Hello. I bought a 99 f350 truck. it has a van turbo and exhaust back pressure delete. The truck wont make more than 3 PSI of boost. Ive got a p1690 wastegate actuator circuit code. unplugging the waste actuator does nothing. With the van turbo, is the actuator required? Is this code stopping the ecu from fueling and creating boost? I did a cylinder balance test, and cylinder 8 failed. Is a single injector not quite balanced enough to make it not boost past 3 psi? The turbo appears brand new (previous owner said it was), charge pipes hold pressure (tested), EBP Sensor tube is clean (shows up to 24 psi). I tested the wastegate actuator, OnDemand5 says if its over 50 ohms, its bad and replace it. its 69.5 ohms. Again, i dont want to replace it if i dont have to, as its not being used (no wastegate on van turbo), but if the ecu is preventing it from spooling because of the solenoid, ill change it.

 

Have you checked the up pipes for leaks? How did you test the CAC system for leaks? You should definitely be making over 3lbs of boost......

 

What are you using to measure the boost? Have you verified your MAP and Baro sensors are working correctly if you are using these for your reference?

 

up pipes are not leaking. the whole intercooler system isnt leaking either. tested to 20 lbs. im measuing boost with a boost gauge as well as with the matco scan tool. baro and map are both working.

 

I would pop the intake tube off the turbo to look at the blades and check for rotation with no in-out movement. I would also have a good look at the EBP reading when you get the low boost. Do you drive the truck long enough to get the Engine OIl Temperature over 140 degrees F? Do you hear a hissing sound as you drive? Do you see scads of soot out the pipe? Is this 3 PSI boost max with your right foot pulling a Fred Flintstone?

 

Intake tube is off, and there is normal movement (no in and out, very little radial movement for oil clearance). The blades do turn just fine. The turbo appears new, and the previous owner said he changed the turbo recently. Im assuming he did so trying to fix the no boost issue, but it didnt fix it so he sold it. The EBP reading (from what i can remember) is about 16 psi at idle and peaked at 24 when revving the **** out of it in neutral or in gear with the brake depressed. I revved the truck at about 1500 rpm until the engine reached operating temp. The smoke that comes out the exhaust ranges from a light to a dark grey. Not super rich, but rich none the less. 3.5psi is the max i can get the truck to make, and it takes a bit of time to get there (4-5 seconds at WOT with or without load.)



I really appreciate the help. i hope the additional information ive given you can help lead you, lead me into a direction to get this thing sorted out.

 

You may want to look at the exhaust side of the turbo to see the condition of that wheel and to make sure the shaft is still in one piece?

 

I disconnected the down pipe from the turbo and used a mirror to view the other side of the turbo. Though there is some soot, the blades appear as new, and don't have any pitting. I didn't ensure that it spun, but seeing as it is making some boost, though not enough, that the shaft is intact. This problem really is a pain.

 

If you still have the ebpv unplug it. Your back pressure is incredibly low. Is there freeplay in the gate actuator rod?

Plug the red line going to the waste gate actuator, safety wire the actuator shut and report back.(shut is the rod pulled towards the driver side)

edit it I just remembered it's a van turbo...

howevrr er that being said based upon drive pressure I'd ber the max you would see is around 7psi. You should get up near 40 psi of drive pressure

 

I'm sorry, drive pressure on what?

 

Your readings in the driveway won't work for us.

Here's what I'm wondering: What is the Turbo Pressure Delta at WOT on a steep uphill grade (to make the WOT longer)? The "delta" is the EBP (drive pressure on turbo) minus the MAP (not the boost). EBP and MAP are both "absolute" pressure (pressure above the vacuum of space), so they both include atmospheric pressure.

 

i could throw a shop plate on the truck, but unfortunately there arent any hills here.... WOT in gear with foot on the brake isnt the same? I can take a video while displaying this information if its helpful.

 

On your opening post, I believe, others here can confirm or correct me, that #8 injector fail on CCT is typical due to it's location at the end of the fuel line.

What are you measuring your boost with? Are you sure that you don't have a kinked or plugged line? Since you can perform a boost leak test what happens when you set that leak tester up and read your boost?

And do you have an EGT gauge? If so what's it doing?

 

I've heard that about the #8 failure too, but I wanted to include as much information as I could.


boost is being read by a matco scan tool, as well as a aeromotive boost gauge. The boost gauge is connected in line with a t with the red line between the factory boost controller and intake manifold. I replaced the hose between the MAP and the intake as it had some cracking. Because of the location of the map, it wouldn't read the charge pipe boost pressure when I'm testing. I did on the other hand use a blow gun lightly on the line going to the boost gauge and tested it with that.

no EGT gauge, unfortunately.

I appreciate the input. Hopefully we can figure this thing out.

 

Two steps back... this 3 PSI of boost is at WOT running down the highway correct? Same with the backpressure? If that's the case your loosing or not generating drive pressure on the turbine side of the turbo. This is the same as back pressure. You don't need a hill to generate a ton of boost, just put the pedal through the floor. 4 cylinders firing generates about 6-8 lbs of boost at WOT.

Post a picture of the turbo. If its new is it a truly new unit, OE? Reman? Manufacturer if reman? I had a spare van turbo out in the shop and it had a waste gate actuator on it. Mind