TDI 1st Gen Tacoma Swap

[jmodge]

Vane levers wear into the ring. If there’s significant play at that point you most likely will never get it to act correctly.

 

[jmodge]

But without seeing what you’re dealing with it’s just a guessing game.
Have you disconnected the rod from the vane actuating lever? The lever should cycle with zero resistance. Somehow the vanes are partially closed if you’re getting boost when the ecu isn’t calling for any, such as when in limp mode

 

[jimbote]

As I was adjusting it this time I was reminded that the rod isn't long enough. Even when the adjuster is just off the threads of the rod there is still a little bit of play in the vane lever. I'm sure I bought some random diaphragm for the lowest price and it just doesn't fit well.

Thete are some turbos that use shorter actuators at the threads and even some with a shorter adjuster heim. Maybe you ended up with one of those?

 

[BimmerTim]

But without seeing what you’re dealing with it’s just a guessing game.
Have you disconnected the rod from the vane actuating lever? The lever should cycle with zero resistance. Somehow the vanes are partially closed if you’re getting boost when the ecu isn’t calling for any, such as when in limp mode

I've had the rod and lever apart a few times and it always feels like the lever moves freely. I think I need to actually set set the down position via vacuum. This time I didn't, but last time I did. I'll do that this week and report back. When I first got everything back together after the IP, injectors, and head refresh with the tune it didn't seem like it was going into limp mode. Then it did once, and then all of the time. Now, post "adjustment" it only does it on the highway.

Thete are some turbos that use shorter actuators at the threads and even some with a shorter adjuster heim. Maybe you ended up with one of those?

Could be. I didn't know there were long/short combos. It would make sense that this engine would be the oddball, since it's from an early 99 mk4.

I took a couple of videos to show what I'm seeing now for symptoms.

This video is showing that at higher RPMs, around 3k, if I let off throttle I'm still making around 10psi. That drops off as RPMs drop, but it seems odd that I would be making that much boost off throttle.

This video is showing a 2nd gear throttle stab and boost spike over 30psi.

For a bit more background. When I do go into limp mode off-throttle boost is 0, and max on throttle boost is 10psi, but only up around 3k. Mostly stays between 5 and 10psi in the 1500-2500 rpm range.

 

[jmodge]

If the rod is set to max length and you’re still getting boost try this. Pull the vacuum line so the diaphragm is at rest. Remove the snap ring to see if the vanes are fully open and the diaphragm is not restricting movement. This I’m asking assuming that with vacuum applied the lever hits the stop screw.

Has the cartridge ever been removed? It seems to me I had installed a vane ring flipped on the wrong side once and it limited range.

 

[BimmerTim]

If the rod is set to max length and you’re still getting boost try this. Pull the vacuum line so the diaphragm is at rest. Remove the snap ring to see if the vanes are fully open and the diaphragm is not restricting movement. This I’m asking assuming that with vacuum applied the lever hits the stop screw.

Has the cartridge ever been removed? It seems to me I had installed a vane ring flipped on the wrong side once and it limited range.

I can't get the rod end off of the actuator arm with the diaphragm installed. When I "fixed" it this last time I just went by memory of where it was installed. I need to verify that the actuator is hitting the stop at 18"Hg. I doubt it, honestly.

To my knowledge, no, but the engine has all of the miles. I have not pulled the cartridge, I have only pulled the compressor housing to clean and clock it.

 

[BimmerTim]

Checked the rod adjustment with MityVac and gauge today. The rod is 100% too short. I checked that the vane actuator arm moves 100% freely from hard stop to hard stop.

When I apply 18 inHg to the diaphragm the threaded rod doesn't reach the adjuster portion even when the lever arm is on the stop.

I think what I did last time was just put minimal threads into the adjuster to get it as close as I could. Now I obviously need to do something about it, since it's causing issues.

 

[jimbote]

Checked the rod adjustment with MityVac and gauge today. The rod is 100% too short. I checked that the vane actuator arm moves 100% freely from hard stop to hard stop.

When I apply 18 inHg to the diaphragm the threaded rod doesn't reach the adjuster portion even when the lever arm is on the stop.

I think what I did last time was just put minimal threads into the adjuster to get it as close as I could. Now I obviously need to do something about it, since it's causing issues.

Can you measure the extended threaded rod (no vacuum) and the heim adjuster? I'll compare to what i have here.

 

[BimmerTim]

Can you measure the extended threaded rod (no vacuum) and the heim adjuster? I'll compare to what i have here.

I finally got out there to take a look at this. With the vacuum actuator off, from the bracket to the tip of the threads is 1-7/8".

My fix was to cut the threads back so they are about 3/4" long, thread a nut all the way down, then put a 1" long coupling nut with a bunch of red locktite all the way down to the first nut and lock them together. Then I took an M6 stainless threaded stud and red locktite that into the other side of the coupling nut, then another nut to lock the stud into the coupling nut. Finally, I cut the stainless stud so that threaded rod tip to vacuum actuator was 2-3/8" long.

I reinstalled and was able to get the actuator arm to touch the stop at 18inHg.

It is no longer going into limp mode for over boost. I still need to log the requested v actual, but I drove it for about hour and it was fine. So, I drove it home and it was totally fine. Obviously, much slower than overboosting to the moon. Haha. I can also get haze out of the exhaust, which I was never able to before.

It was also edging 100 degF yesterday and the A/C was blowing out of the center vent at 47 degF. I love it.

I popped a Scangage in to just monitor a few things. I found that once warm the coolant temps stays between 195-207 degF. Maybe a little higher than I would like on the high end, but not crazy. My favorite finding was that my IATs were only about 5-10 degF above ambient, so I'm SUPER happy with the intercooler performance.

The only annoyance from yesterday was stalling the truck a couple of times, because the A/C adds enough load at idle that it just behaves differently than I'm expecting. If I turn it off it drives normally.

Since putting the truck back together it's basically only idled or been beat the pants off of trying to sort out the little issues I was having. I filled up yesterday and still found it got 26.5 mpg. Now that everything SHOULD be good, or better, we'll see if we can get it over 30.

 

[jimbote]

Very good. Yeah, occasionally, I stall mine with AC on.

 

[BimmerTim]

Yeah, I figure I'll just have remember and/or stall it once in a while. Not too big of a deal.

I just drove it around a bunch to Home Depot and Menards around town and I also noticed that once I've been driving for a bit the boost is more likely to spike boost up to and just over 20-22psi. For the first bit of driving it won't even spike to 20, only 18-ish psi. Maybe this is not an actual issue, but for me the extra boost slips the clutch. Which I do have a Supra clutch to install, so maybe even then it's only an issue temporarily.

Otherwise, I think I might see if @burpod has any suggestions for IQ/timing that I can adjust to smooth out the tune. It seems a little lacking on low end and I think the idle could be smoother.

But, all in all I'm pretty hyped on this thing and driving it is great.

 

[BimmerTim]

Drove it a bunch today. Down the highway 30 minutes and back. Around town to run some errands. No limp mode. Plenty of power all over compared to the OG Tacoma engine.

I love this truck.