wow! look at that.

 

Just got it back today, it seems to be running alright. The replaced the cam shaft sensor, which it was covered under the cummins 100k warranty.

 

man thats nuts. I'm not sold on the FASS pump fix all yet either. still woried thatt the FASS may supply too much preasure. Anyone know the manufatuers specifications for CP3 input preasure. My Case w20B Wheel loader has a bost pump. Its been out for aroungd 18 years. injection pump is working RPM's are down about 300. I have heard that if not blocked by a bad pump, CP3 will suck it's own fuel? Maybe dodges pumps should be redesigne for better flow through the pump?

I suppose you need to have reading on CP# preasure and low preasure side to determine if you have a lift pump problem.

But if you have an intank or intank conversion, I recomend carefully checking htese preasures before condeming the stock pump.

I'm not drag racing so how much volume and preasure does my CP3 really need. Maybe we should just mount our tanks on the roof.

For those of you who dont understand my hummor the roof thing was a joke.

 

You have a new response in your thread about your crazy concern that the FASS is putting too much pressure to the CP3

 

I have been keeping up with your other thread on your situation......it seems like you have another problem on your truck that you tossed a FASS (OR seems like an HPFP from your desctiption) at it to try to fix it without any firm diagnosis. Find out the real problem, get the truck running correctly and then see how the FASS (Or HPFP) works for ya. If you have head pressure, its doing what its designed to do.

You are not going to hurt a thing at the pressures our systems are set at.

 

Try this link for more information on CP3's and preasure.

https://www.dieseltruckresource.com/...p/t-78702.html

 

You only have to worry about running too much pressure on Duramax CP3's. The FCA in thoese pumps do not like to see pressure over 12ish PSI. Anything over this amt will cause rail pressures to increase at idle. This in turn causes a knocking or rattle sound. From what i know, and have delt with, this does not hurt the engine (BUT needs to be fixed due to engine lights and high rail pressure). BUT its letting you i know something is not right and pressure needs to be reduced.

Now talking with John at Floor It Diesel one day, Cummins CP3's have differnant FCA's that can, and DO work just fine with higher head pressures. Some on this site are running 45 PSI with no issues what so ever.

 

Dropped the truck off tonight for the injector replacement and reprogram. Hopefully, this is going to put a stop to this crap. I'm thrilled, however, my servicieng dealer is so receptive and taking care of it without any bs. I'm going to make sure the fuel filter is 7 micron or better and ask him about the 5 micron Baldwin ful filter and if there are any warranty issues with it.

 

Well to update my post, they replaced 2,3,5,6 injectors and it still is not running right. So far all injectors have been replaced along with an ECM and we are still hunting the problem. I sure wish this thing would throw a code of some sort so I can get this over with.

I am going to talk to the service manager again and see what else we can do. It would be nice if they could hook me up with some equipment so I could monitor what is going on when it starts to act up. I am thinking the next most logical problem would be the FCA. Any other suggestions?

 

Don't under estimate the FCA. I thought I had eliminated that as a possibility on my problem, but lo and behold, I replaced it yesterday and my truck seems to be running fine now. Time will tell, but it's cranking right up now, cold or hot. It was $135.00 tax/title/license from the dealer, butthe best money I have spent so far. They say that if you pop the hood and have somebody cycle the key from the off position, to the on position, and then back to the off position, you should be able to hear an audible click coming from the FCA. Get a partner, and try that.

 

I read some of your older posts, mine has different symptoms than yours (start good but run rough when hot) but I imagine it still could be related to the FCA?

Did you ever get that Quadzilla setup that monitors IP and LP pressures? I am going to think seriously about that if I can't get something figured out w/the dealer. If $200 would point me to the problem, it would be well worth the stress reduction. And I think the guage setup would be handy to have anyway.

 

Yes, I did get it hooked up. I like it. It confirms that my LP pressure is good (13-14 psi) and that my rail pressure is good (5000-18,000+ psi). I think it's important to know what these numbers are. I am a firm believer in the following diagnosis methodology:

Make sure fuel, fuel filter are good.
Check for DTC codes and resolve.
Determine your LP and HP fuel pressures.
Perform the FCA "audible click" test.
Test the Rail Pressure Relief Valve (should not leak fuel when idling).
Perform the injector return flow test (no more than 180 mL/min).

Failure of any of the above should pinpoint the problem, unless it is an internal engine issue (burnt valve.....).

It seems like a lot to do, but in reality, if you were to get set up with the proper fittings, gauge(s), etc., it's really only an afternoon and a few beers worth of diagnostics that the dealer probably would damage your beer fund with.

Too much said.....????? My hair is greyer......................

 

Fuel and filter is good, just changed the filter but this problem has been ongoing for about 10,000 miles so it has had plenty of different fuel in it.

I have also checked for codes often, there are none.

I would like to get the FP/IP guage setup, but want to talk with dealer first.

Now about the FCA click test. Should it immediately click? Mine hums/buzzes for a second or two before clicking.

How do you test the relief valve? I am guessing the line from the filter housing needs to be plugged somehow to prevent backflow?

On a couple of occasions the dealer has diagnosed return fuel leaking into the cylinders (?), thus the reason for two sets of new injector sealing washers so far (which have never helped). Now I have all new injectors as well, if that is still happening what else could it be?

Thanks for the help, if nothing else I am definately learning something about this truck.

 

Got the truck back Sat afternoon after all 6 injectors were replaced and some kind of reflash. They enabled my 1220rpm idle feature which is activated by the cruise control button. So far, it runs better than it ever has. I checked to be sure that the fuel filter element that was replaced at 14k miles was the 7 micron and it is. Not sure I want to go to the Baldwin 5 micron and then have lift pump problems. BUT, I will change the factory 7 micron now more often if it will help.

 

Had all my injectors replaces at about 65000 miles i had been having a problem with smoke and a slight knock at times during warm up. Now the truck runs great. I did also have a pwm high pressure regulator replaced too. I think I had a cracked tip and it would leak at certian temps, also with my dodge scanner I could see the demanded pressure and the actual pressure would very and at times would be Ok. meaning the pump was good but the regulator was the problem. These systems are not as hard to repair and trouble shoot as You people think, the only reasion I had the dealer fix it was because it was under warranty. I do service work all the time on these, powerstrokes and Duramaxes...