What is this mess where my inertia switch should be?

[mostly_broncos]

I was tracing some wiring and found this behind the passenger kick plate , the red and black wire are bonded together speaker type wires that run under the mat over and through the firewall near the steering column and were hanging free stripped and corroded beneath the underhood fusebox.

between the connectors on the blue / red wire appears to be a resistor or diode .


I'm trying to track down an issue with my mass air outputting too much voltage and found the mass air ground wire has continuity to the fuel pump monitor , the inertia switch is missing this was carefully constructed by someone . Not sure of the other end of the wires near the fusebox were poked in to a fuse socket and fell out or what was going on.

The truck had a leaky sunroof and water was actually dripping over this blob of wiring whenever it rained hard .

Off the top of my head I'm wondering if this is remains from some aftermarket alarm or remote starting system but I have no clue.

 

[mostly_broncos]

I just removed this and somehow it still starts with no inertia switch and the wires not jumpered together. For some reason the voltmeter shows 10 volts on each wire . I would have thought if you pull the wire connecter off an inertia switch you would get crank but no start , no fuel pump running at all .

10 volts is not battery voltage , its not vref , I feel like one wire should have 12+ volts and the other should be floating . I'm going to try pulling the inertia switch connector I will have access to tomorrow and see what wire has voltage and what happens with it unconnected

 

[410Fortune]

correct
without the inertia switch in place the fuel pump relay would not switch the fuel pump on
Somebody has bypassed your fuel pump circuit yuck

 

[mostly_broncos]

Actually the inertia switch is still here its been moved up under the dash , It still functions , it looks like someone snapped the screw off and just jammed it up under the glove box. These wires appear to have no function .

correct
without the inertia switch in place the fuel pump relay would not switch the fuel pump on
Somebody has bypassed your fuel pump circuit yuck

you gave me the idea when you said this to trace the wires more fully and I found it . I can check this off my list as the cause of why its running strangely

 

[410Fortune]

it must be mounted upright or the steel ball will come out and no longer make up contact = no fuel pump

If there is any question whether it is good or not for testing purposes you can jumper it

 

[mostly_broncos]

It was running in the position it was in but it wasn't stable , pulling the wires off gives a 100% nostart it may have caused intermittent issues I screwed it down in an upright position. Traced all the oddball wiring and it goes nowhere so maybe it was something that is long gone .

Not the source of my weird issues just a speedbump on the journey

 

[J_C]

You seem to be going in different directions that only you know.

What is the initial observed problem with the vehicle? Runs rough, won't accelerate, lousy gas mileage, etc ?

Quote "I'm trying to track down an issue with my mass air outputting too much voltage and found the mass air ground wire has continuity to the fuel pump monitor".

What voltage is it reading and if this is not a '79 bronco then what vehicle year engine etc?

Did you mean to write that the MAF ground wire has continuity to the fuel pump motor ? If that's what you mean, it should have continuity to the fuel pump ground wire, but certainly not the 12V positive lead to it.

From the discussion so far about the inertia switch, I recommend that you try to return everything to the stock wiring state including the location of the inertia switch. Otherwise it's anyone's guess what has been butchered and could be wrong.

 

[mostly_broncos]

It turned out that the fuel pump was the main issue , it wasn't maintaining enough pressure It would initially go over 50 at the rail but once it started would drop very low , sometimes if it was off pressure would bounce back up , the lack of an available gauge sent me down some wrong paths . That wasn't a wiring issue it was the pump itself or that in tank pressure regulator

Its running pretty well now with a new pump . The MAF is still outputting a larger than what I would expect voltage but it seems to run like that. It may have always been that way If I unplug the battery then start it with my scanner Live Data on the lbs/min number is too high but then drops after 10 or 15 minutes and the engine smooths out.

I find it odd that it can show over 1.2 volts at idle but the scanner numbers for lbs /min can be close to what I expect unless the pcm is learning and making an adjustment.
The only thing I really notice is that if you read the ground value on the MAF signal return it is about a half volt lower than the power ground wire right next to it, and if you read the same wire unplugged from the sensor it shows 6 volts , I'm not sure what that indicates , I had an idea I might see 5 volts there without the sensor but I wasn't sure.

I've removed the wiring mess behind the kick panel and rejoined the wires without it , the inertia switch is functioning now , I fastened it in an upright position.

The only other thing going on right now is that while driving the headlights just went completely off on a few occasions . I haven't had a chance to dig into that yet.

Right now I'm seeing driving it around and seeing Long term fuel trims at -5% on both sides which I can live with no codes so far , I've got the vacuum line to the EGR pulled off because it has constant vacuum on it for some reason without any EGR codes thrown , I figure I'll grab some EVP sensors at the junkyard and see if swapping will address that.
.

 

[J_C]

Not stating the vehicle make model year engine etc is very bad form. It wastes time with people guessing or speculating.

 

[mostly_broncos]

Not stating the vehicle make model year engine etc is very bad form. It wastes time with people guessing or speculating.

That was a little unclear now that you mentioned it , I did start out ok by putting the first message in the correct forum but it spiraled a bit. It should have been confined to a single thread . I apologize for going all "stream of consciousness" on y'all , reading it back it looks a little like notes from a therapy session

When I signed up it asked what my vehicle was thats how the 79 bronco got there , the explorer in question isn't mine its a project that was dumped into my lap .