Electrical Gremlin On My BJ70?

[Canuck]

Just coming back from a trip over to the west coast of Vancouver Island and sometimes for no reason that I can figure, the engine coolant gauge and fuel gauge would shoot straight to the top of their ranges hold there for a while, then come down again to the correct readings. The coolant is fine, nice and full and the tank was just freshly filled so I know there was lots of fuel in the tank. Any ideas on what the cause could be?

Oh yeah it's an '85 BJ70 with a 3B.

 

[crushers]

this is typical with both the 70 series and the 60 series, you can spend big money and fix the problem or you can just realise that if both guages go up there is nothing wrong. now if the heat guage heads up but the fuel stays the same then you have a problem. if you plan on fixing the problem go with a mech temp guage. Napa sells one for about 30 bucks that has all the right fittings...
HTH
Wayne

 

[dogstarmessenger]

the 70 i just bought does it to both gauges pin to the top although mine doesnt correct itself(or at least hasnt yet) until the engine is turned off and then back on letting both gauges drop all the way
Prev. owner told me about it and as long as they both do it at the same time i guess theres nothing to worry about

 

[Landpimp]

if its the same as a 60-2 then you can prolly fix it for free, just take the fuel guage out and clean the litttle points/contacts on the back. or get a new fuel guage(for a 60 it was $30). the temp/fuel share the same ground which is on the fuel gauge.

 

[BJ70/85]

My BJ70's Temp gauge is shooting high then returning, but not the fuel. What is the cause?
Also the Oil pressure reads zero @ idle after a long cruise, but no knocking.

 

[Canuck]

Thanks for the help guys. When I get some time I'll pull the cluster asn check-out the contacts and ground.

 

[baby_troupe]

My LJ70 used to do it, but has not done it since I replaced the Battery & had the alternator fixed (about 6 months ago) I don't think they were the cause of the problem, but it does seem mighty coincidental that when that was done, the problem also went away.

 

[BJ70/85]

I put another 2.5 liters of coolant down the thermostat housing by pushing thermostat open with a screwdriver, after I was told that it was flushed/filled... The problem with the coolant temp. has not been back. If it comes back, I'l post.

 

[Stone]

Also the Oil pressure reads zero @ idle after a long cruise, but no knocking.

I found out from Greg that the 70 series oil pressure gauge reads notoriously low, especially at idle when the engine is warm. I've seen a few BJ74s with low readings and when a pressure gauge was hooked up it revealed that there was plenty of oil pressure despite the low reading on the gauge. FWIW my oil pressure gauge needle sits just a little bit above zero when idling with the engine warm.

Could your temp gauge gremlin possibly be caused by a touchy sender or faulty ground?