How I fixed my non-operational carb secondary. Drill down a bit to get to the secondary fix. From my Turdle build thread:
A couple of weeks ago I took the Turdle on its longest trip since I took ownership. It was a trip from Charlotte to Asheboro. I took the scenic route so it took about 2.5 hours. The old Turd did fine but one of the things that has always nagged me about this truck is its gutlessness. It does fine around town but on the highway it struggles with long uphill pulls. I know this is partly due to the 3.70 gears, 33 inch tires and the old 2F but something kept telling me that there was room for improvement.
I de-smogged the truck a while back but was still running the factory carb with all the unnecessary vacuum ports blocked off. I had an old Trollhole carb in my parts stash so I decided to yank the Aisan carb and put on the Trollhole to see what would happen. What happened was this:
The engine bay looks so much cleaner and neater without all the vacuum lines running willy-nilly everywhere. I removed all the vacuum connections on the driver's side fender with the exception of the A/C idle-up. I re-installed that vacuum canister onto the Trollhole in order to keep the functionality. I also disconnected the emissions computer and performed the "green wire mod" by grounding one of the two wires (NOT THE GREEN ONE) to the carb body.
I decided to install a heat resistant sleeve over the fuel line to prevent fuel boiling and help with hot start-ups.
I tuned the carb using my vacuum gauge and set the idle and took it for a short drive. I was very impressed with the performance of the Trollhole as compared with the worn out original carb. The truck had a lot more "pep" off the line and seemed to work it's way up through the rpm range with much less effort than before. Next I decided to check into the vacuum secondary to see if it was working properly. I did the "paper clip trick" which involves placing a paper clip on the secondary actuator rod so that it touches the base of the vacuum can, taking the truck for a spirited drive, and then checking to see that the paper clip had gotten slid down by movement in the actuator rod. My truck failed the paper clip test (I actually tried this trick with the old Aisan carb before I did the carb swap and it wasn't working on that carb either). Apparently the secondary is not receiving enough vacuum to fully operate. Here was my solution:
I took apart the secondary diaphragm canister, removed the factory spring inside and installed a weaker spring from a $15 Holley/Demon carb secondary spring kit. The kit came with seven springs. I used the weakest one (the white one). I used a digital scale to determine the strength of the springs. The Trollhole spring registered 250 grams when I pressed it to almost full stack on my scale. The white Holley spring registered about 200 grams. Re-installed the diaphragm canister and took the truck out again. Viola! The secondary is opening as it should and the Turd is a whole lot less gutless than it was before!
Overall I am much happier with the truck's performance. I can't say that the difference from before is night and day but it is a serious improvement. The truck idles better and pulls harder. I drove the Turd to work today and it had no trouble running 75 mph on the interstate with the A/C on. There really aren't any hills to speak of so the hill pulling test is yet to be performed. I know it will do a lot better though.
