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OBD code 22 with new TPS...JUST REPL by CSM842M4
Started on: 10-09-2018 10:44 PM
Replies: 14 (204 views)
Last post by: Blacktree on 12-01-2018 03:22 PM
CSM842M4
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Report this Post10-09-2018 10:44 PM Click Here to See the Profile for CSM842M4Click Here to Email CSM842M4Send a Private Message to CSM842M4Edit/Delete MessageReply w/QuoteDirect Link to This Post

Just replaced the throttle position sensor on the wife's '84 2.5 4-speed after flashing a code 21. Between that time and today, the ECM had also collected codes 13, 22, 34 and 45. Tired of seeing the CEL glowing, I disconnected the battery negative cable for a bit, took care of some other minor issues and reconnected the battery. Two seconds after start-up, the CEL was back on for the whole trip home. Counting flashes in the driveway now only gives me a 22. Various sources cite the 22 as "TPS signal low" and "TPS out of adjustment". My Chilton's manual describes checking the voltage between TPS connector terminals B and C as an "adjustment". It gives .450 volts to 1.250 volts as the proper range, and the new sensor showed around .850, so right in the sweet spot.
I've read on this forum about a relearn procedure for the ECM, as well as debate about the need for the relearn for anything but an IAC replacement. So, what's the real poop? Is .450-1.250 really the correct range for the TPS for the Fiero ECM? Is the relearn necessary for TPS replacement? If so, how is it done? If the problem is with my aftermarket sensor, is the correct one available from the usual suspects ( Rodney Rickman, Fiero Store, etc.)? If it's not the TPS, where should I look next? I would really like to get the wife's car sorted out so I can get my '86 GT in the garage... Thanks in advance - Chris

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Gall757
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Report this Post10-11-2018 08:31 PM Click Here to See the Profile for Gall757Send a Private Message to Gall757Edit/Delete MessageReply w/QuoteDirect Link to This Post

Any time you disconnect the battery, a re-learn is going to happen. Take a 15 minute trip with speeds over 35 mph. That should be enough, unless the IAC is hung up.

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zobari
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Report this Post10-12-2018 05:50 AM Click Here to See the Profile for zobariClick Here to Email zobariSend a Private Message to zobariEdit/Delete MessageReply w/QuoteDirect Link to This Post

I have the same problem with (2 new tps acdelco) with my 1988 gt v6

http://www.fiero.nl/forum/Forum2/HTML/141840.html

Finally, i have reinstalled my old sensor (the old is working properly).
I think that the acdelco tps doesn't work with the fieros.

[This message has been edited by zobari (edited 10-12-2018).]

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CSM842M4
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Report this Post10-13-2018 02:16 PM Click Here to See the Profile for CSM842M4Click Here to Email CSM842M4Send a Private Message to CSM842M4Edit/Delete MessageReply w/QuoteDirect Link to This Post

Thanks, Gall757 and zobari. My drive to and from work (both jobs) takes at least 15 minutes, with top speeds between 45 and 65 mph, so I should be able to do that this afternoon. Seems like I disconnected the battery once shortly after having replaced the TPS and cleared the CEL, but may have done something else to get it back.

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CSM842M4
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Report this Post10-13-2018 07:16 PM Click Here to See the Profile for CSM842M4Click Here to Email CSM842M4Send a Private Message to CSM842M4Edit/Delete MessageReply w/QuoteDirect Link to This Post

Well, poop. CEL was on again right after start-up, and stayed on the whole trip home. Counting flashes again only shows a 22. Think I'm going to chase the output voltage and see if it's getting all the way to the ECM. Don't know how else to proceed at this point...

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CSM842M4
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Report this Post10-17-2018 10:38 PM Click Here to See the Profile for CSM842M4Click Here to Email CSM842M4Send a Private Message to CSM842M4Edit/Delete MessageReply w/QuoteDirect Link to This Post

Further reading in my Chilton's states that code 22 in a TBI car means "TPS signal high". Checked output voltage at idle and swept the sensor to full throttle, got a low of .708 volts (idle) and high of 4.036 volts (WOT). Again, I'm thinking of getting to the ECM and checking voltage getting to the module.

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Patrick
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Report this Post10-18-2018 01:07 AM Click Here to See the Profile for PatrickClick Here to Email PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post

 
quote
Originally posted by CSM842M4:

Checked output voltage at idle and swept the sensor to full throttle, got a low of .708 volts (idle) and high of 4.036 volts (WOT).


Are you also checking for "dead" spots in between idle and WOT? The voltage change should be gradual and steady as you move the throttle from one end of its travel to the other.

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CSM842M4
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Report this Post10-19-2018 01:54 PM Click Here to See the Profile for CSM842M4Click Here to Email CSM842M4Send a Private Message to CSM842M4Edit/Delete MessageReply w/QuoteDirect Link to This Post

Thanks, Patrick. Yep, the sweep is as smooth and gradual as can be. Kinda wish I had an analog meter to confirm with, but my digital Snap-on (Fluke) shows no drop-out. May swap back to the original TPS and see if problem changes or remains... Also weird; yesterday, while driving to work, the CEL seemed to spend as much time dark as lit. Driving home, it was on most of the time. Can't point to anything out of the ordinary as far as weather conditions to account for this.

[This message has been edited by CSM842M4 (edited 10-19-2018).]

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CSM842M4
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Report this Post11-30-2018 08:12 AM Click Here to See the Profile for CSM842M4Click Here to Email CSM842M4Send a Private Message to CSM842M4Edit/Delete MessageReply w/QuoteDirect Link to This Post

Latest update - had a rare day off yesterday and commuted myself to doing something about the persistent Code 22. Replaced the MAP and TPS wiring from the left side of the throttle body, where everything splits out of the harness, to the sensors. In the process, I took the new wiring around the back of the throttle body, away from the EGR valve and the moving arm of the TPS. Upon first start, the CEL was still on, the code persisted and the car ran as it had before. Not satisfied to leave things that way, I looked for signal coming out of the TPS and found none. Replaced with the one I had taken off a few months ago, which gave me 4.5k ohms at idle and w.12k ohms at WOT and a smooth sweep stop to stop. Long story short, CEL is off, car starts and idles better than I can remember it ever has and throttle response is great. Found some missing insulation on the grey, green and black/orange wires further back in the harness, but will replace them at a later date and put everything in heat-resistant loom. So, for now, great success. Hope this helps someone.

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darbysan
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Report this Post11-30-2018 10:57 AM Click Here to See the Profile for darbysanClick Here to Email darbysanSend a Private Message to darbysanEdit/Delete MessageReply w/QuoteDirect Link to This Post

Something to check. I had a similar problem when i went from carb to Tpi on my Elky. TPS looked the same, but wires internally were reversed. Instead of getting a low voltage reading at idle, I was getting just the opposite- a high reading. Looked OK when I tested it, since I got the proper voltages, etc- just the signal wires were reversed.

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theogre
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Report this Post11-30-2018 01:54 PM Click Here to See the Profile for theogreClick Here to visit theogre's HomePageSend a Private Message to theogreEdit/Delete MessageReply w/QuoteDirect Link to This Post

 
quote
Originally posted by Patrick:
Are you also checking for "dead" spots in between idle and WOT? The voltage change should be gradual and steady as you move the throttle from one end of its travel to the other.
Often this test w/ digital meter is bogus unless sensor dropouts are huge.
Most cheap and some high dollar digital meters don't have a "analog bar" on the display and even then most can't follow any changes/dropouts for a given rage because LCD displays are to slow.
Have better luck using a real analog meter and watch the needle for dips as you slowly rotate the sensor.

ECM scan tools may help to see if ECM sees same as idle volts at the sensor.
Likely they don't match # so then check sensor volts at ECM plug(s). If match that way then ECM likely is "dying." ECM "death" can be many things other than a total dead ECM. Common example: Try to start and injection never turns on because ECM driver(s) have crack solder or dead part(s) anywhere in that circuit but ECM still turns on and seems to work until you use a noid light etc to test fuel injection.

ECM plugs for 84 Duke TPS
Black 5 is Dr Blu Input
White 11 is Gray 5v
Black 11 is Blk ground (Most all black wires are grounds but B11 is ground for that sensor.)

------------------
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(Jurassic Park)


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[This message has been edited by theogre (edited 11-30-2018).]

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CSM842M4
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Report this Post11-30-2018 09:40 PM Click Here to See the Profile for CSM842M4Click Here to Email CSM842M4Send a Private Message to CSM842M4Edit/Delete MessageReply w/QuoteDirect Link to This Post

Thanks, darbysan and ogre. The drives to and from work today were completely uneventful and absent CEL. Throttle response and driveability remain better than ever. Am beginning to believe the problem started with the bare sections of wires touching one another. Will monitor the new wiring and its routing for trouble, but really not expecting any based on early results. Thanks to all for the input.

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Blacktree
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Report this Post11-30-2018 09:53 PM Click Here to See the Profile for BlacktreeClick Here to visit Blacktree's HomePageClick Here to Email BlacktreeSend a Private Message to BlacktreeEdit/Delete MessageReply w/QuoteDirect Link to This Post

I know the service manual says the TPS voltage can be between 0.450 and 1.250 VDC at idle, but I've seen Fieros throwing "TPS volts high" codes with voltages as low as 0.8xx VDC at idle. I'm not sure how or why that happens, but sometimes it does. To avoid that issue, I try to keep it in the 0.500 - 0.700 VDC range at idle.

Also FYI: You can adjust the voltage on the TPS by carefully bending the tab on the little metal arm.

[This message has been edited by Blacktree (edited 11-30-2018).]

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Patrick
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Report this Post11-30-2018 10:46 PM Click Here to See the Profile for PatrickClick Here to Email PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post

 
quote
Originally posted by Blacktree:

Also FYI: You can adjust the voltage on the TPS by carefully bending the tab on the little metal arm.


That's the way I've done it myself in the past... but I now like this alternative method better. Go to 2:50 on the timeline. (Yes, I realize the OP was referring to a duke, but the same principle applies.)



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Blacktree
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Report this Post12-01-2018 03:22 PM Click Here to See the Profile for BlacktreeClick Here to visit Blacktree's HomePageClick Here to Email BlacktreeSend a Private Message to BlacktreeEdit/Delete MessageReply w/QuoteDirect Link to This Post

I think you can also find TPS units from other GM cars where the holes are already slotted.

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