Not able to set idle very high and keep it

[Horror Angel]

1. When in diagnostics, it seems like i am maxing out at like 780-840RPM on average.
2. when i do set to that, the car just adjusts back down to 580-780rpm average (which im trying to prevent 620 and below as it wants to and does stall).

Questions
1. How do i set it to higher than this to keep it above 700RPM when in gear, cause it drops about 100rpm in gear or so (wild guess on numbers there). Could this be fixed by simply turning the screw wile NOT in diagnostics mode?

2. How do i prevent the car from doing this "auto readjust" its doing?



I know, i should probably replace/mess with my TPS before asking eh? Its just that involves the multimeter and i tend to fry everything with that. Like several multimeters

[BLUEnoEQ]

I know it's not supposed to be funny... but the multimeter shit is funny. You probably just need to replace some multimeter fuses. Stop checking the amps of the battery alone and it probably won't happen.

As to the car idle, mine has been acting erratic lately too. In spite of checking the coolant,TPS being spot on, adjusting my distributor with obdII reader (replaced my bad ign coil,) and adjusting the idle screw. I got it down to a reasonable idle, at startup it still requires some prodding to keep er alive, found out my O2 sensor was disconnected and dangling as well. The next logical step is to check with any gypsies or voodoo witch doctors I may have come across to see if I have offended them in some way. Cross your fingers for me.

[NickR]

You could adjust your TPS using the "fan method". With the car in diagnostic mode, ignition on, engine off, the radiator fans should be off, but turn on when you open the throttle ever so slightly. (Or adjust the TPS till the fans come on, then back it off ever so slightly so the fans just turn off.)

[Silverprobe]

You could adjust your TPS using the "fan method". With the car in diagnostic mode, ignition on, engine off, the radiator fans should be off, but turn on when you open the throttle ever so slightly. (Or adjust the TPS till the fans come on, then back it off ever so slightly so the fans just turn off.)

Maybe I should try this too. My idle has been a little too low (and as a result uneven) for my preference for awhile now, but multiple checks of timing and trying to set idle speed after readjusting throttle placement/fan switch with feeler guages, etc has had no effect.

Thinking maybe my idle speed actuator is messed up electrically and needs to be replaced...but the $$$!

[Horror Angel]

So ive compeltely replaced the TPS since i got it for 20$.
The old one went from 0.10- 0.85 , the new one hits the multimeter at about .40-1.00
Is my new one faulty? the TPS writeup on here says it should be around .25-.75 but i cant even attempt to set it down to .25 with the new one.

Im also not sure what im looking for as "the right" setting. My car loves to randomly do stuff and never do it again till im least expecting it so im not sure. I would try to alter Idle after setting it "the right way" but i dunno which setting that is. Should a good TPS settings make it run perfectly without me ever backing off the idle screw?

TBH im getting ultra low RPM with this new setting and its dropped to 580rpm without a sign of it stalling over that. Before the car showed wan to-to-stall issues for sure every drop below 600 and maybe more. The chiltons and hayes and on here of course all say the idle should be higher than 600. On here the fact stands out that we often have to bump the RPM up 100 over the factory recomendations.

One last thing, if i secure one screw on tight and not both, can the TPS turn itself? I swear it was middle yesterday but today it was all the way counter(?) clockwise it could go. I left one screw loose to make it easier to jump out and adjust if i stall. I swore i tightened the other excessively though

[BLUEnoEQ]

Do you have an obdII scanner? I set mine with one, down to 0.0 percent throttle.

[Horror Angel]

yeah i got a adaptor and Torque on android. However those things can be very confusing. What values am i looking for? I swear my emission test showed the o2 as incomplete, would the sensor cut out of the CAT cause the scanner to not read the first sensor? or possibly i was looking in the wrong area.

Im not sure if i can "set" anything at all with the android adaptor scanner though. Are androids really crippled compared to the stand alone ODB2 scanners? Or possibly a addon i need to download?

I looked at some graph i found today and it didnt email it properly so imma record it again and post later

[BLUEnoEQ]

Not familiar with torque. I have a Bosch one. It seems to be full featured. TPS, set to 0.0% if you figure out the datastream.

[Silverprobe]

I feel somewhat green for posting this, but yesterday in an effort to determine why my '94 had been idling so crappy lately, I decided to try resetting my ECU by disconnecting the battery for awhile, and in the process checked my coolant and found that it was low. So, before reconnecting the battery then starting the car to let it run for awhile to relearn it's idle characteristics, I topped off the coolant.

When the car reached operating temp, I shut off the engine, then jumped the GRN and TEN pins in the diagnostics port to check the idle. To my surprise, the idle speed was WAY low. I had to back out the idle screw at least a turn or turn-and-a-half to get the idle back up to the normal rpm.

I haven't taken the car out for a spin yet today to get it up to temp and see where the idle is now, but the fact that it was so low was surprising to say the least, especially since I know I went through the process of burping the coolant system last time I'd had to drain the coolant to do some other work.

I can only assume that the difference in coolant level occurred because the work I'd done was when it was hotter outside, and I didn't think to run the heater to circulate coolant throughout the ENTIRE system when topping off the level.

If that's what happened, sure I'll feel like an idiot for awhile, but at least the car will be running decently again.

I'll post back once I've taken a test drive...

[Back to edit after test drive]: Still had to add a little coolant today to get it to the Full line, but a test drive to full operating temp afterwards still resulted in a much more tolerable/steady idle speed. Sometimes it's the simple stuff, thankfully.

[Horror Angel]

checked my coolant and found that it was low..

you might be a lil off topic here. You may have accidentally posted in the right place for me to see it though. The last couple years when the weather changed to freezing i dumped my full load once each year. Lucky i caught it. I wanna say this year i only seen half it go, but then again that couldve been me running it hard, which seems to make it drop a tiny bit.

ANYWAYS,,, i looked into it and the rubber seals can sometimes change size with temp and/or deteriorate in a way that doesnt make it fail, but will cause some loss when for instance the rubber plug gets smaller during cold weather and the metal rad doesnt shrink. If its the same issue i got, i just watch it. Watch it and if you keep loosing coolant you probably need to presser check your system and replacing the failing part. I should also add i had to do that once and i used vice grips to clamp the metal tooth on the radiator area that was leaking and it was good to go since ! (been like 4-6 years )

[Horror Angel]

Back on topic.
I used the multimeter to see what the TPS sensor will read, but havent used it since. I just adjusted it manually a few times. It felt like my tranny or engine was breaking on me after gunning it then taking foot off the gas, so then i set my IDLE up from average 600rpm to about 720rpm. This converts to a drive gear RPM of 590-650rpm and then jacking it up sets drive to about 670-720RPMs.

Still not sure what the TPS should be effecting, as im not sure other than being able to reset my idle slightly higher when replacing it and adjusting, what im attempting to do with the TPS sensor. I have tons of posts on here saved though so maybe ill reread all them. Possibly i had read im adjusting the throttle plate? Still not sure the feeling i would be looking for in the engine, possibly im still off as it kinda didnt launch from one start yesterday as if it was trying to revert to its want to stall.

Is this something i shouldve adjusted BEFORE it caused problems possibly due to me modifying the air intake? The car in fact did have a different end problem at one point (before adjusting idle, timing, replacing parts like distrubutor/timing belt stuff. Instead of when it was cold it wanted to stall at low RPMS, when i ran the car super hard it would occasionally act like it wanted to stall.

[BLUEnoEQ]

Have you considered getting a second throttle body (just in case this doesn't work out,) and modifying it to get rid of the IAC valve. Setting your idle and adjusting seasonally? I think if you're trying to set a higher idle with the TPS all you're going to do is waste fuel, and not allow the 0 throttle switch in the TPS to cut fuel when you are off the accelerator.
I think the IAC is just going to keep adjusting no matter what you set it to, unless you disable it.

[Silverprobe]

you might be a lil off topic here. You may have accidentally posted in the right place for me to see it though.

How exactly is it off topic if the topic is that your engine isn't idling correctly (too low - the same as mine was doing), and you're looking for possible reasons for what might be the cause?

Thanks for the FYI though. Since this is the first time I've had a mysterious coolant level drop, I'll of course be keeping an eye on it.

[Brizzy]

You installed an intake recently ? Is the vaf sitting perfectly level ? If it's on an angle it can cause stalling and idle issues.

[Level 9]

Vac leak? Was something pulled loose when the intake was installed. Hose going to the back elbow hooked back up?