KA24 Timing/High Idle

[Karlitos]

So the car has been running alright. Except the idle is very high. It has a very stable idle at 2000rpm. No bouncing around, no sputtering, no nothing. I messed with the IACV screw (without unplugging the TPS, i didnt know) and i got idle down to 1500. I was still not happy so I did more searching, and decided to check timing. I had done timing not too long ago, again without disconnecting the TPS, and I had set it to 20* BTDC and it was still there.

So trying to do an Idle/Timing fix, i searched up to find that the TPS should be unplugged. Steps I did today:

1)Started the car, let it warm up.
2) Turn car off
3)Unplug TPS
4) Turn car on.
5) Set idle to 1500ish (its as low as the IACV screw would let me go)
6) Set timing to 20* BTDC (TPS off).
7) Turn car off.
8) Plug TPS back in
9)Restart car, idles at 900ish.
10) Rechecked timing with TPS and it went to 5*ATDC.

My question: Is this normal? Im kinda lost to why timing moved so much when plugging tps in. I had the TPS voltage checked not too long ago, and it checked out.

[cotbu]

You didn't lock the timing in!
Revving the engine 3x to 3000rpm locks the timing.
Now that you got the idle to be more conservative, do it all over again!
Fun isn't it?

[Karlitos]

You didn't lock the timing in!
Revving the engine 3x to 3000rpm locks the timing.
Now that you got the idle to be more conservative, do it all over again!
Fun isn't it?

So rev it after getting it at 20*BTDC with TPS off. Turn car off, Plug Tps in, then it should stay?

Im a linear thinker and need to see shit like that to make sense.

[cotbu]

Well me telling you, that yes that's correct, will not make any sense to you. so now what?
PS, if you messed with the timing chain by moving it to fix that other problem you had, don't even try setting the timing if your mechanical timing is wrong.

sounded better in my head

PPSS, if you're using consult to set timing or idle you don't have to rev or lock it down.

[Karlitos]

Well me telling you, that yes that's correct, will not make any sense to you. so now what?
PS, if you messed with the timing chain by moving it to fix that other problem you had, don't even try setting the timing if your mechanical timing is wrong.

sounded better in my head

I meant, I needed to see steps laid out to make sense. Lol. Wasnt sure where I needed the revs, since others say rev before unplugging, which i had done.

Ill give it a try... Mechanical timing is spot on. Ive checked it already. I had gotten the dizzy to give me 20*BTDC, i just didnt disconnect the TPS. The idle was at 2000 so now I was trying to fix that when these results came out. The timing was still at 20* before unplugging the TPS and playing with it today. Gonna go check, and report back.

[cotbu]

When I used to do KA's alot, I would rev to lock it into timing mode and after I set the timing or idle.
It worked, so that's how I do it with out consult, every time. You may find a different way that works better for you.

[Karlitos]

So revving it to 3k didnt work.

Im have 2 options to leave it at.
1) Time at 20*BTDC with TPS off. Replug TPS and get a normal 800rpm idle but 5*ATDC timing. If I rev with TPS on and let it sit, timing goes to 10*BTDC at idle for about 5 sec before going back to 5*ATDC.

or

2) time at 20*BTDC with TPS on, it'll stay there but idles at 1700ish.

My concern still stands: Should plugging the TPS move timing that much?

[cotbu]

NO!, rewrite your steps for setting timing so I can get a better idea of what you're doing.
Also I think you iavc is out of adjustment, what's your tps voltage?

I set ka's to idle at 750rpm, What is acceptable for you?
You don't have any major vacuum leaks, right?

[cotbu]

try unplugging the iacv, and setting the screw to about 50% then start the car, does it idle lower?

Leave the engine running when disconnecting the TPS, rev 3x to 3000rpm check timing, adjust, after timing/idle set rev 3x to 3000rpm plug in tps, while engine is running

I missed you were turning the car off in between.

[Karlitos]

NO!, rewrite your steps for setting timing so I can get a better idea of what you're doing.
Also I think you iavc is out of adjustment, what's your tps voltage?

I set ka's to idle at 750rpm, What is acceptable for you?
You don't have any major vacuum leaks, right?

Honestly, Ill take a steady idle under 1000rpm right now. Obviously something close to the stock 700rpms would be better. I do prefer to have timing dead on, if it means a 900rpm, over off timing and lower idle.

There is no vacuum leaks. After the EGR delete, everything was capped off properly. Ive checked in by listening and feeling for air around. Ill get to a more accurate carb cleaner check later.

I don't have a multimeter myself to check the TPS voltages, but it was checked a few weeks ago by a friend and it checked out. I don't remember the numbers exactly, though.

try unplugging the iacv, and setting the screw to about 50% then start the car, does it idle lower?

Leave the engine running when disconnecting the TPS, rev 3x to 3000rpm check timing, adjust, after timing/idle set rev 3x to 3000rpm plug in tps, while engine is running

I missed you were turning the car off in between.

I unplugged the IACV and set the screw halfway out. It idled at 1200ish, as soon as I plugged it back in, it went back to 1700.

I let the car warm up. unplugged TPS. revved to 3k, 3 times. lowered idle to 1100 (lowest it would go). Set timing to 20* BTDC. Revved to 3k, 3 times. Plugged TPS back in. Idle went down to 900, and timing to 0*.

So now what?


Anyone else care to chime in?

[cotbu]

What kind of timing light are you using? Hope it's not too fancy!
Tps does needs to be adjusted correctly.
Also make sure the throttle butterfly is closed.
That's all I got, other than get a multimeter and check voltages for all sensors including MAFS.
Sorry I couldn't help.

[Karlitos]

What kind of timing light are you using? Hope it's not too fancy!
Tps does needs to be adjusted correctly.
Also make sure the throttle butterfly is closed.
That's all I got, other than get a multimeter and check voltages for all sensors including MAFS.
Sorry I couldn't help.

The craftsman timing light, lol.

I thought there was no butterflies in s14's intake/tb's. If you mean the TB itself, then I have checked and its closed, with slack on the line so its not pulling it at no throttle.

Im just wondering if I should set it back to where it read 20* again, and leave it with a high idle, since most of my drives are long anyways and I dont idle much (besides too and from the hwy).

But it sounds like I'll need to get a multimeter, and adjust TPS for the next step.

No worries, anything helps. Thank you.

[cotbu]

I would probably set it to 20 or even 18 depending on how sure you are timing is correct.
I meant the throttle body itself. ;)

[Karlitos]

Went to radioshack, bought a multimeter. TPS/MAF/AAC/IACV all checked out in their respective voltages/reistances in respect to the FSM.

Back to timing. I have done searching and disconnecting the TPS, sets whats called base timing. And the reason you disconnect the TPS is because the ECU reads TPS and changes timing as the ECU sees fit.

So since there was no misfires, etc, i decided to reset timing (disconnect tps, rev, idle at 900, time at 20*, rev, connect tps) and again at idle timing went to 0*TDC.
I Revved the engine and as soon as the throttle opened the timing went to 20*, let it go back to idle and it went to 10*, then after a few seconds it went to 0*. I

had read in other searching that that was normal (double idle) so i figure its just the ECU retarding timing at idle for some reason. Its running at 20* when i open the throttle so I guess its fine? And the idle is now at 900 instead of 2000. So problem solved? lol

[project-D180]

great info,i was having that same issue a few months ago