I have pulled all injectors and had them tested. #1 & #6 had high return flow. I replaced the two with high return as well as installed a 3 micron fuel filter, it started fine the first few days ( I have driven less than two hundred miles ), until the nights started getting cooler (<50 degrees), and it started with the long cranks again (multiple 20 second cranking cycles). If I plug in the block heater it starts in 3-5 second crank cycle. After driving I can shut it off any time and it starts within 3-5 second of cranking, just not cold. Prior to all of this I have Never had to plug in the block heater. I also, do not get any codes :banghead:

We are all guessing as to your configuration as you've not added your truck to your signature.First question... Do you still have the grid heaters & are they working? Does the "Wait to start" light come on?

Possible failed injector bleeding down the common rail making it hard on the CP3 to build pressure.

Typically when 1 or 2 injectors go out their matched pair 1/6, 5/2, 3/4 is soon to follow. 10 years of CR maintenance has taught most mechanics to replace/repair all 6 at once.

  AH64ID said:

Typically when 1 or 2 injectors go out their matched pair 1/6, 5/2, 3/4 is soon to follow. 10 years of CR maintenance has taught most mechanics to replace/repair all 6 at once.

THIS^^^^^^ My Bud's '03 started the hard start when cold thing at about 250,000 miles. 6 new injectors solved the problem. He's got 330,000+ miles on it now.

Ok, here is the info.

Purchased truck in 2007 with 52,000 miles. It now has 108,000 miles all stock no add on's.

I found out upon disassembling that all 6 injectors had been replaced. 3 had reman dates of 2005, 3 had reman dates of 2007 (apparently just prior to me buying it in July 2007).

Now as of today, other than the info in my first post.

I used a laser thermometer to check temperatures prior to trying to start it.

Fuel filter housing 39 degrees

Intake heater 38.5 degrees

Key on; waited for glow plug lamp to go out (there was also a clicking noise under the hood next to fire wall that continued for close too two minutes. I waited for it to quit prior to trying to start. Not sure what this is I've never noticed it before).

Intake heater now @ 52 degrees.

15 second crank cycle and started let run for a few minutes and turned off.

Restarted and had a 3-5 second crank cycle

Drove to job site turned off for 1 hour

Started with 3-5 second crank cycle

Went to next job and it sat for 5 hours and started with 3-5 second crank cycle.

I will plug in the block heater tonight and recheck temps prior to starting. If all goes the way I think, it will start in 3-5 seconds.

- - - Updated - - -

Also forgot to mention that the lift pump was also replaced prior to pulling injectors (wishful thinking).

Technically grid heaters in the intake are not the same as glow plugs in the cylinders. Yes, the heater relay can normally be heard.

The ticking noise you heard is the injectors (1&6 I think) firing to purge the rail of air, it's normal and happens every time you sit with the key on and engine off. What filter did you install, and where?Another long shot is the pressure relief valve.

The fuel filter I installed was a 44-FF010 ProGuard D2 F/F purchased is a replacement for the factory filter.

  AGD03Dually said:

The fuel filter I installed was a 44-FF010 ProGuard D2 F/F purchased is a replacement for the factory filter.

Please don't take this comment as me being a Richard...

Get that filter OUT of your truck.

I don't have the spec's in front of me, but if memory serves (and it usually does on filters) it's 3um nominal and 7um absolute, that's what the OEM filter is rated at. Here is the kicker, the AFE filter is not rated for f/w separation so it's WORSE than stock.

Simply put; the best, and only IMHO, filter to run in the OEM canister is the Baldwin PF7977. It's 5um absolute and meets/exceeds the OEM specs on f/w separation. Second to that is OEM or the Donaldson replacement. Aside from those 3 filters..well it's like 2 boys in a hot tub....WRONG!!!

I also highly suggest an additional filter, or two, to help in f/w separation and final filtration. The products sold by Glacier Diesel are my favorite.

Now I'm confused . The place where I bought my injectors said that is what they use in everything and that it was the closest to Cummins specs as you can get for replacement.

This mornings results Air temp 41 degrees

Key off

Engine block 129 degrees

Fuel Filter 65 degrees

Intake heater 100.5

Key On

All temps stayed the same.

Lift pump ran for 2-3 seconds

Started with 3-5 second crank cycle.

Any thoughts?

The AFE filter is not worth running, plain and simple. Put the Baldwin in your truck it's the only filter to exceed cummins specs. The AFE meets them on filtration specs, doesn't exceed, and doesn't filter water.

I will put the Baldwin filter in.Does anyone know what the operating temperature of the Grid heater should be? It seems to me that a 15 degree variance would not be sufficient enough to start, especially when the temperatures are below freezing. Also it seems to me that the heater would more or less need to cycle on and off to some degree with lower temperatures during cold weather driving for engine performance / fuel efficiency, (sorry ADD kicking in). Maybe I'm just over thinking the problem. :think:Thanks to all that have tried to help!

The grid heater heat's up more than that inside, but I am not surprised it's such a low temp outside. It does cycle after the truck is started, for up to 2 minutes or 18 mph, whichever occurs first. http://hoeslidiesel.com/store/media/heatergrid

Thanks John,Does the heater only function below certain temperatures, or does it momentarily cycle on and off with the ignition switch prior to the computer getting signals from all sensors?The reason I am asking this, is that I was just checking the relays with a test light. The side that connects to the battery has power as it should, however the other post is not getting energized when the key is turned on (I had someone to turn on the ignition switch while I held the test light on each terminal).Also is this controlled by the MAF/ATS?Am I wrong in thinking that it might be something other than the injectors?

The grid heater works when the intake manifold temp is below 66°. I don't use a grid heater in the summer and start fine down to 25°, and Cummins states the ISB is rated to start with no aids until 10°F. The grid heater is mainly for emissions, and above freezing is not needed. I bypass mine all the time, don't wait for it, and it always starts instantly.

  AGD03Dually said:

Thanks John, Does the heater only function below certain temperatures, or does it momentarily cycle on and off with the ignition switch prior to the computer getting signals from all sensors? The reason I am asking this, is that I was just checking the relays with a test light. The side that connects to the battery has power as it should, however the other post is not getting energized when the key is turned on (I had someone to turn on the ignition switch while I held the test light on each terminal). Also is this controlled by the MAF/ATS? Am I wrong in thinking that it might be something other than the injectors?

Grids come on at somewhere around 50-60 degree and cycle on and off for 2 min. I fire it up when it's cold let it build oil pressure, set high idle and go in the house 2-5 min and she s ready. Maf/Ats not totally sure on that one.