BJ42 3B - high oil pressure and blinking sedimenter light

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Jul 4, 2010
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Brisbane, Australia
Hey oilers,

Need some help please. This weekend my rig did something weird - normal suburban driving I noticed the sedimenter light blinking and the oil pressure gauge right on the top line.

And this all at about 1800 rpm. Easing off the accelerator then the oil pressure gauge dropped to about 80% and sedimenter stopped blinking. Each time I go over about 1700/1800 rpm for a few seconds then the oil pressure shoots up to 100% and sedimenter light blinks. Even at about 1200-1500 rpm the oil pressure gauge is at about 70%.

I'm hoping to get some idea what it means please?

Thanks
 
You will receive several types of answers... ranging from bad alternator brushs to bad alternator regulator. I vote for the bad regulator.
 
Thanks David, I think I'd be happier (er, less unhappy rather) if it is an electrical something. I noticed also that I have lost my headlights - parking lights work fine - but I have not had a chance to even check the fuses.

I've definitely got some electrical gremlins that I have not chased down - sedimenter light glows at low revs, amp meter never moves although I am not sure if that is normal. I tried a new regulator some months back and saw no difference with the electrics, but this high oil pressure gauge and blinking sedimenter is a new thing.

Appreciate the help, thanks much! Guess I know what I'm doing this weekend:rolleyes:
 
I would would check in order of difficulty - start with the alternator belt tension, ensure its not slipping. Then check the brushes. Then replace the regulator. If you're still pooched, rebuild the alt.
 
... Also notes that a ''bench test'' does not necessarily indicate a malfunction of the regulator. Often, it is show signs of weakness when it is operating ''in situ''.

Although I never experienced this problem with my BJ42 ... that was the case of my ex-BJ60 and my BJ70
 
... I vote for the bad regulator.

Me too.

Put a voltmeter across your battery terminals Gary. The voltage shouldn't exceed 14.7V (and I'm guessing your getting more than this).

If over-voltage is indeed your problem, then one of these from Repco will probably solve it (assuming your regulator has that same rectangular connector):

VoltReg5.jpg

:beer:

Oooops. I see you've already tried a new regulator ...............Oh well ....:hmm: I'll have to think again!
VoltReg5.jpg
 
Thanks guys, appreciate the advice, I'm bloody well going to find this one and I'll update the post.

Some months back I had the battery voltage checked - twice - by an auto electrician. I replaced the original battery at the time, it was cactus. Voltage was consistently around the 14.3-14.7 even at higher revs with both old and new regulator.

(Tom, I'll send you a PM when I get back home in a few days, I tracked down a NOS BJ40 regulator - it's yours if you want it, I'll even spring for postage :))
 
... I noticed the sedimenter light blinking and the oil pressure gauge right on the top line. ...And this all at about 1800 rpm. Easing off the accelerator then the oil pressure gauge dropped to about 80% and sedimenter stopped blinking. Each time I go over about 1700/1800 rpm for a few seconds then the oil pressure shoots up to 100% and sedimenter light blinks. Even at about 1200-1500 rpm the oil pressure gauge is at about 70%......

....I noticed also that I have lost my headlights ..... sedimenter light glows at low revs>>>>


Since all of the above can result from a regulator fault ...it sure is hard for me to look beyond your regulator Gary.

... amp meter never moves although I am not sure if that is normal. ....

I'd ignore this. "No movement" is certainly normal-behaviour for my similarly-wired BJ40 ammeter (for the last 30 years) Gary.

...I tried a new regulator some months back and saw no difference with the electrics, but this high oil pressure gauge and blinking sedimenter is a new thing.....

So if changing the regulator didn't fix the problem but your faults (ie. blown headlights, illuminating sedimenter light, oil pressure gauge reading incorrectly) all still suggest a regulating fault ..... then perhaps there's a fault external-to-the-regulator stopping it from working correctly?

I'd be particularly interested in condtion of your regulator's loom connector! (Any corrosion/muck in there?)

Or are any wires frayed/broken?

....Some months back I had the battery voltage checked - twice - by an auto electrician. I replaced the original battery at the time, it was cactus. Voltage was consistently around the 14.3-14.7 even at higher revs with both old and new regulator. ...

Faults caused by damaged wiring or corrosion can be intermittent rather than continuous. So perhaps when the autoelectrician checked the fault had momentarily disappeared?

If I was you I'd get a multimeter from Dick Smiths, Jaycar or similar and to the tests myself (when those faults are appearing). Good meters are pretty cheap these days.

...Tom, I'll send you a PM when I get back home in a few days, I tracked down a NOS BJ40 regulator - it's yours if you want it, I'll even spring for postage :)
...

Cool. :) I'm keen.
 
I suspect I am in the same boat Gary. Lately my wipers(All 3 of them :D) don't work at idle but they do at higher revs ... :confused:
 
Thanks again for all the advice, thought I'd post an interim update on this although I have not tracked the culprit down yet.

I checked voltage at the battery - at idle it read about 12.8v, slowly creeping up and settling at about 13. At about 1500rpm voltage went up to 13.6/13.7 and stayed there. I worked my way through the harness in the engine bay - one fuse off a positive lead from the battery was buggered and I think this is for the amp meter (it still has not moved though as expected) and one wire to the horn was frayed - fixed that all up, cleaned up connections to the alternator, tidied it all up, removed an old relay that was connected to the alternator but nothing else (PO spotlights I suspect).

I suspect the headlight loss is not related to the high oil pressure gauge and blinking sedimenter light. So I'll check the headlight switch and high-beam switch.

But is it possible that I am having high oil pressure? And if so, is there a way to check this without relying on my truck's (dubious) electrics?

Thanks again guys, I'd be so lost without the help from this forum.
 
12 or 24v?
 
I vote voltage regulator, mine failed last year. But are they remote on a 12v? I don't know
 
Thanks eric, the regulator on my truck is remote. I get the same results when trying it out with a new one unfortunately. I need to test the alternator output, maybe I'll get another multimeter and run some wires to the battery and the alternator and put the two multimeters in the cab whilst I troubleshoot this.

I'm just a bit worried that the high oil pressure reading is true, so is there a way to check the oil pressure conclusively, even if I need to bypass the current system temporarily? If I can eliminate that as a cause for a high meter reading then I'd be a lot more comfortable :)
 
To check oil pressure .... simply plumb in a traditional-type gauge to where your oil pressure sender unit sits now Gary.

Thread = 1/8 inch BSPT
 
To check oil pressure .... simply plumb in a traditional-type gauge to where your oil pressure sender unit sits now Gary.

Thread = 1/8 inch BSPT

Thanks Tom, that helped. I plumbed in a mechanical gauge and T-piece to keep the stock sender. Well, I feel a lot better, and apologise for not completely believing all the advice I have gotten :cheers: Mechanical gauge says the oil pressure is within spec - I'll post some numbers up once I've had a chance to drive it a bit more under different conditions. The stock electric gauge goes off the scale at 2500rpm but the mech gauge reads about 70psi.

Now that I am confident the oil pressure is really okay I can continue tracking down the source of the electric anomalies. I replaced the OEM regulator with the new one I bought, get exactly the same behaviour. Both give me a glowing sedimenter under 1200rpm, both give me crazy oil pressure readings, and a blinking sedimenter light when the oil gauge hits it's top mark.

The journey continues, and I'll post my notes as I go. Thanks again to all for the fantastic assistance.:beer:
 
Just a quick update on this - have not found the source of the bad OEM oil gauge reading yet though. The mechanical gauge reads about 60 at cold idle, 20-25 at warm idle, 70ish at cold driving and about 40-45 at warm driving. I think this is within specs?

But the faulty headlights were definitely not related. Just to put you in the picture - took me a few weeks but I did eventually find that one. Hold on to your seats because you might fall off laughing :bang: After a few weeks of troubleshooting, fixing a few other harness issues and stuff - turns out it was the :censor: fuse

Symptoms were inconsistent, but over the weeks I swear I tested the fuse at least 5 times while still in it's holder, tested the connectors behind the fuse box, refurbed the light switch. You will see from the pics below it looked okay, and when I tested it I put the probes on either end, pushing them ends together - all good. But the inside weld in the fuse was loose. Pushing together obviously closed the loop. And inconsistent results on other tests were obviously as a result of the intermittent connection.

Note to self: just replace the bloody things in the future :eek:
DSC_2205.jpg
DSC_2207.jpg
 
Glad you got it figured out. I have actually had the same problem with barrel type fuses. I put in an inline fuse for a 24v to 12v converter. The converter would only work intermittently. I pulled my hair out for a couple of hours until I realized it was the fuse (that looked perfectly fine) that was the culprit. It can definitely be annoying.

:cheers:
 
Believe it or not, at normal operating temp 4.3 psi or more at idle is OK and 36-85psi at 3000 rpm is what one factory manual lists for 3B oil pressures

Tony
 
I had similar issues with my oil pressure on the 2h, turned out to be a corroded cable to the sender unit. At a certain rpm it could not get a reading.

Got a oil pressure release valve with new springs and gaskets, but have not installed it since the issue got fixed with the cable.

But I guess changing the release valve does not hurt. Could both give high and low pressure, at least on the 2h.

Sent from my GT-I9000 using IH8MUD app.
 

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