My own Grey vs. Black CPS testing
 

I had a chance today to compare the grey and black CPS's side by side, and give you guys some results that you can actually see. I took several pictures showing the size variations, as well as showing the differences in the magnetic strength. The results are conclusive, there are distinguishable difference between the two. Check it out with your own eyes.

First, here are the results of AE and the changes in cylinder rotation. Most cylinders remain mostly the same, however notice the distinct changes in the #3 and #8 cylinders. My #8 drops to zero because I'm running a regulated return and an AD injector instead of an LL. Those with LL injectors probably won't see 0% on #8. I put down the ranges that I saw with each cylinder, with the minimum and maximum values seen after monitoring each cylinder for more than 1 minute each. Engine was completely warmed up each time, with extended drive cycles to ensure that testing was fair and equal.



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This is all the testing I could think of. Unfortunately I don't have other testing materials such as an oscilloscope to compare signal differences between the two. A while back, Swamps offered to run a test between grey and black CPS's using a cam timing gear, a variable speed motor, and an oscilloscope to see if they could in fact find signal differences between the two sensors. A test like that would verify what many PSD owners have seen with scanners hooked up to their trucks. If they do move forward with that test, I would be very interested to see the results.

On my truck, the grey CPS did not pose enough of a problem to actually trigger a check engine light, or to fail the CCT. However, results may vary with other engines. It is obvious that there is an effect on the #3 and #8 cylinders. Most of the rest remained about the same, with only a small rise on #5 with the black CPS installed.

Right now I am taking a guess that the weaker magnet and slightly shorter sensor has an effect on when the CPS actually picks up the cam timing gear, which would have an effect on injection timing as well. Feel free to discuss or post up ideas or additional information.

Either I'm blind, or you're pictures didn't come through. Your results do seem to mirror what others have seen. I noticed the difference in size and magnetic strength also, but was not smart enough to figure out the washer test. I just thought it seemed weaker:-banghead I'll rep you for thinking of that if they'll let me.

I did notice you failed to mention if you noticed a smoother idle when switching over to the black.

As for discussion, it would seem to me the shorter shaft should have the stronger magnet to compensate and keep the readings accurate. I've wondered what effect the new sensor has on timing, and why it seems to have such a negative effect on #3. Since the index marks on the cam gear are on #1 & #4, it appears to me that the cylinders (in firing order) right before the index marks seem to be affected the worst. Almost as if the timing is retarded until the indention in the cam is read and those injectors are cut short to get back on time.

I wanted to check the timing, but couldn't find the #1 plug wire to hook my light to:-missingt

Edit: No go on the reps.

Crap, I need to fix the pictures. They showed up at first.

On edit: are they showing up now?

Very nice Curtis. I'm going to venture a guess and say you're sticking with the old black one?

EDIT: I can see the pictures.

Sweet, pics are working.

As for which one I'm running.... I'm keeping the black one simply because of the numbers. I did drive around with both, had both idling, and tried to tell if there was any difference between the two. To be honest, I couldn't tell. My truck runs really strong and smooth anyway, and with the numbers I pulled from the grey CPS, it seems that it didn't have as large of an effect as some other people have experienced. I'm sure if I had #3 and #8 cylinders showing 5% change in rotational velocity, then probably at that point I would have noticed a difference in idle tone or in the way the truck ran.

I can see the pics now. The biggest difference in idle I noticed was the vibration felt by placing my hand on the stick. Guess you'll just have to take my word for that one. I also noticed it seemed to start a hair quicker, but wrote that off to wishful thinking until others started mentioning it.

I guess what we really need now is someone smart enough to understand all this to cut them open and see what the differences really are. If the old mode of failure had to do with windings, I hope swamps checks this part out as well.

Tried to rep you, got the dreaded "spread it" window.

And here I thought I've spread enough bull....

Stewart :D :D

Great post Curtis. Reps to you. And yeah, it let me. :)

nice write up Curtis! reps sent!

Nice write up, I wish I could have gotten a oscilloscope for you to test this in depth but it sounds like you would need more then just that. I would rep you for all the work put into this but I need to spread "IT" around.

does anyone know why they changed to the grey in the first place, it seems silly to me that they are recalling your trucks to change these over when all you guys are finding them to be worse than what you had..

Nice job Curtis. I'm going to hold out with the black ones I have left for as long as I can.

Thanks, Curtis. I had mine done under warranty back in October, and I haven't noticed any differences either. I'm going to look at mine as well. Currently running the gray, but I'll look around for a black one...

Nice post Curtis, very informative. By any chance do you still have your old dead (black?)CPS?

Yes, I was thinking of cutting it open to look inside. I also have another grey one that I can cut apart too, that way I can compare internal differences. Just gotta find time to set aside and pull them apart.