BJ74 electrical problems.

[nickw]

Okay, so about 2 weeks ago I notice my voltage dropping when I turn my truck on. But it only does this when its cold. If the engine is warm, or mildly warm its okay (ie. warm outside, or if its still warm from running). But what is weird is my batteries are normal voltage if I check them with a multimeter. I was thinking a bad ground. But I can see the ground on the side of the block and it looks good. It was wet and cold so I left it for a better day. Because as soon as the truck ran for about 20-30 seconds voltage would come up.

But something else weird started last night.
After I started my truck and the voltage came up the oil pressure shot up to 95% on the gauge at idle, and higher if the rpm goes up. What is with this? There should not be that kind of oil pressure in there. I am going to change my oil+filter in about 20 minutes just to make sure its not that. But I am thinking this is an electrical issue.
I am also going to check the ground.

Any ideas what is causing this?
I am sure what ever this is caused my electrical problems of a month ago.

Thanks,
Nick.

 

[nickw]

Something else I noticed when I was measuing my voltage.
I was standing beside my truck with it running and measuring the voltage going into the batteries.
It was charging about 28volts.
When the truck is off, each battery is about 13 volts.

I reved the engine up (to see if it made a difference to charging) and I notice a little white smoke out the exhaust. Not much or anything. Is this normal? It only does it around 2000rpm. I am guessing with a load on the engine this would be gone. It is so little I could not see in the mirror. Normal or not?

Cheers.

 

[brownbear]

28 volts charging is normal. Static voltage(not running) on each battery at 13 is normal.

You might have an issue in your gauge cluster. In the FSM they list test procedures for all the gauges. Do you have the FSM for this truck?

I bet its a resistance thing. Don't trust the gauges. If you measured the batteries right on a cold start up then thats the actual voltage.

Cold weather does funny things to machines. Could be moisture in a connectors.

I use an interior warmer. Makes a difference keeping things dry and nice inside. I plug in below minus 5 two hours prior to driving.

Some nights if its snowing I run the interior warmer all night. I hate scrapping the windows.

 

[rove_mcanus]

It's actually normal for your voltage to drop when you first start the truck. Being diesel (bj?) The glow plug system will draw a fair amount of current to warm the motor. The white smoke is unburned fuel, and would actually suggest a probelm with the glow plugs. It would only get more smokey if it were under load.

you should hook a mechanical guage up to double check the oil pressure. If it is high, it would be unrelated to the above problem. you should check the oil pressure valve for that one.

28 volts charging, so you must have a 24 volt system? So that sounds about right. from the few 24 volt systems i've seen they generally charge around 26-28 volts.

 

[nickw]

Hey Guys,

Thanks for the info.
I changed my oil and its still high pressure according the the guage.

Your right about the moisture.
It has been very damp here.
Lots of snow then melts, then snows, etc....
I have had to run my AC a lot stop to keep the from fogging inside.

It could be the moisture.
Some connections somewhere is not right.
I hatr electrical issues.
I will drive it around tonight and see if it dries out.
I might take apart the guage cluster to see if that fixes anything too.

Cheers.
N.

BTW: It was a frusterating day working today.
I forgot to put my nylon gasket back on my oil plug. :dooh:
I aslo broke a bolt when I pulled my voltage regulator.
I broke 3 drill bits drilling it out. double dooh.

 

[Gold Boy]

nick

after the engine has warmed up does the oil presure drop?

 

[nickw]

nick

after the engine has warmed up does the oil presure drop?

Hello GB,

Once the truck warms up a bit it drops a bit. But not even close to normal levels. The guage was basically maxed out. After driving around for about 30 min tonight is started working its way back down, But then it died all together. I am not sure why, but now it does not work at all. it is quite frusteratiing.

I may or may not have time to look at it tomorrow. It might have to wait until next weekend.

Cheers,
N.

 

[Brunei Prado]

Hey guys,

Maybe a wild guess, but what about your earth connection?
I had lots of problems with my other toyota, a 1984 Crown, and it happened to be the earth cable running from the battery directly to the engine block.
It still looked good but after 22 years and lots of moisture I think it was all corroded inside. I changed it for a new welding cable and all my problems were solved.
Cheap solution so maybe worth a try.

Cheers

Brunei Prado

 

[nickw]

My ground is good.

In fact I think I figured out the problem.
In the morning when its cold, my one battery (currently high side, but used to be low side) is around 6v. Other one is good.

Once its warm, or has been charged for a bit, it does okay.
So that is the issue. Probably what caused my problems before.
My 12v/24v converter has been in straigh balance mode since my last episode, but I put it in balance mode to see if it can save battery, seeing as when it is warm it does fine. If they are still dead, I am going to try an get both batteries warrantied before I go buy two new ones.

Now the problem is my oil guage.
It does not work at all anymore.
Any ideas? Where to start. Any easy things?
I will start a new post about this.

Cheers,
Nick.