7.3 yet another no start problem.

[Tncoalroller88]

Ok so heres the story. For a couple of weeks now my 2000 f350 has been starting seemingly slower first thing in the mornings. Also before this one week I let the truck sit the entire week due to being on call for work. Came in turned the key it cranked and cranked till it just stopped cranking after bout 30 seconds like the batteries die, so I thought well gues maybe I left something on. So I waited maybe 2 min while callin my dad for a boost n tried it again. It cranked 2 times and fired right up like there was never a problem. So I chalked it up to just being a fluke. Well after that it seemed to get slower starting when cold over night, but normal when warmed up all day. So I check the warranty on my motorcraft batteries and it hadnt ran out so I take it down to ford and let them test it after work one day.. ford said everything was fine maybe bring it in one day when I could leave it over night so I say ok. Go out to the truck and it starts fine. Parked it and next morning still fine and even all through the week till the weekend. I llet it sit for 2 days and it was back to slow cranking in the morning and after it set for 8 hours. Well I let it go figuring ford wasnt gonna replace my batteries till they died somewhere so I figuree ill jist wait. Well yesterday morning I got to the truck and turned the key to the on position I got no cel light nothing not ever a sputter. I thought welp batteries are dead finally ill get a new set, negative on that turned the key off and back on and it fired up like it had been slow crank then fire. So im thinking wtf at this point but I had to go to work so I drove it. Got on the intersstate and gassed on it to get up to speed truck shuts down almost does completely like you turned the key off but back on. Then I went on a mile or so and gassed it again. This time it died completely like you had flipped a main switch. Dash lights head lights brakes everything went dead. I coast it to the side of the rd in shock as to what the **** just hsppened tried to start. Nothing.... waited a min or so it fired back up and I drove on to work not gassing on it anymore. Got back in it after work it started slow crank bit still started. Gassed it all the way home it did nothing no spit no sputter no sign of a thing wrong. Came home thought maybe its the alternator. Replaced it with a brand new one went to drag races last night gassed on it both there and back no problems. Now this morning I go out to get in it to go to work and it cranks and cranks and no start at all. Got an apt with ford to check batteries again but im stumped. Also note I have retro solutions hid headlights and sometimes when I turn them on it will kill the motor or completely stall it out like ov heard about them doing with dp tuner chips installed but I have a ts chip from gearhead and I know for a fact that the headlight kill it at times its killed it at least 5 times by just flippping on the headlights. Hope someone can help me this is my daily driver without it I am stuck

 

[superpsd]

First off buy a multimeter and learn how to use it. A nice fluke unit only sets you back 70-80$. It can be used to rule areas out and track down the culprit. Second the truck will shutdown if the voltage gets too low this is what may be happening but it does not still seem right. Usually it would restart but shutdown again unless the voltage issue was corrected. I believe 10v is the shutdown point. Isolate and check batteries and clean the connections.

 

[Tncoalroller88]

Going now to have batteries checked and replaced. Dont know if it will help

 

[superpsd]

Might some of the symptoms point to a bad battery like slow cranking. Could be a cable issue as well.

 

[Arisley]

Battery cables.

 

[Tncoalroller88]

Battery cables look new arr you saying replace the battery cables or check them for continuity. Also I have a voltmeter what should I be lookin for ?

 

[Tncoalroller88]

Also took batteries out and driver side battery seems much lighter than the passenger side battery?

 

[Arisley]

Check all of the connections. Ground and positive. The cover can look brand new, and the inside can be corroded to the point of almost no connection. You can special order the positive from O'Reilly's for about 80 bucks. It is much larger than the stock one.

 

[Tncoalroller88]

I thought that cable was in a harness so to speak. Its got everything from both batteries to the starter is this correct?

 

[Tncoalroller88]

This still doesent explain the crank and no start even if the bat cable was bad does it?

 

[Tncoalroller88]

Took batteries to ford they say theyre good dont know what to do now

 

[Tncoalroller88]

So can anyone tell me why after I had the batteries load tested at ford they tell me theyre good even after I cranked it till they were dead this morning? Then I bring it back home put the same batteries back on it and it fires right up first crank??? I also switched sides with the batteries tho

 

[bruce]

Loose or corroded connection. Could be a loose connection to the solenoid, from the solenoid to the starter, or even at the ECM power or ground. To check cables you need to do a voltage drop test, the circuit needs to be isolated in order to measure resistance.

 

[superpsd]

I have had corroded cables show the symptoms you are describing. I take a wire brush on a drill and clean the connections then coat and hook back up.

 

[powerstroke95]

Really sounds like a grounding issue to me. Check the ground cables where they ground to the frame. Id take them off and hit everything with a wire brush.

 

[superpsd]

Another quick check for grounding is grab the jumper cables and run them from the negative terminal on the battery and ground it to the engine. If it starts right up a few times without issue you have a grounding issue.

 

[superpsd]

I have had to use jumpers on old beaters in the past just to get them home.

 

[Tncoalroller88]

Loose or corroded connection. Could be a loose connection to the solenoid, from the solenoid to the starter, or even at the ECM power or ground. To check cables you need to do a voltage drop test, the circuit needs to be isolated in order to measure resistance.

How do I do a voltage drop test?

 

[Tncoalroller88]

Really sounds like a grounding issue to me. Check the ground cables where they ground to the frame. Id take them off and hit everything with a wire brush.

Where exactlt are all the grounds. I know one is on the front of the block and one is on the passenger side head but dont dknow where the rest are.

 

[bruce]

The two leads of the multimeter measure potential difference. A simple way to describe a voltage drop is to put the multimeter on Volts DC and touch the leads to the battery termial (either one) and the clamp around it. If everything is tight and clean (free of corrosion) the voltmeter should read 0vdc because there is no difference in voltage between the 2. If corrosion was present or the battery clamp was loose you might see a .5-1.5 voltage drop or more. Now move on from the clamp to the solenoid, Live circuits, everything intact just like it sits. If everything if correct (free of corrosion) the gauge should always read 0vdc to show that no voltage is lost. This test is better because you can use it on live circuits. To measure resistance you would need to pull the cables off and isolate them from the rest of the circuit.