Got OBDII Code, Now need some Vett Help.
Thread Starter
Team Owner
Joined: Feb 2006
Posts: 23,040
Likes: 117
From: San Antonio Texas
Got OBDII Code, Now need some Vett Help.
OK, Went buy the Autozone on the way home and picked up a code reader.(What a cool little device!) I plugged in and read the code. It says: P0118 (that's a Zero after the P) And scrolling message under that said: Engine coolant temperature circuit high input
OK guys, I can fix just about anything if I'm pointed in the right direction. I just need one of you Vett experts to point. This thing is American made V8
, It's just wrapped up in a computer.
OK guys, I can fix just about anything if I'm pointed in the right direction. I just need one of you Vett experts to point. This thing is American made V8
, It's just wrapped up in a computer.
Race Director
Joined: Apr 2000
Posts: 15,344
Likes: 4,008
From: Texas
Originally Posted by Klondike
OK, Went buy the Autozone on the way home and picked up a code reader.(What a cool little device!) I plugged in and read the code. It says: P0118 (that's a Zero after the P) And scrolling message under that said: Engine coolant temperature circuit high input
OK guys, I can fix just about anything if I'm pointed in the right direction. I just need one of you Vett experts to point. This thing is American made V8 , It's just wrapped up in a computer.
OK guys, I can fix just about anything if I'm pointed in the right direction. I just need one of you Vett experts to point. This thing is American made V8
, It's just wrapped up in a computer.
Le Mans Master
Joined: Oct 2003
Posts: 7,625
Likes: 4
From: Director of Bands
St. Jude Donor '08
Originally Posted by 96GS#007
Either a bad coolant temp sensor (screws into the front of the waterpump) or some chaffed wiring running to the sensor.
Sounds right. I sheared my ECT sensor right off when removing the serpentine belt last year (DOH!). I went to a local dealership and got the new part (not too $$$, IIRC). Just place a some rags under the sensor so that when you take it out you don't get coolant on your optispark. Also make sure that your connections are clean (a no brainer, but sometimes I forget
).My .02.
Last edited by eschoendorff; Mar 23, 2006 at 07:16 AM.
Thread Starter
Team Owner
Joined: Feb 2006
Posts: 23,040
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From: San Antonio Texas
Oh Dude ! I just replaced a rotten belt the day before this started! 
I didn't even see anything down there. I guess I should have taken the air box and all that stuff off to get a better look, It's like a black hole down in there! I'm good a soldering and electrical repair as long as I can see the stuff. Is it on the front of the water pump?
I didn't even see anything down there. I guess I should have taken the air box and all that stuff off to get a better look, It's like a black hole down in there! I'm good a soldering and electrical repair as long as I can see the stuff. Is it on the front of the water pump?
Instructor
Joined: Jan 2006
Posts: 240
Likes: 0
From: San Antonio TEXAS
not the whole story....
Klondike didn't tell you that the car essentially won't run. He had intermittant rough running periods associated with wierd temp guage
readings (like 32*F), then the engine would clear up as the guage switched to a more realistic temp. Does this sound right? Does the sender your talking about go to the guage or the ECM or both? Just trying to get him rolling as soon as possible before he loses it again
Quote "I'm glad I kept a Ford to chase parts"...hey, at least you figured out what they're good for! 
readings (like 32*F), then the engine would clear up as the guage switched to a more realistic temp. Does this sound right? Does the sender your talking about go to the guage or the ECM or both? Just trying to get him rolling as soon as possible before he loses it again
Quote "I'm glad I kept a Ford to chase parts"...hey, at least you figured out what they're good for!
Le Mans Master
Joined: Jan 2006
Posts: 6,564
Likes: 6
From: Woodstock Georgia
Yep. And almost dead center over the opti spark. Like he said be SURE YOU DON'T get coolant on the optispark when you change the sensor. A lot of coolant will want to drain out when you pull the sensor. Also, be sure to use bleeder to purge out the air when refilling the coolant.
Race Director
Joined: Apr 2000
Posts: 15,344
Likes: 4,008
From: Texas
Originally Posted by Red3644
Klondike didn't tell you that the car essentially won't run. He had intermittant rough running periods associated with wierd temp guage
readings (like 32*F), then the engine would clear up as the guage switched to a more realistic temp. Does this sound right? Does the sender your talking about go to the guage or the ECM or both? Just trying to get him rolling as soon as possible before he loses it again Quote "I'm glad I kept a Ford to chase parts"...hey, at least you figured out what they're good for!
readings (like 32*F), then the engine would clear up as the guage switched to a more realistic temp. Does this sound right? Does the sender your talking about go to the guage or the ECM or both? Just trying to get him rolling as soon as possible before he loses it again
Quote "I'm glad I kept a Ford to chase parts"...hey, at least you figured out what they're good for! The analog gauge uses a sending unit located in the passenger side cylinder head.
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Le Mans Master
Joined: Jan 2006
Posts: 6,564
Likes: 6
From: Woodstock Georgia
Originally Posted by Klondike
Ok Bro! Grab a wrench or hold the light, we're gonna' fix this thing. Maybe we'll invent an Optispark shield while we're at it 
If you are new to the lt1 be sure to locate the air purge (bleeder) valve for refilling the coolant. If you don't bleed the air out when refilling you will have problems.
Instructor
Joined: Jan 2006
Posts: 240
Likes: 0
From: San Antonio TEXAS
It's an LT4. Anything different on that intake? Can you tell me a little more about the "purge". I'm thinking he may have damaged the wires
when he changed the serpentine belt and can fix that...maybe. Thanks.
when he changed the serpentine belt and can fix that...maybe. Thanks.
Le Mans Master
Joined: Jan 2006
Posts: 6,564
Likes: 6
From: Woodstock Georgia
Originally Posted by Red3644
It's an LT4. Anything different on that intake? Can you tell me a little more about the "purge". I'm thinking he may have damaged the wires
when he changed the serpentine belt and can fix that...maybe. Thanks.
when he changed the serpentine belt and can fix that...maybe. Thanks.
Thread Starter
Team Owner
Joined: Feb 2006
Posts: 23,040
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From: San Antonio Texas
Aminnich, Thanks for the replys. I'm thinking I had that sensor unplugged the other day, but I can't remember if it was while I was doing the belt or cleaning things up in there. This car was like new on the surface and 18 wheeler nasty from the valve covers down. I might have got crud in the plug or disturbed an almost broken wire while I was in there. I'm going to go micro deep into that little wiring harness tonight to check it out before I pull that sensor and make an antifreeze mess. There might be a chance there's nothing wrong with that sensor. Things didn't start turning sour till I decided to clean it up in there. I was trying to not get anything on "Mr. Opti." but might have got something into that plug. (Corroded pins or whatever). Are those plugs and pins available for replacement/repairs or do you just have to live with or fix what you've broken yourself?
Race Director
Joined: Apr 2000
Posts: 15,344
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From: Texas
Originally Posted by Klondike
Are those plugs and pins available for replacement/repairs or do you just have to live with or fix what you've broken yourself?
Le Mans Master
Joined: Dec 2000
Posts: 7,839
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From: San Diego, Ca
Sensor is also used in your Ford (assuming it's not carb'd) and any computer controlled engine. PCM sends a 5 volt reference to the sensor which decreases in resistance as it warms up meaning that the voltage seen by the ECM drops. The code your getting means that it didn't drop, so it's either unplugged or the signal wire (more often than not Yellow) has opened. If the signal wire was touching ground the voltage would drop to zero and you'd get a P0117. Check connections carefully - if you need a new one, they're about 9 Bucks at the Discounters and come with a pigtail. Note: Sensor replaces the choke with higher voltages meaning lower temps so the PCM fattens up the injector on time to give it more gas. As you've seen, the lowest possible parameter built into it is -32 degrees and until it starts running on backup, it isn't going to run very well because it's getting too much fuel.
Thread Starter
Team Owner
Joined: Feb 2006
Posts: 23,040
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From: San Antonio Texas
I did some testing last nite and have come to the conclusion that the harness and plug are OK. I carefully cleaned the plug contacts with a needle file and re-tensioned them. I had seen some figures for the resistance at varying temperatures so I rigged up a variable test resistor from some electronis stuff I had laying around. I took a tiny variable pot and soldered some .047 guitar string on two of the legs and used that to simulate the temp sensor. Turned the key on and varied the resistance and was able to see temp changes on the digital display change from about 100* to 200*. So I'm assuming the harness and plug are OK. I'm going to reassemble everything later this afternoon and see if it was just a bad connection or if the sensor is truly the fault.
That OBDII reader is really a great little diagnostic tool
!
P.S. That piece of guitar string (6th E string) works as a great little plug contact cleaning file. It's not too agressive and it's the perfect size to fit into those plugs and clean out dibris and corrosion.
That OBDII reader is really a great little diagnostic tool
!P.S. That piece of guitar string (6th E string) works as a great little plug contact cleaning file. It's not too agressive and it's the perfect size to fit into those plugs and clean out dibris and corrosion.
Thread Starter
Team Owner
Joined: Feb 2006
Posts: 23,040
Likes: 117
From: San Antonio Texas
Time to lay this thread to rest!
We have lift off ! Checked and cleaned all plugs and sensor prongs and reassembled after my test with the substitute variable resistor, and everything checked OK. No Codes 
Went for a short drive through the neighborhood and monitored the digi. Temp. gauge and everything runs and reads fine now. That little code reader is wonderful 
The only thing my Mustangs ever told me was "Try again" I know
Thanks to all for leading me in the right direction with all the tech info and experienced comments. This is going to be an informative place to hang out.
Went for a short drive through the neighborhood and monitored the digi. Temp. gauge and everything runs and reads fine now. That little code reader is wonderful The only thing my Mustangs ever told me was "Try again" I know
Thanks to all for leading me in the right direction with all the tech info and experienced comments. This is going to be an informative place to hang out.
Le Mans Master
Joined: Jan 2006
Posts: 6,564
Likes: 6
From: Woodstock Georgia
Originally Posted by Klondike
We have lift off ! Checked and cleaned all plugs and sensor prongs and reassembled after my test with the substitute variable resistor, and everything checked OK. No Codes Went for a short drive through the neighborhood and monitored the digi. Temp. gauge and everything runs and reads fine now. That little code reader is wonderful
The only thing my Mustangs ever told me was "Try again" I know
Thanks to all for leading me in the right direction with all the tech info and experienced comments. This is going to be an informative place to hang out.
Went for a short drive through the neighborhood and monitored the digi. Temp. gauge and everything runs and reads fine now. That little code reader is wonderful The only thing my Mustangs ever told me was "Try again" I know
Thanks to all for leading me in the right direction with all the tech info and experienced comments. This is going to be an informative place to hang out.
