joe rush

??? This is all new to me. i have a 97 12 valve. just took it in to the dealer for loss in power. there is 100,450 miles on it. still a pup i hope? this will be the first major repair to it that i have done since i have bought it new. i have read some of the lifter pump forums. where can i get a psi gauge and how hard are they to install. oh, i use my truck to. it has been plowin snow and towing since new. can you fine folks throw some helpful hints my way. thank god for this site

JFellman

You already took it in? Too bad, there's a lot of experience and help on this site. The shop may find that the catalytic converter is plugged up or something fuel related like a plugged filter or screen or a malfunctioning fuel return valve. It might even be as simple as the shutdown valve not fully opening. Hope they don't find that the injection pump is bad...that is expensive. Good luck and let us know what the shop finds wrong.

kd460

You should be able to find plenty of info on pressure checking by doing a search on this forum. Sorry, not familiar enough to give you advice (newbie). But I think you need a special &quot;banjo bolt adapter&quot; for the gauge to check the pressures.<br><br>The 1998.5 and above have fittings on the top of the filter housing to check pressures. I see on my 1997 that I have the &quot;recess&quot; in the top of the filter housing where the fittings would be tapped and in place on the 1998.5 and above. So why can't I just drill, tap, and install fitting? Any reason why not? Wouldn't this be the best location to install a pressure gauge? Good luck Kevin

JFellman

Kevin, the top of the fuel filter seems like the best place to install a fuel pressure tap to me also...although the 12 valves with the mechanical lift pumps seem to be a lot more reliable than the 24 valve motors with the electric lift pumps that seem to fail quite regularly. The fuel pressure gauge in the cab seems to be almost mandatory for those 24 valve trucks in order to keep from destroying the injection pump do to low fuel delivery pressure. From what I have read, the 12 valve injection pump is more tolerant of low pressure...may run bad but won't destroy itself quickly like the 24 valve pumps.

kd460

Hi John, yes thats what I have heard as well. Went to the cummins dealer today, talked with one of the mechanics, he sayed it would work as well (tapping into the top housing like the 24 valves).<br><br> I am chasing down a slight miss at 900 to 1500 rpms, and I figure a perssure test port right on top would make life easy. So far I have replaced the fuel lines, filter, cleaned prefilter, re-stretched overflow spring, air filter, and have some injector cleaner in it. Just picked up a new prefilter kit with new o-ring, and the hose that connects the prefilter to the regular filter. Need o install those tonight. <br><br>I did not notice the miss till after I changed the fuel filter, BUT this truck was running so poorly, it may have been there and I just could not tell. Changing the lines and filter made a big improvement in how it runs. The miss is only slight, but I feel it. <br><br>Next will be checking the valve lash, but I have a receipt from previous owner that states it was done 18,000 miles ago so not sure if that will help. Maybe timing. I'll keep hunting, thought a bout installing some temporary clear line to see if it's sucking air somewhere. Thanks again, Kevin<br><br>BTW joe, I responded to your other post, change the fuel lines, it is due if not done before. What about valve lash, prefilter, and overflow valve? The dealer will nail you on those parts, try to find a cummins parts dealer to buy any of the above. It will save you $$$$$ and they will give you a book showing all the exploded diagrams with part numbers so it's easier to call and check for next time. Kevin