I finished up my Fass install, but now I have "hard Starting". In the instructions it says the diaphragm is ka-put in the VP44.

Can you just get that replaced?
Or is it time for a new VP44?

 

I don't know if I would believe the claim and replace the VP just because of a hard hot start. It is a common issue and there is a reason the OEM LP does not run full bore when cranking. Too bad aftermarket systems think they can pressurize the VP to the limit, should be following the logic Cummins used in this case, I would think.

 

I also have frequent "dead pedal"
I was hoping the Fass would fix but it didn't.

 

What's your fuel pressure on start-up? Too much pressure will cause hard starts.
The dead pedal may be an APPS problem. Have you checked for codes?
Mike

 

This morning I leave on a 3800 mile road trip, over the next week. Right now I'm in a little podunk town that doesn't even have...well...anything. So doing truck work is tough. I'll end my trip by Seattle and I'll be able to install the pressure gauge that I bought and fix this problem what ever it might be. I was just hoping that if I had to I could stop along the way and have that diaphragm replace if it were an easy job
Wish me luck

 

The diaphragm is not replaceable by a shop. However, this is probably NOT your problem. I think your pressure on your FASS is set too high, and it is forcing the diaphragm to one side. It will be hard to start but run fine once running. The FASS is adjustable for pressure, and I believe should be turned down to 10 psi or so.

 

Hard starting is irritating, but it is your dead pedal that is more worrying. Good luck on your long trip and hopefully it is not your VP44. Replacing that on side of the road would not be too bad if you have proper tools, it is getting it delivered quickly that might be difficult away from civilization.
-P

 

I've been running 21 at idle 18 wot for almost two years and my truck starts as soon as I touch the key. Its unlikely that your problem is from pressue being to high. The dead pedal is an issue you need to address and its unlikely that the fass is causing it.

 

Dead pedal quickly led to injector pump replacement in my case. Thankfully, my truck was still under warranty. When I put the FASS pump into my truck, I got a bit of a hesitation on the start but over time it has improved. At idle I've got just under 15 psi and at WOT, about 12.5 psi. I do run fuel additives most of the time and "Sea Foam" periodically to clean things out.

Good luck! Randy.

 

I made it!
A little over 4,000 miles. Dead pedal all the way. Sometimes every mile. Put in the clutch, let the rpms drop to idle, let out the clutch and go. One day it lasted 9.5 hours without a dead pedal. Seems to get less dead pedal when it's cool (morning, evening, or raining) than when it's hot. But not always. When I used the cruse control, it would dead pedal and I would reach down with my foot to the gas pedal and it would be tight against the floor and I would be slowing down. Turn off the cruse, put in the clutch, drop the rpms, let out the clutch, press on the gas and go.

It almost seemed as though it were something electrical. Maybe getting to hot and going into oscillation?

It was really stressful.

I need to get this fixed, but don't have a lot of cash to experiment with.

 

check codes 0121 or 0122 will be the APPS, 0216 it's the vp44. my coins on the pump

 

It sure does sound electrical, like the injection pump circuit board. What you describe is the classic symptom of cracked traces on the board that make intermittent contact when heated up.

 

Is that board in the pump, or outboard?
I'm wondering if it could be replaced if defective, without replacing the whole pump.

I've also had hard hot starting since the Fass install, as I mentioned before.

 

You have to get the whole pump. This should fix your hard starts also.

 

Guess I know where our check from IRS is going