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Proper TPS adjustment tips???; This seems to be the root of my idling problems.
Topic Started: Feb 10 2013, 06:36 PM (2,397 Views)
cwatkin


It looks like the last of my my problems with cold idle may have been related to a TPS (throttle position sensor) that was not adjusted properly. I have adjusted it and I think I am still a little off but things are MUCH improved! I had never messed with this before as Geo Glenn jokingly told me not to mess with this under penalty of death. I guess someone else had it out of adjustment or it had crept out of position over time.

Here is what I did.
1. Looked around for directions here how to adjust the TPS here. It looks like there are quite a few different ways depending on your year and model of car.
2. I have the 1994 with the advanced emissions and the idle speed controller (ISC) instead of the IAC like the older models. The directions were different for this.
3. I noticed the directions called for the use of a 3.5mm feeler gage stuck in the throttle stop/lever during the adjustment. I didn't have a 3.5mm gage so I went online and looked up the thickness of coins. A penny and nickel stacked are 3.5mm thick so I used this as my feeler gage. This is probably not perfect but it seemed to work ok....
4. The throttle stop has a screw and looking nut and I do not know if this is set correctly either but I didn't mess with it.
5. I loosened the TPS and moved it until the voltage was 0.99-1.00V on my multimeter and then tightened the screws back down.
6. I fired it up basically cold and the idle was much better and smoother than before but seemed like it was just a tad too fast.
7. I drove the car a while and it did fine.
8. I let it idle when I got back and there was a fast-slow-fast-slow rhythm to the idle. It seemed to be surging on a regular schedule so to speak. This happened every 2-3 seconds.
9. I let it idle in 1st gear and noted the same surge and dropoff in the power every 2-3 seconds or so.

I would say that my situation is greatly improved and I seem to be on the right track but don't feel have it perfect yet. I called some parts stores while typing this and none have a 3.5mm thick gage of any kind. I guess I can try to stack feeler gage blades in a way to get this thickness. We will see...

Any other suggestions?

Conor
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HelterSkelter
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#1 Pizza Driver

cwatkin
Feb 10 2013, 06:36 PM
It looks like the last of my my problems with cold idle may have been related to a TPS (throttle position sensor) that was not adjusted properly. I have adjusted it and I think I am still a little off but things are MUCH improved! I had never messed with this before as Geo Glenn jokingly told me not to mess with this under penalty of death. I guess someone else had it out of adjustment or it had crept out of position over time.

Here is what I did.
1. Looked around for directions here how to adjust the TPS here. It looks like there are quite a few different ways depending on your year and model of car.
2. I have the 1994 with the advanced emissions and the idle speed controller (ISC) instead of the IAC like the older models. The directions were different for this.
3. I noticed the directions called for the use of a 3.5mm feeler gage stuck in the throttle stop/lever during the adjustment. I didn't have a 3.5mm gage so I went online and looked up the thickness of coins. A penny and nickel stacked are 3.5mm thick so I used this as my feeler gage. This is probably not perfect but it seemed to work ok....
4. The throttle stop has a screw and looking nut and I do not know if this is set correctly either but I didn't mess with it.
5. I loosened the TPS and moved it until the voltage was 0.99-1.00V on my multimeter and then tightened the screws back down.
6. I fired it up basically cold and the idle was much better and smoother than before but seemed like it was just a tad too fast.
7. I drove the car a while and it did fine.
8. I let it idle when I got back and there was a fast-slow-fast-slow rhythm to the idle. It seemed to be surging on a regular schedule so to speak. This happened every 2-3 seconds.
9. I let it idle in 1st gear and noted the same surge and dropoff in the power every 2-3 seconds or so.

I would say that my situation is greatly improved and I seem to be on the right track but don't feel have it perfect yet. I called some parts stores while typing this and none have a 3.5mm thick gage of any kind. I guess I can try to stack feeler gage blades in a way to get this thickness. We will see...

Any other suggestions?

Conor



you buy a feeler gauge and then you measure out 3.5mm worth of it. feeler gauges don't come in large sizes like 3.5mm, they come in sets of 20 or so smaller sizes that you have to add up to what you want to use.
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cwatkin


Gotcha! This fits with my idea of "stacking" feeler gage blades to make 3.5mm.

Thanks,

Conor
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Vkhelldog
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Your idle will surge until you put it back how it was/ were it belongs.... Been there done that...... Also this adjustment should be done with car warm...
Edited by Vkhelldog, Feb 10 2013, 07:39 PM.
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cwatkin


Ok, I took apart my pocket knife type style feeler gage and stacked the proper blades up 3.5mm in thickness and repeated this adjustment. It seems to be surging more than the stacked penny and nickel method I used earlier.

So, what is my next step? Do I swap TPS units or do I need to adjust something in a different way?

Conor
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rjsdotorg
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If your TPS is sending a steady 1V at 800-850, then it is fine.
Check other sensors.
This assumes the idle stops have not been messed with...
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Vkhelldog
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If you marked it put it back how it was.... If not, keep trying... I am pretty sure that's way to thick.... I think (of course my square box ts maybe different than yours) I used a .014 inch feeler, adjusted as my post how to adjust ts states... The idea is when no throttle it sits at .000 volts, at barely touching throttle (the feeler guage) it hits 1 volt, at full throttle 75%-100% it shows 4 volts or what not.... Mostly I hope you marked it and can put it back how it was.
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cwatkin


I have already checked the injector and cleaned it for good measure just in case. I replaced all vacuum lines due to a few being split early on and sprayed carb cleaner throughout. Everything seems tight. I found the http://geometroforum.com/topic/4829866/1/ and http://geometroforum.com/single/?p=456968&t=4239868 which all indicate I need to use .14" or 3.5mm between the throttle stop. I don't know if mine has been messed with so that is the problem.

It also looks like I may need to reset the ECM between adjustments. Is this right?

Conor
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Vkhelldog
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No need to reset ECM. A penny and a dime together seems way to thick to me... Pretty sure my fsm says .014 inch? Ill try to find my post..
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cwatkin


I double checked these other posts and they are clearly .14 inch or 3.5mm. I have also seen reference to .014 inch. Let me know what worked for you.

Thanks,

Conor
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Vkhelldog
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http://geometroforum.com/topic/1341780/1/

.014 inch feeler...
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Vkhelldog
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http://geometroforum.com/topic/5009604/1/#new

Yes .014" worked for me. And as usual geo Glenn set me straight on it. ;-)
Edited by Vkhelldog, Feb 10 2013, 10:04 PM.
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cwatkin


I decided to look at my feeler gage stack again as it seemed to make things worse than the penny and nickel stack. First, I brought it in and it was WAY thicker than the penny and nickel combo. I then measured it with a ruler and it was over 4mm. I then used a digital caliper and it was over 4mm. So, I pulled out a couple leaves where it measured 3.5 on the caliper and the lowly ruler. This put it right around the thickness of the penny and dime. Anyway, I went back out to the car and adjusted it back to that setting.

It fires right up cold and idles smoothly. There is a slight surging to the idle once warm but it isn't as noticeable as the first time with the penny and dime. Either way, it is much better than it was before I messed with it so I am going to leave it this way for now.

I do not know if there was a cumulative rounding error on the feeler gage leaves or what but the second try was way too big of a gap. I may still be too far out but we will see.

Conor
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cwatkin


Your car looks to have a totally different setup than mine. IT looks like they made some changes in 1994 and some 1994's are more like your model while some are more like the 1995+. Mine is one of those newer styles.

Anyway, hopefully I will hear something from Glenn if I am wrong. I am leaving it how it is now as it is better than it was.

Conor
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Vkhelldog
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http://geometroforum.com/topic/1341780/1/. This post is nothing like mine also states .014" feeler, but if it works and your happy your good. :-).. I still think its your ics, I am stubborn like that. Lol and I'd do a compression test and check timing... :-)
Edited by Vkhelldog, Feb 10 2013, 11:07 PM.
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