SAMI : CARB ISSUES

I had some carb over-fueling issues on the last tour, leaving me stranded a few times, and I only managed to get it running just enough to get me home. 

I didn't get to the bottom of the problem, so I've come to the conclusion that these cheap Chinese carbs are plain junk. So the TBI is going back on.

The TBI is uglier, with more wiring, but this time I'll make a nicer job of the wiring by keeping most of it inside by the passenger, extending the sensor wires where needed.

The TBI has a bunch of sensors required for the ECU;

TPS Throttle position Sensor - monitors your right foot ;)

ECT Engine Coolant Temperature Sensor - shows 300 ohms @ 180F, and reads (back probed) 0.6vdc

EGR Exhaust Gas Recirculator - Reduces Nitrous Oxides at the tailpipe by crudely lowering combustion temperatures, by leaking exhaust into the induction system.
The ECU commands the EGR to open via the Vacuum Solenoid Valve VSV and then the EGR MOD measures the pressure drop.

EGR MOD
P = pressure side (VSV) and vacuum
Q = EGR main side

IAC Idle Air Controller Sensor - Works with the ISC to controls idle at all times, hot or cold

ISC Idle Speed Control valve

MAP Manifold Air Pressure - used to calculate air flow through the engine, with the aid of the IAT

O2 Sensor - Narrow band oxygen sensor

VSV Vacuum Solenoid Valves - gates vacuum to DP, Evap and EGR

DP Dash Pot - Pushes open the throttle commanded by the ECU via the VSV to open and vacuum then retracts this device.

FPR Fuel Pressure Regulator - Compensates only for altitude, it's air cleaner side pressure. (it can also compensate for a dirty air cleaner in this case it does go to vacuum levels with a packed filter)

SAMI : ALTERNATOR ISSUE

When I turned on the Zuk to get it ready for the January club run I noticed only 12v on the voltmeter.

Turns out this, my 2nd, 1 month old GM CS130D alternator is also gone bad.

So I decided to rip out the GM conversion brackets that came with the Zuk, and re-fit the OEM brackets and a modest 55A OEM alternator from the junk pile.

I only wanted the big alternator for the extra current when winching, but I barely use the winch these days, so I'd prefer reliability and the extra few HP ;-)

SAMI : MUDDY MYRA JAN 2019

Took the crew out for a tour of a very icy Muddy Myra.

The bridge bypass was 100% ice all the way, but the spooled up Zuk took it no problem :-)

This time of year the Muddy Myra is mostly just filled in, with little opportunity to play, so we were out by 11:30!!

So, I took us to the pipeline that runs from Aerotech to Fall River, where there's a small quarry to play in.

I ended up having carb issues. After performing some donuts near the end of Muddy Myra, the carb started over fueling. I checked out the float and got it working again. Then we headed over to the pipeline. By the time we got to the end of the pipeline, it started over fueling again. This time so bad it wouldn't start. So after a some more tinkering with the float, I got it going enough to get me home.

I've come to the conclusion that these cheap Chinese carbs are junk, so the TBI is going back on.

SAMI : REAR SPOOL

Wheeling in snow and ice with open differentials sucks!! With little to no traction on all 4 corners, frustration kicks in and you eventually start hitting the gas hard and pushing your rig to it's limits, breaking things....like tcase mounts!

So, when a Yukon Spool came up on sale and I had some unspent vouchers, I had to buy it. It's not 100% drop in tho...

The Zuk's rear end is Samurai housing with a 2-pin Sidekick front differential to get 5.13 gears.

Problem 1 - The spool requires a Samurai 4-pin carrier because that carrier has a removable 'lid' to fit the spool into where the spider gears are meant to live. Luckily I have a spare Sami carrier to swap the Tracker gears onto.

Problem 2 - On the Samurai 4-pin carrier, it's the ring gear that keeps the pins in place, as the pins are free floating. But, the Sidekick ring gear is shallower and larger in diameter than the the Samurai ring gear. So we need to add a can and a shim. The can holds the pins in place, and the shim allows for proper side bearing adjustment.