Gauge Question - Please help if you can

[guy99]

It seems like the fuel gauge in my 1984 310 Limited may be bad. The shop which is working on it wants to try a new gauge to determine if that is indeed the problem. In order to do that they need to make sure that the sending unit and the new gauge are compatible BUT they do not recognize the insignia on the gauge (the red things which looks kind of like a "T"). So they aren't sure hoe to look it up.

Does anyone know the manufacturer of this gauge?

Does anyone know how to match the sending unit in the Motorhome to a new gauge?

[87MH]

Originally Posted by guy99

It seems like the fuel gauge in my 1984 310 Limited may be bad. The shop which is working on it wants to try a new gauge to determine if that is indeed the problem......Does anyone know how to match the sending unit in the Motorhome to a new gauge?

I'm pretty sure your '84 has a 0 to 90 ohm fuel sender/sensor.

You could easily check it - just before a fillup check the resistance reading across the sensor (gauge disconnected), then after fill up, check it again - a swing of close to 0 to 90 ohms indicates that the sending unit is working.

I think some marine fuel indicators have 0 to 90 ohm units - and I 'm pretty sure VDO still has some 0 to 90 units - they did a couple of years ago, anyway.


BTW - the sending unit is a BEEATCH to get to.

Let us know what you find.

[guy99]

Thanks. I know about the sender replacement. When I first bought the MH (1.5 years ago) I took it to a different shop and asked them to fix the fuel gauge among other things. They decide the sender was bad and charged me about $300 to replace. It improved the operation of the gauge but it still ocillates pretty wildly, Even when the MH is not moving. I never took it back because the shop is 100 miles away and I was leaving on a trip - I haven't been back to that shop.

Now I have a new shop which has done a pretty good job so far so I thought I'd throw this at them. If the get this right, I'll have them look into my intermittant 'low coolant' problem.

[47WeeWind]

Originally Posted by guy99

.... They decide the sender was bad and charged me about $300 to replace. It improved the operation of the gauge but it still ocillates pretty wildly, Even when the MH is not moving.

Did the old or new shop run an extra ground wire from underneath a screw on the outside edge of the fuel gauge sender unit to the chassis to make sure the sending unit has an excellent and clean ground connection? The fuel tank may not be metal or may not be well grounded to the chassis. Weak ground connections are sometimes the cause of oscillating instrument readings. An ounce of ground wire may outweigh a pound of labor.

[GlenCoombe]

Fred hits it on the head. I've also got some weak ground issues and am planing to replace the ground strap next weekend. I've got intermittant low coolant, wiper fluid and water in fuel (on gas engine) warning lights. I know the signs of weak ground also as when the headlights are on the volt meter goes down, the water temp goes up. Hope the ground strap does it as I'm not looking forward to trying to reground the dash with all its loops.
Let us know what you find out.
P.S. I've just looked at a fuel flow meter from Navman that does a totaling function. Check it out.

[guy99]

Interesting.

Fred, I don't know if they did ran a ground from the sending unit to good ground and I imagine it will be difficult to determine with the tank in the MH.

Glen, By ground strap are you referring to the stap which grounds the batteries to the chassis? If that was bad wouldn't it cause problems with everything in the 12 V system. But, I must say that I have many of the symptoms you describe, flakey gas gauge, Volt meter read about 1v low, low coolant light come on and off at random. Volatge drops with headlights on (haven't noticed temprature going up) .

[mcneon]

Ditto on what everybody else has said. I'd wager that 75% of 12-volt system problems are due to bad grounds, especially on older vehicles. Manufacturers once upon a time didn't pay enough attention to making solid, long-lasting grounds, and so we suffer the consequences now.

One of the great offshoots of the modern, computerized vehicle world is that connectors and connections had to get WAY better or nothing would work reliably.

I think the red "T" symbol on the fuel gauge stands for Teleflex, by the way.

Bob in Nashville

[guy99]

I spoke with the shop doing the work and they claim to have checked the ground. They say they get 0 ohms between the dash ground and ground. Don't know if they are measuring ground at the battery or the chassis.

Thanks for the pointer to Teleflex. I have these gauges on my 1959 Massey Ferguson TO35.

[wascobob]

guy99--please keep posting on this thread. My fuel gage also fluctuates wildly on the bottom half of the tank. The top half of the tank is ok but as it reaches just below half it begins slowly. At a quarter the swings become much violent and the low fuel light begins to flash with the needle swings.

Lets see, light flashes with the needle swings, I wander if there is a clue here!!! Seems that fuel gages may be a common problem on Airstreams.

Anyway, I do not see any of the other electrical symtoms you guys noted.

Keep us up on this please.---Thanks Bob

[GlenCoombe]

Guy99, I was refering to the ground strap that runs from the frame to the engine block. My old Champion had the same braided ground strap. One day I made a call right around the corner from home. Came out and the beast would not start. The ground strap was so corroded that it just about disintigrated in my hand. Changed it out for a new cable type and away I went. It is the main ground from which all else grounds to I believe.

[85/345]

Check this out they might be able to help.

http://www.custominstrumentpanels.com/automoti.htm

[guy99]

Looks like a bad gauge. The shop which is working on the problem connected a new gauge designed to work with a 0-90 ohm sender. The gauge gave a steady reading.

The old gauge is a model number 9203674, I looked up the old gauge on the Teleflex web site. It says to substitute a model 61706. When I looked up the 61706, there was unintelligible (to me) notation for the sender for that gauge, it read "Requires AC, N/A From TFX". So I emailed Teleflex, here is the reply I got this morning:

Hello Guy, the term AC means it’s an AC-Delco compatible gauge 1 empty- 90 full ohms. 61706 (Amega Series) will do the job but will not look the same as your 9203674 (XL Series) gauge. But then, nothing will.

I have run out of time for this before I leave for Mexico, so I'll have to follow up when I get back. First I'm going to try to have this gauge fixed, 85/345 sent me a link to a shop which might be helpful - thanks. If anyone has other suggestions about someone who might do this, let me know. If that doesn't pan out, I'll try to get a model 61706 installed.

[guy99]

When I bought my 1984 310 Limited MH in June 2004, 30,000 miles ago the fuel gauge would swing wildly, often moving back and forth even when the vehicle had been parked. I took it to a mechanic who concluded I needed a new sending unit (and charged me a good bit to install it since the gas tank had to be removed). This MAY have help a little but the gauge was still only somewhat useful. Recently, after watching the darned gauge swing back and forth for 30,000 miles I became determined to fix it even if I ended up with mismatched gauges. So to it to my mechanic, he thought it was the gauge and hooked up a replacement gauge which was compatible with the sending unit. This gauge gave a rock solid reading but did not fit the dash. I had them remove my old gauge and called these guys: http://www.speedometershop.com/ and asked if they could repair a Teleflex fuel gauge from a 1984 MH. They said yes, so I sent it to them. A few weeks later when I hadn't heard anything from them, I called. They said, oh yea, we were just going to call you. The passed me to the tech who said - can not repair, no parts. I asked myself (but not them) why they had me send it to them if they knew they couldn't get parts.

Oh well, called these guys ttp://www.custominstrumentpanels.com/index.html and they said they could provide a CIP XL Style gauge which is very similar but not identical to the old gauge which was an XL Style gauge. I had them send it to me and got it installed. Works great and since there is a piece of Plexiglas over all the gauges, you really can't see that it is a different style gauge.

All's well that ends well.