CPS Failures
#1
03-24-2006, 11:19 AM
CPS Failures
OK, guys, here goes.
I am going to launch a bit of research on CPS failures. If you are contemplating replacing yours, it's likely that yours is "getting intermittent". If it has "failed completely", you can still participate in this, though it may still cost you the price of a new CPS.
Since these are solid-state devices, and solder joints are "usually" pretty dependable, there's one place that is suspect to me, the connector itself, or more accurately, the integrity of each individual connection to remain extremely low-impedance (almost zero ohms). Due to the relatively-low level of the signal, and it's susceptibility to PCM-confusing "noise", connection integrity is paramount.
Remember that Ford made a production change and there are CPS's for "early" and "late"? They used standard "tinning" on the early connector pins, while "late" is gold-plated. There is no other difference except the part number. You don't want to use dissimilar metals in connectors, thus the different CPS's to match the material used in the truck's harness as it came from the factory.
Ford didn't make that change for no reason. Gold-plating is resistant to corrosion, and gold-on-gold is NASA-quality. Ford wouldn't go to the use of gold-plated pins unless they suspected a problem with maintaining the electrical integrity of those connections. I can't imagine the pressure on the engineer who told management that it was necessary to ADD cost to the product. But they did it, and that should tell us something.
My engine was occasionally "stumbling", and I have a spare in the glove box as any prudent 7.3 owner should have, but not stumbling so bad as to be much more than an occasional irritation (and embarrassment), so I haven't changed it. I just thought about it, waiting for that Round Tuit....
A couple of weeks ago, I thought it was time to familiarize myself with the procedure and location so that when the time came I could go straight to it. I even went so far as to reach up and release the connector's "lock" and pulled it apart. It was clean inside, with no grease, oil, or contaminants of any kind, but I began to wonder about the "insertion pressures" of these connections. the smallest spec of dust could interrupt the signal if the connections aren't tight. I mated and re-mated the connection a couple of times more to knock off anything microscopic that might be coming between the pins and their sockets, and crawled out from underneath with a question in my mind.
Since that day, I have not had another "stumble" of any kind.
Coincidence? Maybe. But that's not what my avionics background tells me.
So, here's the deal. We need a LOT more feedback on this to see if there's anything to what I'm seeing.
I'm asking any of you that are seeing even a hint of "stumbling" to reach up and de-mate and re-mate the CPS connector at least three times, looking to see if it's spotlessly-clean inside.
Then let us know if yours continues to stumble. We may learn something about the Powerstroke's most common sensor failure.
And sure, I may be WAAAAAY off-base, but I believe it's worth investigating, and we certainly have a large test-base group here.
Oh yea, expect to hear me "drone-on" about this until its proved one way or the other. I can cut-n-paste this until the regulars around here are sick of seeing it. Then, bear with me just a little-bit longer, OK?
Maybe you can comment on this to give it a "bump" occasionally, too.
Pop
I am going to launch a bit of research on CPS failures. If you are contemplating replacing yours, it's likely that yours is "getting intermittent". If it has "failed completely", you can still participate in this, though it may still cost you the price of a new CPS.
Since these are solid-state devices, and solder joints are "usually" pretty dependable, there's one place that is suspect to me, the connector itself, or more accurately, the integrity of each individual connection to remain extremely low-impedance (almost zero ohms). Due to the relatively-low level of the signal, and it's susceptibility to PCM-confusing "noise", connection integrity is paramount.
Remember that Ford made a production change and there are CPS's for "early" and "late"? They used standard "tinning" on the early connector pins, while "late" is gold-plated. There is no other difference except the part number. You don't want to use dissimilar metals in connectors, thus the different CPS's to match the material used in the truck's harness as it came from the factory.
Ford didn't make that change for no reason. Gold-plating is resistant to corrosion, and gold-on-gold is NASA-quality. Ford wouldn't go to the use of gold-plated pins unless they suspected a problem with maintaining the electrical integrity of those connections. I can't imagine the pressure on the engineer who told management that it was necessary to ADD cost to the product. But they did it, and that should tell us something.
My engine was occasionally "stumbling", and I have a spare in the glove box as any prudent 7.3 owner should have, but not stumbling so bad as to be much more than an occasional irritation (and embarrassment), so I haven't changed it. I just thought about it, waiting for that Round Tuit....
A couple of weeks ago, I thought it was time to familiarize myself with the procedure and location so that when the time came I could go straight to it. I even went so far as to reach up and release the connector's "lock" and pulled it apart. It was clean inside, with no grease, oil, or contaminants of any kind, but I began to wonder about the "insertion pressures" of these connections. the smallest spec of dust could interrupt the signal if the connections aren't tight. I mated and re-mated the connection a couple of times more to knock off anything microscopic that might be coming between the pins and their sockets, and crawled out from underneath with a question in my mind.
Since that day, I have not had another "stumble" of any kind.
Coincidence? Maybe. But that's not what my avionics background tells me.
So, here's the deal. We need a LOT more feedback on this to see if there's anything to what I'm seeing.
I'm asking any of you that are seeing even a hint of "stumbling" to reach up and de-mate and re-mate the CPS connector at least three times, looking to see if it's spotlessly-clean inside.
Then let us know if yours continues to stumble. We may learn something about the Powerstroke's most common sensor failure.
And sure, I may be WAAAAAY off-base, but I believe it's worth investigating, and we certainly have a large test-base group here.
Oh yea, expect to hear me "drone-on" about this until its proved one way or the other. I can cut-n-paste this until the regulars around here are sick of seeing it. Then, bear with me just a little-bit longer, OK?
Maybe you can comment on this to give it a "bump" occasionally, too.
Pop
Last edited by SpringerPop; 03-24-2006 at 12:08 PM.
#2
03-24-2006, 11:24 AM
Insertion may play a small role in the CPS failures. I have a background (many, many years)in IT, hardware tech and QC testing equipment for automotive. I will back you up on the insertion and the microscopic "dirt". Many problems can be overcome by simply removing and re-inserting the connection. I am curious to see what comes up with this thread.
#3
03-24-2006, 11:36 AM
Mine stumbled the 1st time last night coming home from Houston IAH where it was 40 deg and damp. Truck hadn't really had time to get hot when it happend. I have a spare black CPS and am trying to replace it this morning. I have already posted my alternator in the way and broken adapter. I'm letting it soak at thia time.
#4
03-24-2006, 11:42 AM
Jeff,
In the avionics business we referred to this method as "rack and re-rack". Troubleshot a lot of aircraft that way. It confirmed a good box with a bad connection.
If this "pans out", I'm gonna' call it the "Pop Fix". Grab the connector, Pop it out, then Pop it back in.....
Pop
In the avionics business we referred to this method as "rack and re-rack". Troubleshot a lot of aircraft that way. It confirmed a good box with a bad connection.
If this "pans out", I'm gonna' call it the "Pop Fix". Grab the connector, Pop it out, then Pop it back in.....
Pop
Last edited by SpringerPop; 03-24-2006 at 12:40 PM.
#5
03-24-2006, 12:50 PM
#6
03-24-2006, 01:26 PM
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Pop, with any luck it will be several years before I have to participate in this test.
Sounds like a reasonable test though. Why spend $60 if a couple of jiggles will do it?
According to that last CPS poll I seem to have a rare truck as there are only a few left with less than 50,000 miles on them.
Sounds like a reasonable test though. Why spend $60 if a couple of jiggles will do it?
According to that last CPS poll I seem to have a rare truck as there are only a few left with less than 50,000 miles on them.
#7
03-24-2006, 04:05 PM
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I just received my new black CPS off of ebay and was going to replace it this weekend. The only trouble I've had is a "split second" hesitation on dead start - initial "lurch" forward, instantaneous hesitation, then "bat outa hell". Don't know if this is CPS related, but figured I'd do it after all the recent threads about CPS. Can the CPS cause this? If so, I guess I could try this and see.
I agree with the potential of your "fix". I'm a UNIX administrator and consequently deal with LOTS of computer hardware. Can't tell you how many times I've had to "reseat" memory, processors, etc.
I agree with the potential of your "fix". I'm a UNIX administrator and consequently deal with LOTS of computer hardware. Can't tell you how many times I've had to "reseat" memory, processors, etc.
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#8
03-24-2006, 04:10 PM
Pop, I was just wondering if you thought CPS failures could be related to chips and programmers? I should have ask when the poll was active. I know mine went out shortly after I installed my programmer. I do like the idea you have and will certainly try it if mine fails. Also, if anyone has one that they think has failed and has time to play, they could reinstall it and test your theory. I think I was so Pi**d, I tossed it down through the woods along side the road.
#9
03-24-2006, 04:52 PM
I'm pretty certain that a CPS "failure" is in no way related to the installation or removal of a performance "chip". Yes, the CPS feeds a signal to the PCM (Powertrain Control Module) and the chip is added to the PCM, but they do different things.
It would be sorta' like saying, "I got a new mouse for my computer, and now I can only see half my monitor's screen." They both involve the CPU, but are pretty unrelated.
I'm sure there are some who can draw better analogies, and those that could tie a mouse to a monitor, but you get the idea...
Pop
It would be sorta' like saying, "I got a new mouse for my computer, and now I can only see half my monitor's screen." They both involve the CPU, but are pretty unrelated.
I'm sure there are some who can draw better analogies, and those that could tie a mouse to a monitor, but you get the idea...
Pop
#10
03-24-2006, 05:27 PM
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Pop,
You may have something here with the connector issue. With the cyclic temps
the device sees over time i suspect it may have a part in the failure too.
Several folks reported they think high temps lead to the failure of their CPS's.
Also, one person mentioned moisture may possibly be a contributing factor.
I'm currently using a new conductive lube on my automotive/home electrical connections to ensure a good longlasting and reliable connection. I'm thinking
i might like to try it on the CPS connection. It seals out the elements real good
and i remember the boat mechanics in the Coast Guard using it all the time.
Nut
You may have something here with the connector issue. With the cyclic temps
the device sees over time i suspect it may have a part in the failure too.
Several folks reported they think high temps lead to the failure of their CPS's.
Also, one person mentioned moisture may possibly be a contributing factor.
I'm currently using a new conductive lube on my automotive/home electrical connections to ensure a good longlasting and reliable connection. I'm thinking
i might like to try it on the CPS connection. It seals out the elements real good
and i remember the boat mechanics in the Coast Guard using it all the time.
Nut
#11
03-24-2006, 05:48 PM
Nut,
Yes! Thermal cycles, too. Thanks for bringing that up!
Moisture, dust, thermal cycles, questionable insertion-pressures, and vibration, all affecting the connector which carries low-level, noise-laden signals that MUST get through reliably for the engine to continue running. Whew!
What an environment for the use of OEM-grade (read: cheapest bidder) connectors. Except for number of pins and physical size, these are basically the same design (except for the plating) as the chassis plug to which the trailer pigtail mates. Not that it's fault-prone, but it has 12-volt power running through it, not square-wave logic signals.
What were they thinking?
Just be very careful about using conductive grease around connectors where you might cause an electrical path between adjacent pins, thus causing further problems.
Pop
Yes! Thermal cycles, too. Thanks for bringing that up!
Moisture, dust, thermal cycles, questionable insertion-pressures, and vibration, all affecting the connector which carries low-level, noise-laden signals that MUST get through reliably for the engine to continue running. Whew!
What an environment for the use of OEM-grade (read: cheapest bidder) connectors. Except for number of pins and physical size, these are basically the same design (except for the plating) as the chassis plug to which the trailer pigtail mates. Not that it's fault-prone, but it has 12-volt power running through it, not square-wave logic signals.
What were they thinking?
Just be very careful about using conductive grease around connectors where you might cause an electrical path between adjacent pins, thus causing further problems.
Pop
Last edited by SpringerPop; 03-24-2006 at 06:29 PM.
#12
03-24-2006, 06:02 PM
Originally Posted by SpringerPop
It would be sorta' like saying, "I got a new mouse for my computer, and now I can only see half my monitor's screen." They both involve the CPU, but are pretty unrelated.
Pop
Pop
I agree that connections is a very weak link with all of the sensors. I work with computer controlled machinary and HVAC equipment. Most of the sensors and relays are in a much cleaner location than that of our trucks. In a lot of cases where controllers and sensors quit working we pull the connectors and clean with contact cleaner and wha-la it works again.
#13
03-24-2006, 06:22 PM
Originally Posted by SpringerPop
Just be careful about using conductive grease around connectors where you might cause an electrical path between adjacent pins, thus causing further problems.
#14
03-24-2006, 06:27 PM
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Originally Posted by jtharvey
I loaded up my connector with dielectric grease when I re installed it, in hopes of sealing out dust and moisture. I've made it a habit to use it on any electrical connector that is exposed to the elements.
Nut
#15
03-24-2006, 06:32 PM
