98 to a 99 PCM... fuel gauge not working.
 

I understand that some tuning must be done to have a working fuel gauge in a 1998 trans AM with a 1999 PCM swapped in.

I purchased the vehicle after this had all been completed, and the fuel gauge never worked from the beginning (the previous owner also neglected to tell me, advising that it worked fine).

Can someone explain to me what is required?

I ask because I am on the verge of buying a racetronix fuel pump and for the life of me can't find a fuel sending unit for a 98 LS1.
I'm hoping the original owener just didn't have it tuned in,

A 99 pcm u need to put the info in reverse. Meaning in fuel gauge calibration the valves go from -8.91 to 116.58 in 99+ pcm while 98 pcm goes 116.58 to -8.91. Should work then.

Interesting. Thanks for your response.
I am going to take in to Champion motors and have em work their magic - but there is also the possibility that the sending uint is pooched - i really hope not.

Thanks for the response.

pretty common for senders to die on older cars this E10 shit gas we have now just destroys them since they were not made to be resistant to crap fuel we have now.

Sometimes reversing the gauge output works but the best precise way of doing it is doing a fuel gauge segement swap on the OS.

jAMES@SHORTUNING:

Can you explain that a little further? I am interested in doing it the best way possible. Not sure what you mean by doing a fuel gauge segment swap.

Thanks!

The 98 fuel sending unit uses a different ohm output from the sender than the newer 99-up LS Fcar uses. We do not have the tables to physically adjust the sensor range so we have to rely on programming GM did for other vehicles.

The calibrations on these platforms are separated into segements. Engine, Transmission, Diagnostics, System, Fuel etc are some of the different segements in a calibration. So finding a tune file that uses the correct ohm output but uses the same operating system is what must be done to properly setup the fuel gauge in a 98 car using the new PCM. The 2002 Chevy Express Van still used the older style sending unit like the 98. So the popular swap is to move the fuel segement from a 12212156 2002 Express Van file over to a 2002 12212156 Fbody. Once the fuel segement is done you arent out of the woodwork just yet, you must calibrate the fuel tank size, gauge output and volume vs sender reading. So it is a bit involved but luckily most tuners have figured this out and can save you time by writing the right file to your PCM for you.

*** edited for mis-information

Thats incredibly helpful. Thanks so much.

Hey you guys not wanting to highjack this thread but im going through the same bs.
 

I bought a 1998 roller off of here previous owner installed 01-02 style pcm and i did a 99+ style fuel tank assembly in it from the filter and plastic hoses to the fuel cap.
I spoke with my tuner and i understand the concept of needing some tweeking to callibrate the sensors and what not. I am using the stock 98 style fuel pump harness since the plug on my 99 was half burnt. So my tuner at frost tunning "great guys over there " i recommend them if you need a tune" advised me to either use a 99 style fuel pump harness or i need to look into reaaranging some wires on the 98 harness. So if anyone has a clue what wires to mess with please give me a shout out 3132658824 thank you guys

Wow 4 year bump! No hijacking here.

:)

I've purchased a 98 harness ECM and I am reverting back.
Just waiting for some responses in my new thread.

Cheers. Best of luck.

If you get it working - do a write up.

Gas Gage 98 camaro need help
 

Rough translation- "Has anybody bypassed the PCM for the fuel gauge in a '98 Camaro?"

I have a 98 Camaro no pcm ls1 stand alone fuel injection system and my fuel Gage won't work