Talk about the 7.3L CPS Here!

May as well get this out of the road. The INFAMOUS CPS thread.

If there is any ONE failure, that can almost be gauranteed on a 7.3 liter powerstroke, its the failure of the CPS.

The CPS is called many things. Ford calls it a "Synchronizer". International calls it a CAMP or CMP. Both names mean one thing. Camshaft Position Sensor.

The failure could be random, such as the truck just randomly dies for no reason, but restarts quickly and runs fine. The failure could also be absolute. Truck dies, never to start again. Or it could be a combination of both, truck dies, but if you wait 10 mins, it will restart.

The CPS failure hardly ever sets a "check engine" light, if you DO get a light, scan for the following codes:

p0340: Inactive CMP signal detected during engine cranking when ICP pressure was sufficient for starting.
p0341: Electrical noise detected, check wire routing and grounds.
p0344: Incorrect number of sync to transition counts detected, possible intermittent CMP sensor/circuit fault.

If you find any of those codes, replace your CPS and check your connectors.

However, the majority of CPS failures will not give you those codes. Another troubleshooting trick must be used, but this one only works on trucks 2001 and older WITHOUT the factory transmission temp gauge in the dash.

On 2001 and older trucks, you can use the TACH needle to troubleshoot a CPS failure. During a long, extended crank with no start, the TACH needle should bounce ever so slightly. Maybe 100 RPM or so. If you have an AIC (Ford Automatic Idle Controller, or APCM) installed, the digital display should also display a low RPM. If you get NO NEEDLE MOVEMENT, and/or NO AIC RPM DISPLAY, its very likely you have a failed CPS. Again, this trick does NOT WORK on 2002 and newer trucks with the factory transmission temp gauge.

Part numbers:

Ford Part Number for mid 97 and newer trucks is F7TZ-12K073-A
Ford Part Number for mid 97 and OLDER trucks is F6TZ-12K073-A
International goes by Serial number:
Engine Serial # 375548 and below is part# 1821720-C99 (mid 97 trucks and older, engine build date of mid 96 and down)
Engine Serial # 375549 and up is part # 1825899-C93 (Mid 97 trucks and newer, engine build date of mid 96 and up)
NAPA Part CSS-512

The Engine serial number is located on a machined pad by the oil filter. You should see something that looks like "7.4 HU2 U *XXXXXX* " where the X's are the serial number.

The difference between the two parts is the electrical connector. All things considered, the two parts are identical with the exception of the connector material. The older trucks use a "tinned" silver color contact, and the newer trucks use a "gold" colored contact. The only reason not to mix them is dissimiliar metals could corrode over time. If you have a mid-97 truck, you should either check the engine serial number, or pull your CPS connector and check the color of the pins on the connector. In an emergency, ANY CPS WILL WORK ON ANY YEAR 7.3 POWERSTROKE.

OK, enough with the history and troubleshooting.

How to fix it.

First, locate a replacement CPS. Ford, International, NAPA, and EBAY all carry the CPS. Ford is most expensive at over 200 dollars. International is around 100 dollars. Napa claims 125 bucks, and Ebay can range from 50-120 depending on the seller and demand. HOWEVER, thru special arraingement for SuperDutyDiesel visitors, www.powerstrokeshop.com sells the correct International/Ford CPS for around 90 dollars. ALWAYS carry a SPARE CPS in the glovebox, it WILL FAIL, and it will do it at the WORST possible time. Be Prepared!

To fix it, your going to need a 10mm wrench (or socket with a short 3" extension, experiment at home to find the exact tool you think you will need if stranded on the side of the road, at night, in the cold and rain). A flathead screwdriver, and a replacement CPS.

Locate the CPS. It is on the passenger side of the engine block. Accesible from under the truck, and located about the 10 o'clock position behind the crankshaft front pulley. Reach up and unplug the wiring harness, remove the 10mm bolt, and GENTLY pry the bad CPS out with the flat screwdriver. The bolt may be VERY TIGHT. Do not round it off. Make sure you have the socket or wrench on SQUARE before really torqing on it. It may even help to break it loose and retighten while at home, to make sure it can be removed easily when broke down on the side of the road.

If your old CPS has shims, do not re-use them with the new CPS. Tolerances have been tightened with the newer CPS' and shims should not be needed.

CLICK HERE FOR A PICTURE

Installation is opposite of removal. Make sure to put a little engine oil on the new sensor's O-ring to easy installation. Tighten and start your truck!

If your truck STILL doesnt start, you've got bigger issues.

 

Daryl GREAT write up, maybe the mods could make this a sticky for a while

 

Nicely done, Daryl.

 

Well done

 

Great write-up Daryl. The only thing I would add would be to stress using a 6 point 10mm socket in 3/8" drive. The 6 point design prevents rounding off. A 3/8" drive is robust enough to get the really tight little buggers out, but not too big to work with in such a tight space. Again...well done.

 

Daryl,

Excellent writeup. Thanks for taking the time to make this contribution to our site.

Mike

 

Great to start out with this info.

If I didnt already have this info when mine went out a few moths back , I would have freaked-out.

This post sould be mandatory reading for all new members. It will reduce a great deal of stress for many Powerstrokers.

 

Been there too

I just had my truck die on the road and I was leaving town, so I dropped it off at the local Ford Dealer. The truck would restart and die right away. Ford diesel specialist said it was my fuel pump. They changed it out with a new one and told me my warranty was voided due to my modified fuel system. The truck continued to die while driving and would restart right away. I changed the CPS and all is well. Now I have to hassel with the Ford dealer about my replaced fuel pump.
I also just picked up another CPS just because.

 

4 degree advance CPS?

I have been told that injector timing can be advanced by 4 degrees by installing a 1807339CXX CPS used for the DT466E International engine. Has anybody done this or know anything about it?

 

This is a great thread. $90 +- is cheap insurance for a failure out on the road. I figure if I don't use it while I own my truck, I could easily get $50 for it at the time of sale of my truck. That makes it a great investment and eliminates the fear of being caught 50 miles from nowhere at 2:00am.
Don't forget in addition to the 10mm socket, make sure you have a good flash light. I bought a LED flash lite for each of my vehicles and left one on for 2 1/2 days and it was still bright. I love them.
Jim