Fuel gauge help

[SSean]

A stock Gen3 fuel calibration will not work the 98 gauge. Assuming the wiring is correct---It is the tune.

Jeff

Well im tuned by flaco and itz a speed density tune, I have a 4-barrel throttle body. My harness...well itz actully 2 harnesses. One is the stock 350 vortec and the other is a Nelson Performance stand alone.
How would the tune make it mark the fuel gauge? You lost me. lol

[Lextech]

There are several settings in the PCM for the fuel gauge. Two of those settings definitely need to be changed for the Gen3 calibration to properly run the 98-2000 GMT400 gauge. I have no idea if your wiring is correct. Assuming it is, and your gauge works, then it is in the tune.

Jeff

[1991SSP]

Can the fuel gauge on a 1998 model be functional without being pinned into the new PCM??? I can't get mine to work at all, I have the purple wire for the gauge and the purple with white stripe from the tank spliced together and the gauge reads past full

[Lextech]

Can the fuel gauge on a 1998 model be functional without being pinned into the new PCM??? I can't get mine to work at all, I have the purple wire for the gauge and the purple with white stripe from the tank spliced together and the gauge reads past full

The 1998 Fuel Gauge is controlled by PWM. Its signal has to come from the PCM. The fuel sender outputs to the PCM and the PCM outputs to the fuel gauge.
Jeff

[1991SSP]

Can you help me out on how I can get it functioning properly???

[Mickeymotormount]

Try this link. It 's a wiring diagram for your truck: Be sure to use the user name and password below the link.
http://arrc.ebscohost.com/searches?c...rument_cluster

USER NAME: student
PASSWORD: watc

[1991SSP]

Try this link. It 's a wiring diagram for your truck: Be sure to use the user name and password below the link.
http://arrc.ebscohost.com/searches?c...rument_cluster

USER NAME: student
PASSWORD: watc

Thanks for the info, I have all the wiring figured out,,, lex answered the reason why I can't get the gauge to work........... now I just need to figure where to pin it on the new PCM

[kewljay223]

There are several settings in the PCM for the fuel gauge. Two of those settings definitely need to be changed for the Gen3 calibration to properly run the 98-2000 GMT400 gauge. I have no idea if your wiring is correct. Assuming it is, and your gauge works, then it is in the tune.

Jeff

you say 98-2000 but what about the earlier years? i have a 95 that im about to swap a 03 lq9 in. will i be running into this same issue? will the tune need to be adjusted just like this or is it different? im not sure if the gauge gluster is the same.

[Lextech]

The fuel gauge info does not come from the PCM on the 97 and earlier trucks. It goes from the fuel sender to the gauge. It only goes through the PCM on 98 and up trucks.

Jeff

[1991SSP]

All I can say is this site is a blessing for anyone doing a swap... I always love a challenge and learning new things...