howdy all, I've been searching here for a couple hours and don't see anything....so I'm posting a new thread.

99 Montero full size NOT sport pretty sure its a 3.5 base model no sunroof no leather

I drove about 200 miles, 75 mph, very hot out 99f. The thermostat got a little over the mid level, so I turned on the heat to full and kept going. The thermostat went back to normal (in the middle). Then, I got off the freeway and had to drive 20 steep miles up into the mountains. I kept the heat on full, and the thermostat gauge went up,but never too much past the middle. 1/4 mile before the crest, my montero shut off. I got it safely off to the side of the road and tried to start it. It cranked but no turnover. I looked under the hood, and noticed the 20a multipoint injection fusible link had blown. So, I replaced it with a new one, let her cool off for an hour, and then she started right up and I got her home.

But, after going for another short drive, the multipoint futile link blew again. Any suggestions on what is causing it to blow? It doesn't blow instantly, but about 5 minutes after the engine warms up.

thanks

 

so...I took out the battery, and removed the 4 bolts which hold in the under hood fuse box. The #3 fusible link for the multipoint injection is a thin gauge black and yellow wire. I checked for any signs of melted wire insulation and don't see any, but the thin black and yellow wire disappears into a larger cluster of wires coming off the fuse box. It then heads into the body of the car. I assume it's heading into the interior cabin? Anyone know exactly where it heads? And what else should I check that will share that same circuit and fusible link?

Thanks!

 

Blowing out a fusible link most likely an indication that you have a short to ground somewhere in the system. It could be as simple as fuel pump or related components (relays) are shorting out when it gets hot. Another likely cause is a short somewhere in the wiring harness (worn out insulation).

 

so I've been working on the Montero all day, and it turns out I had a rear o2 sensor cable that was resting on the exhaust and melted. One of the four wires was completely separated, one was melted and exposed, and two were fine. I spent hours inspecting all over, and that's the only obviously trashed wiring. My question....can a micro low voltage short in an o2 sensor cause a 20a fusible link to blow??

 

so yeah, I found an o2 sensor with melted wires...that must've been what kept shorting the multipoint injection fusible link. I can't afford a new o2 sensor..so I removed it, and spliced the wires that had melted in half back together. I did a 25 mile trip, going as hard as possible up long steep grades...so far so good. I know eventually I will need to get a new o2 sensor. With the

The two post cat o2 sensors, the ones under the vehicle, not in the engine bay....they had wiggled loose from the little clip that is there to keep them off the exhaust. I got code p0141, which i think is 'bank 2 downstream 1'.

So... anyone out there who keeps blowing the multi-point injection fusible link, check your o2 sensors. It seems very easy for them to fall down onto the hot exhaust and melt.

 

she just passed smog today :-) in case anyone is reading this and wondering (like I did) if splicing and e taping o2 sensor wires creates weird resistance levels....it doesn't. Several people told me it would, and that I needed to buy new o2 sensors. But, hallelujah I'm good to go for another two years.

 

I just want to pop in and say thank you for giving everyone an update. This was a very unique issue I've never seen or would even consider, I'm sure somewhere down the line someone will see this and benefit from your solution. Glad you passed smog, happy driving!

Something else I want to mention is that if properly done, splicing should not cause any resistance issues. Use the correct gauge wire matching the original, use high quality connectors, crimp them well, and heat shrink sleeve the spliced area. This should be plenty good enough to fix it. One could go a step further and solder the wires together and then heat shrink it but it's not 100% necessary. Biggest thing to remember is that these wires are exposed to the elements, including but not limited to water spray and if you're in a colder climate, or near an ocean, salt water intrusion could cause issues by corroding the splice. Make sure to weatherproof the splice and you're good.