temp gauge pegged

island45 · 07-01-08, 12:21 AM

After my rewire all gauges worked but the temp rises slowly and always pegs on hot. I know it isnt hot because i can hold my hand on the radiator and it pegs so quickly. I tried another sender from an '83 block and it acted the same. There are 2 senders about 6" apart, so it's a bit confusing. It's a '76 2f. I switched the sender at the rear of the block because it seems thats the one that goes to the gauge. What do I try next? Thanks

rsbcruiser · 07-01-08, 12:54 AM

If you take the temp sender wire and ground it, bet the temp goes to full. Maybe you are getting a partial ground on that circuit. Hey Island, hear about the tall ship that grounded on your island? can,t believe they didn't sink it, not too many places there friendly to ship groundings. One other thought. If there is air trapped in the head then that would cause the temp to look high. Maybe vent the head by disconnecting the heater hose.

Richard

island45 · 07-01-08, 10:32 AM

Thanks. After work I will try to vent any air from the system. One other clue is that when these gauges were in the '76 donor vehicle, the temp and fuel gauge both stopped working at some point while I owned it. After filling the gas tank in the 45 last night for the first time, it registers just a bit over 1/2 and I know it's full. So the the fuel gauge AND the temp gauge are operating,but wrong... Maybe a common grounding problem. They both worked fine in the '76 when I bought it last January. Also I am using the original tank and sender from the 45 and connected to the later model gauge. And the sailing ship thing. I gotta agree. It's not like it would hit a sand bar.... more like a rock bar. We all refer to our island as 'the rock'.....

spotcruiser · 07-01-08, 07:47 PM

Hi Gary,

IIRC, one of the two temp sensors in the head is a sender for the gauge and the other is a switch for emissions control. One should be red and the other green (plastic potting around terminal) and I believe the emissions control switch is red. You want the gauge hooked up to the sender, of course. You can pull both of them and test them in boiling water. I think the switch is open above ~130 F. The sender resistance will vary from 90 ohms at 140F to 27 ohms at 212F, per the FSM.

For the fuel gauge issue, the old senders are not compatible with the newer gauges. IIRC, their functions are reversed, resistance-wise. You need to install the later style fuel sender to match the 76 gauge.

Todd.

radioridge · 07-05-08, 07:00 PM

fj62s have a common problem of the temp gauge and fuel gauge both peging . i dont know if its the same problem but you may gain some insight from a search in the 60 section

07-01-08, 12:21 AM	#1
island45 'Pops' Join Date: Dec 2007 Location: Orcas Island in NW Washington State Posts: 417	temp gauge pegged After my rewire all gauges worked but the temp rises slowly and always pegs on hot. I know it isnt hot because i can hold my hand on the radiator and it pegs so quickly. I tried another sender from an '83 block and it acted the same. There are 2 senders about 6" apart, so it's a bit confusing. It's a '76 2f. I switched the sender at the rear of the block because it seems thats the one that goes to the gauge. What do I try next? Thanks __________________ Some old Ford one ton pickups,'66 fj 45 lpb, '79 fj 55, '66 BSA 441 victor special,BMW r75/5 toaster tank, Ancient one lung engines (1912 Stover...6" bore, 12"stroke, 8 hp at max 300 rpms, 2125 lbs) Never without an old 'cruiser for 23 years. Everything runs, and is mostly original, That's how we roll on Mt. Pickett.... 'Rusty ol' floorboards, hot on their feet...' Alan Jackson

07-01-08, 12:54 AM	#2
rsbcruiser IH8MUD Lifer Join Date: Aug 2007 Posts: 1,087	If you take the temp sender wire and ground it, bet the temp goes to full. Maybe you are getting a partial ground on that circuit. Hey Island, hear about the tall ship that grounded on your island? can,t believe they didn't sink it, not too many places there friendly to ship groundings. One other thought. If there is air trapped in the head then that would cause the temp to look high. Maybe vent the head by disconnecting the heater hose. Richard __________________ Originally Posted by Atticus: rsbcruiser, poet laureate of the truly inane.

07-01-08, 10:32 AM	#3
island45 'Pops' Join Date: Dec 2007 Location: Orcas Island in NW Washington State Posts: 417	Thanks. After work I will try to vent any air from the system. One other clue is that when these gauges were in the '76 donor vehicle, the temp and fuel gauge both stopped working at some point while I owned it. After filling the gas tank in the 45 last night for the first time, it registers just a bit over 1/2 and I know it's full. So the the fuel gauge AND the temp gauge are operating,but wrong... Maybe a common grounding problem. They both worked fine in the '76 when I bought it last January. Also I am using the original tank and sender from the 45 and connected to the later model gauge. And the sailing ship thing. I gotta agree. It's not like it would hit a sand bar.... more like a rock bar. We all refer to our island as 'the rock'..... __________________ Some old Ford one ton pickups,'66 fj 45 lpb, '79 fj 55, '66 BSA 441 victor special,BMW r75/5 toaster tank, Ancient one lung engines (1912 Stover...6" bore, 12"stroke, 8 hp at max 300 rpms, 2125 lbs) Never without an old 'cruiser for 23 years. Everything runs, and is mostly original, That's how we roll on Mt. Pickett.... 'Rusty ol' floorboards, hot on their feet...' Alan Jackson Last edited by island45; 07-01-08 at 10:36 AM. Reason: left something out.

07-01-08, 07:47 PM	#4
spotcruiser IH8MUD Addict Join Date: Jan 2003 Location: Western WA TLCA# 10016 Posts: 842	Hi Gary, IIRC, one of the two temp sensors in the head is a sender for the gauge and the other is a switch for emissions control. One should be red and the other green (plastic potting around terminal) and I believe the emissions control switch is red. You want the gauge hooked up to the sender, of course. You can pull both of them and test them in boiling water. I think the switch is open above ~130 F. The sender resistance will vary from 90 ohms at 140F to 27 ohms at 212F, per the FSM. For the fuel gauge issue, the old senders are not compatible with the newer gauges. IIRC, their functions are reversed, resistance-wise. You need to install the later style fuel sender to match the 76 gauge. Todd. __________________ http://seattlecruiserheads.com/

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07-05-08, 07:00 PM	#5
radioridge IH8MUD Rookie Join Date: Feb 2008 Location: jasper tn TLCA# 17613 Posts: 39	fj62s have a common problem of the temp gauge and fuel gauge both peging . i dont know if its the same problem but you may gain some insight from a search in the 60 section