My MiniTruck - 29 - changing a fuel pump for no reason. (Suspected Bad relay)

[@owlerlane]

TW in the back ground! Same here, thanks' for the vid added it to my save list - just received a 97 carry yesterday

[@JimsEquipmentShed]

Ha! Ha! Yup, a lot of mini truck owners gravitate to slow but steady bikes. The TW is a tank!

[@robinduffey5669]

For 1993 mitsubishi mini truck its under glove box instead breather boxcover

[@shawnmrfixitlee6478]

we have all been there Jim ! I have been so sure of what the problem was , Then I ended up wrong !

[@JimsEquipmentShed]

It’s always a bummer when you realize that not only did you not fix the problem, but you created a new one…. ;-)

[@Liberty4Ever]

@@JimsEquipmentShed - I replaced the starter on my Tacoma only to realize that didn't fix the problem. There was corrosion inside the positive battery cable... after I replaced the visibly corroded negative cable. I'm an electrical engineer! It's embarrassing!

[@JimsEquipmentShed]

@@Liberty4Ever I suspect this truck lived near the ocean, a lot of the harness has dead spots in it. I randomly had the cluster lights go out a little while back, And I still have to track that down. The bulbs are fine, there is no potentiometer for dimming them, and the schematic seemed to just show them running right off the lighting circuit. They don’t go through the ignition switch and everything else seems fine. (All the exterior lights and their fuses work) I’m going to pull the cluster again and work my way back from there. My first go around, I could not find power in the cluster bundle when the lights were on. But all the indicators work fine. (I pulled the bulbs and tested those two and they worked fine.)

[@Liberty4Ever]

@@JimsEquipmentShed - The lighting on my Daihatsu Hijet mini truck is switched ground. +12V is run to the bulb and the ground is switched in and out to turn the bulb on or off. It's weird by western standards. There's a potentially good semiconductor reason to do that (NPN transistors are more efficient than PNP) but I doubt that's why they do it and given that the truck chassis is grounded, it seems weird to run a separate switched ground.

[@Liberty4Ever]

My Hijet fuel pump just crapped out. It looks identical to your Carry fuel pump. Symptom - the truck would intermittently die, presumably from fuel exhaustion. Wait a few minutes and it'd start and run again. I noticed that it only happens when the fuel tank is less than half full. Sure enough, that's the level of the fuel pump so it's apparently gravity feeding through the seized fuel pump when the tank is full. I checked after driving it today (full tank so it ran well) and the fuel pump was hot to the touch so it's apparently stuck in the open position that allows fuel to flow through it. The stalled motor may be overheating the fuel pump and vaporizing it, causing a vapor lock. I was going to replace the fuel pump with a genuine Daihatsu part (probably a Mitsubishi part) but my mini truck has an electric fuel pump near the fuel tank and the $111 fuel pump I found online is apparently a mechanical fuel pump. I ordered a $12 universal fuel pump on Amazon that looks exactly like the after market universal fuel pump in your video. If it doesn't last, I'll source the Daihatsu fuel pump.

[@JimsEquipmentShed]

Have you bench tested the pump? It wasn’t until I pulled the pump and cut my wires that I noticed the black wire rot. It wasn’t just the truck wiring, it was on the pump side of the quick connector as well. I only discovered it when I cut the pump wires in preparation to use the existing quick connector. (I like to keep things serviceable) So the wire was bad on the harness side, as well as on the pump side of the quick connector. Those geared pumps are super tough. And has some kind of pressure regulation like a diaphragm pump, because when mine hits a head. (Blocked pressure) it reduces speed. They can run a little warm, but running hot is bad though, so maybe yours really is dead.

[@Liberty4Ever]

@@JimsEquipmentShed - I haven't bench tested the fuel pump and I should do that before I cut off the connector to splice to the new universal fuel pump, but I was fairly sure it was toast when I determined that the truck dies when the fuel level in the tank is below the fuel pump but not when there is more head pressure in a full tank, and my confidence in the dead fuel pump increased when I felt it after a two mile trip and the fuel pump housing was so hot that I couldn't leave my finger on it for more than a second. The fuel pump is cooled by the fuel that it's pumping. I'm fairly sure this pump is seized and the stalled motor is drawing extra current while not pumping anything. I'm glad that high stalled motor current isn't being switched by the low current ignition switch. ;-) Maybe I'll move the fuel tank to the top of the cab and use a gravity flow fuel system that doesn't need a fuel pump. :-D

[@JimsEquipmentShed]

@@Liberty4Ever Mine (fuel pump) is maybe just a little lower than the tank, as soon as I pulled the lines, it wanted to syphon its own fuel out. I had to block the line with a bolt. (I couldn't lift it high enough to get it above the tank, as those hoses are really short.

[@Liberty4Ever]

@@JimsEquipmentShed - I thought of 3D printing some fuel line plugs when working on the Hijet fuel system, but I used needle nose vise grip pliers to clamp the fuel line to the tank. Next time, I'll use a jar to catch some of the fuel from the tank to examine it for sediment. I inadvertently snapped a plastic fitting off the fuel vapor carbon filter when examining the fuel system last night in preparation for the fuel pump replacement tomorrow. I epoxied the fitting back on and the evaporator canister is better than new and ready to be reinstalled.

[@Antique803]

So where's the video on getting to the relay?

[@JimsEquipmentShed]

Yea, I was waiting on that myself….. sadly, I just got an e-mail stating that the vendor can no longer get them, Suzuki stopped making that part. I started on a video, then didn’t finish it, I guess I probably should. On the bright side, there have been no I’ll effects by simply running the pump as a direct wire off from an ignition switched source.

[@JimsEquipmentShed]

Video #30 has the removal of the fuel relay.

[@wyattoneable]

It looks like you weren't even there.

[@JimsEquipmentShed]

Like it never even happened….although it still doesn’t run. ;-) I have the relay ordered.

[@bctruck]

Diagnosis is half the work. No one will ever know you had the pump off,,,, I mean besides the billion or so KZbinrs.

[@JimsEquipmentShed]

Yea, I like to share my boneheadedness with the world. Hopefully so they just test the pump before cutting the wires…… ;-/