Mr. Wise

I've been running the FASS for about 3 weeks now and has been working great. I run pressures between 18 and 22 which is as advertised. However last week I was on a long trip cross country and was 130 miles from anywhere when I sprung a leak at the injection pump. There is a cap on the left side of the injection pump, which I believe covers the governor plunger (not a VP44 expert here), at least that's what I think the mechanic called it. Anyway it cracked in half and I had to be towed. A mechanic for cummins said this happens all the time, however I wonder does the extra pressure inside the VP44 from the FASS have anything to do with this? Luckily I was able to get a cap off an old core and swapped the cap out with no problems, with the exception of finding a 5 point tamper resistant bit for the screws. I haven't seen anywhere on the forums where someone else had the same problem.

Additionally I wonder why the FASS spring has changed recently. I know you can install a lower pressure spring now for the FASS. It makes me suspect that someone realized that 19-22 psi was too much pressure for the VP44.

Anyone have thoughts, answers, or personal stories. I'd like to hear them. Thanks.

RowJ

I get 18-19 psi all the time....with no problems! I do believe, anything over 12 psi is just circulating more fuel with no real advantage.

Have not heard or read of your problem anywhere else??

RJ

zukgod1

That would be some good info to know, I was wondering the same thing a while back. Why the lower spring/pressure option? I think I'll be following this thread to see what comes up.

dan

ds1rider

I get 19-21 psi all the time.

Diesel-Dan

Its a cat and mouse game for us. We had pressures at 13-15 to start with. Then people wanted more pressure. SO we gave more pressure. Then the pressure was "...Too high, and causing hard starts" (Which actually has nothing to do with the pressure of the FASS, only its ability to "Instantly" make pressure and outdated ECM software.). SO now we have the spring that was back at 13-15 PSI in our kits. Which is stock pressure for these trucks.....someone wants more pressure, they can change the spring out and do so.

We didnt change it back due to pump damage. Rather dealer requests for a lower pressure spring. I have never personaly heard of high inlet pressure knocking out a VP-44. OR causing any leaks for that fact. Yours is the first i have heard of this type of issue.

The new PS-1002 we are currently using is at 13-15 PSI. If you feel the need for this spring, you can call your dealer and he can get it for you.

rbattle

This confirms what I was wondering. I am running 21-22psi and I was wondering if that was too high. The truck is running well however, so I don't see any need to change it. Thanks Dan! The FASS system is doing its job!
R

Mr. Wise

Well Thanks to all thus far for your input.

Dan, thanks for your tech advice too. It makes me feel a bit better knowing the story behind the changes of the springs. It makes sense.

Anyway I'll continue to monitor this thread and see if anyone else runs into the same problem I had. Maybe I just had one of those weird flukes, however I thought it was worth sharing.