2004 Ford F350 - No Start At Times FIXED!!!!

[liljoe]

This truck came in for no start when hot, but not every time, the customer had pulled the valve covers and ran it and seen a small oil leak around one of the injectors, he had me pull and re-seal all the injectors. Did not solve the problem, I finnally got the truck to not start for a min, and while cranking the high pressure system was acting like it should, desired and actual matched. What I did notice was that the RPM was showing around 60 when cranking and no start, before I could go any futher it started and failed to not start the rest of the two next days, stuck a new crank sensor from ford in and gave truck back ( on a friday ) monday it was back with the same problem.

When it wouldn't start it was now showing zero on the RPM. checked the wireing for crank sensor and it checked good, the PCM has three connectors, the crank sensor goes into the center one, during no start if you have meter or scope hooked on the two crank sensor wires, it shows zero volts a/c and a basicly flat line, you can unplug the center connector on the PCM and you now have a signal from the crank signal, plug it in and signal goes away. While testing had a jumper wire ran from the starter relay undr dash to under the hood so I could crank and watch my scope at same time, when I hit it with the jumper wire the truck started, shut it off and no start with key, hit jumper and fired right up, did this three times, by time I got in truck to test volts a ign switch, it decided to start starting with the key.

Discussed with customer ( who happens to be industral electrician ) and left him some jumper wires under dash to crank with if it happened agian to see if it would start then, that was friday. He took truck and it started fine the rest of the day and on saturday, sunday when he went to leave church, it would not start. Went back sunday night and still no start. Monday morn it fired up and ran great, drove it here and it has only failed to start one time. I checked the signals from the PCM to the FICM on the IDM fuel delevery wire and the IDM cyl ID wire, both signals looked the same as when it will start. Any one got any advice that does not include explosives???? If so, MANY THANKS!!!!!!!!!!!!!!!!!

[liljoe]

Forgot to add that sunday the truck wouldn't start even with the jumper wires. My thinking was that maybe the ign switch had a bad place in it.

[steven kiser]

not sure if this is the engine, but if the crank sensor slides into the block to read a reluctor ring on the crank remove it and hone the hole. we use an old wire hone we used on the g.m. calipers. clean the heck out of the hole and look inside. you may see a little rust collar. if there is this is your issue. it must be removed. it's right where the seal sits and will under different temperatures will shift the sensor just enough to make a no start issue. i had one that i banged my head over. the local dealer claimed it needed a crank or possibly a block because it was loosing or misreading the signal.

these engines have an issue with breathing and the way the sensor sits it allows water to puddle up in the sleeve. it's a real pain to see inside the hole and i purchased a remote vision tool from snappy. i had a provision i used in the past but when i saw the snappy one it was love at first sight. the probe was so flexible it was amazing and user friendly.

[liljoe]

I will pop the sensor back out and take the snappy gyno cam and take a look see in the hole for any rust. Just looked at the old sensor I took out and it is rust free, I know that says nothing about the hole, so I will look in just a bit. Thanks, and yes the gyno cam is an awesum tool for many different things, beats the old flash light and mirror deal of the past!!!! Of course they came out with the first one and I had to have it right away, then not long later they made me have to have the one that records and takes pics, now they have one that the moniter is wireless, but it takes no pics or vid, so I think I will kepp the one I am useing now.

[brianp87]

Gl I have no ideas I would try to get him to leave it until it does it for you

[liljoe]

Right now I have the truck for a few days. It has started at least 20 times today already, I have my scopes and meters on the ready incase it fails to start for me. I hope to find the problem and get this behind me, it is causeing me too many grey hairs....

[brianp87]

I know the feeling I have a jeep here that never starts for them but always for me.

[steven kiser]

we have a tool that plugs into the diagnostic port and will record all information while it's plugged in. all we ask is that the car is brought in within 24 hours after it exibits the problem. it will record over it if not. we've identified some real busters this way. we plug it into the main shop computer and can see frame by frame what's happening when it's doing what's it's doing. the customer can leave once we take the recorder off and we'll call them with a diagnose, price, and appointment schedule.

[liljoe]

we have a tool that plugs into the diagnostic port and will record all information while it's plugged in. all we ask is that the car is brought in within 24 hours after it exibits the problem. it will record over it if not. we've identified some real busters this way. we plug it into the main shop computer and can see frame by frame what's happening when it's doing what's it's doing. the customer can leave once we take the recorder off and we'll call them with a diagnose, price, and appointment schedule.

I have the Crecorder, that is what it does. The only thing that is happening on the scan data when it will not start is that the RPM reads zero and FICMsync is "no". All the other PIDs are the same as when it will start. The weird thing is that if you scope the wires from the crank sensor at the PCM while it will not start, you have no crank signal, just un-latch the connector from the PCM and the signal is a nice looking sine wave of about .9 volts a/c with a double size wave at TDC. You do not have to move the connector to un-plug it from the PCM, you can wiggle the wires and it has no effect on the signal. I had thought that the PCM was bad, but we swaped it from another truck and the problem is still on this truck and the other still has no problem.

I honed the crank sensor hole yesterday till it shines like new money, still waiting to see if it fails to start any today. It only did one time yesterday, but it was before I honed the hole.

My thinking towards the ign switch seems to flawed, the FICM voltage is at battery voltage when cranking (on the scanner) during the no start. It is hard to track down a ghost that only appears randomly and for short peorids of time. If it would only start as reliably for the customer as it does for me, all would be good enough for him.......

[steven kiser]

i'll light a prayer candle for you.

[liljoe]

i'll light a prayer candle for you.

I hope it is red paper covered with a green wick (fuse)!!!

[steven kiser]

christ joe i'm not fishin, i'm prayen............ ever paid for one prayer candle and go wild and light two? living on the edge. since you mentioned the red stick have you ever wiped the sweat off the stick and flicked it against something? don't be drinkin when you do it. you could accidentally flick it into the sawdust the "candles" are in. oh ya, don't do it to long you may get a headache...........the nitro will give you a major cranial ache. the vapors will get to ya.

[liljoe]

Finnally got the truck fixed lst week during vacation week. Found a wire from the pcm to the trans shift solenoids that was rubbed through on the top of the trans on one of the ribs on the case. When the wire would ground, the PCM would pull the crank signal down, I started unhooking one wire at a time from the PCM and finnally found the problem. I could make the truck start or not start when I would ground or unground the wire, after the rapair I kept the truck for the rest of the week and started it over 100 times over four days with no problems If this problem came in again and I hadnot had this experance, I think that I would prob still be condeming the PCM for this problem. Strange thing is that when it would not start, I could scope the wires form the crank sens and while cranking and watching the signal ( at 0.2 volts) I cut one of the two wires and tha side of the signal came back, cut the other and both sides were normal. I had each wire from the sensor hooked to its own channell on the scope and could see each part of the signal ( high and low) seperate fom each other. Thanks for all the ideas on this one, I am sure glad to see it not on my lot ( of course so is the trucks owner ) ......

[brianp87]

nice work

[steven kiser]

nice find

[wbuxton]

Gotta watch for them tranny issues!

[liljoe]

Gotta watch for them tranny issues!

Not gonna make a comment on this one.......