99 hard start

[hotairgypsy]

I have been searching for info and all i am finding is people saying the glow plug relay or glow plugs. I do not think that has anything to do with my problem. We are almost 80s today and i have the same hard start. I have to crank it a few seconds to get it going. Up until a couple of weeks it would start in less than a second. I have replaced the injectors and a few weeks later i pull them out and replaced the orings again due to them failing. No change with both rounds of injectors. here is a run down on pertinent info.

Both batteries were replaced less than a year ago.
new reman injectors with new orings
glow plugs test out fine.
Plugging in overnight does not help
unplugged ICP and no help in starting...just threw a service engine soon
no smoke while driving....mild puff of black when starting


i do have a snap on mt2500 scanner to check stuff if i knew what to check .

so what ya all think is causing my hard start problem???

[redogg322]

Check your injector control pressure.

Go big or go home

[hotairgypsy]

that is the ICP I assume...what am i looking for in the readings and is there a special way to test it? just idle? certain RPM?

[jesilvas]

Watch the ICP while cranking since that's your main issue, along with IPR.

[hotairgypsy]

at start up the ICP 400 to 700 psi.

At idle the ICP 400 to700 psi and the IPR duty cycle is 9 to 14%

At cruise ICP is 700 to 1200 psi and IPR is 15 to 20%

With normal acceleration ICP is 1200 to 2000 psi and IPR is 20 to 30%

Under WOT the ICP can go up 3600 psi but don't worry if it is less 3000 psi is just fine and the IPR is 35% or higher.

If you are not seeing any ICP pressure(bad ICP sensor) or it seems low (Going bad ICP sensor) you can unplug the ICP sensor that should default it to 700 psi.



does this make sense???

[Justin@DP-Tuner]

I agree with watching your ICP and IPR duty cycle while cranking. You need to have 500psi for the truck to fire, but it should be a lot more than that.