Monthly Archives: February 2015

K2500 MAP Sensor

I was home way early yesterday because William threw up at school, but after I picked him up he seemed perfectly fine. I was going to need to drive the pickup today because Mary needed to go to Santa Fe all day. I had bought a $15 MAP sensor on Amazon, but the people sent me the wrong part (a Subaru knock sensor).

So we got home and I ran through a test procedure for the existing MAP sensor. You disconnect its vacuum hose and connect a multimeter between its sensor wire and battery negative. With the key on, the MAP sensor should output about 4.7 vdc with no vacuum, and as you apply vacuum, the voltage should drop. Well, it didn’t, so that confirmed a bad MAP sensor.

I bought a replacement one at AutoZone for $50 (with a $20 discount because my loyalty card had accumulated enough points) and installed it.

Wow, that made the truck run better. No more stalling in reverse or when coming to a stop, and idle is predictable and steady. Shifting is improved as well.

… then, after I had driven the truck around the neighborhood and shut it off for several hours, it started leaking coolant on the driveway. The lower radiator hose has a leak.

So I didn’t get to drive the truck this morning after all. Mary took William to school in the Tahoe and drove to Santa Fe. I rode the Goldwing and will ride it down to William’s school at about 5:30, walk him over to Flying Star, and hang out for a while. Or maybe the library.


So I need to get a couple of radiator hoses. Now’s not a good time, money-wise, though.


The people from whom I bought the MAP sensor on Amazon are unwilling to ship me the correct part until they’ve confirmed I’ve shipped back their knock sensor. They’re dicking me around over a $13 part. Good move, guys. I advised them that I will be much more likely to give them a favorable review if they cross-ship, as their delay caused me problems.


K2500 Poor Fuel Economy

I filled up the K2500 at Murphy in Albuquerque. It’s getting terrible fuel economy — 6.6 mpg. Could be timing (needs to be advanced?). We’ll see what happens after I replace the manifold absolute pressure sensor and ignition control module, which are on order. I had thought the new TPS had solved its issues, but it only solved a few; it’s still stalling, especially in reverse and after coming to a stop. I’m not sure if that has something to do with the brake booster taking more vacuum than the engine can produce at idle, or what.

Weekend Vehicle Work

Got a lot of vehicle work done this weekend.

Cleaned all the windows in Kevin’s truck and took it to the Montessa transfer station. Once we shut down and started unloading, Kevin noticed that coolant was pouring out from under the truck. The radiator was boiling over into the overflow jug, and it was dumping coolant onto the ground. I replaced the radiator cap, and that solved the issue.

Got the dirt bikes out and threadlocked many fasteners on the KX250, and tightened down / replaced others. Checked various fluids. Repacked the KX250’s muffler with steel wool, and replaced a missing sheet metal bolt that holds on the muffler cap. This made the KX250 significantly less loud, though it’s still very loud.

Kevin zipped around on the PW80.

Checked the Goldwing’s fluids. The coolant was still fine, and the brake reservoir is slowly draining, but still serviceable.

(previous weekend) took the tachometer off and lubed it with graphite, which didn’t work well. I ended up using all-in-one oil, which worked better but will probably dry out eventually.

Replaced the K2500’s wipers.

Titled and registered the K2500 at ASAP MVD in LL.

Replaced the trailer’s tail light lens.

Fixed (?) the K2500

I fixed — somewhat — Kevin’s truck this weekend. It turns out the fuel pump did not need to be replaced; the fuel tank was almost empty. Once I put five gallons of gas in it, it started up — but still ran like crap.

I looked into things I could do to troubleshoot. One of those things was to unplug the throttle position sensor, as the truck’s symptoms (backfiring, hesitating on quick acceleration, lack of power, failing to idle, poor shifting) were consistent with a bad TPS.

It drove better after unplugging, so I spent $48 on a new throttle position sensor at AutoZone and replaced it. The truck runs and drives amazingly better now. It still wants to not idle well immediately after startup, but then the idle smooths out. The backfiring is gone, as is hesitating on acceleration and poor shifting. Power is still not where it should be, but there are several other things that could be causing that.

At this point, the truck is driveable, which means it’s registerable.

Tahoe Blower Resistor Pack

Yesterday morning was tough because the Tahoe’s front blower stopped working, so defrosting the windshield was nearly impossible.

Googling revealed the problem was likely caused by the blower motor resistor pack. I got under the passenger side duct (just two screws) and removed the resistor pack (another two screws). Sure enough, the connector from the resistor pack to the blower was partially melted in several places.

The part was $51 at O’Reilly, and fixed the issue. The new one is a different design, so hopefully it will be less prone to melting — this is a chronic problem according to owners of GM pickups/Tahoes/Suburbans.

Goldwing Tach Cable

Kevin and I replaced the tach cable on the Goldwing, which turned out to be a really easy job — no need to remove the fuel tank, and you just tape the old tach cable to the new one and use the old cable to pull the new one through.

Unfortunately, after hooking the new cable up and starting the bike, it became apparent that the squealing is inside the tach itself, and wasn’t caused by the cable.

Now I need to take the tach gauge off and lube it.