Slow crank/No start

[Brad Clayton]

This vehicle is a 2004 F-350 with a no start condition. I verified the concern with a very slow crank/no crank along with starter motor clicking and gages flickering. The batteries were run down. I charged the batteries at 10 amps for a couple of hours. I isolated the left battery from the right and tested both ok.

 

 

This is my base voltage reading for the system with both batteries connected. I next checked starter draw and it pegged my amp clamp which is capable of reading 600 amps.

 

 

I was able to snap this shot before the meter read O.L. I am pretty certain that the starter motor is bad. I bar the engine over by hand to make sure it is not binding or “locked up” and it spins freely with an 18 mm wrench. I wanted to know how the cables were so I performed a voltage drop test on both cables.

 

 

I hooked up my meter from the positive battery terminal to the B (battery) connection of the starter like pictured. To get an accurate view of how the solenoid internal connections are the meter lead should be put on the M (motor) connection of the solenoid. Now it’s time to crank the engine again so the circuit has some of those tiny little electrons flowing through it. The flow of electricity (circuit under load) is needed while performing a voltage drop test.

 

 

Ford’s spec. for the positive cable is .5 volts. I would rather see it as close to zero as possible. As seen here the reading is a little out of spec. but not the cause of my starter problem.

 

 

The negative cable spec. is .2 volts and this one is a little high but still good enough to move on to removing the starter for closer inspection.

 

 

The starter was cooked by the customer dealing with a hot no start issue. I was going to perform a bench (no-load) test but the solenoid fell apart when I took the starter off. So I replaced the unit and rechecked the starter draw. I was interested in seeing how the higher than normal voltage drops would affect things in the real world.

 

 

An acceptable range for this unit is around 170 amps. As seen here the bad connections and worn cables are putting extra strain on the new starter motor.

 

 

Unchecked cable maintenance has lead to corrosion creeping into the cable strands and a source of voltage drop. The customer said he just replaced these batteries recently. The fact that this cable was overlooked and not cleaned and maintained is putting undue stress on all the electrical systems.

[Keith Browning]

Nice write up Brad but that battery doesen't look too new.

[Brad Clayton]

I think my customers concept of time is a little off.

[Jim Warman]

Something to consider when testing starting systems - step the first should be to make sure that the battery connections are clean and tight....

 

Back in the day, breaker point ignition systems would nearly force an owner into a spring tune up and a fall tune up. Some of the things we were supposed to do (but, there were enough charlatans out there that would simply pocket the profits without performing the service) included cleaning the battery terminals. Back then, the cables had lead connections.

 

We would remove the cable and, using a wire brush designed for the task, clean the inside of the cable connection and the outside of the battery post. When reassembled, we would apply a liberal amount of grease to the connection (including the felt washer under the connection that should have been replaced - yes, they were available commercially but hard to get because nobody replaced them except for curmudgeons-in-the-making).

 

Today "cleaning battery cables" consists of spraying shit on the battery, watching it foam up and then splashing water on it. The battery now looks pretty - but we haven't done squat for the electrical connection. We are still charlatans - but at least now we are classy charlatans.

 

Making sure that the battery connections are clean and tight is priority one when diagnosing starting system problems - remembering that we are talking about "electrically clean and tight" rather than "esthetically clean and tight" is paramount.

 

You have an excellent grasp on how to use a voltmeter and this will take you far.

 

50% of all doctors graduated in the bottom half of their class.

[Brad Clayton]

The interesting thing about this truck is the owner does not care anything about it. He just wants it to run with the least amount of work possible. This translates to don't do anything but the bare minimum. I would have loved to have gone right thru this truck from top to bottom and done things right but it would have been on my dime. I couldn't do that considering the shape the rest of the truck is in. It really should be removed from highway duty and motoring around with the unsuspecting public.

 

Autos amaze me everyday, they can take a beating and survive severe neglect and keep on ticking. And then sometimes they just lay down no matter how well they are cared for.

[Jim Warman]

So... you are telling me that the owner of the truck is diagnosing the concern(s)?

 

I look at a truck... I perform diag to whatever point I can... including the odd "repair <this> and reassess". I prepare and offer a repair estimate. I reaffirm that some conditions may be masked and that this is an estimate only. If you live in an area with some of that anal consumer protection, bid high - use words like "may" and "perhaps".

 

If the customer returns saying "you didn't fix my truck" you can reply "you didn't do what I wanted".

 

Now.. the condition of the rest of the truck... My bay has a 4 post lift... I push a button and a minute later the truck is above me making inspection somewhat easier... All the same, setting a two post hoist doesn't take long. I'm sure you have the report cards to fill out just like the rest of us. Rear brakes are a common issue in our area because of the mud... a quick peek at the inboard rear pads tells a big story.

 

Spend the time - make the estimate - if you aren't doing anything else, at least you are covering your ass.

 

It doesn't matter what the owner wants. The truck is saying "I want this". You are the messenger - you go to the owner and say "your truck wants this". If the owner tries to shoot you, all you can say is "count me out".

 

Face it... you are either going to do those things you want to do... or you are not going to fix the concern.

 

Boil it down... the customer is going to do those things I feel we need to do. If not, we are wasting each others time.

 

Never, ever let your customer dictate your efforts. If he is so smart, why is he dealing with you?

 

If you feel a truck needs "X" and the customer doesn't want "X" you are done. There is no more. If you begin to diagnose beyond your initial diagnosis you are announcing that you aren't confident with your diagnosis.

 

You need <THIS> - after we do that it is either fixed or it puts us in a place where we can reassess our concern.

 

The truck you are working on is more complex than anything they ever sent to the moon or to Mars or whatever...

 

Read my lips... "if you do not want this repair then I am sorry... I cannot help you past this point". To say anything different is the same as saying "fuckifIknow".

 

We have to accept the responsibilty that is thrust upon us.

[Brad Clayton]

Been down that road with this truck already. I looked it over originally 2 weeks ago and made my recommendations. All my efforts were shot down and I refused to test drive the truck after I repaired a driveability concern. The guy towed it back after it wouldn't start because he said it was something we did. This was obviously not the case and it still needs a whole lot more work than a starter motor. This truck will not get the work and when it is towed back in again or the bald tires or loose ball joints cause a 20 car pile up on the interstate, it will be documented in our database as to why.

[Jim Warman]

Many many years ago..... there was a customer faced with a spendy repair. He asked if it could be done for less money.

 

I replied "Of course it can!! What parts do you want me to leave out?".

 

Without seeing the actual wording used on your RO, accurate assessment of the situation can be difficult. Careful documentation on your part is absolutely essential. Along with playing CYA, make sure your customer has enough rope to hang himself with. Include, where possible, statements indicating that the customer requested something that testing or symptoms indicated as being inappropriate.

 

The internet has turned everyone into an exspurt (sic)... "Yayyyy!!".

[Brad Clayton]

I conferred with Bruce (I am assuming there is only one Bruce in this crowd and if there is more, I further assume that everyone knows which Bruce I am referring to, his last name rhymes with amacker) anywho Bruce suggested adding the before and after cranking data to the thread. This is quite important and I did not have it with me. So I am adding it now. The before data wouldn't even register because the thing turned so slowly and then shat right out. The after data is right on spot though.

 

Bruce suggested using the relative compression data which is nice because it gives the mean (average) RPM after the 10 second crank.