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cold start; geo wont start when cold
Topic Started: Feb 27 2009, 09:09 PM (4,161 Views)
MR1 Kingsbury
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David95237
Aug 11 2017, 03:09 PM
wrong feeler gauge. .14 not.014
Correct... you need to 'stack' up the feelers to get .14 inches. Then loosen the TPS if it does not read 1.00volts, and rotate it until it is right at 1.0v
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Bank2me
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MR1 Kingsbury
Aug 11 2017, 07:16 PM
David95237
Aug 11 2017, 03:09 PM
wrong feeler gauge. .14 not.014
Correct... you need to 'stack' up the feelers to get .14 inches. Then loosen the TPS if it does not read 1.00volts, and rotate it until it is right at 1.0v
Ok so just so I got this right. I need to get the engine to normal operating temperature then shut the engine off. Then I need to put the probes in on the 1 and 3 terminals on the TPS/TPS plug and then put in feeler guages adding up to .14 then turn the key ahead with engine OFF and read the voltage? And adjust/move if necessary? What if I can't get the voltage up to the .98-1.0 voltage range?
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suzukitom
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Tom

With the 0.14 " feeler gauge inserted, and the throttle at idle position, the TPS range of rotation would only span between about 0.90V to around 1.10 volts. It's a pretty narrow range.

With no feeler gauge inserted at all, I think the voltage would be around 0.7 volts. ( edit: corrected)

On never Metros like yours, it should not take long to warm up enough to perform this procedure. .maybe 4 or 5 minutes at most.

Edit: added picture
Example of multimeter voltage readings you might see.. (I added a test port on my wiring harness so it will look different than your factory TPS connector)

Posted Image


Edited by suzukitom, Aug 11 2017, 08:21 PM.
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Bank2me
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Thanks SuzukiTom I will try it tommorow and report back. Mine is the 94 Metro base. And one last thing... if I get the TPS in that range, how do I tell if the TPS is bad?
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suzukitom
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Tom

Bank2me
Aug 11 2017, 08:34 PM
Thanks SuzukiTom I will try it tommorow and report back. Mine is the 94 Metro base. And one last thing... if I get the TPS in that range, how do I tell if the TPS is bad?
If you find the TPS to be in that 0.98 to1.02 volt range don't try to adjust it.

It could mean that your problem is not a worn or misadjusted TPS at all, but a problem with the ISC (idle speed control) motor, and/or a worn throttle plate.

Lets stop and think about why your cold idle is too slow. Newer Metros with an ISC motor have a built in idle switch. For various reasons this built in idle switch may not be on when you are starting the cold engine, so the engine computer will not command the ISC motor to increase the throttle, and the idle speed will be too low

So first confirm that the TPS voltage is in the correct range and we can go from there..
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Bank2me
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suzukitom
Aug 11 2017, 11:17 PM
Bank2me
Aug 11 2017, 08:34 PM
Thanks SuzukiTom I will try it tommorow and report back. Mine is the 94 Metro base. And one last thing... if I get the TPS in that range, how do I tell if the TPS is bad?
If you find the TPS to be in that 0.98 to1.02 volt range don't try to adjust it.

It could mean that your problem is not a worn or misadjusted TPS at all, but a problem with the ISC (idle speed control) motor, and/or a worn throttle plate.

Lets stop and think about why your cold idle is too slow. Newer Metros with an ISC motor have a built in idle switch. For various reasons this built in idle switch may not be on when you are starting the cold engine, so the engine computer will not command the ISC motor to increase the throttle, and the idle speed will be too low

So first confirm that the TPS voltage is in the correct range and we can go from there..
Thanks SuzukiTom I will do more testing tonight and get back to you. I appreciate the help!!
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Bank2me
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suzukitom
Aug 11 2017, 11:17 PM
Bank2me
Aug 11 2017, 08:34 PM
Thanks SuzukiTom I will try it tommorow and report back. Mine is the 94 Metro base. And one last thing... if I get the TPS in that range, how do I tell if the TPS is bad?
If you find the TPS to be in that 0.98 to1.02 volt range don't try to adjust it.

It could mean that your problem is not a worn or misadjusted TPS at all, but a problem with the ISC (idle speed control) motor, and/or a worn throttle plate.

Lets stop and think about why your cold idle is too slow. Newer Metros with an ISC motor have a built in idle switch. For various reasons this built in idle switch may not be on when you are starting the cold engine, so the engine computer will not command the ISC motor to increase the throttle, and the idle speed will be too low

So first confirm that the TPS voltage is in the correct range and we can go from there..
Ok SuzukiTom so the TPS is adjusted to 1.0 volts and I go to start it up at cold idle and it does the same thing. Starts then dies immediately. Then I noticed when she gets warmed up it is like it idles super low to where the car shakes.
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suzukitom
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Tom

Quote:
 

Ok SuzukiTom so the TPS is adjusted to 1.0 volts and I go to start it up at cold idle and it does the same thing. Starts then dies immediately. Then I noticed when she gets warmed up it is like it idles super low to where the car shakes.


What was the voltage reading before making the adjustment?

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Bank2me
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suzukitom
Aug 13 2017, 01:55 PM
Quote:
 

Ok SuzukiTom so the TPS is adjusted to 1.0 volts and I go to start it up at cold idle and it does the same thing. Starts then dies immediately. Then I noticed when she gets warmed up it is like it idles super low to where the car shakes.


What was the voltage reading before making the adjustment?

I think it was like .85 or something like that. But it may have been off because I had adjusted it before thinking it was the right way to do it. Til I talked to you lol. I just want this damn thing fixed. It's frustrating.
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MR1 Kingsbury
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i think we determined early on that you have upgraded emissions with the ISC on the back of throttle body. Is there still a black tamper proof cap on the throttle plate adjustment? Where you put the feeler gages at?
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suzukitom
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Tom

Regardless of the prior adjustments made to your TPS, let's assume that you have now inserted the 0.14 feeler gauges at the throttle stop, and performed the TPS adjustment to produce 1.0 Volt. If that is correct, the TPS should now be close to where it should be.

You say that the idle is now very low when the engine is warmed up. This supports the idea that your throttle plate is worn and no longer fully closing, at idle. This causes the idle switch built into the ISC motor to not be in 'Idle' mode and the ISC motor will not extend its plunger to control your idle speed to 850RPM (warm), or to provide a faster idle during a cold start up.


The picture below is a close up of the ISC motor plunger making contact with its own stop located on the throttle lever.

The red circle shows the contact point for the ISC motor plunger (white plastic disc) and wear over time requires something like a 10 cent coin (dime) to be glued onto the ISC plunger stop (metal disc on a threaded rod) to simulate having a new ISC motor installed. Some experts may choose to adjust the ISC motor stop instead of replacing the ISC motor, but please do NOT do that yourself at this point.

Posted Image

Here is a link to a relevant post made to this forum about this ISC test.

http://geometroforum.com/single/?p=720386&t=5008123

Goodman98155
Dec 8 2012, 11:24 AM
starscream5000
Nov 29 2012, 01:32 PM
Remove the ISC, superglue a dime to the throttle stop, and run the car like that until you locate a new ISC to put in it. Remove the dime when you get a NEW ISC of course.

The dime is just the right thickness to let the motor idle correctly when warm. You may need to feather the throttle on first startup, but once you get going, you'll be fine :thumb
Now that's a fix I can afford! I think it has come to that. So you think the ISC itself is the problem?
I suspect it is. You'll know in 5 minutes time as that's about all the time you'll need to do what I said above.
Attached to this post:
Attachments: isc_worn.jpg (187.48 KB)
Edited by suzukitom, Aug 13 2017, 08:42 PM.
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suzukitom
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Tom

Since so many TPS pictures posted to photobucket have now been lost, I think it might be useful to provide a new picture of where the feeler gauge is inserted when performing the TPS adjustment.

At the center of this picture shows the black anti tamper cap covering the throttle stop screw and the feeler gauge (marked with green tape) inserted between the screw tip and the throttle lever. (The ISC motor plunger can be seen below the springs.)

Posted Image

Attached to this post:
Attachments: 20170813_194233_resized.jpg (84.8 KB)
Edited by suzukitom, Aug 14 2017, 12:25 AM.
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MR1 Kingsbury
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Thanks Tom for all the great new pics... I really need to start my camera up and get some of my own posted up.
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Bank2me
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suzukitom
Aug 14 2017, 12:19 AM
Since so many TPS pictures posted to photobucket have now been lost, I think it might be useful to provide a new picture of where the feeler gauge is inserted when performing the TPS adjustment.

At the center of this picture shows the black anti tamper cap covering the throttle stop screw and the feeler gauge (marked with green tape) inserted between the screw tip and the throttle lever. (The ISC motor plunger can be seen below the springs.)

Posted Image

Tom I used the 9/64 Allen wrench to put in between were the feeler guages are and it doesn't look like my black cap is on there.
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MR1 Kingsbury
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Bank2me
Aug 14 2017, 06:40 AM
suzukitom
Aug 14 2017, 12:19 AM
Since so many TPS pictures posted to photobucket have now been lost, I think it might be useful to provide a new picture of where the feeler gauge is inserted when performing the TPS adjustment.

At the center of this picture shows the black anti tamper cap covering the throttle stop screw and the feeler gauge (marked with green tape) inserted between the screw tip and the throttle lever. (The ISC motor plunger can be seen below the springs.)

Posted Image

Tom I used the 9/64 Allen wrench to put in between were the feeler guages are and it doesn't look like my black cap is on there.
uh-oh.... the dreaded do not adjust has been adjusted.... that's why your idle speed is low with proper TPS setting.

Now it gets tricky, but SuzukiTom has posted and will likely repost here, the details to work out that adjustment.... first on the throttle plate, then the TPS to follow it... I did that adjust to my 1st '96 last month and it worked perfect. Good luck.
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