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Topic: 8.3 Cummins mechanical power issues & remedies (Read 551 times) previous topic - next topic

8.3 Cummins mechanical power issues & remedies

When I purchased my 1996 270 in Spokane Washington in  Oct. 2011. I met with the private seller, took it for a test drive (down to the bank) I knew it had my name on it before I left home 300 miles away...

So once I got onto I-90 westbound headed for home I was happy as a clam thinking what a sweet ride!! You guys know the feeling smooth and quiet like riding on the cloud...
Ok first good grade Vantage 12 miles out of the Columbia River basin. Pedal to the floor making no heat, thinking this thing is a dog!! Thinking no wonder I got such a bargain...sure ran good otherwise though.
Did I mention it had six new Toyo tires, all new batteries, graphics, fuel lines, $3500 brake job and 58k miles.
So anyways off to Arizona in December that year to winter abode outside of Yuma.

It was time to dig into the power issue:

1st. thing open up the exhaust - replaced with Aeroturbine resonated muffler 4040 XL stayed with the stock 4 inch for the turbine effect?? Plus didn't have to replace so many parts$.
Test drive around town - sounded good but still lacked the gitty up! My old 280 with the 3208 cat performed a lot better than this one.

2nd. Replaced the stock fuel return valve with a Tork Tek Cummins adjustable overflow valve. By the way my old stock valve spring was broke in two. thinking that this would really make a difference, still didn't do much for the Getty up.

3rd. Squeezed off the rubber hose that went from the fuel pump to the turbo wastegate actuator and took it for a spin.
BINGO!! the front wheels almost came off the ground... :))  Replaced with a stock Cummins wastegate actuator set at 26 psi. The old one had a leak in the can itself that was spilling off boost, takes boost to open up the fuel valve in the pump.

Also installed boost and exhaust temperature gauges.
23 psi boost and stays cool on all West Coast grades....


Doug W.
96 36' U270 CSGI #4946
04 Toyota Tacoma 4x4
PNW

Re: 8.3 Cummins mechanical power issues & remedies

Reply #1 –
Doug,

 This is real good info that my help others out.  Jerry Whiteaker is one that comes to mind as he has a 8.3 with power issues also.

Pamela & Mike
Pamela & Mike 97 U 320

"It's not what happens to you, but how you react to it that matters."

Re: 8.3 Cummins mechanical power issues & remedies

Reply #3 –
Doug, those links have to be seperated for them to work. Just post one at a time then or send them to me to post.
JohnH
Coachless, now use aircraft. 2003 Ford Travelair TC280 class C. Super shape. Just for 1 yr .
1994 Ford E350 ClassC,total renovation inside and out. Now sold.
2000 U295  36' Cummins 350 c/w Banks Stinger, Resonator upgrade,Solar, LED lites.Residential fridge with slide out pantry. Build 5674. Sold
ex 92 GV 022C ored Cummins. Sold
ex 95 GV240 cat 3116. Sold
2017 Mini cooper s & 2016 land Rover LR2 HSE  LUX.
jhaygarth@aol.com    SKP #130098
treat everyone as you would like to be.

Re: 8.3 Cummins mechanical power issues & remedies

Reply #4 –
John, sorry about the links...I'm out of my comfort zone!!
Doug W.
96 36' U270 CSGI #4946
04 Toyota Tacoma 4x4
PNW

Re: 8.3 Cummins mechanical power issues & remedies

Reply #5 –
We had a similar lack of power issue in our previous SOB 8.3. Struggled with it from Oregon to Charlotte, NC.Finally took it to Cummins shop. Dyno confirmed problem; only putting out about 1/3 HP that it should. Tech immediately started checking fuel pressures. He inadvertently felt air escaping at the bottom of a large rubber elbow in the piping from the CAC to the intake manifold. Found a slit in the bottom along a seam; lees than a $20 part and made a huge difference.
Just another thing to keep in mind.
Dick
Dick, '03 U320 40' Tag, 2 slides, Coach #6075
Full Timers
2009 Honda CR-V

Re: 8.3 Cummins mechanical power issues & remedies

Reply #6 –
Doug,

Since you seem to be a person who likes to look at gauges, you might consider adding a fuel pressure gauge.  It is pretty simple to install one in the engine compartment. It will allow you to verify the setting on your adjustable overflow valve, plus it is a good diagnostic tool.  Changes in fuel pressure at the injection pump can give early warning of more serious problems, like plugged fuel filters or collapsed hoses.  Here is a thread showing my gauge installation, in case you are interested.  (I originally used a 30 psi gauge, but found this was not satisfactory.  I recently replaced it with a 60 psi gauge, which is a better choice for this application)

Fuel System Science Project
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Surely, no age has been more fraught with insecurity than our own present time."

Re: 8.3 Cummins mechanical power issues & remedies

Reply #7 –
We were running just fine, but decided to preventatively change the mechanical fuel lift pump ourselves.  Well, to our amazement take offs were smoother and we felt more power.  We must have been running lean without knowing it.
After the new lift pump, we added electric fuel pressure gauge and a new fuel return valve.  If we had the pressure gauge before the new pump, we would have had before & after pressure readings, but we are stuck with only knowing we run better and pressures are 15 to 30 psi.