So took the boat to the marina yesterday, truck ran perfectly. On the way home it cut out a couple times like I was taking my foot off the throttle. A couple hours later and heading back to the marina only to get a block from the house and the throttle starts cutting off. What I noticed first was I would have to press the accelerator about 1/2 way before getting any response then it died at which point I managed to coast into a parking lot.

Cranking and it would hit and miss but I noticed the dash cluster going haywire with the glow coil light clicking on as the engine would cut in and out. Couldn't get it to stay running so pulled the codes and showing a cam position sensor and crank position sensor. I reset the plugs going into the PCM on the left inner fender and tried to start it again but intermittent run/die, glow coil light (with audible clicking noise under the dash in sync with the light), intermittent pedal response during the run phase of the run/die. Did watch the HPOP during one crank and it was up around 650, FICM voltage stayed at 48 and battery voltage never dropped below 12 (per torque)

I gave up and we walked 2 blocks back to the house and grabbed the 95 dually to go tow the 04 home. Got back to the 04 and pulled up behind it to have the wife tow me backwards to get lined up with the side street so she wouldn't have to pull me out on a major busy road. I hopped in and turned the key on to put the truck in neutral and bumped the starter and it fired just perfect. I hopped out, grabbed the chain and waved the wife back. Drove home under its own power just fine.

I find it hard to swallow that the crank and cam position sensors would both go at the same time. I found bad wiring going to the VGT a few weeks ago so I'm going out on a limb and assuming its a wiring problem but need some input from those on here that know.

 

try unplugging the EBP sensor

 

Sounds like an electrical problem that is related to heat. After it cools down, it runs fine.

.

 

My thoughts exactly.

 

The thing is though it had sat for 2 hours then only a block away everything went haywire. After giving up and going to get the other truck was all of 10 minutes when it started right up.

Now this morning I go out to start my Saturday ritual of trying to keep the truck running for another week and the batteries are gone, showing 12.6v at rest but as soon as I key it on they drop to around 9v. These are interstate batteries with 01/14 tags so not sure when they were put in but they were manufactured this year.

I cannot find my Snap On battery tester so I don't have a way to actually test them but with that being said would or could bad batteries be some or all of the problem?

 

You need to check ALL your cable connections at the batteries and the block. I suspect some corrosion has gotten into a connection somewhere, either battery cables, PCM power, or a relay under the hood. When you get voltage that low the PCM starts doing a reset and crazy things can result. I suspect your CPS and CKS codes came from the stall event not from an actual mechanical problem.

 

Thanks, that's exactly what I'm thinking. I have already done dielectric grease on the PCM as well as check all the grounding points but at this point today I just want to get it running long enough to make it 10 miles to the Dealer to trade it off.

 

So my batteries are checking out fine, 12.8 volts now at rest and 12.3 under load. Pulling the wire from the starter on the right fender and touching it to the hot post and the truck cranks perfectly. That's where everything goes wrong, turn the key to the crank position and I either get nothing or at the very best one half a crank followed by clicking like a dead battery. No matter what I try that's the best I get. I have tried turning the key on and cranking it with the wire on the fender from the starter but again all I get is cranking and no start.

Going to go put the gauges on and try a crank from the fender wire with the key and and see what I get as far as voltages and such.

Where are the starter relays etc located?

 

Been through the wiring from the battery to inside the cab and something isn't adding up. I thought I had found the problem with the battery cable going from the left battery to the fuse block because I cut the repaired end off it and just holding it tot the battery I was able to get a crank.

Ran to Autozone and purchased a repair cable, repaired the cables, checked and battery voltage at the fuse block was showing the same as the battery itself, checked all grounds, cable to the starter etc. Tried another crank after insuring the batteries were fully topped off and nothing then while sitting there with the key in the run position connecting the OBD I heard a relay click and the fuel pump come on and cycle so I hit the starter and a crank but never fired.

I gave up for a little bit, put the charger back on and set about pulling all the relays from under the hood and the fuse block in an attempt to find one corroded or something. Let it charge for a while and tried a start again. It cranked and acted like a miss-fire kicking back the starter so I keyed off then on and tried again and back to the acting like its a dead battery.

I'm at a loss at this point as to where or what to look at next. I think that at least one problem is a low voltage issue to the PCM but not knowing where or how the PCM gets its power I'm not sure how or what to check. Even when using the key to attempt to start it and getting what acts like low batteries I can go pull the starter wire at the fender and it cranks full bore yet the key produces a lethargic crank at best or nothing at worst.

The batteries check out with an old school load tester but I don't trust those yet I don't want to go drop $400 on new batteries only to find that doesn't make a difference.

 

Look at the Vref voltage.



Sean

 

Just another place to check. If you lift up the under hood fuse block and pull it forward you'll find this connection. I think it's the main power connection to the batteries for the junction block. Worth a look.



Heres a better shot of it's location on the back side - toward the firewall:


It has this little cover over it:

 

I have an early 04 4WD so will this still apply since it's for an 06?

Like I said above, mine is an early 04 so the fuse/relay block is quite a bit different and is actually two separate parts, one with fuses and relays and the other with just relays.

I have just pulled the interior fuse block and completely disassembled it, polished every fuse, relay and breaker blade as well as all the connections on the back side. I reassembled it with dielectric grease on everything and was able to get a super strong crank from the key but no fire till it misfired and kicked back against the starter. I'm done with it for today so am going to start chasing the VREF and see what I can find there tomorrow.

 

Ask Miles about what a nightmare Vref can be and he has an early.
You still need the Vref for things like the accelerator and all the temp
sensors. I will try to find an early 03~04 and post it for you.


Sean

 

So I have given up trying to R&R the engine wiring harness in the truck so I have begun the process of pulling the harness completely so I can lay it out on the bench and open it up. My plan is to replace any questionable wire with aircraft grade wires.

I have however run into a stumbling block, the harness goes down the front right (passenger side) of the motor and through the bracket for the belt tensioner. There are three leads after that point, 1 to the AC clutch, one to one of the AC lines and a third that disappears behind the AC compressor. Where does the one that goes behind the compressor go? I assume its either the crank or cam position sensor but I'm stumped on that and also stumped as to how to get the connector for the sensor on the AC line through the bracket without removing the bracket itself.

Any insight from some one who has pulled and/or replaced the harness with the engine in the truck? I have the rest of the harness completely free except this one run behind the tensioner bracket.

 

The 04 lives again. Replaced the entire VREF circuit along with every pigtail attached to the engine and the ICP sensor. Hooked up the batteries and fired instantly. Let it warm up to operating temps, smoked the tires down the block and all is well........for at least........well till the next time I try to drive it.

Have no idea where the problem was at, found the ICP and EBP sensors had both had the pigtails replaced at some point. A little oil from the ICP so I replaced everything and all is well for now.