A few years ago I had trouble with my 99, Ford F205, 7.3 L. I changed the CPS and have driven trouble-free for a long time. I am experiencing the same problem now, running very rough and now the vehicle will not start. The CPS that I replaced had a grey body, which I was told was the new style. Could it be that this unit has gone bad also? The symptoms are the same and the DTCS code I am receiving is p1670. I think that I was clever enough at the time I replaced the original CPS that I bought two of them! I have it in my toolbox now and can install it in the morning.
Comments please?

 

It's easy enough to do. Why not do it.

 

Yes I know and I will do it in the morning. Just looking for a little confirmation on my thoughts. I was thinking about the frequency that these sensors could possibly have, like how many miles could I reasonably expect for one to last.

 

The p1670 code is specific to the IDM, (unless there are multiple codes). Unlike the p1668 which just lets you know the IDM has a stored code, and more often than not is the UVCH, this one is definitive. It is communications loss between the PCM and IDM. To rule out wiring:

Key off , PCM disconnected, Disconnect IDM, Check for intermittent open in the following circuits:

Measure resistance on (FDCS) Circuit 821 (BR/O) between IDM connector Pin 17 and PCM Pin 95.

Measure resistance on (EF) Circuit 818 (GY/W) between IDM connector Pin 4 and PCM Pin 48.

Grasp the harness close to the IDM connector. Wiggle, shake the harness while working your way back to the PCM, while looking for a spike on the DVOM.

All readings should be below 5Ω

Hopefully you will find a chafe or broken wire. If not, the IDM "may" be defective. But further testing is required with a bi-directional scanner.

 

I am not sure I know where all those things are, Tom. I do know that the CPS will prohibit the start and it will make it run rough. Which is the same thing that it did when I replaced the original one. I think I will need to replace the CPS before I try other things because that is the only thing that I can do, on my own, right now. But my query is how long can I expect this CPS to last? is this something that will need replacement every few hundred thousand miles?

 

There is no rhyme or reason as to why some last longer than others as long as they are FORD or International OEM parts. I had one in a 2000 X that went bad at 2000 miles. Replaced it and that one went an additional 180K. Then, after that I have never had another one fail. I do keep an additional CPS in my glove box along with a 10mm socket, 1/4 in extension and drive just in case. One and lesson learned.

 

Oh absolutely since you have one.

It's actually a CMP (Crankshaft Position). CPS is Cycles Per Second. Whatever...

The CMP signals the IDM via the PCM that the #1 Cylinder is just before TDC and the IDM is signaled to initiate injector pulse to deliver fuel in order of programming.

Its a Hall Effect Sensor. One of the oldest types found in vehicles. Meaning its either on or off for a prescribed period of time using a magnet to close the circuit.

They should have a very long life span. Ford did have problems with them 99 - 02. I've never changed the one in my personal truck (99) but have it in the Glove Box in the event it ever goes. I figure why replace it if its still working. Some people don't have much luck with them lasting any time and others (like myself) have gotten 200k miles without an issue. I do think the OEM is the way to go though.

You may also wish to check the UVCH anyway to see if there is a problem their. Even though the code should not relate to that if its the only hard code, doesn't mean that's not the problem I've found.

You can't always go by the Factory Service Manual or you'd go frigging crazy.

 

Thanks Tom - yes, the one I have is genuine Ford. As soon as the rain stops tomorrow, I'll "get out and get under".

 

CPS is the weakest link. Always check it first, and carry another one. The second weakest link is the valve cover connector. The third weakest link is wires rubbing through so they short out. But check that CPS first.

Riffraff has the latest CPS version (C) at the best price and EXCELLENT customer service!

Good LUCK!

 

Just waiting for the sun to come up to do that. I have a new one ready to go in in my tool box.

 

Waiting for the Sun in Sunshine. That's funny!

Good luck!

 

Yes, but there is rain, too! I'm getting pretty tired of Louisiana! Thanks...This is my second one, not at 350,000 miles.

 

I am on my 3rd at 270k. When the first one went the truck was almost new. Scared the crap out of me. That is when I first joined FTE. They told me the problem before the dealer could. Been here every since! FTE is a great wealth of knowledge along with some smart people.

 

Yes, that is exactly why I am here! I've been a member since 05!

 

An update to share. I have changed the crank position sensor for a new one. I have changed the injector pressure regulator. It now appears, with the help of my local diesel mechanic, That D Ford cylinder on the passenger side is not running properly, too cold. It appears as though that in injector has gone on vacation or perhaps to the graveyard? Does anyone have a good idea where I can get a good working used injector? My truck has 350,000 miles on it and I do not see the sense to install a new injector. Therefore I am looking for a working used injector as all the other seven have now also 350,000 miles on them. If it's not broken, don't fix it.