02 3500 89k miles
 

I am a new Cummins owner. Please don't laugh or judge. I inherited an 02 3500 w/ a 6 speed manual from my late brother. I don't know much about the truck except I know it sat quite a bit. I actually drove it from KC, Kansas to Central IL several times pulling a goose neck and hauling other equipment home and the truck seemed to run great. Over the last couple of months, I noticed that the stock fuel pressure gauge in the cab was showing the pressure dropping slowly, like one trip would be 7 psi, the next trip would be 6 psi finally it slowly worked it's way down to 0 but still seemed to have plenty of power. I was pulling the trailer, the truck was running fine, but when I pulled in to town and turned on my street I got a check engine light and the dead pedal. I limped it the rest of the way home, 1 mile, unhooked the trailer, and parked. Idled fine, just no throttle. I went to the internet and this forum and started reading that I could have some costly repairs. I let it sit for a couple of days and checked the error codes. P1693 (I know there is nothing diagnostic about this one) and ECU P0121, P0602. I started it and pumped the pedal and it gave me throttle again and my fuel pressure was back up to 12-14 psi. I drove it to town thinking it was a fluke, check engine light went out, truck ran better than it ever has. On the way home, 1.5 miles out on a 20 mile trip, dead pedal again, check engine light again, but still 12-14 psi on the fuel pressure gauge.

Other things I have noticed about the truck since reading the forums:

EGT seems to peak when pulling the trailer at moderate loads. How can I drop EGT when pulling loads at highway speeds without slowing down and dropping a gear.
5-7 second turbo lag.
Stock exhaust, but rusted and missing halfway back. I intend to put 4" on soon after I get the dead pedal fixed.

I've read posts about the APPS, VP44, ECM, lift pumps, but looking to narrow this down for a starting point. Thanks for everyone's help.

I believe it has a Superchips 3705 Max Micro Tuner installed, but haven't actually hooked it up to verify. I found the programmer in the tool box.

P0121 is a TPS codes. The other is a computer program issue. Could be caused by the tuner. I would highly recommend an aftermarket lift pump, VP pumps don't like low fuel pressures.

1693 is a companion code meaning there is another code on the ecm/pcm side.. Need a decent scanner to pull it up..

0121 is an apps code 9-10 times youll need to replace it.. I would go with a timbo apps

0602 is a fueling code could be caused by the superchips..

As far as egts what are you peaking at? These trucks can run all day at 1200 degrees.. Once you get into the 1350 area it should only be for a very short amount of time.. Ive peaked 14-1500 for a few sec with no issues..

5-7 sec lag could be many reasons.. Your apps code, Low fuel pressure,boost leak,Tuner problems(if installed) Dirty air filter.. Also will depend on if you are pulling/hauling anything heavy.. They arent like the new diesels with vgt turbos where they can spool very quickly...


If at anytime you find yourself with low fuel pressure you need to pull over immediately.. These vps should never see anything less than 10psi but 14psi is ideal.. The vps are very picky when it comes to fuel since they are cooled and lubed by the fuel.. Would be looking at a min of a 1,000 for a new one if it does go..

I highly recommend a fass 150.. Will give you plenty of room to bump up the hp if you ever decide to but its also nice for the water separator and fuel filter part of it.. My fass 150 is currently 8 years old and still pumping along..