Hooking up 97 fuel gauge to 12200411 PCM

[CBenZ71]

Just gonna leave this here in case anyone else wants to do this, or ends up with a 98+ Vortec swap on an earlier truck.

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Those sender values will get you into the right ballpark, but I will be the first to admit they're not perfect, and I haven't really bothered trying to get them perfect.... Your gauge will show empty when you have about 4-5 gallons left, but from full to half-tank, isn't too far off.

On the other hand, I spent several hours getting the gauge output PWM table right, so that one SHOULD be just about perfect.

Okay, I took the truck to the tuner and we copied this exactly and fuel gauge went to Empty when we had a full tank... any guesses as to why this would happen? Thanks for all your info and work.

 

[AK49BWL]

Uh oh... I had a suspicion the sending units might have different resistance values on the 98+ due to the changes to the fuel pump unit for those years, and the fact that the PCM reads it... Guess this confirms it. And unfortunately, without a data logger capable of reading the fuel tank level sensor voltage, I'm not going to be much help in getting the table corrected. My table is for the old senders that usually go straight to the gauge.

 

[Supercharged111]

I put a Denali cluster in my 97 dually with old style fuel system, updated my tank capacity to 34 gallons, and it works fine.

 

[L31MaxExpress]

I put a Denali cluster in my 97 dually with old style fuel system, updated my tank capacity to 34 gallons, and it works fine.

96-02 Express used the same fuel pump assembly from a 4.3 to an 8.1.

 

[AK49BWL]

That's not a GMT400.

 

[L31MaxExpress]

That's not a GMT400.

GMT400 based....Point is the sending unit ohms did not change atleast on the newer stuff that was PCM linked.. 98+ truck is the same as a 96-02 Express. I have updated several 98+ trucks to the 0411 and have not had to change the scaling yet other than scale the fuel tank capacity appropriately and the fuel gauge worked properly. My 99 Tahoe is very accurate using the 8.1 van based tables.

My coworker put an 06 5.3 into his 99 K1500. When he wired the truck we simply hooked the sending unit to the gauge cluster input and bypassed the 06 PCM since it lacked the correct output to work the gauge.

 

[AK49BWL]

Welp, if that's the case, then I'm not sure what's up with the setup not working on @CBenZ71's truck...

 

[LovesDunes]

Just gonna leave this here in case anyone else wants to do this, or ends up with a 98+ Vortec swap on an earlier truck.

You must be registered for see images attach

Those sender values will get you into the right ballpark, but I will be the first to admit they're not perfect, and I haven't really bothered trying to get them perfect.... Your gauge will show empty when you have about 4-5 gallons left, but from full to half-tank, isn't too far off.

On the other hand, I spent several hours getting the gauge output PWM table right, so that one SHOULD be just about perfect.

Hi. I recently finished the LS swap on our 97 Tahoe. Runs awesome, but the gas gauge reads way beyond full.

I swapped the 97 in-tank fuel pump / sending unit out for a 99 unit because I needed Fuel Tank Pressure Sensor. I am pretty sure the Ohms on the newer sending unit is different than the 97.

Do you think the HP Tuners program will help get the gauge working correctly, or will I need to address the Ohms thing first?

 

[AK49BWL]

The ohms are indeed different on the 98+ sender, because on those trucks, the gauge WAS actually controlled by the PCM as opposed to running directly to the sender. The new senders run from 40-250 ohms, whereas the 88-97 were 0-90. You'll need to adjust the "Fuel Primary Volume vs Level" table to match that change, which you can do with HPT - as for the values.....lol I couldn't say, I'm still running a 0-90.


You might be able to get the correct values from a 98-00 GMT400 tune from the tune repo, but I'm not sure if that table could be modified on those years.

 

[LovesDunes]

The ohms are indeed different on the 98+ sender, because on those trucks, the gauge WAS actually controlled by the PCM as opposed to running directly to the sender. The new senders run from 40-250 ohms, whereas the 88-97 were 0-90. You'll need to adjust the "Fuel Primary Volume vs Level" table to match that change, which you can do with HPT - as for the values.....lol I couldn't say, I'm still running a 0-90.


You might be able to get the correct values from a 98-00 GMT400 tune from the tune repo, but I'm not sure if that table could be modified on those years.

Thanks for the reply. I'm glad you are up so late there in Texas. I am hoping to meet up tomorrow with the guy that disabled the VATS for me. I need his to disable the Fuel Compensator stuff too. I'll see if he has ever dealt with the fuel level stuff before. I'll let you know if we were able to figure anything out.