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22RE 1986 Dolphin EFI

Alas, the check engine light went on again as soon as I pulled out of the driveway. 
This time the codes were 4 & 11

4 is Water Thermo Sensor - which I just replaced.  Is there anything else on that to check?  I topped off the radiator fluid and the sensor is firmly screwed in and plugged in.  After I did that I got a new battery (disconnected computer) and the code flashed one - normal operation, no code stored.

Both offer a defective ECU option.  Wouldn't there be more things going wrong if the ECU were defective?

11 is a short circuit in Check connector T with A/C switch on or TPS - IDL point OFF
or a defective TPS.  I thought I was done messing with the TPS. 

The vehicle drove ok but at low power, and occasionally felt like it was hiccuping (hard to tell when windy and on a less than smooth road). No other symptoms I could observe.  Half way I checked the new battery for getting over charged and it was at 14.3 with no load and engine on.

So now I'm in the Metropolis of Albuquerque on a holiday weekend.  What would YOU do next?

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Remove both battery cables touch them together for a minute or so reconnect them and see what you get. This will reset everything in the ECM.

Edited by Maineah
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Cue Hee-Haw--- Grandpaw Jones and Archie Campbell sing "If it weren't for bad luck I wouldn't have any luck at all"

Here is the codes from LC engineering. You have the codes already, but they have the pin outs for the ECU. You do a resistance check on the WTS and TPS and check again through the wire harness. That will give you the condition of the wires and connectors, if thats good then your looking at an ECU.

http://www.lcengineering.com/LCNewsletter/2014/DECEMBER/troublecodes_TECHNOTE.html

Absolutely left field peanut gallery :clown2: suggestion check the  - battery connections EVERY WHERE, at the battery, at the ground to the chassis. And then check the engine ground strap at the engine and where it connects to the frame. 

 

Edited by WME
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Unlike a modern ECU it has no way to reset codes via a code reader without external input it relays on the defective part replacement to fix it this does not always work there are two methods remove the fuse or disconnect the battery. There can be residual voltage present this is why it sometimes takes shorting the removed cables together. If the code returns after that then the problem is not corrected. 

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11 hours ago, DanAatTheCape said:

shorting the cables??     Never heard of such.    Disconnect the power, wait a minute then reconnect.

 

Nope, pretty common procedure. All though there is not a great deal going on in a 30 year old vehicle but there is residual voltages in capacitors clock and radio memories (we are talking milli amps here) but touching the cables together you are assured that there is nothing left to keep alive a hard set code. It's pretty obvious if the problem is not repaired the code will come right  back but hard codes are not necessarily cleared by pulling a fuse or disconnecting cables granted it's more of an issues in a more modern vehicles because of the number of code possibilities and electronics but it can be so even in an old toy home it's the only real way to total clear codes. Removing one cable and turning on the head lights would produce the same results but it might be a good time to clean the cables any way. 

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a )  there is no clock and I don't use the radio because it is so bad.  The tape deck doesn't appear to work either.
b ) just changed out the whole battery so if a simple battery disconnect were all it took, that would've been done already
c ) cables are clean
will shorting the cables also short the driver?
And sorry, WME, someone already beat ya to the punch on the Hee Haw song.
More info soon...

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Ok Sports Fans,  I completely removed the battery and cleaned up all of the old corrosion from before lurking underneath and on the hold down bar.  Then I noticed that the new battery terminal I got for the positive side of the battery had an N on it.  Why?  Yes, I see that the post on positive is 3/8 and the negative is 5/16, but the threaded bit I needed was the correct size on the one labelled N.  Doubtful that it would be any different (both cast lead with brass wing nuts) I dutifully put on the one labelled P.  I had to use the smaller threaded bolt. 

Not sure if the disconnect from the battery or the dumb terminal was at fault, but there are now no codes flashing.  Later today I'm going to Costco and we'll see if they kick in when I actually drive.

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:( Ck engine light went on again. Back to 4 & 5 codes.  Just wonderful. 

Also, I'm still feeling an intermittent hesitation shudder at about 30 mph. I guess I need to learn how to remove and check the injectors myself if this is going to keep on.

Going back to the boonies tomorrow - Dolphin permitting.

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Ok you are back to square one 

19 hours ago, Cynxing said:

Ok Sports Fans,  I completely removed the battery and cleaned up all of the old corrosion from before lurking underneath and on the hold down bar.  Then I noticed that the new battery terminal I got for the positive side of the battery had an N on it.  Why?  Yes, I see that the post on positive is 3/8 and the negative is 5/16, but the threaded bit I needed was the correct size on the one labelled N.  Doubtful that it would be any different (both cast lead with brass wing nuts) I dutifully put on the one labelled P.  I had to use the smaller threaded bolt. 

Not sure if the disconnect from the battery or the dumb terminal was at fault, but there are now no codes flashing.  Later today I'm going to Costco and we'll see if they kick in when I actually drive.

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Just a little hint the positive post is always bigger on every automotive battery and the bolt on the removable cables is larger on the positive side it's really has nothing to do with the way it works but it does make it easier to ID the cables to avoid reversing them. Usually the negative cable won't fit on the positive bolt if everything is done right. I really see no sense having removable cables on the truck battery that's usually for batteries that are removable to charge or store them but if it works don't fix it..

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13 hours ago, Cynxing said:

:( Ck engine light went on again. Back to 4 & 5 codes.  Just wonderful. 

Also, I'm still feeling an intermittent hesitation shudder at about 30 mph. I guess I need to learn how to remove and check the injectors myself if this is going to keep on.

Going back to the boonies tomorrow - Dolphin permitting.

Now that you have truly reset the ECU you know your codes are real. You can remove the injectors if you like but how do you figure you are going to check them? Do they squat ? Yes. how is the pattern? Well they squart. If I recall the fuel rail holds the injectors in and they are "O" ringed meaning it will be real hard to even see what they are doing. Fuel pressure is important also it needs to be about 35 psi anything much lower or higher will cause problems that will affect the O2 sensor. You know the codes and TPS is new I kind of hate to say this but you need to check the wiring from the ECU to the TPS a bad injector may affect your O2 sensor output but not the TPS. The O2 sensor is a easy check is makes voltage in the 0 to around 1 volt range. With the engine warm and running at idle the voltage should vary and swing from high to low and back again. If it's lazy and not actively going from high to low it's bad. 

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I made it back to Middleofnowhereville.  The truck ran well, and cruised at 60 - 65 with little effort.  And that was carrying some water in the tank and a full gas tank.  Heavier.  Go figure.

I'm happy for it not to be the injectors.  I don't have the equipment to check it properly.  When the mechanic in Tucson checked the fuel pressure after replacing the faulty injector it was resting at 35.  I can check all the connections for snug fit.  I replaced the 02 sensor back in Oxnard 2 months ago because the wires were worn apart. 

A clue:  after the computer reset the codes read one flash - normal - no stored codes.  It was only after starting to drive, rpm up, that it complained.  Helpful?

The TPS is not new, but it also hasn't been giving me any trouble lately.  Not since the adjustment in Tucson by Tyson the Rogue Toyota guy.

Wire check and O2 voltage check up next...

 

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Wiring harness looks ok - to check each wire I'd have to unwrap the protective tape.  Both O2 sensor and Water thermo sensor read 0 volts.  Haven't done the running at idle thing yet. 

Challenged by the cold.  Will put that into a different post in the appropriate section.

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Without the key on there will be no voltage at the sensors. The TPS is like a volume control the harder the throttle the higher the voltage is back to the ECU however that's not the practical way to check them. It's done with static resistance key off as there are two outputs. When I say check the wiring back to the ECU it means removing the connector at the ECU to get a TPS reading after the TPS itself has been checked and found to be good. None of this stuff is for the faint of heart it's not easy to find problems with some thing 30 years old there are a lot of variables.

Edited by Maineah
because I can
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I don't think it's the TPS.  We went through the checking of the TPS back in Oxnard and again in Tucson. 

I'm not really sure where the ECU lives under the hood.  Cuddled up next to the alternator? I'll find it when it gets warm enough to stand outside for more than 5 minutes.

"static resistance key off as there are two outputs" - foreign language to me.  Care to translate?

I am hardly faint of heart.  I'm talkin' to the forum, ain't I?  And I understand complexity as I am a good deal older than 30 myself.

 

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ECU should be in the right kick panel (passenger right foot) In post 3 there is a link to the LC Engineering site. They have a chart of the pins. 

If you check the part terminal to ground then you need to check the cable connector pin to ground. If you are checking between 2 pins on the part then you need to check between the 2 correct pins on the connector. OF course the parts have to be connected to the harness.

Have you checked all the battery and engine grounds?, computer things hate funky grounds.

IF there has been any leakage in the cowl area water can run down and get the computer wet, water and computers are not compatible.

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  • 2 weeks later...

So - codes 4 & 5 are flashing again.  They are the H20 thermo sensor and 02 sensor respectively.  Both have been replaced by me since December and February.  After replacing 02 sensor, no codes for over a month.  Replaced the H20 sensor to deal with the code that popped up a few weeks ago.  Stopped briefly when I cleared the codes, and then started again when I started driving.  Drives well, if not a bit sluggish on inclines - but I sort of expect that.  

Retired Toyota mechanic in nearby RV offered the idea that non-Toyota parts can make for wonky codes.  Thoughts on that?

The new H20 sensor was a NapaTS5520SB with a grey connector.  The old one had a green connector.

Of course that guy also said to put black tape over the check engine light and call it good, so grain of salt where he's concerned.

Can't  inspect and register in VT with codes flashing.  Not inclined to wait until the last minute to solve. Also it sets my teeth on edge when the truck isn't running right.

That's all I've got.

 

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I have had mixed results with name brand aftermarket O2 sensors, 

On my Escaper I had CEL codes, I replaced the O2 sensor with a Kragen Auto sensor. After 2 months the code came back. As an experiment I took the original O2 sensor ( you keep old stuff as a spare, RIGHT?) and heated it with a propane torch to "clean" it. Put the old one back and for the next 3 years, no more codes.

I also used a Kragen sensor in my 92 Dodge Caravan and had no problems

 The temp sensor should read around 1K ohm at 60 degrees and around 225 ohms at operating temp, 200 degrees.

Edited by WME
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YES, I have a pile of the old stuff - and new spares - piling up just in case.  The old O2 sensor is pitched, however because the wires were severed.  I think it's interesting that the computer codes were mute until I started messing around with the TPS.  After I started "fixing" things the computer got chatty.  Maybe it has developed AI and is trying to keep me on the roll of replacing parts to stay alive as long as possible.  Can you tell I have Cabin Fever? Wind gusts up to 40 kts. all day.

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Emboldened from my victory over the stinky "saddlebag caddy" I am looking at the O2 and water thermo sensors again.

Two observations - unlikely but you never know - The plastic clip that snaps into the water thermo sensor is not very tight - one edge of the plastic is broken - and it is not lined up flat with the other sensor to the left of it.  Does that matter?  Would that make the code come up?  When I screwed in the new sensor I was moving fast to prevent too much radiator fluid from escaping.  Should the two sensors line up flat?

Other than that I guess I could replace the snap on connector piece...?

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