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question on loss of power

 
dog.94 dog.94
New User | Posts: 6 | Joined: 03/10
Posted: 03/09/10
05:22 AM

I have a '94 5.9 L cummins which intermittently loses power.  Previous owner says it is the throttle position sensor which I have replaced and didn't fix the problem.Truck starts fine,  no smoke with no load you can tach out the engine but not as quickly as when it is running right.  You can tell when you start the truck, when it runs correctly it will start without a full crank of the starter, when not running right it will crank 2 or 3 revolutions.  Truck won't shift correctly when in this mode, won't pull any hills but picks up speed on a flat or downhill.  It will do this for several days then all of a sudden it will take off and run correctly.  I really don't think it is a fuel delivery problem, I am at a loss.....  

pbrbullhauler pbrbullhauler
Enthusiast | Posts: 556 | Joined: 03/09
Posted: 03/09/10
10:13 AM

not sure but is their a crank sensor on that year model truck. sounds like a timing issue  

MarineOne MarineOne
Addict | Posts: 2063 | Joined: 09/08
Posted: 03/09/10
11:01 AM

Man I hate saying it, but with it being a '94 it could be plenty of things.

I would check the simple stuff first like the lift pump, but like Rich said it could very well be a crank sensor.  It could also be injectors, the VE pump, or another sensor.  After 16 years of driving its going to be hard to pinpoint.

I would suggest some basic troubleshooting, like new air/fuel filters, checking the lift pump pressure, check your grounds, and then the sensors .... trying to narrow it down in the process.



Kris  

2006 Dodge Ram 2500 QC 5.9L - Smarty CR S-06 on SW #5

2008 Dodge Ram 3500 QC 6.7L - H&S MiniMaxx on DPF tune for towing
Titan Fuel Tank
Aero Muffler 4040XL
Nathan AirChime K3LA

nmdiesel22 nmdiesel22
New User | Posts: 21 | Joined: 10/09
Posted: 03/09/10
01:58 PM

I had a similar problem on my old 94 and I ended up replacing the computer and wiring harness, fixed it for about a year and then it started doing it again after putting way to much money in it I just sold it and went back to the first gen. So there is no telling what it might be.  

dog.94 dog.94
New User | Posts: 6 | Joined: 03/10
Posted: 03/09/10
07:18 PM

Thanks for the input, I don't know if there is a crank sensor on it or not I will check into it.  On my 7.3 L ford the engine shuts right down when the crank sensor goes, been there done that..  Thanks  

dog.94 dog.94
New User | Posts: 6 | Joined: 03/10
Posted: 03/09/10
07:37 PM

Thanks Kris,   I have changed all the filters more than once, haven't checked lift pump pressure yet, not much of a mechanic mostly a carpenter with enough tools to be dangerous.  Another guy mentioned the hoses to and the AFC on the end of the Injector pump and I found it in my manual but not sure what its purpose is.  He suggested taking it off and covering the hole and taking it for a ride, but i can't get at it to get it off, I checked the hoses and fiddled around and the truck went back into power mode at least for the 2 miles I drove it.  Thanks again I will keep trying  

White_Lightning White_Lightning
Guru | Posts: 941 | Joined: 07/09
Posted: 03/11/10
01:35 PM

I would like to correct MarineOne in saying that a 1994 has the P7100 injection pump. I will place money it is the shutoff solenoid not pulling up all the way. I had an issue similar to this, when it worked, it pulled all the way up and I had full power. Without it pulled all the way up, you can't get full rack travel in the injection pump and thus never achieve full fuel.  
Logan
1995 12 valve Cummins 6.0L, 5 speed, 4x4, 600hp Valair Clutch. Air Dog 4GHD lift pump, no fuel plate, 2095 rack plug, 024 DV's, pump benched at 440cc, SDX 5x.014 injectors, Hamilton 181/210 cam and HD pushrods, Stage 2 Port job, 5 angle valve job, 60lb valve springs, ARP studs, O-ringed head, .020" over head gasket, coated pistons, balanced bottom end, Fluidampr, PDI exhaust manifold, homemade intake manifold, 63/68/0.80 over 80/92/1.32 compound turbos.

dog.94 dog.94
New User | Posts: 6 | Joined: 03/10
Posted: 03/11/10
02:16 PM

Thanks White Lightning,
   I was just fiddling with that solenoid and it didn't feel like it was working right.  In your situation it wasn't either off or on?  You are saying it was stuck in the middle?  After I messed with it the truck ran fine for a short ride.  Another guy says it could be the AFC not working which would restrict the governor  from having full travel also.  Did you replace the solenoid and fix the problem?  Thanks, dog.94  

MarineOne MarineOne
Addict | Posts: 2063 | Joined: 09/08
Posted: 03/12/10
12:58 AM

Yeah my bad, '94 was the first year for the P7100 and it could definately be the shutoff solenoid.


Kris  

2006 Dodge Ram 2500 QC 5.9L - Smarty CR S-06 on SW #5

2008 Dodge Ram 3500 QC 6.7L - H&S MiniMaxx on DPF tune for towing
Titan Fuel Tank
Aero Muffler 4040XL
Nathan AirChime K3LA

dog.94 dog.94
New User | Posts: 6 | Joined: 03/10
Posted: 03/12/10
11:45 AM

Hey marine one :    White lightning wins the money,  I wired the solenoid up in the on position and it ran just fine, I also found out why they call it a fuel shut off.  To my surprise when I shut the key off the truck just sat there running Ha Ha.  I had to get out and loosen the wire then push the shutoff bracket to shut the engine down, then after startup had to push the solenoid up until it stuck and the truck ran fine.  I have driven this truck for 3 yrs. now with this intermittent power problem and am very pleased from all the input and soon to be fixed problem.   Thanks guys.  dog 94  

diesels-built-by-cecil diesels-built-by-cecil
User | Posts: 104 | Joined: 07/09
Posted: 03/12/10
12:14 PM

this is to nmdiesel22 i just want to let you know that a 94 cummins doesn't have a computer. so how could you have changed it if there isn't such a thing???  

White_Lightning White_Lightning
Guru | Posts: 941 | Joined: 07/09
Posted: 03/12/10
02:52 PM

Yeah I just had to replace mine. When I turned the key on, it would pull up enough to run but not enough to get full power. I figured it out when I shut the key off one time, and it was stuck in the on position and kept running after I shut off the key.  
Logan
1995 12 valve Cummins 6.0L, 5 speed, 4x4, 600hp Valair Clutch. Air Dog 4GHD lift pump, no fuel plate, 2095 rack plug, 024 DV's, pump benched at 440cc, SDX 5x.014 injectors, Hamilton 181/210 cam and HD pushrods, Stage 2 Port job, 5 angle valve job, 60lb valve springs, ARP studs, O-ringed head, .020" over head gasket, coated pistons, balanced bottom end, Fluidampr, PDI exhaust manifold, homemade intake manifold, 63/68/0.80 over 80/92/1.32 compound turbos.

dwwthedoc dwwthedoc
New User | Posts: 1 | Joined: 03/10
Posted: 03/30/10
04:47 PM

I've got a 1999 Dodge Cummins with the same problem but I find that when it loses power and the throttle is on the floor to maintain 60mph, if I turn off the ignition and turn it back on, the power is restored instantly. Fuel starvation not caused by filter but possibly transfer pump or the solenoid as someone suggested. I'm going to replace the soleniod to start. Seems like the easiest place. Any other ideas?  

pbrbullhauler pbrbullhauler
Enthusiast | Posts: 556 | Joined: 03/09
Posted: 03/30/10
07:01 PM

there is a computer on the early 2nd gens its the pcm that controls the a/c and altenator and a few other items. dwwthedoc sounds like a lift pump issue there is no selinoid on the 24v motors  

tango6 tango6
New User | Posts: 3 | Joined: 07/10
Posted: 07/24/10
12:30 PM

I have this exact same problem. It has been happening for 3 weeks now and getting more frequent.

My truck is an 2001 with 160k on it.

Some days it runs just fine. High RPM under power for hours.
Other days as soon as you run it at 2000 rpm or higher for 30 seconds plus the RPM just drop to about idle. Then it will kick back on then drop again. If you drive it at 1600 rpm or less it's fine.

I checked the codes, and have no codes.
I replaced the APPS/TPS but that didn't fix it.
Have a fuel preasure sender at the VP44, and it's shows steady good preasure 17 psi.
The VP44 was replaced about 2 years ago.
Lift pump is a new air dog 150.
When this starts happening if I turn it off and turn it back on again, the problem continues.
If I let it cool down over night it may or may not happen the next day.
The problem doesn't seem to happen if the engine is cool, and seems to happen on hotter days, or you have been driving for 30+ minutes. 8 hours into a 16 hour drive it almost guarenteed to start happening.

From reading above I do not have that shut off celinoid do I?
The crank case sensor was deleted from the 2001 and 2002 models, and it uses a camshaft sensor. so, I'm going to replace the camshaft sensor on monday or tuesday and see if that is it.

What else could it be? Any ideas?  

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