Truck won’t start after neg disconnected from battery

Went to change vct on passenger side unhooked neg on battery n unhooked connector from vct noticed that valve cover need to be removed so decide to wait so hooked vct back up n neg back to battery but truck wouldn’t start unhooked battery all together n waited 15 mins hooked back up but nothing works just headlights

Please helping

Pardon my ignorance I do not know vct. Guess I only worked on older Ford Trucks. Out of my league, sorry.

It’s variable camshaft timing n I get use to older stuff for sure

Before we get to the guessing stage, you need to check your battery with a battery tester and check and clean all battery connections. Then test to see if the starter is getting enough current. It may have worked before the disconnect but the interruption could have affected something. Either way this is the first step to diagnosing this problem. Then come back and post the year and engine size. Then we can come back and make some guesses like anti theft, relays and such.

Does it crank normally but the engine doesn’t fire? Is the cranking slower than it used to be (aside from a low battery due to cranking caused by this issue)?

No there is nothing when ya go to turn the key battery tested great all was done was unhook neg from battery was off for maybe hour or so hooked back up n now it’s dead to the world

Does not crank at all everything was good just before neg was disconnected for about hour was hooked back up n nothing battery tested great getting power just when turn key to start there is nothing fuel pump kicks in pcm kicks in :man_shrugging: Just weird

what year is your truck?

04 f150 5.4 4x4

you can try this to see if it helps.
How to reset the anti-theft system in a Ford F-150 - Summit County Voice

Will try in the morning if not resolved sending it to the shop definitely don’t wanna keep stabbing at it n make things worse just kinda silly to unhook a neg off battery to have it sent to shop cuz it’s not wanting to start :man_shrugging:

A very common problem is a dirty battery terminal causing a poor connection. But if you’re sure that you have Voltage while cranking, such as the dome light being on, then it can’t be that. You didn’t happen to pull a connector out of the starter relay or anything did you? If you’re not familiar with testing electrical stuff then getting someone who does to come over to help would probably be best.

When you do find out what is the problem, please let us know… “Enquiring minds want to know”

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Will post as soon as I know

Nothing else was pulled it’s crazy thought theft mode but fuel pump kicks in I would think if it was in theft mode it would shut down fuel pump

17 year old vehicle… possibly the negative cable is internally corroded/crumbling. Can you safely hook a jumper cable in its place, temporarily?

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First thing I would do is go underneath the truck with a multimeter and make sure the appropriate starter terminals are in fact getting battery voltage with the key in start position . . .


Have you tried shorting the two battery cables together (after disconnecting them from the battery of course). Sometimes there are capacitors which are charged and need to be drained to zero volts in order to reset all of the on-board computers vehicles have now-a-days. It might take some amount of time leaving the cables shorted together to drain those capacitors. Worth a shot anyway. If that doesn’t work and the above ideas don’t pan out, either the on-board computer network needs to be reset (may require a high-end scan tool), or there’s a security system problem.

It was battery had some short in it and there was a short to on board computer n the truck only had one key n was kicking into thrift mode n not recognize key but new keys shirt fixed n new battery n truck is running

Hmm, new battery fixes problem. Go figure.