Have 1999 4dr LS with the fuel pump going out but guage sender works
Have a 2000 2dr LS ZR2 with good fuel pump but bad guage sender...
I want to buy a new unit for the ZR2 and then remove pump from the old unit and install in the 4dr LS with the good sender...
I'm noticing on the parts store app that there are specific pumps for each truck 2dr vs. 4dr
Anyone have any good input?

 

I cannot help you on the surgery question but keep in mind that this can be a bitch of a job, especially with fuel in the tank and no lift so evaluate if you care about possibly having to do this job twice. I did mine 100,000 miles ago and tomorrow would still be too soon to do it again and I like working on vehicles with a garage full of tools. If you like tinkering and have the time that’s different. Oh and AC Delco or Delphi pumps only.


George

 

Thanks George but has partially worked itself out as I sold the 99... My keeper, the 2000 ZR2 actually has a 3" body lift... But you are right in that I'm not real excited about dropping that tank to replace the unit just for a chance my fuel gauge will again work...
Which brings me to a question..
On a Ford ranger you can jump a wire as a test to see if the fuel gauge actually works and the sender is bad... Do these blazers work like that too?

 

There is no special purpose test point but you can create such a test by disconnecting the sender wire and putting a variable resistor in the senders place and see if you can get full range fuel gauge behavior.

George

 

Could I run a jumper from battery to that same plug and bypass the sender to see if I read full on the Guage?

 

No, you need to substitute the variable resistor of the sender with some resistors from the harness connector (purple) to ground. Most GM vehicles from '98 on have sender values of 40 ohms (40R) full and 250 ohms (250R) empty. A resistor kit like this can get you there:


George

 

So I build a resistor setup over 40ohms and put it between ground and the purple in the tank harness and I should get movement on the Guage... Varying the ohms from 40 being full, 105 being half, and 250 being empty???
Is that correct?

 

And if I put the purple briefly straight to ground with no reststor... Will it jump to full or will it booger something up?
If not mistaking that is how I checked the sender on my ranger... Jumped the sender wire straight to ground showing that everything worked after the sender... Bad sender...but can't remember for sure now if it was to ground or to batt(+)... Same basic concept...

 

Yes.

George

 

This will probably work but I dont know what the drive circuit is in the PCM so I dont know if it cares about being shorted to ground.

George