91 Ls 400 Gas Guage Problem

[havsone]

Hey everyone.. Im pretty familiar with all of the regular problems associated with the LS 400 (91). But now I have something new wrong with it. Whenever I fill up my car at the pump, the guage doesnt go all the way up. I put premium gas and I do fill it up all the way. This has happened more the once, so I finally decided to post this topic to see if anyone has any advice or recomendations. I'll really appreciate any help. Thanks for looking

LS 400 Owner

[1991LS400]

deleted

[92Lex]

Hey everyone.. Im pretty familiar with all of the regular problems associated with the LS 400 (91). But now I have something new wrong with it. Whenever I fill up my car at the pump, the guage doesnt go all the way up. I put premium gas and I do fill it up all the way. This has happened more the once, so I finally decided to post this topic to see if anyone has any advice or recomendations. I'll really appreciate any help. Thanks for looking

LS 400 Owner

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Capacitor C142 and C147 on the instrument cluster board. You have to remove the instrument cluster and circuit board and replace those 2 caps. There's a pinned post on how to remove the instrument cluster and board from your vehicle.

[Lexls]

Capacitor C142 and C147 on the instrument cluster board. You have to remove the instrument cluster and circuit board and replace those 2 caps. There's a pinned post on how to remove the instrument cluster and board from your vehicle.

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C142 and C147 capacitors do not exist in 90-92 LS's. Although the clusters look the same, 90-92 clusters are different than 93-94 clusters ;). The fuel gauge problem has nothing to do with the fuel pump or floater in the gas tank.

You are right about re-capping. This fixed the fuel gauge problem on my 91 cluster. My fuel gauge finally goes all the way to the top, and fairly quickly too :D. I have a tutorial for this in the works...I've just been working on all the tutorials 92Lex sent me.

[92Lex]

My bad for misinforming you, I looked at an old post and it was based on a 93 LS.

Which caps should he look for?

[Lexls]

I have one I think was the culprit through my own testing. I can't say which one exactly right now because I currently don't have a multimeter that tests capacitors and don't have my materials out. I bought 2 non working clusters on ebay to do testing. Once it snows here I'll be more likely to keep working on this :whistles: . Right now I say just replace all the caps on the power source circuit board. There aren't that many. I will eventually sell a kit to fix this problem on my site. If you need parts PM or email me and I'll get my !Removed! in gear on this.