Gray Ford Recall CPS vs Black International CPS

Keith Browning · August 9, 2011

This was a post from the Diesel Stop that I thought was interesting. Except for a few isolated vehicles I don't recall having many issues with the grey CMP sensor though I know we had some discussion on it. If you read this post it's hard not to think that there isn't some truth to it but I also cant help but wonder is some of these 7.3L owners don't have pre-existing problems that the new sensors make more evident. I know these sensors can affect timing...

I've

Recently I was having a problem with the engine missing pretty bad. I researched here and discovered problems with the UVCH. I got an AutoEnginuity from ITP (kudos Dennis) to confirm. Also found out about the small repair clips from here. Did the scan, found out which side was bad and made the repairs. Again with helpful instructions (kudos guzzle) found here.

Afterwards I started playing with the different features of the Auto Enginuity only to discover that cylinder #8 failed the CCT. So I did the Cylinder Rotational Velocity test. Well #3 and #8 %s were high. I also had a ever so slight miss after the CPSrecall, but it was so slight that I ignored it.

These test results get me all worried though, thinking that I've got a real problem. I was thinking bad injectors, worn rings, burnt piston, and buying myself all sorts of troubles. Back to the site I go looking for answers. I stumble across some posts about the gray CPS causing the same problems I'm experiencing. I can't figure out how the CPS can be the cause of the failed #8 CCT or the PREDELS being so out of whack for #3 and #8. But nonetheless that's what a few members have suggested.

Researching here I discover that IH has a replacement CPS. So off I go to McCandless International Trucks in Las Vegas, on a Sunday no less, for the recommended replacement. Out the door for only $48. I figure for that price it's worth a shot. I replaced the CPS and here's the results:

Gray Ford Recall Replacement CPS:

EOT: 190.85*F

CCT: P0284 Cyl #8 Injector Circuit Contribution Balance Fault

Cylinder Rotational Velocity Change % (PERDELS):

#1 0.9%

#2 0.5%

#3 2.5%

#4 0.7%

#5 0.0%

#6 0.0%

#7 0.0%

#8 4.3%

Black IH CPS (P/N 1821720C99):

EOT: 190.4*F

CCT: Test Successfull

Cylinder Rotational Velocity Change (PERDELS):

#1 1.0%

#2 0.0%

#3 0.2%

#4 0.4%

#5 0.4%

#6 0.0%

#7 0.0%

#8 1.2%

There you have it folks. The numbers speak for themselves. I think this is pretty definitive. The gray ford cps, while it resolves the stalling issue, has created another performance issue.

My engine also idles smoother than when it was new. That annoying vibration that was always present since the truck was brand new is also now gone.

There you go. If you're experiencing that ever so slight engine miss, try a new CPS from IH.

I also want to note that the diameter of the IH CPS is larger than the ford cps.

Thanks again for all the help you guys have given me. I hope this bit of information will help someone else.

See ya on the road,

Pat

Black IH CPS (P/N 1821720C99):

This is the part number for the older 7.3's but from what I have read, they work in the newer ones too. The part number for the newer trucks is 1825899C93, but I have been told that those are now the gray ones, just like Ford.

Back when both CPSs were black, the earlier one cut off in mid '96, IIRC, with the difference being the older one had different plating on the connector pins. I think it was tin vs. gold. The story was if you mixed the two (gold cps in an older truck with tin plated connector or tin cps with newer gold plated connector) corrosion could occur and cause problems. Otherwise I believe the early and late CPS were identical. Only the later CPS was affected by the recall, as far as I know. If your truck is on Ford's radar (serviced at a dealer), then you should have gotten a recall letter if the 97's were included in the recall.

Here is some additional data, with a little background info. My original CPS acted up a couple of times about a year and a half ago (around 120k), but never completely died. The first time, it didn't throw a CPS code, but did the second time, so I replaced it with a new gray one. This was before the recall, which I still haven't had done. I kept my original black CPS, and bought an additional gray one as a backup. I did a cylinder contribution test and the Cylinder Rotational Velocity Change % with each of the four sensors. I ran the engine between each CPS change to get the oil temperature in the same range for each test. The oil temperature was between 162-165*F for each one.

The "New Black CPS" is an IH CPS (# 1821720C99) that I picked up today at my local IH dealer for $40 and change. The CCT passed with this one. This is actually the part number for the older 7.3s, but also seems to work in the newer trucks.

The "Old Black CPS" is the original one that came in my truck. I put it back in just to run these tests. The CCT passed with this one also.

The "Old Gray CPS" is a Ford gray CPS that has been in my truck for the past year and a half. The CCT failed on cylinders # 3 and # 8 with this one.

The "New Gray CPS" is a brand new Ford gray CPS that I have had for over a year, but it just came out of the package today to run this test. The CCT failed only on cylinder # 8 with this one.

Here is the Cylinder Rotational Velocity Change % data:

Cylinder...New Black CPS...Old Black CPS...Old Gray CPS...New Gray CPS

....1...............0.1.................0.1....... ..........0.1.................0.1

....2...............0.7.................0.6....... ..........0.5.................0.6

....3...............0.0.................0.0....... ..........1.6.................1.5

....4...............0.2.................0.3....... ..........0.2.................0.1

....5...............0.1.................0.1....... ..........0.0.................0.0

....6...............0.0.................0.0....... ..........0.0.................0.0

....7...............0.0.................0.0....... ..........0.0.................0.0

....8...............0.9.................0.8....... ..........2.8.................2.7

It's clear that on my truck, there is a difference between the black and gray sensors on cylinders # 3 and # 8. Even though # 3 passed with the new gray sensor, the rotational velocity was only 0.1% different than the older gray one that failed on this cylinder. I'm going to stick with the black on for now, but will probably recheck these numbers in a few weeks.

DieselD · August 9, 2011

I have to wonder if these guys are just looking from something to talk about and over think. With the craze of internet forums it always seems someone is looking for internet fame.

I have had a couple issues installing the grey cmp with a stall or no start but its always been related to the connector on the wire harness having a pin fit issue. replacing it takes care of it.

A couple red flags pop up here with this guy. One he is using a aftermarket scan tool, are we sure there is not a flaw in its programming? sorta like when we have the false codes? I remember cyl 8 failing the contribution test quite often even on perfect running trucks. I also remember having to run that test multiple times to get a average reading and even at that I would double check with another method to conferm

Jim Warman · August 9, 2011

A lot of posters over in the monkeyhouse are too busy practicing "one-upmanship" to actually do much of anything. I used to tell them "if you turn over enough rocks, you will find bugs". But, for many of them, the thrill isn't in having a diesel truck - instead, it is in being "smarter" than any tech or engineer.

This yahoo is chasing something that might be more inagined than real... and to make matters even more dubious, he is using the good old "pantsometer" as much as anything else.

We are used to seeing the perdels for #8 to be out of whack with the other cylinders and, unless I am sadly mistaken, isn't #3 the cylinder that gets most of the solid trash out of the airstream?

You have a truck that may well have had an open weave filter for a long time affecting cylinder seal... shit under a valve... exhaust valves that are about <that far> from hanging open due to crap on the stems/guides.

The guys testing has shown some differences but I don't see anything scientific or definitive. He does list oil temp with his data - but localized temps within the motor may differ from the temperature surrounding the EOT sensor.

What about other engine mods? Zoodad? 10K? Chipped? Is his oil fresh? Or has Spamsoil told him the crap is good for another 30K as long as he replaces the spamsoil filter?

You'll be happy to know I will have wayyyyy too much time on my hands for a few days yet.... Posted Image