okay so ive done some more work on my truck lately, so it used to idle at around 1500-1800 rpms so I thought MAYBE my tachometer was off. I know my 90 shares interchangeable parts between 89-92 and on youtube I saw that a 92 ford f-250 tachometer repair was done with the removal of the tachometer, then resoldering the joints on the backside, so that is exactly what I did to my tach, the video said only one corner of the solder joints are the cause but I ended up reflowing the solder on the entire board just so I wouldnt have to take it apart again.
Now my idle sits steady around 1100 RPMS and when I input my details into a "Tire speed calculator" or "Final drive ratio calculator" the numbers FINALLY MATCH!
So I know my idle wasn't entirely fixed, but I decided to move on for now.
Next thing I did was went for my 99 alternator from the donor truck... it was rusted shut, okay pick n pull time then. I bought a pick n pull alternator for $35 with a 30 day warranty, took it straight to Oreilly's auto parts to get it tested, failed 2/3 tests so I brought it back to pick n pull the same day and got another, straight back to the auto parts store to test the 2nd. Passed the parts store test very well, the man behind the counter said only problem is it screams like hell
oh no I thought... lol
My 90 alternator was giving me a headache with its squeal, so I tore it apart after youtube disassembly videos and found both bearings. spun them around my finger, the rear one had very loose tolerances and wouldnt spin good, the front (Belt driven side) spun pretty good and had tight action. So I checked the parts store for the bearings, one was $7 the other was $15. I was dead broke and it just so turned out the worn out bearing was the $7 one so I caught a break here, headed to the parts store and got it after returning some cans and bottles. The other bearing that was somewhat alright I decided to take the side plates off of it that seal the grease in, removed all the grease and packed as much grease in there as possible, popped it all back together and installed the alternator.
So, alternator installed, now the plug issue. the old 2 plugs had 5 wires, the new single plug has 2 wires in the plug, and one 6 gauge positive wire from the post.
The two white wires I believe were an alternator field wire? went from one plug to the other, this wire was deleted because the new alternator i am assuming fielded itself from within, or didn't need that.
There is a green wire (I forgot the stripe color) that goes straight to the voltage meter on the dash, 1990 and 99 wires to the volt meter are the same color with the same color stripe, they probably kept this the same for technicians.
So that covers 3 of the 5 wires from the 1990 alternator plug's. the 4th was a blue wire, it was the only I couldnt figure out what was going on with it, I couldnt tell if it was a spare fuse slot or something else but I ran it over to the remaining 1 wire left in the new alternator plug.
Now we have 1 red or black/org wire leaving the 1990 plug that is 6 or 8ga. and we have the 99 alternator with a 6ga wire on the positive terminal. I deleted these wires because they were tiny, the 90 positive wire went directly to the fender mounted starter solenoid, so I replaced that with a 4ga super flexible amp wire I found in a junkyard explorer with "FX AUDIO" stickers, looked like someone already stripped the amp and subs so I stripped the super flexible 12 ft 4ga wire for projects.
So now that the alternator is entirely wired, I heard a trick online to keep your alternator cooler, aparently they not only output/produce positive current, but also negative current. Now the theory is your negative current has to travel through the engine block to the tiny ground strap to the firewall, then around the fenders to your chassis, then to your chassis to battery ground and this long path creates resistance, the resistance keeps the negative current choked near the rear of the alternator inhibiting the circuit board in the alternator or I was thinking, possibly even the bearing in the rear to wear out quicker "Fords commonly have squealing alternators". So I ran a 4ga wire from the top of one of the alternator mounting bolts directly to the negative battery terminal, because electricity chooses the path of least resistance.
Starter her up and no more funny noises
Moved onto the throttle body mod, I bought a 70mm throttle body that I pulled from a ford expedition v8 I believe. I knife edged the throttle plate and ported the step in the bored, then ported the opening where the intake hose fit on so the lip was smooth and didnt cause turbulence before air even got to the throttle plate. I did have to buy a round headed screw and some nuts from a hardware store to make the head that the throttle cable snaps onto, I used a bench grinder to shape the head of the screw to the right shape and put the screw in an existing hole on the throttle body. YOU MUST DO THIS, why? because if you bolt the throttle body on, upside down (Ford logo facing the ground rather than the hood or "UP" which is what I did, I faced my logo downwards) Then with the throttle body attached in this position which is the only position that will work, then the throttle body will only accept a throttle cable coming from the grill coming back towards the motor, which is 180 degrees from where the rangers actual throttle cable comes from. so there is an existing hole which you can put a bolt and nut through to snap the throttle cable on.
I didnt like the throttle body spacer so I removed it, except im already planning to make a spacer from a sheet of delrin because the throttle plate makes contact with the plastic inside the plenum AND whistles, the whistle is actually very sharp and hurts my ears while driving so a spacer is a MUST. But the factory spacer really really restricts the bore, so you must make a custom spacer and you cannot bore the factory spacer because the perfect bore is directly where the rubber seal is, which would make it ineffective.
So my next mods im looking at is the throttle body spacer, then i already have picked 90% of the parts from a junkyard for an electric fan swap, then after that ill probably hit the 1100 rpm idle problem and see where its coming from.
btw, I got a volvo 740 electric fan and relay, siemens fan, apparently that is the highest CFM electric fan you can possibly find at a junkyard and its relay controller, plus some jeep siemens relays so I can wire it directly to my key on switch so my fan will turn off when the key is off but that is NOT hard wiring it, I will be using hi/lo/off features from the fan, controlled by a BMW temp switch. It sounds complex, it may actually be the most complex route of doing this mod, but I assure you its not that hard. My goal is to make it so you get in, turn the truck on and drive like everything is absolutely factory and there is no (Let me watch my temp gauge until I see a temp I need to switch my fan on and off at) there wont be any manual fan switch, it will all be controlled by relays and temp switches entirely. The part most people leave out is a relay to the key ignition so your fan doesnt continue after the key is off and drain your battery.
The parts I have left to find for the electric fan conversion is a radiator hose adapter to thread my temp switch into, and some scrap aluminum for making the fan shroud.