Engine died a few minutes after starting. Crank but no start as well as no wts light. Let it sit overnight and the wts light back on and starts like normal. Started multiple times over several days. Got bold and took to the road and it fied 2 miles from home. Back to crank no start and no wts light. Got towed and checked after sitting overnight and wts light back on and starts fine. Afraid to hit the road again. Pcm was replaced in 2015 but that time it just died and that was it. Can a Pcm quit and then start working again after sitting over night? Thanks in advance.

 

Power supply relay getting old and erratic perhaps? All the grounds in good condition? Do you live in the rust belt? Salt will make its way into the wiring and corrode it from the inside out.

 

Like he said on the relay, cheap insurance if it isn't the problem, assuming of course that you buy a quality relay vs cheapo. Also the fuel bowl heater can mess with PCM without actually blowing the fuse, and if the heater is already unplugged the actual fuse can cause issues from age/corrosion and not blow, a new fuse can fix that

 

I unplugged the bowl heater and replaced fuse even tho it seemed fine this morning. I will pick up and install a new relay. I live in Tennessee so no salt. So I guess I will have to hit the road with a tow rope just in case.

 

I've had the PCM diode get loose in it's contacts in the fuse box killing the engine. Hit a bump and it would die. Once I figured out the problem I was able to use a small pick to pry the slots back into shape for a good snug fit. No issues since.

 

Well now I have to go check mine!

 

I had a similar problem, truck would cut out, then it died and wouldn't start. Ended up being a bad EBP sensor that killed power to the PCM.

If you get a crank no start w/o WTS light try unplugging each sensor that the PCM monitors one by one and recheck for WTS.

 

Thanks. Will do. It’s currently running. As I keep trying different things I carry a tow rope and stay close to home.

 

I will play your little game. So Sat I was going fishing. I unplug the and hop in the truck, its about 75F and it's 5:30AM Turn it one wait about a 15 sec. About the time the radio starts up. Crank Crank start. Pull up a bit backup and hook up the boat. Pull the boat out and shut her down. This takes about 5 min. I load up the gear, lock up the house That takes maybe 5 min. Turn her on wait a bit and crank crank crank no start. Turn her off, maybe I rushed her. Wait a bit, you never want to rush a lady, even if she is a stinker. Turn her on, the GP are still lit up, wait and giver her a shot, crank crank crank crank, no start. I open the hood, you can hear the GP contractor. I try it again. There is a strange gerrr sound from under the dash. I try this about 5 times. I unload the truck and go back to bed. I getup around 7AM make breakfast. At 8AM, I hop in the truck, turn her on wait for a min, crank crank start. I put the boat away. All weekend I try to get her to fail to start, She only does it once more, but she starts on the third try. Today I got her to repeat the failure and on video. It was after work, it's about 88F. You turn her on and she does the normal stuff except the wait to start light does not stay lit. It flashs on but is off while a wait about a 15 sec before cranking. When I start to crank her you can see the WTS light coming back on. After I stop cranking in the KO position, the WTS light now remains on. I turn her off wait a moment and repeat, same results and I can hear that gerrr sound, and the tech is bouncing, the fuel pressure is good. On my 3rd try, its back to crank crank start. I don't know how to post the video.
What do you think? She is a 2000 F250, which relay?

 

The game is called: Find the loose electrical connection. Some win, some lose.

 

Really, I have had the truck since 2016. When I first picked her up, she had issues. I replaces the usual sensor and CPS, and she has not skipped a beat. She is a driveway queen. If shes not towing, shes not going. She sits there on her trickle charger for weeks at a time. This time two weeks. She lives in SoCal, but she is not a Cal truck. No Cat, no rust. She has about 270K on the clock. What do you think?

 

Best plan of action is to get Forscan set up and start getting some readings while you are cranking during the no-start situation.
But before all that, the symptoms sound to me like intermittant power supply and/or loose grounds. Or both. I recommend cleaning both posts on both batteries down to bright shiny metal, make sure the two ground points on the engine block are the same, nice and clean down to bare metal. Check every body ground you can find and clean. Maybe replace the fuses for the engine management. Sometimes the bridge cracks with age without actually blowing. Relays? Nothing is above suspician with a 20+ year old vehicle.
Do you have a chip installed on the PCM? Try removing it and see what happens.

 

So I have been fuxing around with ForScan for two days now. For some reason Forscan does not want to talk to the dongle. You have to tell it to use the old truck ID data, then it starts to talk, (lites up). Today I got the pids set up. It's a pain to get it to work. It seems that when the truck is cranking, it loses connection. It seems to be working KOEO, but when you crank it says it lost connection. It does not indicate any RPM. I will have more time on Fri. to check the connections. She cranks fine, but the rest of the electrical system might have a bad connection i guess.

 

some of the dongles aren't as stable as they should be.
I have 3, and one of them is bad.

I have a USB that works great for Laptops, and a new Vlinker brand recommended by ForScan on their website.

 

Here is todays update. I pulled cleaned and re-installed all of the fuses under the dash and under the hood. I pulled and reinstalled off of the relays under the hood. I cleaned the battery terminals. Yea, today she starts right up, on every try. The only thing I noticed when I looked at the data after a start, it said the voltage was 11.7V. It recovered to 14.2 V after running few min. I tried it again, I checked for a voltage drop at the battery connections. They look good. This time I noticed it as low as11.9V when the GP were lit. She fires right up today. She spins fine. I need a wiring diagram to check the wiring under the hood. She is a 2000 auto 4x4, white ext cab. What voltage should I see when the GP are lit?