Engine/Transmission (1994 - 1998) My First post....I need help

[Jhenson96]

I apologize for such a long post. I guess I need to explain. Bought the truck 5 years ago. Daily driver. Had very few problems. Truck isstock except for plate slid forward and BHAF. 4:10 gears. Truck starts and runs good.
Last year bought an RV. 8400lbs empty. Pulled local, noproblems. Truck will pull the heck out of it.
Last summer we took the camper on a 3.5-hour trip away fromhome. I got on I-10 and decided to seewhat she would do. I got her up to 75mph pretty quick. Truck is wound up at 75. Truck makes a groaning noise when you shiredown on it like going up a grade in 5th​ gear. You can hear and feel the torque of themotor.
Truck pulled great!!! Old ugly truck with paint falling off of it blowing by everyone. I was really pleased with how well it pulls.
Stopped to eat. Gotback on road, heavy traffic. On theother side of San Antonio traffic went away and I noticed I could barely get to65. I got behind someone and tried topass and I had no power. I gave it fullthrottle and no smoke. So, I limped itto camp site. Truck wouldn’t groananymore past 45 to 50 mph. Takes foreverto climb up to 65 and wouldn’t do 70. Nomore groaning….
Got a local mechanic to change fuel filter. Without pulling camper it drives fine. Hooked up to come home and same thing, nopower. Got home and took a white bucketand changed fuel filter again. No dirtin filter.
Got a fuel gauge to mount on top side of filter. Read 40 psi. Ordered new overflow valve. Nowpressure at idle is about 23ish, needle bumping up and down. Old overflow was stuck closed. New on readingas it should. But..No change….Goingthrough gears I can get a lot of smoke up to 4th​ gear. Once I reach 50 miles per hour it seems I amlosing fuel. No more smoke.
Where do I go from here? I know the truck will pull. Iknow the motor will run good I just don’t have the fuel delivery I need…..
Help please…

 

[BigPapa]

Welcome.

How about a long reply?

The first thing I would suggest you check is that the shut-off solenoid is pulling all the way up.

Check the boot and make sure it's not coming apart and binding it. If it is coming apart, just rip it all off, remove the solenoid and clean the plunger and the barrel, DO NOT lube it, and put it back on and try it. Don't worry about not having a boot. Mine hasn't had one for over 300K miles.

If that's not it, next check to make sure the woodruff key is still on the shut-off lever shaft. It is VERY small and easy to drop and not miss it when you put the lever back on. Just loosen the 8mm bolt and slide the lever off the shaft. If it's there, put it back together.

If that's not the problem, turn the key on, bump the starter but don't turn the switch off. See if you can pull the shut-off lever up more than it is. Pull it all the way up and see if it stays. If it does, drive it and see how it feels. If this is the problem, I would start off by replacing the relay on the fire wall and see if it makes a difference. They are available at O'Reilly's, part #25-0102, for @ $10.00. If that doesn't help you'll need to replace the shut-off solenoid.

 

[Jhenson96]

I have done that...and thanks for your reply

 

[BigPapa]

I have done that...and thanks for your reply

Sorry, I was editing my post to add some info when you replied.

 

[Jhenson96]

Sorry I did not read your complete reply, got a distraction.

I replaced the shut off a couple of years ago. I checked it a couple of weeks ago. It is going all the way up after bumping the starter. boot is good.

 

[crabman]

Can you see what the fuel pressure is while you are driving? Fuel pressure can read good at idle but if there is any restriction at all in the supply the pressure will drop under load. Check the pre filter screen for debris. https://www.genosgarage.com/product/3845400s/fuel-system-accessories-replacement-parts
If this doesn't solve the problem check all the clamps on the hoses from the turbo to the inlet for tightness. If you can rig up something to pressurize the system from turbo to inlet it would be better. Soap & water sprayed on all the parts would be a great indicator for any air leaks.

 

[crabman]

https://www.turbodieselregister.com...-the-intake-to-find-leaks?p=935024#post935024
https://www.turbodieselregister.com...Testing-Air-Intake-System?p=208675#post208675

 

[Wayne M.]

Yes, be positive about no boost leaks from turbo to head. Not sure about your injector pump setup, but you need to check for a small air line going from the intake to the injector pump. This is the air/fuel/ boost line that makes the pump rack more fuel according to boost.
No extra fuel, no boost- no boost, no extra fuel.
If you have no boost leaks, your turbo is spinning good/ not damaged, and your boost line to the pump is good, the part of the pump that does that job (where the plate is) could have a problem.

Your comment about no more smoke is a big clue about the pump not fueling.

And welcome to the TDR.

 

[Jhenson96]

Thanks for all the replies. So what I am gathering is to first check that I have no boost air leaks and eliminate that possibility.

What about the diaphragm on the waste gate area of the turbo? Does it fail? What does it do? Do I need to check that?

I guess I need to get one of those hose things so I can put my fuel pressure gauage in the cab with me. That would answer some questions....

 

[JMcCoy]

I would checkler the fuel return line behind the pump. A small pin hole made my truck act similar. Also check you throttle linkages. They may have stretched some.

 

[Jhenson96]

ok finally got a chance to work on truck.....In the process of installing a boost gauge we found a small leak just below the turbo. We fixed that. We installed a tube that goes into the cab to read boost. In the process, we started the truck with the air horn off. Plenty of air flow but hard to tell about "pressure". Once installed I read "NO" pressure at all. NONE! Turbo whistles a bit revving the motor but no pressure read on gauge. There is a bleed off valve on the end of the gauge set up. I can feel only a very small amount of air coming through. We soaped all fittings that we could get to. Fuel gauge reading 23 lbs throughout the whole process.

one peculiar thing....The actuator rod on the turbo. We tried moving that. It appeared stuck about a week ago. My helper thought he freed it up. It appeared stuck today as well. We freed it up before we tested for pressure.

No what do I do? Help....

 

[Jhenson96]

oh and I checked on the fuel shut off. It is pulled fully upward. so its good

 

[B.G. Smith]

You will not be able to show pressure on the turbo unless you are able to run the truck on the road with some kind of load, maybe flooring it while going up a grade etc. bg

 

[Jhenson96]

Update. I did run the truck on the road. Up hills and on the highway to 65. I have 4:10 gears. As best as I can tell with the gauge I have I am doing about 10lb of boost.

 

[DonFitzwater]

Not enough boost. Find out why........leaks in the charge air side is the norm. Plug off your intercooler and pressure it up and look for leaks with soapy water.

 

[BigPapa]

Waste gate could be stuck open.

 

[sgmans]

I had a problem with my '94 that was similar. I had no power, would slow down on hills, I felt like I could jump out and out run the thing! I was getting 17 psi of boost, I couldn't figure out what was wrong with it. Took it to a local diesel shop who adjusted the valves, checked the timing on the fuel pump and still no power. They finally figured out that the wastegate was stuck and wasn't working. Once they replaced the wastegate, it was like a totally different truck.