I have been driving this truck as much as possible, took it out today on a Datsun Cruise, I determined that I had the wrong vehicle as everyone else had cars, and then there was me in my dually diesel truck trying to keep up on winding Mountain roads, one of the guys behind me said I had one rear dually side wheel airborne and spinning, I don't believe it is true, as I didn't feel it break lose, but the front tires were squealing and my front brakes almost caught fire.
Anyway my throttle cable dropped out of position and rested on the exhaust manifold head pipe and all of a sudden I had throttle issues, it would not drop to idle anymore, well after we got to the top of the hill the guys stopped and had to repair another guys throttle return spring, so mine cooled off enough to act normally again, but I started having issues again on my way home, that is when I figured out my issue, after I got home.
So I got the throttle cable moving slightly better and went to the auto parts store and ordered a new one(supposed to be here Monday), so I went home and then made a modification to my engine, I put a hose from my vacuum throttle control line to my boost gauge line with a boost controller valve in the middle, I believe that the boost will help push the rack to a richer position when I have boost, but when I let off the pedal I will have vacuum, this will help pull the rack to the idle postion, my thinking is that I cannot seem to get enough fuel, especially on the hiway, so after talking to the guy that did the turbo bomb thread, I decided to try this mod.
I entered the hiway and opened up the boost control knob and I could feel it, that dead spot at 2500rpms was gone and I kept gaining speed, I noticed at about the same time that I hit 18psi that something came apart, I let off and slowed down some, as that was the fastest I had ever went in this truck, I was of the opinion that I lost a transmission bearing, I tried 4th gear but it didn't seem to change, so I made a quick decision to get off the freeway now and limp home, I tried all the gears and the sound continued till I got home.
Once home I popped the hood while it was running to see if I could figure out what the noise was, my idle was also a little high but I thought it was a throttle cable issue, well it didn't take long, my home made vacuum release valve made of PVC had blown apart, I figure that it was just to hot in the engine compartment for the PVC material, and 18psi was just to much for it to hold together, where the cotter pin was had just pulled thru the hot PVC material till it let loose, I will take a photo of the part later, I just drilled another hole 90 degrees off and put it back together.
I am happy to say that the modification worked, I had way more power on that last test drive, it quickly went up to 70mph+ just before blowing the valve apart, but I didn't have enough time to get a lot of input, I was looking at the gauges, boost controller adjustment, and the road ahead of me along with all the traffic, I have no idea if it was blowing black smoke, nor did I have enough time to see what the EGTs were going to do, I believe I will need a 20 mile trip on the hiway to get a good idea of what is going on.
I also need to make a metal valve, as the PVC is not going to hold up, but first I need a good throttle cable that doesn't stick.
I learned a lot today, one was that if I go on another Datsun cruise, take the Roadster!!!
“The difference between genius and stupidly is that genius has its limits” Albert Einstein