just bought a dodge 5.9 runs nicely but hard to start when temperature drops close to freezing point. Has 300000 kms . Could it be the grid heater?

 

Does your volt gauge drop below 13 and the lights dim?

 

yes...volt meter drops and comes back up few minutes after started

 

Describe "hard to start". Does it turn over slowly, or crank at normal speed but just take a while of cranking before it lights off? Any white smoke when it does start?
What is your start up procedure? Do you let the heater cycle completely before attempting to start? How old are the batteries?

 

That means your grid heater is working as designed.

 

plug your truck in when temps aproach freezing & switch to 5W40 oil. Use a good injector cleaner on your next fill up & change your fuel filter. After doing this if your starting troubles are not resolved then your have more serious issues developing.

 

I'm having the same problem too. I have a 2003 cummins and its taking forever to crank over. Ive replaced the fuel filter but still taking a while. I tried starting it this morning after sitting for about 2 days and no luck! Its cranks but it wont turn over.

 

I have an in tank lift pump and my ecm was reflashed. TSB-18-017-05.

It fired up right away with ether just now!

 

its your injecors going out, cold weather increases the gaps in the body and allow the fuel to flow back causing low rail pressure, therefor causing hard start.

 

What he said. Very common on the 03' trucks. You need to have a return flow test done on each injector to find the bad one or just take them out and send them to F1 diesel to be rebuilt and upgraded to 50 hp tips. It is alot cheaper than new ones.

RP needs to be around 5K for the truck to fire off.

 

Re-torque your injector cross tubes(39ft lbs), prior to doing anything else. There current torque will tell you alot. If they are all fairly even in torque, and not loose, then yes, other things to look into. If they are loose, or even if only one is loose, you have found one of the reasons it's starting hard.

 

Kool thanks for the heads up I will have a look this weekend!

 

I had the same "No Start" when it got colder.

I would definately suggest buying the injector cap off tool and test each line one at a time. Once you cap off the leaky injector the Rail Pressure will satisfy the computer and the fuel will flow and the truck will start on 5 cyls. That is as long as it is an injector issue.

Here's a link to my issue post and testing results:

https://www.dieseltruckresource.com/...91#post2806791

 

Thanks heaps for the info! I just watched all the videos and the fuel system is making more sense to me now. I'll update u on the results.

P.s. I noticed the fuel filter cap is broken a little bit, reveiling a little bit of o-ring but is not leaking any fuel from the canister. Can that be a problem at all? thanks

 

This is not true. I do not have a grid heater (removed it and put in a delete) and my lights will dim and my volt meter will dip in cold weather...
Using ether is no bueno... if it hits the hot grid heater it could explode in the intake.

Starting fine with ether is a sign of bad injectors. There are a few other things, like a rail pressure sensor, so make sure you do your homework before you start throwing money at stuff. Fuel system repairs can get expensive if you just throw money at stuff.