mchan68 Posted March 20, 2010 Share Posted March 20, 2010 Hello gents. I have one here sent to us by a good parts customer. They've borrowed my 'tester' FICM and it failed to start. They've replaced the CMP and CKP sensor without success. When I got to it, I monitored my usual favourite 6.0L no-start PIDs and found the following: MAP reading at 13.95 psi (lower than the other two, but insignificant) ICP psi and volts well within specs at KOEO and while cranking, even though P2285 and P2286 were set FICM PIDs dropping out as weak. (I ran a buzz test and got all eight injector circuit low DTCs typical of that of a FICM failure. Plugged mine in, and I hear a good strong buzzing and passes buzz test) RPM increases only to 35 MAX RPM and intermittently drops to ZERO (even though the shop already replaced a CKP and CMP sensor). FICM SYNC and SYNC fail to switch from 'NO' to 'YES' despite good battery voltage I ohmed out both the CMP and CKP circuits at C1381C (PCM connector) with 839 ohms on the CMP and 369 ohms on the CKP (WELL WITHIN SPECS) I even swapped a known good PCM temporarily for shits and giggles and got the same readings My question now, is where do I go with this? I know that '04 model years are pretty notorious for engine harness failures, but this would contradict the fact that I have GOOD ohm readings wouldn't it? This leaves the crank sensor tone ring as the only thing possible that could be suspect, correct? There is a P0336 set in memory, which is consistent with the erratic RPM readings while cranking the engine over. Vehicle is a late-build 2004 with 87,000 kms. on it (about 50,000 and change miles). Quote Link to comment Share on other sites More sharing options...
Alex Bruene Posted March 20, 2010 Share Posted March 20, 2010 Make sure the sensors are pushed in far enough, and not hung up on the o-rings. Quote Link to comment Share on other sites More sharing options...
Bruce Amacker Posted March 20, 2010 Share Posted March 20, 2010 What's cranking RPM? A good one is 215 warm, I like to see a minimum of 175 cold. Quote Link to comment Share on other sites More sharing options...
mchan68 Posted March 20, 2010 Author Share Posted March 20, 2010 What's cranking RPM? A good one is 215 warm, I like to see a minimum of 175 cold. RPM increases only to 35 MAX RPM and intermittently drops to ZERO (even though the shop already replaced a CKP and CMP sensor). FICM SYNC and SYNC fail to switch from 'NO' to 'YES' despite good battery voltage Which I call bullshit on. I had two booster sources hooked up while cranking the engine over, and I can tell you that it's easily cranking better than 150 RPMs if not more. I have a couple of old 12B637 harnesses laying around that I might snip the CKP pigtail and the PCM female pins out of, to overlay the circuit on Monday before I dig into the pan. Even though both the CKP and CMP circuits check out good, I guess it's something else I can check quickly. I just have this awful feeling that pulling the pan isn't going to reveal much if anything. Quote Link to comment Share on other sites More sharing options...
2006 Posted March 20, 2010 Share Posted March 20, 2010 Is this a E or F series. If its a E, its more likely to be a wiring harness Quote Link to comment Share on other sites More sharing options...
mchan68 Posted March 20, 2010 Author Share Posted March 20, 2010 Is this a E or F series. If its a E, its more likely to be a wiring harness F-350 Regular Cab 4x4. Quote Link to comment Share on other sites More sharing options...
Bruce Amacker Posted March 20, 2010 Share Posted March 20, 2010 Like Alex said, make sure the sensors are bottomed. I think Keith had one or two CMP's where they were held up by rust, you might want to pull them out and buff the flanges. Perhaps looking at the CKP reluctor (and probing it with a screwdriver) is not a bad idea in case it came loose on the crank. Look through the hole with a penlight while someone turns the crank very slowly. (This may require yanking the A/C) I'd only pull the pan after coming to at least two reasons to pull the pan- bad waveform, loose reluctor, low cranking voltage, etc. I was involved with one not long ago that had a BENT reluctor tooth on the CKP, too, and the shop changed the short block without letting us know what bent the tooth. (Damn!) The scope pattern showed the bend very clearly, I have captures if you want to see them. Overlaying the harnesses is a good idea. I've seen a few situations where the wire "looked" good but bled voltage through the vinyl insulation. It was a real MF to diagnose. IH has a lot of problems where overlays fix it. Getting out the scope is another option, I've posted known good waveforms here somewhere, and don't forget the remote possibility of a bad starter causing CKP interference. Someone on DTS had that a year or two back with a LCF where a new starter fixed it. Sorry to give you a laundry list, I'll look in my Sync notes for more stuff to check... Good Luck! Quote Link to comment Share on other sites More sharing options...
Alex Bruene Posted March 20, 2010 Share Posted March 20, 2010 Last year, I had a DIY have a truck towed in for us to program a new FICM... Upon replacement of said FICM, the truck still wouldn't start... Then I got the real story... Turns out he had all the usual FICM codes, as well as P2614 and P2617. So, in the DIY world, those codes mean it needs CMP and CKP sensors, so he replaced those with no success, then replaced the FICM (not realizing it needed programming), it still wouldn't start (obviously), so he towed it in for programming. I programmed then FICM, still wouldn't start... I checked the usual no start PIDS, and it was only showing 45 RPM cranking speed, I checked the sensor resistance at the PCM, which was okay... so I was about remove the oil pan to check the tone ring, but being a manual transmission I chose to R+I the CKP sensor instead, where I found it not pushed in... Good thing it wasn't an automatic, or I'd have probably wasted my time removing the oil pan... Quote Link to comment Share on other sites More sharing options...
Jonathan302 Posted March 20, 2010 Share Posted March 20, 2010 Like Alex said, make sure the sensors are bottomed. I think Keith had one or two CMP's where they were held up by rust, you might want to pull them out and buff the flanges. Good Luck! +1 check out for rust under these 2 sensors. I've seen that on a couple of 6.0l.(Thanks for the very salty road here in winter) The rust pust out the CMP or the CKP and lost the trigger signal espacially in cold weather. Take a closer look to the CKP since you lose RPM signal(CMP is likely to affect FICM sync pid) Try to carefully heat the CMP with a heat gun(to make it expand)Sometimes it works and save me to push or pull the fucking truck inside the garage Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted March 20, 2010 Share Posted March 20, 2010 CLICKIE HERE to read the topic where I found that the block had rusted under the CMP and literally lifted the CMP sensor away from the block causing a weak signal. There are several more good topics on using the oscilloscope and cam/crank signals. Quote Link to comment Share on other sites More sharing options...
mchan68 Posted March 25, 2010 Author Share Posted March 25, 2010 Well, after testing those two sensors, with the 150 to 190 Hz readings for CKP and 1.1 to 1.9 Hz that Hotline gave me, I ended up with CKP readings of 150 and change, and 1.2 and change for the CMP, dead smack within those specs listed. I checked those readings with both my own CKP and CMP pigtails, as well as at pins 30, 31, 41 and 43 at C1381C achieving similar readings. Shooting it with Brake Clean managed to get it fired up and stay running on its own accord. A little wiggling of the harness at the ICP sensor area caused it to sputter, fart and quit. Soooooo, a harness, FICM and MAP sensor later, life is all good again. Meanwhile, Hotline was almost insistent upon me pulling the pan (which would've ended up being wasted time). Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.