Engine help, Cat 3126 turbo diesel

[SkwerI]

I'm hoping someone here may have some experience with this issue and be able to offer some advice. About a week or two ago my truck began to develop a tiny stutter at full throttle and seemed slightly down on power. It has always run strong so my first thought was a clogged fuel filter. Last week I changed both fuel filters and that had no affect. I also used my air line to blow out the fuel line back to the tank to make sure there was no obstruction. The truck seems weaker every day and the exhaust is louder, although it runs perfectly smooth when revved up in neutral without a load on the motor. Had it in the shop today and had the fuel system checked out, over 110 lbs fuel pressure and the motor isn't missing on any cylinders. It was running bad enough that I was afraid to drive it 35 miles to my job at Disney.

Ran out of time so I had to take the truck (work scheduled the next 3 days) but he said nothing is critically wrong and he suspects it's the turbo. Another mechanic suggested the turbo wastegate may not be shutting all the way. I did a quick Google search and found a couple discussions and I'm beginning to think this may be my issue.

Most of the time it appears replacing the turbo is the only recommended option although one discussion suggested that some penetrating fluid may clean the wastegate enough to allow it to function again. Any of you turbo diesel owners have any experience with anything like this? I'd love to get this resolved myself over the weekend instead of buying a new turbo next week. I just got my credit card paid off from the last major truck repair last November, my mechanic is very expensive.

 

[bonner1040]

Isnt that like stealing from your mechanic?



I couldnt resist.

 

[SkwerI]

Isnt that like stealing from your mechanic?



I couldnt resist.

 

[bonner1040]

Good Luck Brian! I would offer something valuable but I know less about diesel motors than my dog does.

 

[sotc]

If the engine is not computer controlled you can just plug the waste gate off, I don't know if they make a chip or boost fooler for those but if they do that will give more power without throwing codes. Do you just shut the truck off as soon as you park it? I know some HEUI fuel pumps get a bad reading if a sensor is going out, I think it is the cam position sensor. Replacing a turbo is quite easy most times if you want to save money and slap a new one in your self.

 

[SkwerI]

No engine codes at all according to the mechanic and I try to let the truck idle about 2-3 minutes before shutting it off. When I pull into the yard I have to get out to move my pickup out of my parking spot and then park the truck.

The truck is a 2001 so I'm not sure exactly what is or isn't computer controlled. I know it has the throttle by wire instead of an actual throttle cable. Without taking the turbo off and inspecting it closely I probably couldn't even identify the wastegate so I'm not confident in my ability to plug it off safely.

 

[sotc]

It would probably only throw codes if you plugged it, worst case would be limp mode. Have you made sure none of the lines from the turbo to the intercooler are cracked or loose? That will rob you of power and isn't uncommon to blow one off, you can spray soapy water on them to see if they are leaking. Probably want to check it with someone stepping on the go pedal too

 

[sawinredneck]

This will show you the basics on the waste gate, crappy video, but I found it quick,
<iframe width="560" height="315" src="http://www.youtube.com/embed/q-cNZWworNo" frameborder="0" allowfullscreen></iframe>

Normally the diaphragm in the waste gate goes out and it's stuck closed, but I'm not going to say the linkage isn't getting corroded. But now you know what to look for, so get some PB Blaster and start soaking it down and working it. If it's moving freely, you have other problems, my first suspect would be to find out if it has a lift pump of some sort, either mechanical, mounted on the side of the engine like the fuel pumps of old. Or electric, most likely in the tank or under the frame somewhere.
The lift pump pumps the fuel from the tank at low pressure into the injector pump. I've seen this several times on diesel equipment and the first thing people want to do is throw a new turbo on it, when a $60 fuel pump will fix it.
Just some ideas to look at that are cheap and easy to check.

 

[sotc]

He mentioned the lift pump tested good

 

[SkwerI]

Yup, lift pump is good and injector pump was replaced 6 months ago ($1200, not $60). Fuel pressure is perfect.

Thanks for the video, Andy.

 

[sawinredneck]

No problem, Brian, missed the lift pump already checking out, but there is a BIG difference in price between and injector pump and a lift pump!
Anyway, you know what to look for now, you just have to find it!

 

[treesandsurf]

Did your mechanic do a buzz test to make sure all your injectors are 100%?

jp

 

[cory]

I have a '99 3126. It's all computer controlled afaik. Reading your post, first thing I thought of was fuel lines/ fuel system but you said the lines and filters are all good. All I can add is that if your mechanic is expensive he should be able to fix the problem, it's not intermittent. I know that good mechanics, at any price, are extremely hard to find.

 

[SkwerI]

He can fix it, but I surprised him by popping in today unexpected. I originally was going to drop it off Thursday but I got scared heading to work this morning and turned back before heading 40 miles down the road with the truck not running right. He simply didn't have time to address it thoroughly today. I'm sure he could have it running perfect on Monday in about 4 hours and $1500 or so.


Fuel lines were replaced 3 years ago when the truck wouldn't hold a prime. The quick connect fittings were cracked and leaking.

 

[cory]

Well, even if he is expensive, if he can fix it right the first time, that is key.

 

[SkwerI]

Cory, how many hours are on your truck now? I just turned 12,000 hours about 2 weeks ago. Seems like I've had an extraordinary amount of repairs but I've learned a lot about the truck.

 

[top_notch]

Something really simple to check is all the clamps that hold the turbo's boots on. My truck had some loose when I checked them. The loose ones were the simple pipe clamps. When I tightened them the truck seemed to accelerate faster and have more power, but it may just be placebo effect.

 

[sotc]

Nope, it's real

 

[CurSedVoyce]

Turbo hoses and their connection is the easiest first check for power loss.

 

[SoonerFan]

My placebo effect is... my truck runs better after I wash it. :what:

 

[arborworks1]

I swear mine get better mpg, after a wash!!!

 

[cory]

Cory, how many hours are on your truck now? I just turned 12,000 hours about 2 weeks ago. Seems like I've had an extraordinary amount of repairs but I've learned a lot about the truck.

Geez, I'm drawing a blank, I'll check tomm. I have a 3116 with 10k hours that's been perfect, knock on wood. With the 3126, other than that it needed new injectors early on , it's been good.

 

[SkwerI]

I finished up work about 3pm and decided to bring the truck home and take a look at the wastegate. I removed and inspected all the cold side air piping and the entire air filter assembly. The bearings in the turbo have some slop but it doesn't seem excessive (although I really don't know). I used my air nozzle to check the wastegate assembly and it opens and closes properly. I'm guessing that my mechanic will check it out Monday and tell me I need a new turbo. If so then I'll buy one and replace it myself.

 

[squisher]

Dang Brian sorry to hear. Mine(3126b) was starting to throw an engine code but a oil change, new filters, and a blowing out of the rad cured my problems. Heat was the issue here for sure.

 

[SkwerI]

Keep an eye on your temp gauge. If it stays on the high side of normal under average use then your radiator is most likely plugged. My truck had zero maintenance for the first 5 years (lease truck) so I've had to repair dozens of items that could have been avoided with normal, routine maintenance.