Brad Clayton Posted November 27, 2011 Share Posted November 27, 2011 First I gotta give a big thanks to DTS and all it's participating members. I finally ran into a rusted cam sensor. It had failed in a odd way though. The truck would start and stall but would run with some throttle. The sync pid read ok. It had cam/crank codes in the PCM but they can be set by other failures due to erratic/long cranking. If I hadn't heard about it on here, I could have turned a couple of hour job into a week long nightmare. I honestly would have been chasing or throwing parts at this thing for some time. Well, that's it thanks again to all our members having everybodys' back. Quote Link to comment Share on other sites More sharing options...
mchan68 Posted November 27, 2011 Share Posted November 27, 2011 I have "thrown" way more than my share of engine harnesses at these trucks with the very symptom you describe, so far with a 100% success of repair rate. Of course, this is not before checking the simple things first, like a rusted out CMP sensor flange the way you describe FIRST. Quote Link to comment Share on other sites More sharing options...
Jim Warman Posted November 27, 2011 Share Posted November 27, 2011 I have one on the go as this is written. It is an intermittent cranks/no start. It originally came in with a P2614 along with the "usual" host of other codes. It was SYNC = NO and FICM_SYNC = NO. When the tech working on it at that time wiggled the CMP connector, both PIDs toggled to YES and the truck started. CMP pigtail was replaced, other necessary work was performed and the truck was released. Fast forward to about last Wednesday. Truck was towed in as a no start. Of course I drove it into the shop - no trouble starting it. P2614 and P0528. Verified that it needs a fan clutch. Started the truck several times over a period of time and a visual revealed nothing. Went to back the truck out of the shop.... SYNC and FICM_SYNC = NO. I don't have the adapter for the BOB so I opted for check AC volts and Hz for the CMP (circuit resistance for the CMP and wiring was 835ish ohms). 0 Hz an the signal from the sensor while cranking would only surge to a little over 0.1 volt. A weak signal, thought I. R&I the CMP and found a little skiff of rust on the CMP pad - a few strokes with some emery and it is shiny new (certainly not the displacing mounds of rust I've seen in a couple of pics). The business end of the sensor was growing a little fur - took care of that. The pigtail had been added without twisting the wire pair and without adding any shielding - being the anal !?@#%! that I am, I took care of that, too. The harness was opened from the PCM past the spot where it rubs on the valve cover as well as the entire take-out to the CMP sensor. Both circuits were load tested to about 4 amps as well as for integrity. Reassemble everything and get the same Hz and volt readings on the sensor circuit except that the truck starts and runs once again. After two days of thermocycling the truck, starting it time and again, no repeat failures but I have a hard time accepting what little I did as a "fix". It is going to be a pita trying to back probe the connector but, if the concern reappears, I can only resort to the VMM and looking for a viable pattern. (Oh, if only I hadn't been lazy and done that back when it was a no start. Quote Link to comment Share on other sites More sharing options...
garyb Posted January 12, 2012 Share Posted January 12, 2012 got a 06 f-250 personal truck in shop now and crank no start, ficm sync yes and sync no, with rpm around 92, no dtc's present ficmmpwr, ficmlpwr, ficmvpwr all ok, fuel pressure is 50 psi, icp makes over 500 psi, ipr is at 84% and icp will go up to 1500 psi before ipr starts going down to 50%forgot to check fuel pw while cranking but suspect since the sync pid changes to no may be cam sensor problem? Quote Link to comment Share on other sites More sharing options...
Aaron Posted January 12, 2012 Share Posted January 12, 2012 Also - look in the bore for the sensor, have seen rust up there too, near the o-ring land causing issues as well. If you have one that wont start, pull the o-rings off and install it as a fluke. Quote Link to comment Share on other sites More sharing options...
cbriggs Posted January 13, 2012 Share Posted January 13, 2012 92 rpm is pretty low cranking speed as well. Quote Link to comment Share on other sites More sharing options...
Clark Posted January 19, 2012 Share Posted January 19, 2012 Just curious, what exactly is it about the rust buildup that causes an issue? Quote Link to comment Share on other sites More sharing options...
Bruce Amacker Posted January 19, 2012 Share Posted January 19, 2012 Rust buildup increases the sensor air gap which lowers its voltage output. We're only talking about 2.5VAC idling on a good engine and .5VAC while cranking, so it's important that the air gap not be increased or hard starting (and other freaky, hard to diag problems) will result. 1 Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted January 19, 2012 Share Posted January 19, 2012 ooooh and don't I know it! Quote Link to comment Share on other sites More sharing options...
Brad Clayton Posted February 5, 2014 Author Share Posted February 5, 2014 I thought I had put this document in here some where but I can't find it. This may be a reload. 60 stalls.pdf 1 Quote Link to comment Share on other sites More sharing options...
Mekanik Posted February 6, 2014 Share Posted February 6, 2014 Rust behind a CMP has burned a lot of techs. I mentioned this to a coworker years ago who had a 6.0L that was a no start. The tech kind of blew off what advice I had to offer. 1 FICM and 8 injectors later he was ready to listen. Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted September 22, 2014 Share Posted September 22, 2014 I just had a cam sensor break off in the block trying to remove it. BAD rust. I was taking my time and trying to work it out. Anyone ever had this happen and what was your plan of attack to repair? Maybe I can clean out some of the rust in front of the o-ring and try putting a screw in it to pull on it. Other than that I suppose I am screwed and the engine has to come out. Quote Link to comment Share on other sites More sharing options...
Steve Mutter Posted September 22, 2014 Share Posted September 22, 2014 I had one a couple of years ago. I tried forever and could not get it out but another tech in our shop was able to. He was able to get a screw in the centre and pulled it out with a heel bar. 1 Quote Link to comment Share on other sites More sharing options...
mchan68 Posted September 23, 2014 Share Posted September 23, 2014 I had one a couple of years ago. I tried forever and could not get it out but another tech in our shop was able to. He was able to get a screw in the centre and pulled it out with a heel bar. That's what I did on a plow truck a couple years ago. Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted September 23, 2014 Share Posted September 23, 2014 I have done this several times with crank sensors, this will be more of a challenge Quote Link to comment Share on other sites More sharing options...
Brad Clayton Posted September 23, 2014 Author Share Posted September 23, 2014 If the sensor is rather brittle, then I will heat the extractor screw up a bit with a small torch before threading it in. 1 Quote Link to comment Share on other sites More sharing options...
forddieseldoctor Posted September 23, 2014 Share Posted September 23, 2014 I had a oss sensor on a 4r100 that I 2 part epoxied a lag bolt into it to get the rest of the sensor out. Quote Link to comment Share on other sites More sharing options...
BrunoWilimek Posted September 26, 2014 Share Posted September 26, 2014 I also had one break off and the screw trick and a lot of patience paid off. If you have a very small carbide burr, you could very carefully work around the edge of the hole to remove rust buildup. Good luck with it. 1 Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted September 27, 2014 Share Posted September 27, 2014 Forgot to update my last post: I got the sensor out without resorting to anything drastic but this was a first for me with regard to the severity of the rust. The sensor bore had rusted badly up to the point where the o-ing was and ironically this is where the problem lies as the o-ring is what gets stuck on the rust. When I broke off the top of the sensor it broke cleanly at the o-ring groove. Once I picked the o-ring out the sensor literally slid out on its own... until the o-ring on the other end got caught on the rust. At this point I had a good piece of the sensor to grab onto and work it out. Cleaned up the hole and prepared it for a new sensor. There was a lot of metal missing around AND INSIDE of the hole at this point after I got it all cleaned up. I opted to seal it with a little anaerobic sealant. This leads me to two things we do not talk about in depth yet:First, What to do to mitigate continued rusting at the block and the CMP sensor mount? I believe rust must be completely removed if possible otherwise prevention methods will be reduced in effectiveness. Paint is one option however paint apparently does not last in some areas of the country especially where I am in New Jersey. For now I have resigned to using a liberal coating of anti-size compound applied to the bare metal and around the immediate area. So far, so good for me as I have not had any repeat failures from this concern in the last 6 or 7 years since I have been seeing it. I am sure there are other methods/products that would work - please share if you have anything to add!Second, the issue at hand here is RUST JACKING of the sensor. This means that the metal under the sensor expands the surface and literally lifts the sensor away from the cylinder block effectively increasing the gap at the tip of the sensor causing weak cam signals. But what about the repair process and removing the rust which has removed and displaced the metal? Now you have a sensor mount that might allow the sensor to install further into the block potentially causing it to strike the pin on the camshaft that creates the signal thus damaging it. I do not know what the normal gap is and how much tolerance we have to deal with here but you get my point.I have looked at this and determined that on every single one of these I have "repaired" the block had not rusted under the metal insert of the sensor mount where the mounting bolt goes, effectively leaving an un-rusted circle on the block. I am of the opinion that preserving this area will allow a new sensor to seat and remain at the desired position despite there being a gap between the rest of the sensor mount and the block. So it is important to recognize and observe that circle around the sensor bolt hole on the block. Quote Link to comment Share on other sites More sharing options...
Bruce Amacker Posted September 27, 2014 Share Posted September 27, 2014 First, What to do to mitigate continued rusting at the block and the CMP sensor mount? I believe rust must be completely removed if possible otherwise prevention methods will be reduced in effectiveness. Paint is one option however paint apparently does not last in some areas of the country especially where I am in New Jersey. For now I have resigned to using a liberal coating of anti-size compound applied to the bare metal and around the immediate area. So far, so good for me as I have not had any repeat failures from this concern in the last 6 or 7 years since I have been seeing it. I'm glad you were able to remove the sensor, that would be a real PITA if it escalated to the point of engine removal (or worse) for extraction. I've used chassis grease for decades in situations where I needed to stop repeat rust, a coating of grease on the sensor as it goes into the hole will stop future corrosion for many years. A good spray lube could be used to prevent the problem by shooting the sensor area ahead of time to slow or prevent rust jacking. "Good spray lube" IMO is one that does not dry up to a dusty residue after a year or more. Cheap spray lubes do this. Sidebar- IH uses the same PN sensor as a CKP in a DTEGR/MFDT engine and it has the same rust jacking problem. It's mounted (dry) into the flywheel housing, external of lubricated components, reading a trigger wheel pressed onto the crank between the RMS and the flywheel. In worst case scenarios the techs drill the sensor out, letting the crap fall into the bottom of the bell to lay forever, and install a new sensor. Quote Link to comment Share on other sites More sharing options...
Aaron Posted October 12, 2014 Share Posted October 12, 2014 I use a tek screw, heat it up glowing and ram it into the sensor. Go have a smoke and let it cool then pop it out with a heel bar. failing that I have a die grinder similar to those used in dentistry. Get the tiniest bit on it and let it eat. Makes quick work of that. Works good on broken bolts you just can't weld to as well (rearmost one on the left side of an ls in a GM pickup) Quote Link to comment Share on other sites More sharing options...
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