KA24DE help in Los Angeles????

[finn]

Thats cold sitting still or after a twenty minute drive?

[oaklandsyd]

Hot , Cold, and warmed & revved according to the FSM... I've tried them all.

No codes flashing. All sensors in normal tolerances (The TPS is 1.5ohms closed, 9.5 open...can't imagine that would be the main issue, as the resistance gap is the same as the FSM 2 to 10. I could be wrong....).

It runs *mostly* fine. I'm happy with it, but just can't help but think that something is not right. Plus I'd like it to get decent mileage on the upcoming adventure...

[finn]

you need to be a little more discriptive in your diy troubleshooting methods, just so that were not asking tons of questions.

after i replaced some of the components on my valve, i adjusted it full down. started the car, watched the rpm started around 2K, drop to 1,5k, but didn't go much further than that. it wasn't til i took it on a nice drive around town and stopped at a redlight to notice that it would then come to rest at 8 or 900 rpm.

when you pinch the inlet hose by the throttle body, does it drop to 750?

[okayfine]

No matter what I do, I CANNOT get the IACV to adjust idle down to 750.

Reconnect the TPS it idles fine at 750ish.

I'm confused.

[oaklandsyd]

Sorry for the lack of description enough, kinda figured you'd guess I was using the FSM ignition timing and idle adjustment procedures, and not just... guessing.

According to the holy FSM, you unhook the TPS when adjusting the IACV screw and the engine timing. It should adjust down to 750rpm at 20 BTDC. Then you reconnect the TPS.

Mine never gets down that low with the TPS unhooked. ever. With the TPS unhooked and the IACV fully closed, it sits around 1200rpm at 20 BTDC.

Once the TPS is hooked up, it drops to 750rpm, but it will backfire from time to time and runs a bit rich. Makes me think something is not right in some other system, maybe I still have a secret vacuum leak, or it's not something to even worry about (though it isn't running all that well right now).

[okayfine]

Gotcha. No, that's not normal. Should run lean if there's a vac leak. I don't recall having much of any luck adjusting the IACV when I had my KA. The ECU would do whatever it wanted. I'll dig around the FSM...

[oaklandsyd]

I can't really find anything, other than references to vacuum leaks. I don't know what else would cause high idle with the TPS unhooked.

Could it be an engine-side issue? air leak in the valves? should I check the compression? Just lobbing ideas out there, it'd be nice to have an idea of things to look for.

[okayfine]

What happens if you take the IACV out of the system and just crack the throttle plate with the screw (if I'm correct in remembering there was a screw on the throttle shaft)? Do you have a spare known-good TPS?

Vac leak and running rich don't make sense to me. Vac leaks suck in air, but sucking in unmetered air would make it run leaner, and having a leak before the MAF isn't possible.

[oaklandsyd]

I'll take IACV out of the loop tonight and see what happens. The one thing I haven't done is run it with all the emissions sensors unhooked. and plug things back in one at a time.

Worst case, I may do a delete of the idle system and just run idle off the throttle. but that won't really solve the problem that I can't find...

[oaklandsyd]

OK. updates. Following FSM instructions.

TESTS

Test 1: Pinching IACV-Air Regulator hose when cold the engine dies. When warm, it does not die.
Test 1a: Pinching IACV-AAC Valve hose when warm or cold the engine dies.
Test 1b: Pinching off the Breather Hose did nothing.

Test 2: When engine is cold, and the gas pedal fully depressed, does the car start? Yes, but it was definitely more difficult than a normal start. It struggled, but eventually did.

Test 3: Disconnect IACV Valve (Brown plug), does Idle drop? YES

Test 4: Unplugging the IACV-Air Regulator when warm, did nothing.

Test 5: (This one was a long shot, but I was replicating someone else's solution from zilvia.net) Unplugged both IACV and TPS., then checked Timing and idle checked idle. Both were way off, so I reset to 20BTDC and 750rpm. When I plugged the IACV back in, and the timing changed to 40BTDC, ran at 1800rpm. I then plugged TPS back in, and the timing went to 10BTDC and 800rpm. In doing this experiment, I learned that the TPS is adjusting engine timing by 20-30 degrees, and the IACV is adjusting it about as much. I took this as a sign that it the IACV should be plugged in when adjusting timing and idle. When resetting everything back to FSM methods, and with everything hooked back up correctly, still having the same idling issues.

Test 6: Check Throttle and Throttle cable. All is good.

Test 7: Check TPS, IACV electrical. Everything as it should be in according to FSM.

Conclusions according to the FSM

1: Clogging somewhere
2: Power Balance/Injector issue
3: ECM issue
4: Random Electrical issue or bad connections

Personal Conclusions.
- Does anyone know what the timing should read with the TPS Plugged in?
- Still on the hunt for vacuum leaks.
- Could it be something with the Dizzy??
- Something more nefarious I can't even think of?

[oaklandsyd]

I just found this post at Fresh Alloy... http://www.freshalloy.com/archive/index ... 18274.html

Not only is the description identical to mine, but the guys name is Robert (mine). Weird.

The one response that caught my eye:

...adjust your timing and idle 700+-50rpm at the same time so they match when you reach 20deg +-2 deg. When you adjust the idle with the TPS unplugged it will also change the timing , so adjust idle down then move some timing move idle down a lil more again and adjust some more timing so they match in the end(20 +-2deg and 700+-50rpm). When you finish and have them both at the same time cut the car off and plug the TPS back in and crank and let sit for 1 min or so and race the engine to 2-3000 rpms a couple times and let it settle down to normal idle and check it with a gun should be right on 20 +-2 deg advance.

Is that true? If so, I've never done it that way, and it could explain a lot.... May have to try this tomorrow.

Lastly, is there a proper 'idle relearn' procedure?

[Three B's Racing]

Have you checked the voltage at the throttle position sensor at full closed and full open? I have a S14 SR20DE in my 510 and this is the procedure I use to set timing ya I know you have a KA24DE but it should pretty much be the same.

Here is the method as stated in the FSM:
1.Start engine and warm it up until engine coolant temperature indicator points to the middle of the gauge. Ensure engine speed stays below 1,000 rpm.
2.Run engine at about 2,000 rpm for about 2 minutes under no-load [this means turn off all accessories].
3.Rev engine two or three times under no-load, then run engine at idle speed for about 1 minute.
4.Turn off engine and disconnect the Throttle Position Sensor (TPS) The TPS is shown in the image to the left. It is the plug that is on top (brown). An SE-R mailing list member told me that only the 1998 and 99 models come with two plugs. If you have a pre-1998 model you should only have one plug. That will be your TPS.
5.Start engine. Rev engine (2,000-3,000 rpm) 2 or 3 times under no-load [This will lock the engine in timing mod]. Let engine run at idle speed

Alternate Timing Method:

This procedure is a lot simpler than the one listed in the FSM. Warm up the car to normal operating temperatures, disconnect the TPS while the car is still running, rev the engine three times to about 3,000 rpm to lock in the engine in timing mod, then adjust the timing. I like this procedure and I will use it in the future.
While the TPS is still disconnected, you can check your idle speed. The FSM recommends setting your base idle (with TPS disconnected) to 750 rpm. To adjust your base idle turn the idle speed adjusting screw to your left. After your done reconnect the TPS.
>>>>

Lou

[oaklandsyd]

Yep. Definitely done all that a half dozen times or so...

I'm thinking there may be something obvious I'm missing, or something outside the IACV and TPS systems that is throwing this all off (Even though I can get the engine to run well with both unhooked).

[oaklandsyd]

Found two vacuum leaks with the help of a Sweet Swisha!

Still holding my breath that its the problem, because one of the leaks is the tiny hose up under the intake. (see attached img...).

Yikes. that will be a knuckle buster. I replaced the back most one, which has some clearance and it was still a nightmare.

Repairing, testing, and trying again.

Anyone know what the timing of the motor is when the TPS is hooked up? just for a reference. Want to have all my notes in order.

[oaklandsyd]

I *THINK* it's fixed. After patching the vacuum leaks, I ran the standard process and the idle was still high. Freaked out, and then did a bit of breathing and research...

That is when I found this similar problem posted at the SR20 Forum. http://www.sr20forum.com/technical-info ... -idle.html

Half way down, I found this suggestion...

Are you unplugging the iacv? If not ,unplug the brown connector on it and adjust idle to 1200 with tps unplugged. Then shut car off and plug iacv/tps back start car let it stabilize idle then unplug tps for a minute or two plug back in . I have dones this with s3's to stabilze idle a 1k rpms to reduce lope. Hope it works for you.

Tried it and holy hell. it worked. The IACV is now allowing me to dial it down below 1000rpm!!

Here is what I did:
1. Warmed up the car, did the standard timing adjustment phases, ran at 2k rpm for 2 mins, raced the motor 3 times, so on.
2. Turned the car off, unplugged Brown IACV plug and the TPS.
3. Tried to start the car, but the IACV was so closed off that it wouldn't start. Opened it up a few turns. Started the car. It ran about 1000-1200 rpms
4. Let it run for a little while, and then raced it a couple times to see if the idle would stabilize any lower.
5. Shut the car off, plugged in IACV and TPS. Turned the car on, ran it for a minute, then unplugged the TPS.
6. Sat for a minute. As it was sitting it started to settle in a bit lower than it was previously running. I screwed the IACV in further and it dropped down!
7. So I dialed the IACV in, revved it a bit, let it settle, then hooked up the TPS.
8. Everything ran as normal, revved again and it settled in fine. Let it run for a couple minutes and turned it off.

I'm going to run it a bit and keep an eye on it. See what happens next. Not going to press my normally shitty luck.

I'm guessing that the ECM sets a baseline airflow through the IACV, and by unplugging the brown plug and the TPS, then setting the Idle adjustment screw about half way, then plugging the Brown IACV and TPS connectors back in resets the baseline or something. Whatever the hell happened got it to drop down to where it should be. (though it could have been a combination of several things, like fixing the vacuum leak...)

Next headache... Rear wheel bearings.