this morning and she ran great, all day when I wanted to drive it was perfect, with idle high around 2 grand, but sometimes it would calm down to 750 or so. I figured it had worked out it's issues so I adjusted idle back down to were it was originally. I hopped in it to go to safeways and it didn't start til the third time I cranked it, I held it at 1500 for a few seconds then it seemed fine, made it to safeways, left safeways and went to the post office, when I pulled in at usps, it died, and I couldn't get it to idle on the drive home either, consequently dying whenever I stopped.
It'll probably do about the same thing in the morning, run perfectly until afternoon. It's a bit frustrating, and ideas on what I should do?

 

[2slow4now]

I know this is cleche but my car did the same thing erradict idle with something different with the idle every other time I drove it. Just to eliminate the possibility of crank walk I would check crank endplay to eliminate the idea that the dreaded crankwalk has struck. I know "it's a 6 bolt ie no crankwalk" but all engines can have crankwalk. Just for peice of mind I would look into the subject and eliminate that as a possibility then look into other possibilities.

 

[Gasolinebaptism]

Not only is it a 6 bolt but it's only got 98,xxx miles and is bone stock. I'm not worried about crank walk, but if you still want me to, I guess I can.

 

[2slow4now]

Well i would do it just for peice of mind. Our cars are known for it and the 6 bolt isn't immune to the possibility. Just a question did you push start it since it had been sitting for long? Low lube pressure at start can play havoc on the thrust bearing. Some guys even eliminate the clutch safety switch so they can start the car in neutral without engaging the clutch so no pressure is on the thrust bearing. It might be a good start before you try to track down an electronic demon or adjustment problem.

 

[Gasolinebaptism]

Well I never pushed it, but a couple times that it died when I was coming to a stop and it died I threw it back in fist and dropped the clutch, which is basically a push start, why?

And I read a thread recently about the new ECU to the car trying to figure out good settings for the car, so it changes setting until it finds the sweet spot?

 

[2slow4now]

I just wondered about the push start because the oil pump is not pumping when you depress the clutch so the clutch is pushing on the crank to the thrust bearing. low lube = metal to metal = grindy grindy.

Don't want to waste your time just looking for possibilities.

Haven't read about the new ecu yet.

 

[Gasolinebaptism]

Well it's not really a "new ecu." It's a rebuilt ecu from 1990 AWD, and I switched the pins, that's how I finally got it to start.
And supposedly the first few days after a memory wipe the ecu finds a sweet spot to run everything at. And possibly the ecu is adjusting to everything correctly, but the cars condition is changing so rapidly, because it's clearing out the gunk that has accumulated over the last 7 years, that the ecu can't keep up, and it goes to a good setting, but soon the setting isn't working because fuel is flowing better.

Or maybe the fuel pump is weak?

And I havn't changed the fuel filter.

 

[steve]

It sure sounds like a bad ISC or you IPS isn't telling the ECU the throttle is closed.
Hopefully during the rebuild they fixed all the ISC drivers. Did you just have it rebuilt?

You should measure all the ECU coils. Each should be about 28ohms and check that the IPS is grounding the green wire when the throttle is closed.

I've seen a lot of people who are missing the ground strap for the throttle body causing the IPS not to work.

 

[Gasolinebaptism]

Wasn't recently rebuilt, but recently got running w/ you help Steve, took a new ecu, CAS, and power transistor.

 

[steve]

Then the ECU is questionable. (and with some shops it could still be questionable even if you just got it back)

About half of the ECUs that come here have some sort of ISC problem, one or more traces open from the caps leaking or blown drivers. You can see and smell the bad ones. I can smell burnt electronics before I even open the package sometimes but others show no outward signs until I test the drivers.

Check the easy things first, and then move up the list. This doesn't sound like a ECU needs to learn the trims in order to idle kind of problem.

 

[Gasolinebaptism]

So you recommend checking the TPS first, then heading for the ECU.
Can you give me a layout of how to test the ecu?

What about the IAC? and BISS?

 

[steve]

So you recommend checking the TPS first, then heading for the ECU.
Can you give me a layout of how to test the ecu?

What about the IAC? and BISS?

I don't think I said TPS. You should check the IPS on the back of the throttle body to make sure it grounding when the throttle is closed.

Other than visually checking the ECU for a burnt up driver there's not much you can do. I've made special tools and software to allow me to exercise the drivers.

The instructions for measuring the ISC windings in it's coils are posted but here's it again.

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Measure the resistance between terminals 2 and 1, between 2 and 3, between 5 and 4, and between 5 and 6. The resistance should be in the range of 28 to 33 ohms for the original and older models, and ~40 ohms for the black plastic version.

The BISS adjustments are in the factory service manual that everyone should already have. http://www.dsmtuners.com/forums/fre...tions/344490-download-1g-service-manuals.html

You can't adjust the BISS until the ISC is functioning.

 

[Gasolinebaptism]

Okay, thankyou, and I also read on dsmisc.com that you can perform another test on this after testing resistance, and that is to apply a 6 volt battery, and listen for it to turn on, sounds pretty simple, I think I'll give that a shot afterwords. Thanks, It sounds like a start for the morning.

 

[steve]

It's a stepper motor not a DC motor so don't expect it to move very far when you hook the battery up. You have to power the windings in sequence to make it move in and out.

 

[Gasolinebaptism]

Well Steve, all ports that you told me to test are between 26.8 and 27 ohms. Now that's off, but is it so far off that it would put enough of a load on the ECU to function improperly?

 

[steve]

Well Steve, all ports that you told me to test are between 26.8 and 27 ohms. Now that's off, but is it so far off that it would put enough of a load on the ECU to function improperly?

It's just slightly out of spec but it depends on the temp when you measured. I wouldn't worry about the ISC which leaves the IPS, ECU, BISS and of course the TB itself.

 

[Gasolinebaptism]

What is the IPS?
It was cold when I measured it.
It didn't want to start this morning, I adjusted the BISS until I got it to idle, which was at about 500, then I adjusted it out to an 800 idle, right now, it's hot, and idles about 850, so that's pretty good right now. but when I left my sisters house an hour ago or so it didn't want to start, and when I got it going it idled 1500, then walked up to about 2300, I drove it, then it settled back down, but it was still hot when I tried to start it back up, it sat 20 minutes or so. and I will probably have the same problem if I try to start it again in a few.
I'll go measure it again.

measured hot, terminals all between 36.9 and 37.2 ohms.

 

[9!'clipseDOHC]

What is the IPS?

\
I'm sure he meant TPS, Throttle Position Sensor.

 

[steve]

IPS = Idle Position Switch
It's located on the back of the throttle body above the pulley. Looks like a bolt with a single spade connector on the top. It grounds the wire from the ECU when the throttle is closed.

http://members.shaw.ca/dsm.1000q/Engineprimer/1G/idleswitch.htm

To set the BISS you have to warm the car up then ground both the timing check terminals in the engine bay and the mode pin (#10) on the diagnostic connector by the drivers left foot and then adjust the BISS for a 750 RPM idle.

Have you downloaded the PDF's of the factory manual?

I'm sure he meant TPS, Throttle Position Sensor.

No I meant IPS.

 

[Gasolinebaptism]

Well he said IPS earlier, and when I asked about checking the TPS he said he didn't say anything about it, but I'm still leaning towards that, now I'm gonna read and figure out testing that, see where it get me.

 

[steve]

Well he said IPS earlier, and when I asked about checking the TPS he said he didn't say anything about it, but I'm still leaning towards that, now I'm gonna read and figure out testing that, see where it get me.

The TPS has nothing to do with idle on a 1G. It has nothing to do with surging on a 1G. You set it to read 0.5v and leave it alone unless it starts having drop outs and spikes when it moves.

 

[Gasolinebaptism]

I have downloaded manuals, and I read about adjusting the BISS the right way, but I was just attempting to get it in a state where it would run at all, and that I did.

 

[9!'clipseDOHC]

Sorry I thought thats what you were talking about, not the idle stop/position switch.

 

[Gasolinebaptism]

Okay, now how do I test the IPS?
And it sounds like it would be wise to take off the TB and clean out whatever gunk may be in there, say stuff that dried up in the bast 7 years, prevents the TB plate from always completely closing.

 

[steve]

There are two things to check.

The throttle body is supposed to have a ground strap from one of the mounting bolts to the top of the TB.

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And when the throttle is closed the IPS will ground the wire. When it's open the wire will have at least 5v on it and 0v when closed.