Slow to start

[Fader]

Hello. I am experiencing some really slow starts on my '97.
It clearly sounds like it is turning over slow. Depending on how cold it is...it can take between 5-15 seconds of cranking to turn over. Even in 50°+ temps it is still cranking slow.

I pulled the matching pair of batteries & load tested them. They are two years old & test out great. Alternator is doing its job.
I cleaned/replaced all battery cable ends & visually inspected the cables.
I pulled the starter & installed a new contact kit from Geno's even though it didn't look too bad at all.

My question is...is there any chance that a bad/dirty injector could be causing this slow labored crank?

I was thinking of replacing all of the battery cables next but it occurred to me that this scenario began around the time that I believe I had some questionable fuel.

I dropped the tank & cleaned it out plus the screen inside. Changed the fuel filter since then as well. She runs good once started but yesterday it was 20° & I had to make an unexpected trip so she wasn't plugged in. She started but it barely sounded like it was going to pop off.

Pickup only gets driven once a week +/-.

What would you do next? New battery cables, New injectors, or something else?

'97 Ram nv4500 215hp p-pump.

 

[BigPapa]

Nothing fuel related will cause the starter to turn the engine over slowly. This is my experience with a slow starter.

A few years ago my starter kept getting slower and slower. I figured it was the starter but I decided to check my batteries and cables first. I've always kept what I could see clean, so I was SURE it wasn't my cables. When I pulled the cables off, the terminals and battery posts had a layer of corrosion between them. While cleaning my crossover cable, I noticed corrosion on the copper under the insulation. I cut the insulation back at least 7"-8" and there was still corrosion. I ended up making a new crossover cable with eyes and put eyes on the other cables and went to the "military" style terminals. After thoroughly cleaning the battery posts and putting everything back together, my weak, slow starter turned back into the monster it used to be.

 

[Fader]

That makes the most sense. Timing with the fuel incident made me second guess myself. Cables may still be original...26 years & 250k miles later.

Nothing fuel related will cause the starter to turn the engine over slowly. This is my experience with a slow starter.

A few years ago my starter kept getting slower and slower. I figured it was the starter but I decided to check my batteries and cables first. I've always kept what I could see clean, so I was SURE it wasn't my cables. When I pulled the cables off, the terminals and battery posts had a layer of corrosion between them. While cleaning my crossover cable, I noticed corrosion on the copper under the insulation. I cut the insulation back at least 7"-8" and there was still corrosion. I ended up making a new crossover cable with eyes and put eyes on the other cables and went to the "military" style terminals. After thoroughly cleaning the battery posts and putting everything back together, my weak, slow starter turned back into the monster it used to be.

Nothing fuel related will cause the starter to turn the engine over slowly. This is my experience with a slow starter.

A few years ago my starter kept getting slower and slower. I figured it was the starter but I decided to check my batteries and cables first. I've always kept what I could see clean, so I was SURE it wasn't my cables. When I pulled the cables off, the terminals and battery posts had a layer of corrosion between them. While cleaning my crossover cable, I noticed corrosion on the copper under the insulation. I cut the insulation back at least 7"-8" and there was still corrosion. I ended up making a new crossover cable with eyes and put eyes on the other cables and went to the "military" style terminals. After thoroughly cleaning the battery posts and putting everything back together, my weak, slow starter turned back into the monster it used to be.

 

[Fader]

A few weeks ago I went & replaced every battery cable with new 2/0 copper cables.
Crossover cable, cable to starter, & both battery grounds.
I took extra care to clean up the ground locations & cleaned up/replaced all of the smaller grounds as well.

She now cranks a little stronger but it really did not make the change that I was hoping for.

Starter contacts were already replaced. Debating trying a new starter altogether & probably going to pull the injectors today.

 

[petersonj]

It clearly sounds like it is turning over slow. Depending on how cold it is...it can take between 5-15 seconds of cranking to turn over.

I only mention the following for clarity:

"It clearly sounds like it is turning over slow..." I think you mean that the starter is cranking the engine over but no injectors are firing.

"...it can take between 5-15 seconds of cranking to turn over." Cranking and turning over are the same thing. I think you mean "5-15 seconds of cranking to make an injector fire".

When a compression ignition engine is cranking slowly, many things are working against getting the engine started. The injection pump is rotating slower that it should, consequently building pressure to open an injector will be slow and late. The fuel will depart the injector tip at a dismal rate and will poorly atomize into a cold cylinder. The slow cranking speed will also allow air pressure to bleed off around the piston rings during the compression stroke, thus not attaining a compression ignition temperature for the poorly atomizing fuel to burn. It will take several revolutions of the crankshaft to build enough heat in the cylinder to fire an injector. Proper cranking speed is important.

If I were in your situation I would focus on getting the engine cranking speed back to normal before I did anything with the injectors. I think the injectors will fire right away if the cranking speed is brought to normal.

From what I have read, you have done an excellent job with replacing the heavy gauge wiring. I think the starter should be the next thing to look at for the slow cranking speed symptom.

- John

 

[Fader]

I wanted to follow back up with the ultimate solution for anyone reading this post in the future.

The extremely slow cranking speed was ultimately caused by the starter.

I don’t drive the Ram very often & she needs all sorts of other repairs… (front end suspension & 5th gear fix)

She has what appears to be the original Denso starter so I didn’t want to just replace it with a parts store unit.

She failed to start about a month ago when I was moving a trailer around my yard. So, I finally got around to pulling the starter off.
A buddy who operates a salvage yard gave me a nice looking Denso starter that had slightly different mounting plate.
I pulled both units apart thinking that I may swap the internal parts between the two.
Once I got them both open, I realized that my internal starter motor looked great & the other looked pretty scorched but my contacts were almost gone.

Rather than use the half worn set from the other Starter, I elected to order a set from Larrry B.

It was right around $100 & it also included the plunger & copper contacts that I had previously replaced in an attempt to speed up my starter.

The main ring with the contacts did require two solder connections to be made.

My soldering iron was not up to the challenge… I ended up buying a cheap butane torch with a soldering tip from Menards & that got the job done.

It’s been 0 degrees or less here lately so I’ve been waiting to install the starter. Today got up to 30 degrees so it was ‘go-time’.

I got the rebuilt starter installed along with the two batteries which have been hanging out in the warm shop for the last month.

After sitting for over a month… she cranked to life faster than I can ever recall!! Hallelujah!

Thank you everyone for the tips & advice. Even though the 2/0 battery cable upgrade didn’t fix my issue… I’m sure that I am now in better shape going forward.