03 4.0l no crank no start problem

[Scurvy]

As far as grounds, you should have the battery ground, a smaller wire off that to the front body structure or fender, a grounding strap from the rear of the motor near back of intake to the fire wall and possibly one down below frm the tranny to the frame.

Thanks! I'll take a look for those later and see if I can find 'em/check their condition!

 

[MakinJeepsWeep!]

No problem, i will say my brother had a 06 f250 gas that started having tranny issues not long after he got it. When he bough it the people said they had rebuilt the engine. Well it ran great for a short time so clearly the people where not clueless and it never did have a engine problem but the tranny did. After being rebuilt at a shop in Dallas it only lasted about 2K miles before symptoms came back, most likely due to it already being loaded down with all of our welding gear. However it was under warranty and they fixed it again, they called after a week and said they where taking it out a third time because it just still wasnt shifting right, another week and a half went by and they found that whenever it had been removed from the truck the first time, assuming when motor was out, the ground strap the was soley for the tranny never got put back on and was causing the trans to burn itself up because the electric servos could not work right. So all that was caused by 10$ of braided wire about a foot long. Truck is still on the road right now still a welding truck and doesnt miss a lick. He lives in OK and works mainly in Dallas and all over Texas. All in all grounds can make life terrible!

 

[Tshaw88]

the voltage reading at the starter and the lack of a voltage drop across the battery when the key is turned makes me think that circuit isnt complete. there should be a large voltage drop across the battery when the key is turned. if this is the 4.0 sohc motor then there are two bolts holding the starter to the bell housing, the side bolt accessed from the drivers side wheel well is a typical hex bolt and then the 2nd bolt is under the car, its a stud with two nuts on it. there is a ground wire that is supposed to be there between the two nuts.

 

[MakinJeepsWeep!]

Hence why after playing music or somthing to long you cant crank your truck up. battery isnt dead persay but does not have the excess voltage needed to turn over the engine.

 

[Tshaw88]

i have an 05 with a 4.0 sohc, currently not running i have the motor in my shop to redo my timing chains, but the motor i pulled from an 02 thats still in my driveway so i double checked both last night, there is a ground cable on both that connects to the mounting bolt on the bottom of the starter.

 

[MakinJeepsWeep!]

i have an 05 with a 4.0 sohc, currently not running i have the motor in my shop to redo my timing chains, but the motor i pulled from an 02 thats still in my driveway so i double checked both last night, there is a ground cable on both that connects to the mounting bolt on the bottom of the starter.

And the hot it on the solenoid correct and then the small signal wire as well?

 

[Scurvy]

the voltage reading at the starter and the lack of a voltage drop across the battery when the key is turned makes me think that circuit isnt complete. there should be a large voltage drop across the battery when the key is turned. if this is the 4.0 sohc motor then there are two bolts holding the starter to the bell housing, the side bolt accessed from the drivers side wheel well is a typical hex bolt and then the 2nd bolt is under the car, its a stud with two nuts on it. there is a ground wire that is supposed to be there between the two nuts.

Interesting. My truck is a 4.0, but both starter bolts are in fact bolts, no nuts, no stud, etc. and no ground wire coming off it.

It runs just fine right now, haven't had an issue since cleaning up the mounting surface and bolts, so I can only assume there was never a ground there...? My friend did suggest running a new ground wire off one of the bolts if nothing else works, but it doesn't seem like a necessary step at this moment...?

 

[MakinJeepsWeep!]

I

Interesting. My truck is a 4.0, but both starter bolts are in fact bolts, no nuts, no stud, etc. and no ground wire coming off it.

It runs just fine right now, haven't had an issue since cleaning up the mounting surface and bolts, so I can only assume there was never a ground there...? My friend did suggest running a new ground wire off one of the bolts if nothing else works, but it doesn't seem like a necessary step at this moment...?

It really shouldnt be because it should ground through the block regardless, through another ground. If it is rolling over good everything is good and clean, make sure its all nice and tight(dont crack it ive seen it done) and leaver alone! Good work, there is now alot of info on grounds and options for people to read over.

 

[Scurvy]

Aaaaaaaaand its not fixed! GOD DAMN IT!

Been having intermittent issues still, always after sitting for a day or two so I figured the battery was on the fritz despite the voltage reading A-OK. If the voltage dropped below about 12.7v it wouldn't start anymore, at rest voltage after driving was ~12.93v and it would lose a 0.1-0.2v overnight. The lowest I've seen it is 12.4v after 3 nights of not being used (didn't have any chance for it to sit longer). I pulled the battery cable one night and it stayed at 12.93v overnight.

When it wouldn't start I would hook up my battery charger set to the jump start setting, and it would fire up. Sometimes I would have to let it sit hooked up and "jumping" for a handful of seconds (15? 30 maybe?) and then it would fire up no problem.

Today I fired the truck up, drove 5 minutes to pick up my son (in the pouring rain, so full blast on the vents, wipers and rear defrost going), turned it off and now it wont start. I tried hooking up a truck to jump it, but that did not work. I am getting no cranking, no clicking, nothing.

Battery was still under warranty (AC Delco from Lordco) so I borrowed a vehicle and took it to Lordco and they replaced it. Put the new battery in the truck, and still no click no crank nothing. Reads 12.6-something on my voltmeter.

I got a ride home and plan to get the truck towed tomorrow. If anyone has some insight to this problem I would love to hear it!

 

[TechGuru]

Bad starter?

 

[iowa_hick]

Did you check the PCM fuse? #41 in the power distribution box under the hood.

Good luck!
Jake

 

[Scurvy]

Bad starter?

That was my first thought. Already replaced it. The old one seemed to still work when I pulled it (bench tested it) so in hindsight I think replacing it was a waste of money, but at least it eliminates that as the issue. I feel like it has to be some sort of electrical issue, but at this point I have no idea what it could be other than its highly unlikely to be the starter or the battery at this point as they've both been replaced.

Did you check the PCM fuse? #41 in the power distribution box under the hood.

Good luck!
Jake

Would that cause it to start with 12.9v but not even crank with 12.6v? Fuses are either blown or ok normally aren't they?

 

[iowa_hick]

No, it wouldn't do that, but if you replaced the battery, it might be worth checking. Could possibly be a bad Starter Relay too.

 

[Scurvy]

No, it wouldn't do that, but if you replaced the battery, it might be worth checking. Could possibly be a bad Starter Relay too.

I didn't check the starter relay last night, but I did check it previously and it checked out fine (clicked, had voltage at the right terminals).

 

[iowa_hick]

I didn't check the starter relay last night, but I did check it previously and it checked out fine (clicked, had voltage at the right terminals).

Just to be on the safe side, I would swap it with an identical relay within the distribution box and see if the problem moves.

 

[Scurvy]

Just to be on the safe side, I would swap it with an identical relay within the distribution box and see if the problem moves.

I did try that when I was checking it last time. I'll try that again later today when I go back to call a tow truck.

The fact it would start at 12.9v but won't even crank at 12.6v makes me feel like its a wiring issue.... Did I mention I hate electrical!?

 

[MakinJeepsWeep!]

A good battery with a good alt and not somthing drawing on it hard should stay at 12.6 and above and running should be closer to 14v. You at least should be one full volt over 12v while running to cover the battery actually getting a charge and everything else drawing from that extra volt. If you get it cranked up and un hook the battery does it stay running? It should no problem. However it should at leasgt give the click click if battery is to low to really turn it over. However a older battery with a getting tired starter on a alt that isnt really boosting the battery could be a case. trickle effect. I would see if she will run with the battery unhooked.

 

[Scurvy]

A good battery with a good alt and not somthing drawing on it hard should stay at 12.6 and above and running should be closer to 14v. You at least should be one full volt over 12v while running to cover the battery actually getting a charge and everything else drawing from that extra volt. If you get it cranked up and un hook the battery does it stay running? It should no problem. However it should at leasgt give the click click if battery is to low to really turn it over. However a older battery with a getting tired starter on a alt that isnt really boosting the battery could be a case. trickle effect. I would see if she will run with the battery unhooked.

And there is the issue. With high enough voltage on the battery it will turn right over no problem. Drop that voltage just a little bit and it will click, drop that voltage a tiny bit more and you get nothing. At 12.9v it starts, at 12.6v it doesn't even click.

Last week when I checked I was getting 14+V with the truck running, alternator doesn't seem to be an issue.

Jumpstarting the truck with another vehicle doesn't work, but hooking up my battery charger and setting it to the jumpstart setting does.

Battery and starter have been replaced (although I have no reason to believe either of them were actually bad, the starter was bench tested and worked fine).

While waiting for the tow truck I did some messing around with my voltmeter. With the voltmeter on the battery posts, my voltage only drops a bit when I crank the engine (less than a volt). Meanwhile, the constant power to the starter (measured from the starter bolt) drops immensely, down to 4V or less.

I did a voltage drop test on the constant power (volt meter attached to constant power at the starter, and the positive battery post) and I got less than 0.1v. I have not been able to do a voltage drop test on the negative yet.

Edit: Truck got towed home earlier. Just tried to start it with the aid of my battery charger and it didn't work this time.

 

[TechGuru]

Have you tried jumping from the battery to starter directly?

 

[Scurvy]

Have you tried jumping from the battery to starter directly?

As in running a cable from the positive battery terminal to the bolt on the back of the starter where constant power connects? I tried that yesterday while waiting for the tow truck, with no luck, although I'm not certain I had a good connection with my cables (starter isn't exactly super accessible without taking off a tire)

I did a voltage drop test on the constant power and it gave me under 0.1v, which should mean I'm not getting too much resistance on that part of the circuit right? I need to do the same to the negative side tonight if I can find the time.