Help!!!! Cummins 8.3 no power!!!!

[whited44]

Hi guys. I have a 94 gulfstream tourmaster with a 250 horse cummins 8.3. Yesterday we started off for Florida and the thing ran horrible. Barely got it home. It doesn't seem like it's building boost? Or getting fuel? Around town it is somewhat drivable but on the freeway or on the slightest grade it won't go over 30 mph!!!! Any ideas???? Maybe fuel filters? Wastegate not letting it build boost? Air Fuel Control valve? ANY HELP WOULD BE GREAT! I NEED TO GET BACK ON THE ROAD!!!!

[palehorse89]

How long has it been since you serviced it? Fuel filters?

[whited44]

About 1 1/2 years on the fuel filters. And maybe 10k miles

[Pig Trapper]

I believe that the fuel filter will be your problem. I have a big rig and that sounds exactly like a fuel filter problem. I find that changing at least 2 times a year depending on use.

[whited44]

And this is the worst it has ran. Last time we had it out it was bad and underpowered but it was driveable. So the problem has slowly gotten worse and worse. That's kind of what makes me think it's the filters. Slowly getting more and more plugged up. It's a the Cummins place now. Hopefully I will have an answer soon

[wb6epp]

Two things to check. Carefully remove fuel filter, and with a glass jar, pour the fuel in it. Let it set for about 30 minutes, check for water. While your coach was setting did you have your tanks full and stabilizer in the fuel? Next thing to test is the primary pump pressure as the primary pump is ahead of the P7100 and has a screen filter in it {or at least mine did} and it turned out to be clogged. This is rarely checked!!! Hope info helps

[wb6epp]

Forgot to ask, do you have exhaust brake installed? If so, please varify that it is opening and closing correctly.

[whited44]

Yes there is a pac brake on it. I can move the butterfly with my hand open and closed so I know it's not stuck. Just seems like either filers clogged and got progressivly worse or building no boost.

[J Walker]

Check for any codes set in the engine ECM. Did a dash light for a code flash? Silverleaf has a monitor to read out codes and I would surely get one.

[num1dgh]

Quote:

Originally Posted by J Walker Check for any codes set in the engine ECM. Did a dash light for a code flash? Silverleaf has a monitor to read out codes and I would surely get one.

Check for codes & also consider your speed sensors. Our coach was doing a similar thing. We replaced all three speed sensors & the u joint.

[whited44]

Quote:

Originally Posted by J Walker Check for any codes set in the engine ECM. Did a dash light for a code flash? Silverleaf has a monitor to read out codes and I would surely get one.

I thought these engines were mechanical? No computer? There were no check engine lights or anything like that....

[wb6epp]

94's are mechanical, no ecm! Check primary pump as well.

[HeapBigEngin]

I agree...it does "sound" like a fuel filter. If it turns out to be that, you might want to consider if algae may not be the underlying problem here. If you live in a humid area or if you don't regularly "consume" the fuel in the tank, then you have a good breeding ground for algae. Since water presence in diesel fuel in not uncommon, algae will thrive in dormant diesel fuel. Suggest you do a forum search on the subject....lots of great info here. A good biocide product treatment would be in order if you detect that nasty slime ANYWHERE in your fuel system. PLEASE let us know what you discover...thanks!

[timex]

I agree checking the fuel filters first. But I had a odd thing happen once, A fitting on the air line between the intake and fuel pump broke where it attached on the back of the fuel pump. That line lets the pump know your engine is building turbo pressure and to go ahead and turn on the fuel without making a lot of smoke. No signal and your pump will restrict the amount of fuel it delivers to the engine.