BJ Fuel filter light staying on (1 Viewer)

[caper]

So. first time in 15 years my filter light is staying on , so i drain sediment can and no water in it but a bit of rust , i check float switch and works correctly, has continuity as ya rase float , so i read somewhere it can be indicative of a charging system issue also , oh my god help me trying to get an alternator or whatever is needed for a 24v system in canada this is gona be fun , put in a new tank anyways she rusting on the inside , 43 years old no shame. I guess , any help on where to start testing charging system ?

 

[Bandit_guy]

If I were a betting man, which I am not, I would put money on the charging issue. It's easy to check, disconnect the sediment sensor wire, make sure it's not grounded and if the light stays on with the engine running your alternator is not charging, or charging enough. It's a simpler fix than you think. I had this many times before, when my brushes were worn out. I replaced the brushes and it ran for a few more years. You can do it right on the truck no need to remove the alternator if you don't want to. Just pull out the brush holder and solder in new brushes and push it back in. It's a bit tricky because the brushes are spring loaded but nothing too crazy. Any overhaul shop can do it in no time if you have one in your area. The other possibility could be the voltage regulator that is faulty, if you find the exact toyota part it's an easy swap if not any old 24 volt external voltage regualtor will work it's just the proper wiring that will be a challenge.

I was done with the drama of my old alternator and installed a universal 40 amp one I bought from Australia on ebay. You have some adjusting to do to get it to line up and replace the pulley with a smaller one but it wasn't too hard to get it sorted. Radd cruisers in Duncan sells them as well.

 

[caper]

I believe my alternator has a vacuum pump on the back , was that the same as yours ? , looks like no fun taking it out , found this other PO jem after taking some tape off a wire goin to a JB off the positive side of battery but its not my issue , i dont know where to start here , I don’t want to load the parts cannon if I don’t have to .

 

[Bandit_guy]

The alternator will always have a succion pump on the back it's how your break booster get's it's succion. It's not real diffcult to remove but I just leave it on when removing the alternator. The oil lines don't have much in them so they don't make a mess when you take them off. Your voltage regualtor looks pretty clean inside. A voltage regulator is just a big relay that turns on and off continuously 1000's of times per minute to keep the voltage at 28 volts. If it's burnt out or super corroded it would be obvious, yours looks decent enough, however it only takes one little wire to break for it to stop working. On your fusible link the white and blue wire comes off the Alternator and connects through to the other two wires to provide power to the rest of the rig. The other wire all messed up wouldn't cause the filter flight to come on. I would check the brushes on the alternator first they should be around 20mm to 24 mm long. If the are real short they probably don't make proper contact anymore.

I have my old alternator on the bench I'll pop the cover off later today and post a picture of the brushes.

 

[Bandit_guy]

You need an 8mm and a 10 mm to take the cover off an the brush holder just pops out. The brushes are 28mm X 8mm X 5mm and need a copper wire tale. You just de solder the old ones out and resolder the new ones in. The ones in the picture measured at 19mm which is probably why I was have trouble sometimes.

Hope this helps you out

 

[caper]

Well i looked at voltage reg with it running has no movement between contacts , so i pull brushes and they nothing but nubs , so i guess i’ll throw brushes at it , but wait theres a plot twist i can only find one through toyota in all of North America lol , ya’ll got any 27371-54412 brushes, i may have found some others but they don’t ship to Canada , this is always the way the US guys don’t know how lucky yas are down there for parts availability , drives me crazy lol

 

[Bandit_guy]

If it's not a perfect fit it will still work just fine, have a look for AC delco E772a or equivalent from another manufacturer. Rockauto or Ebay.

 

[caper]

There is a little rectangle gasket that goes here mine is half gone (deteriorated) not sure if it was a full rectangle or a U shape when new , i figure its 1/8 inch thick , i wonder if i put it back together without it will they make contact enough to tell me if its the real issue before i go nuts looking for brushes immediately only to find out it’s another issue ?

Its not in good enough shape to reinstall anyways even when i find new brushes

 

[caper]

New brushes did not fix , what steps-do i take now to fjgure out if its the alternator or regulator ?

 

[lacalvette]

Batteries voltage, should be around 25V
If it is less the B output should pull full charge around 28V. Might disconnect batteries to be sure.
Thé FSM is pretty good for the test to be perform. Lots of info here.

 

[Bandit_guy]

There's two ways you can check them.
Option A "the safe method":
1) Checking the voltage regualtor: Have a power source of that you can control the voltage, like three 9v batteries soldered in series to up to make 27 volts with a potentiometer wired in to change the volatage above and below 24 volts. Check for continuity above between ingnition post and field post (Black yellow wire and white green, on the BJ42 wiring diagram) when voltage of less than approximately 25 volts is applied to post "N" (small white blue wire) grounded Via E (white black wire) and no continuity when high voltage is applied. It should go on and off when voltage is applied above and below. If building the power source is not your cup of tea you can do it with a battery charger turned on and off attached to the batteries (one 24 volt unit or two 12 volt units on each battery). The voltage regulator should "kick off" when high power is applied and stay on when the charger is disconnected. Make sure you test this with the key on.

2) Checking the alternator is replace the voltage regulator with a known working one and see if it charges or take the alternator to a shop to bench test it.

Option B: "the sketchy method":
1) Checking the Alternator: Disconnect the voltge regulator from the alternator (the three pin plug right on the alternator),Start the engine, Run a wire from the positive side of the high battery and connect it to post F (white green wire) on the alternator. Check voltage on post B on the alternator and look for high voltage. It will no longer be regulated so 33 volts is pretty common at idle. It's pretty common to see sparks when you touch that wire to the plug on post F, hence the sktechy method. You can tune down the sketchiness by having everything coneected before you start the engine and as soon as you see high voltage turn off the engine. The point being if your alternator is making power, it's good. You can then assume your voltage regulator is faulty. A few seconds at that super high voltage won't fry anything but anything longer you will start to destroy things

If in both methods of checking the components result in components that are functioning then a broken wire somewhere is the culprit.

I hope this makes sense and gets you the answer to you issue.

Good luck

 

[caper]

The alternator is at fault , so next question i have 2 spare engines i bought 15 years ago , CDN edition 3B’s , couldn’t even remember if they had alternators on em lol haven’t laid eyes on em in 15 years , one has an alternator that looks identical to mine , sane vacuum pump other one vac pump is a little different , both have round plugs tho , mine is square , can i just swap out my whole brush holder with square plug and put on the spare alternator?

 

[Bandit_guy]

Yup if they are 24 volt. They did have some 12 volt models. You can also swap the connector. It takes a little messing around but you just have to press the tab on the brass conector and you can pull the connector from the plastic plug. You need a pick or small common screw driver and the pop out. You have to push from the plug side. For my curiosity what is faulty with your alternator ?

 

[caper]

Open circuit in rotor assembly according to the shop that tested it

 

[Bandit_guy]

Ah, that's unfortunate but it seems like you have lot's of spares. If they don't work out I installed this a few months ago and it's been working out good needed some fitting, replace the pulley that came with it for a smaller V-belt one and swap some wires in the plugs but over all not much needed to get it going.

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[caper]

Holy that be $1200 by the time i got it to my door lol , i’ll try to get one of my 3 working first but the saga continues, i swapped in one of my spares and now the filter light flashes and the voltage reg pulses with the flash lol like a heart beat , still only getting 24 v from wire on top of alternator to battery ? took original one apart to see if it was just a broken wire on the rotor or somewhere but everything looks ok , but not sure of testing procedure for continuity gota research this , got continuity from slip rings to green wires goin into rotor but not sure how to test further

 

[caper]

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