Fuel Sending Unit question!
02-28-2019, 05:50 PM
#21
Instructor
My tale of woe...
Fuel gauge was wonky last summer, not picking up a signal until I had burned off 15 or 20 miles on a fillup; then it would read normally all the way down. Techroned the heck out of it and it straightened out for a while but got sillier over time. Eventually (November) it gave up the ghost. Obviously the sender.
So I read all the threads on replacing the sending unit. Looks like about a 50% failure rate on home-done, amateur repairs, with most of the problems arising from shortcuts in dropping the tanks or tryng to avoid doing so... No fingerpointing there; I've done shortcuts myself over the years. Sometimes they work and sometimes they don't, but in this particular repair you DO NOT want to have to go back and do it again when something doesn't work because you misconnected something you couldn't see and could barely get fingers on. Lotsa places to go wrong.
Anyway, I'd been figuring on getting the senders and fuel pumps replaced once the constant Chk Eng light and DIC notice got too annoying. But then, one evening a month or so ago I got back from a run with the bride in the cool Arizona winter air and when I got out of the car the fan was running. I got back in an found that the coolant temp was 220F, not the usual 180F. I test drove it in the morning and it stabilized at 220 under steady-state driving but fluctuated with load - classic lazy thermostat. Got home and discovered low coolant. Cutting to the chase, I took it to a shop (see next para) and they diagnosed not just a thermostat but also a cracked plastic coolant junction fitting and a radiator ready for replacement at 93,000 miles. And as long as that's going on, do the water pump, too.
I'm fortunate in that there's a shop down the street here and the owner and friend drives a Callaway Z06 in the Nevada Silver State Classic and occasional other speed events. You might say he's a Vette guy and he's always got a couple guys on staff who know Vettes. And he favors law enforcement with a discount, for which I qualify.
My own guesstimate is easily in the multi-thousands for all the work; $5K is my hoped-for guess; labor will be a big issue. It could run more depending on what else they might find. I'll wait until it's done and post a number here if anyone is interested.
Here's what gonna be done:
New radiator (OEM; I'll be dead before I use another one up.)
Water pump
Thermostat
All under-hood hoses, etc.
All fluids, front and rear
Drop both tanks, which requires dropping the torque tube which requires many other things (labor)
New fuel pumps and sending units
New crossover tube and other hoses
New AT linkage cable from shift lever to tranny (look it up if you don't know it; known. failure item that disables shifting)
Check all bearing, shims, spacers (opportunity to find other problems; I hope not, esp. torque tube issues)
Reassemble in reverse order.
That I no longer have shop space to do this myself may be a blessing in disguise since if I still had space and tools I'd try it myself, thus putting to the test my motto that I never screwed up anything so bad I couldn't throw it away. In this case, any errors are on the guy doing the work and his boss.
Pilgrim
Fuel gauge was wonky last summer, not picking up a signal until I had burned off 15 or 20 miles on a fillup; then it would read normally all the way down. Techroned the heck out of it and it straightened out for a while but got sillier over time. Eventually (November) it gave up the ghost. Obviously the sender.
So I read all the threads on replacing the sending unit. Looks like about a 50% failure rate on home-done, amateur repairs, with most of the problems arising from shortcuts in dropping the tanks or tryng to avoid doing so... No fingerpointing there; I've done shortcuts myself over the years. Sometimes they work and sometimes they don't, but in this particular repair you DO NOT want to have to go back and do it again when something doesn't work because you misconnected something you couldn't see and could barely get fingers on. Lotsa places to go wrong.
Anyway, I'd been figuring on getting the senders and fuel pumps replaced once the constant Chk Eng light and DIC notice got too annoying. But then, one evening a month or so ago I got back from a run with the bride in the cool Arizona winter air and when I got out of the car the fan was running. I got back in an found that the coolant temp was 220F, not the usual 180F. I test drove it in the morning and it stabilized at 220 under steady-state driving but fluctuated with load - classic lazy thermostat. Got home and discovered low coolant. Cutting to the chase, I took it to a shop (see next para) and they diagnosed not just a thermostat but also a cracked plastic coolant junction fitting and a radiator ready for replacement at 93,000 miles. And as long as that's going on, do the water pump, too.
I'm fortunate in that there's a shop down the street here and the owner and friend drives a Callaway Z06 in the Nevada Silver State Classic and occasional other speed events. You might say he's a Vette guy and he's always got a couple guys on staff who know Vettes. And he favors law enforcement with a discount, for which I qualify.
My own guesstimate is easily in the multi-thousands for all the work; $5K is my hoped-for guess; labor will be a big issue. It could run more depending on what else they might find. I'll wait until it's done and post a number here if anyone is interested.
Here's what gonna be done:
New radiator (OEM; I'll be dead before I use another one up.)
Water pump
Thermostat
All under-hood hoses, etc.
All fluids, front and rear
Drop both tanks, which requires dropping the torque tube which requires many other things (labor)
New fuel pumps and sending units
New crossover tube and other hoses
New AT linkage cable from shift lever to tranny (look it up if you don't know it; known. failure item that disables shifting)
Check all bearing, shims, spacers (opportunity to find other problems; I hope not, esp. torque tube issues)
Reassemble in reverse order.
That I no longer have shop space to do this myself may be a blessing in disguise since if I still had space and tools I'd try it myself, thus putting to the test my motto that I never screwed up anything so bad I couldn't throw it away. In this case, any errors are on the guy doing the work and his boss.
Pilgrim
Last edited by Pilgrim86314; 02-28-2019 at 05:54 PM.
