Engine Specific Info and Questions > IDI Engine
AAZ Vanagon boost peaks holds for a second then drops off after adjusting fuel
RockOcean:
Hello, wow it's been a long time since I have posted on here. I hope everyone is well.
I have had my K03 set at 15psi for quite some time now. Recently I noticed my egts getting a little high so I decided to turn in my max fuel screw a half turn to see if that brought them down a little bit.
Well after I did that my boost at half throttle now goes to 10psi which it use to do (would only hit 15psi at 3/4 to full throttle) hold there for a second or two then quickly drops off to like 3 psi. If I stay off the pedal and then get back on it, it continues to do this. Sometimes the boost does not go back up to 10psi.. I turned the fuel screw back to where it was and it still does this. I tested the line going to the boost gauge for leaks which is all good. When I tested the wastage actuator it worked but I noticed the wastegate flap was stuck closed. So I freed that up and took it for another spin and got the same results. I then disabled the wastegate actuator entirely still got the same results.
Is it possible that adjusting the max fuel screw could cause this? Or did my turbo just bite the dust at the same time I adjusted it? Or could it be something in the IP? The turbines look good with no signs of them hitting the housing, but it does have maybe 1mm of in and out axial play.
The engine is a little tired with #4 cylinder low on compression so I have been thinking about a rebuild or maybe finally going AHU m-tdi. Are the AAZ & AHU turbos interchangeable? I have read that the housing is a little bit bigger on the AHU turbo but will it still bolt on and will my AAZ intake pipe fit to it? What is a good source for the LR 300TDI pumps lately?
I have settled in Montana and don't travel much anymore since my last post. I also picked up 3 more Vanagons! One to use as a donor to fix all four corners that were rusted out on my van. I got a smoking deal on an old Adventure Wagon that has no interior in the back which I plan on restoring. Then I found an 89 Carat that had been in town for 6 years after being rolled. It had the 16" wheels I had always wanted and lift springs so I snatched it up. Also has a good auto trans & runs! Then I finally just got the wheels on my van with some 16/235/70 Falken Wild Peak tires. I'm looking forward to hopefully painting the rest of the van this summer, we'll see tho if I put an AHU or rebuild the AAZ again I might have to wait.
TheGeneral&Opheilia by RockOcean.com, on Flickr
GeneralGraft by RockOcean.com, on Flickr
TheFAM by RockOcean.com, on Flickr
4CornerRustRepaired by RockOcean.com, on Flickr
StanleyOn16-235-70 by RockOcean.com, on Flickr
fatmobile:
It seems more like a turbo issue than a max fuel screw issue.
Can't help you much on what will fit in the vanagon.
You could PM libby, show him a link to this post.
He knows a lot about running diesels in vans.
RockOcean:
Well I changed out the turbo cartridge and it still does the same thing. I am not too familiar with the IP but isn't there a diaphragm in there that works with the boost pin? If this diaphragm went bad would that cause the sudden lose of boost pressure? My IP has been leaking out of the aneroid at higher boost for some time now. I have also noticed when the engine is warm it holds the boost fine but once at operating temperature is when it will hold for a second then drop right off.
I think I am just gonna bite the bullet get the pump rebuilt, and rebuild the engine. It's something I have been putting off for a couple years.
ORCoaster:
Yes, the boost pin is controlled by a diaphragm. Just pull the top off and see what is going on there. Not a hard thing to see, but getting it out can be a problem sometimes as it gets caught on the little pin at the bottom of the boost pin. I find wiggling the throttle to help get the whole assembly out.
RockOcean:
There was a lot of oil in there I imagine due to all the blow by. I had no trouble at all getting it out while I was taking this photo it shot out all by itself. Would this mean something has broke off down there? These are the only parts that came out, the diaphragm connected to the boost pin, an upper spring seat, and the spring. The boost pin is flat on one side but fits in there anyway you position it. It was also interesting to see that the aneroid just screws out and there is no o-ring for it. Any idea where I can source a new diaphragm and aneroid? Or would the aneroid not leak if there was not a ton of oil in there? I purchased a Bosch Seal Kit 1467010059 & The Shaft Seal 1460283312 for a complete re seal that I might attempt myself. A guy in town wants to charge around $500 is that a little steep, or have prices just gone up that much?
Oilyphram by RockOcean.com, on Flickr
Oilyphrambowl by RockOcean.com, on Flickr
Diaphram Hole by RockOcean.com, on Flickr
Springnboostpin by RockOcean.com, on Flickr
I am not sure if I am referring to the aneroid correct but it's 336 in the diagram (top center right) that has been spraying oil and fuel in the engine bay for quite some time when hitting higher boost while running normally other wise.
VEPumpExplode by RockOcean.com, on Flickr
Navigation
[0] Message Index
[#] Next page
Go to full version