Have any of you tried one of the reproduction sending units. I got one in today and it is wired like the later models. I checked it out and it didnt work with just the wires hooked up. When I grounded the unit to the tank it lit up like a Roman candle. Has any one got one to work? If not watch out it could be a bomb.
-
-
How to bench test sending unit?
How would I go about bench testing the unit? I hope that's not why they're half the price. I've been giving a lot of people the info to order them.
Thanks, Brandon -
Re: How to bench test sending unit?
The 63-67 applies voltage to one end of the resistor and the sender reads the voltage drop throughout the range of that resistor. Voltage is also applied to the guage. It needs both voltages. That is why many of them get stuck either in the top half or the bottom half of the range. The newer style uses only two wires one being the ground. On that style voltage is applied to the guage only and it passes through and to the sender which varies the resistence to ground. The new guage had the two terminals and the ground lug but one wire was soldered to ground which makes no sence to me.Comment
-
Re: New Mid Year Repro. Fuel Sending Unit
Several months ago we ordered two senders from a reputable catalog house based on cost being so much lower than Chevy list. Mechanic installed one in customer's car only to find it didn't work. Brought to me and we talked about how he did this/that during install. Sounded 'right' but there were a few stumbles/hesitations here/there, so I sent him back to the shop with the second unit after counsel....
Within the hour he returned reporting that unit too failed to work. I smelled 'Denmark'. Took the first unit and opened it on my bench and found the wire wound potentiometer open circuited. Looked at the second one too -- same. Pulled the wiring diagram (poor excuse for schematic Mr. Goodwrench!) and with the help of '66 and later Chassis Service Manuals providing thumbnail sketch of theory of operation induced this is a Whetstone Bridge circuit topology to eliminate effects of supply voltage variation on tank/gauge readings.
Then, ohming out the sender unit I discover horror of horrors it's wired improperly from the factory source!!!! Anytime this sender is installed in a real McCoy mid-year fuel tank it's GOT to see current overload and do a melt down. This is a THREAT TO LIFE LIMB AND PROPERTY!!!!
As a degreed electrical engineer, I run to the phone, contact the catalog house, force my way to management authority and report. We almost blew the shop up, you've got to STOP shipping these units and do an immediate recall. A few hours tick by, I get a cognizant return call of thanks and am told shipment has ceased and an active recall is in progress. Plus, we'll be spotted real McCoy GM replacements at catalog house's expense. All was done as advertized.
To hear months later some of these foreign sourced DEFECTIVELY designed, manufactured and tested senders are still out there MAKES MY BLOOD BOIL!!! Somewhere, sometime there's gonna be a KABOOM and all those in the manufacturing and distribution channel involved should do jail time for their negligence.
That's one level of joke about the GM Licensed Program -- there's no police work (apparently) with things at arm's length over drawing transfer. I don't know if this product was made under the Program or not. I don't know who the source manufacturer is. I don't what steps my reputable catalog supply house took to escalate the information they had two months back. I can say, sparks and gasoline DON'T MIX and some responsible parties should be taken behind the woodshed and horse whipped for this SNAFU!!!
As far as building a bench tester, that's the first thing I did that afternoon two months ago! Want to bring your car or sender to the shop, I'll be happy to help. Want to do it yourself -- crack a book and dig up some wiring like I did.Comment
-
Re: How to bench test sending unit?
Sorry I didnt answer the original question of how to bench test the unit. On 63-67 there are two things that have to be checked. The resistor should be 90 ohms from the terminal marked I to ground, and the value from the S terminal to I should vary with the movement of the float from 0 to 90 through the range with no erattic spots. On 68 up there is only one terminal other than the ground and the value should vary from 0 to 90 ohms to ground.Comment
-
Re: New Mid Year Repro. Fuel Sending Unit
I have done a bunch of these things. I can even make a late one work in the Mid-years but I took one look at this thing and said WOAH this aint gonna work.Comment
-
Re: New Mid Year Repro. Fuel Sending Unit
Dear Wayne,
I bought a repro unit from Ecklers, it was backordered for some time and I finally recived one...is this the part you are talking about?Dino LannoComment
-
Re: New Mid Year Repro. Fuel Sending Unit
Thanks for your enlightenment Jack. Kabooom license plates are presently in the design stages here on the mountain. The first legitimate KABOOM gets a free plate! Keep me posted.
Varooom!Comment
-
Re: New Mid Year Repro. Fuel Sending Unit
If it didn't come in a GM/Chevy box, you're blind as to source/quality without testing looking before you install. If you look REAL CLOSELY at the defective design unit from the far east next to the original you remove, you'll see wires going in/out of the pick-up tube pot are routed differently. The original has only one ground point to the pick-up tube shaft(means two wires at the pot go to the sender's in/out terminals and are fully insulated) while the defective foreign made 'bargain' unit has one of the two leads from the pot soldered to the pick-up tube. This adds the KABOOM 'feature' to the assy....
So long as sender's pot is fully submerged in gas (no air pocket for combustion around wire-windings inside pot that will melt/open-circuit), you'll escape the Big Bang. However, if tank is VERY low and pot is exposed to air, there's a clear and present danger these defective senders will ignite residual gas vapors in the tank....
Point is clear. Chevy list on these senders (still available from the General) runs in the $225 range. The far east defective senders appear to be catalog bargains, running half price or less. While there's nothing wrong with saving money, you sometimes ask what you get for what you pay. In this case, if there is a KABOOM out there, I've put in public domain the responsibility chain is clear and has been known since Feb of 2000!!!! Make the 'dudes' pay for their gross negligence, I say.Comment
Comment