Check engine light after turning over several times before finally starting

So this morning I went to start up my truck and it turned over several times.Then it started and was running at a low rpm.I just put engine coolant in because It didn't seem to have any.And oil is good.I have no leaks I can see.So after I put in engine coolant it started fine,but my check engine light came on for the first time.Can anyone help? Maybe alternator? The only thing I found that look out of ordinary was this.

 

Alternator will not trigger a mil light. Usually sensor related.

If coolant continued to self drain somehow, you might be burning it internally if there's no visual external leak. Crack head or headgasket. Also worth shining a light between head and manifold by knock sensor harness to see if there's a pool of coolant between head.

 

Look like your knock sensor harness

 

There is no pool or leaks.The only thing I noticed are those wires look chewed maybe.Would that knock sensor make my truck start poorly?

 

My experience with defective or completely unplugged knock sensor will just trigger the mil light. Vehicle still start and idle fine.

If a rat chew that, i wonder what else did the rat chew

 

A rat chewed that wire.I just looked and found droppings in there.I don't see anything else.

 

From the picture, it look like the wire is from the harness side that got chew. You might be able to salvage the connector and solder an extension to the connector and add the difference in length to the harness side

 

Yeah or at least splice bare wire to it and tape it up?

 

I wouldn't use quick connector and tape. Soldering the wires together gives you a better connection then shrink/heat wrap it follow with some 1/4" wire loom.

Don't use bare wire. Make sure the extension have some kind of insulation/protection and not fully exposed to the element.

 

So can I get away just twisting the wires back up and tape and loom it?

 

Sure, you could probably "get away" with that. But spend the extra 3 minutes and do it right.

Also, if you are loosing coolant and don't have puddles of it, the chewed wire is really the least of your worries...

 

I wouldn't do that if i were you. You're not working on your house electrical. Your vehicle sensor is sensitive.

 

Just solder it, if you don't know how, watch a few YouTube videos. It's easy and everyone should know how to do it...

 

Yeah I don't know.I filled it up with coolant probably a couple months ago and it was pretty low this morning.If there's no leaks of it what can be the issue? I just started it up just to see how it started and it takes at least twice as many turns to start.And when it turns on it idles a lot lower than it normally does when it's cold.Right under 1k rpm.And my check engine light is on.Regardless I need to fix the wire.But I don't think it needs a head gasket

 

Yeah I'm gonna try it.Im sure I can do it.Im a welder for a living.Ill look it up on YouTube.

 

If there aren't any coolant puddles on the ground, that means the coolant is likely going out the tailpipe. That means your coolant is getting into places it shouldn't. You say "the oil is good", but how did you check that?

If your check engine light is on, you likely have some error codes. Either get a OBDII code reader yourself, or most auto parts stores will read them for you for free (but you have to drive it there).

As for soldering, it's not too hard. It's kinda like mini oxy welding or brazing.

A lot of fluff at the beginning, but not bad techniques:

https://www.youtube.com/watch?v=Zu3TYBs65FM

 

Thanks man.Now for what reason is it idling low then?

 

It could be a multitude of things, but like I said, get your error codes checked. Then think about changing your oil. You say your oil is "fine", how did you check that?

Dump your oil and see if it looks "milky". If it's anything other than brown (black if it's old oil), you have oil and coolant mixing = bad.

 

so if I change the oil and it still idles rough.What multitude of things could it be? Cap and rotor? Spark plugs? Distributor? Does that wire have anything to do with the idle?