MJfan94 Posted February 16, 2015 Share Posted February 16, 2015 The gas gauge on my 89 MJ keeps fluctuating. When i drive below 25 or stop, the gas gauge drops about quarter tank then when i drive above 35 the gauge needle goes back to where it should be. I think it might be something with the fuel pressure but if someone knows what it might be that would be helpful. Link to comment Share on other sites More sharing options...
Zebvance Posted February 16, 2015 Share Posted February 16, 2015 mine does this a lot also Link to comment Share on other sites More sharing options...
Jeep Driver Posted February 16, 2015 Share Posted February 16, 2015 As does mine. Link to comment Share on other sites More sharing options...
benjy_26 Posted February 16, 2015 Share Posted February 16, 2015 Unbaffled tanks? Link to comment Share on other sites More sharing options...
Zebvance Posted February 16, 2015 Share Posted February 16, 2015 What do you mean by that? Link to comment Share on other sites More sharing options...
gogmorgo Posted February 16, 2015 Share Posted February 16, 2015 The gas sloshing around in the tank could change the level the sending unit picks up. Baffles prevent slosh, but only so much. I always found my gauge wandered around a lot with inclines and accel/decel, but it would also do so while cruising at constant speed on reasonably level terrain. I'd chock it up mostly to 23+ year old wiring. Could also be related to the voltmeter fluctuations that were discussed recently, if it's a dash/gauge thing instead of a sending until thing. Link to comment Share on other sites More sharing options...
Eagle Posted February 16, 2015 Share Posted February 16, 2015 Two points: First, the tanks are baffled, to an extent, but the float isn't dead center. The level will read significantly different if the nose is point up a slope, as compared to if the nose is pointing down-slope. Second, check your voltage at idle and above 1500 or 2000 RPM. If there's a voltage drop at low RPM, that will affect the readin. Link to comment Share on other sites More sharing options...
Jeep Driver Posted February 16, 2015 Share Posted February 16, 2015 I live in the mountains. If I have 1/4 tank and I'm going down the mountain it reads closer to 1/2 tank, if I'm going up the mountain it reads closer to empty. Been doing the same thing for three years now, predictable. Link to comment Share on other sites More sharing options...
Lee21490 Posted February 16, 2015 Share Posted February 16, 2015 Mine used to be really bad, For some reason when i swapped out my fuel pressure regulator, It quit fluctuating as much.. Still does it.. But now i can actually use my gas gauge. Link to comment Share on other sites More sharing options...
ParadiseMJ Posted February 17, 2015 Share Posted February 17, 2015 I've always thought this was normal, since both of my Jeeps have done it. When I'm going downhill or decelerating, stopping (in the XJ) the gauge goes up and does the opposite when accelerating or going uphill turning left. The MJ does the exact opposite. However they're accurate when I'm just cruising along on a semi-flat road at a steady speed. By the way, my Nissan Sentra commuter does basically the same thing only not as pronounced. Link to comment Share on other sites More sharing options...
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