Archived Intermittent Loss of Power

[DAMorlock]

My 1999 Cummins is not responding to power demands. Acceleration is limited when this failure occurs. On hills which it normally climbs with no problem, I must floor it in 4th gear just to maintain 42 mph. Then, suddenly it comes back to life and all is well. Sometimes it will not come back to life and I must wait for the hill to end. Sometimes it comes alive and dies several times before coming alive. Once I get to 2500 rpm, it seems to have power. This just started. The temperature has been 14º-35º for the last week.

 

[Joe Mc]

First off welcome to TDR-Land. Please create a signature so when you post everyone knows what the specifics are on your truck - also so you don't have to keep typing what your truck is. Go to "Discussion Forums" pull down at top of page and select "User Control Panel" then go from there.

So, is the CEL on? Get a code reader and see if anything is there before doing anything. Maybe the APPS sensor is acting up? If you back out of the go pedal all the way and then re-apply does it do the same thing? It's hard to tell what it could be? Need to see if there's any codes to really help. It could be the cam or crank sensor even the ecm or VP. Gotta scan for codes. VPs can go many different ways but most often with-out any notice - just "shuts-down" like someone pulled the plug and other times acts whacky for a while then it's OK can never really tell when they're going to give up the ghost.

Hopefully there's someone else out there that can be more helpful. I've been pretty fortunate w/my truck as far as when things go wrong being able to figure it out with scan reader and a ton of help here.

Good luck and keep us posted.

 

[mrtrombley]

Sounds like the fuel filter needs to be changed! Do you get your fuel at a large volume seller, underground tanks can get water in them, especially when getting toward empty. It may also help to put additives in the fuel. That is a simple answer but could very well be the problem. Worth the cost of a filter to find out, but if your fuel has water in it, the filter could soon plug up again but would at least run clean for a while.

 

[Sticks]

Filter or transfer pump. Need to check that fuel pressure.

 

[DAMorlock]

Progress on Intermittent Power

I changed the fuel filter and the problem remains. It is like there is a switch that is turning the output of the turbo on and off. Varying the GO pedal position has some effect, but not predictable.

 

[Joe Mc]

Any codes?

 

[Sticks]

I've had some '99s do it. Try the Key on-off procedure to pull codes.

No, there is not a switch that controls the turbo. It might be going bad as well.

Given your brief description of your symptoms, there are a lot of different possibilities that could be causing this.

Bad Throttle Position Sensor
Bad Transfer pump
Bad Manifold Air Pressure Sensor
Bad Fuel
Failing VP44 Injection Pump
Failing Turbo
Restricted air filter

What transmission is in your truck? Auto or Manual. It could be a transmission issue.

Did you do anything prior to the when the problem started? Change something? Had an accident? Ran over something big?

We need info on your truck other than what year.

Mileage
Mods (performance and other aftermarket tweaks if any)
Transmission
Last service
2 or 4wd

Look at some of the other members signatures to get an idea of what we need to know.

 

[DAMorlock]

The CEL is not lit

 

[Sticks]

Does not mean there are no codes.

 

[DAMorlock]

I can't get any codes. Please review the key cycling procedure for me.

 

[Joe Mc]

99 doesn't have the key trick deal = need a code reader.

 

[desertbull]

Really sounds like a APPS... I've replaced 4 of them in both my trucks over the years, but Timbo built a great fix, check out Genos Garage to purchase one. Oo.

 

[Sticks]

99 doesn't have the key trick deal = need a code reader.

Some do, some don't. I have not found a pattern.



Ignition to "Run", Wait for 1 chime, Ignition to "Off", wait 1 second, Ignition to "Run", Chime, "Off", then back to run, watch the odometer window.

 

[DAMorlock]

Power Problem Update

There are no codes seen. There is no blockage in the intake; filter is new, TAG2 is clear, turbo impeller turns freely and smoothly. With only 26,800 miles, could the wastegate be stuck open. If yes, how do I free it? What drives the wastegate?

 

[Sticks]

In order to help you, we really need to know more about your truck! All we know is that it is a 1999 w/ 27k miles.

*Auto or Manual

*What performance accessories have you installed, other than the TAG2? I. E. injectors, programmer, performance box, exhaust, turbo, exhaust brake, anything purple or has "Banks" on it...

Gauges - EGT, Fuel Pressure, Boost, Trans Temp (these are aftermarket items)

Any Daimler Chrysler updates and flashes to your ECM. I. E. In tank fuel transfer pump, ECM flash for cold weather warm up...
.

The wastegate is actuated by boost pressure. Once enough pressure is built, the actuator rod will push out, opening the wastegate.

Let's try a rev test.

Engine at operating temperature. From Idle, fully depress the throttle and hold it (you won't hurt the engine, this is referred to by Cummins as "High Idle"). Watch the tachometer and listen. The engine should increase RPMs smoothly and without any hesitation or surges.

Let the engine return to idle, and repeat, but this time watch the passenger side mirror and watch the exhaust output. If everything is good, maybe a light puff of black smoke, then clear.

Get a fuel pressure test kit if you don't have one already, or don't have gauges installed. Something like this from Geno's Garage
VULCAN PERFORMANCE - FUEL PRESSURE TEST KIT ('98. 5-'02)-Dodge Cummins Diesel Truck Accessories - Geno's Garage

or any fuel pressure gauge that will test the fuel pressure at the schrader valve equipped banjo bolts on the filter housing and VP44 inlet. You should have no less than 10psi of fuel pressure at all times.

 

[DAMorlock]

I have no gauges and found a recommended tech, who measured everything and found the lift pump as the culprit. Thanks for all the input. Hope I won't need an injector pump.