John Strenk?!?! Need you on this one (fuel gauge problems)
I have searched and searched the forum and am at a loss. Replaced the fuel sending unit with a stuart warner 20gal sending unit. Tried original CJ fuel gauge and temp gauge. Temp gauge would peg after some time (10mins of running). Fuel gauge would read only 1/2 when full. Replaced fuel and temp gauges with OMIX (suppose to be re-done to really be more better quality ). After replacing fuel and temp gauge my fuel gauge only moves a tad bit off E. I have checked OHMs for all post and they all appear to be in spec except the ground from A post. Ground from A post is only giving me ~25 OHMs. Don't know if this is a problem or not. I got the stuart warner fuel sending unit as I wanted to go with a quality sending unit. Any thoughts on why it only moves a tad bit of E? Hooked op the original gauge and it read accurately now (Dang don't wanna pull the gauge cluster apart once again).. Could something be grounding out in the gauge cluster housing?? Should I drop the tank once again and check the sendind unit, once again?? oh btw, I did check the gauge by momentarily grounding the S term and it will go to full. Thanks for any input any of you can provide.
Last edited by donjon677; 01-03-2012 at 12:17 AM..
Thanks for the input guys but I have not given up yet... Anyone else have some ideas? Ther is what looks like an adjuster screw on the fuel gauge is it possible that this just needs to be adjusted since my old fuel gauge is kinda accurate?
The adjustment I think you are talking about the side adjustment that will control the dwell time. Say it bumps it's way up to the right position. Adjusting it will smooth out the bumps. That does not sound like your problem.
There are other adjustments for Zero and full scale but I would use a couple of resistors to make those adjustments.
Let see if this works.
A repost of an old posting.
Need two Resistors one around 73 Ohms and one around 10 Ohms
For those who need to have everything perfect. One final adjustment....
First lets have a look at the back of a typical OEM style Fuel gauge.
You probably never noticed the extra slots in the back but those are used for doing a calibration. They are actually quite clever in coming up with such a simple adjustment.
If you look inside an OEM gauge you will see two windings around two swperate bi-metalic strips. One is the often miss-labeled "Voltage Regulator" side and the other is for the needle or indicator movement.
As the windings heat up around the bi-metalis strip, one end of the strip will move. This free end is attached to the needle. The way the calibration works is there is a slot in the end of the needle were the pin on the end of the bi-metalicstrip fits. Depending upon the position of this pin in the slot determines how much the needle moves in relationship to the movement of BM strip. The closer the pin is to the pivot of the needle the greater the travel of the needle. THis is the Full Scale Adjustment. So if your gauge is not reading "Full" when the resitance is 10 ohms then you need to adjust the position of the pin.
THe other adjustment just sets the starting position of the needle or "Zero Adjustment" So if your gauge isn't reading empty when it's at 78 Ohms then you need to change this adjustment.
Note these adjustment are interrelated meaning that if you adjust the "Zero Point", then the needle might not reach "Full" so you will have to go back and re-adjust the "Full Scale" adjustment.
Start with the Zero Point first.
I attached the proper resistance (73 ohms) to the "S" terminal and ground and attached the power and ground leads.
I used 10-32 nuts and wire lugs to make the connection easier.
THen I adjusted the Zero point to read "E" as best I could using a flat bladed screwdriver. Then you replace the 73 ohm resistor with a 10 ohm resistor and adjust the FUll Scale adjustment. Note it might take a minuet for the needle to Stop moving so you might want to read a chapeter in your FSM while your waiting. . It also makes several jumps when going to "F". THis is normal.
Now the replacement gauges I have work a bit differently. Mine was quite bent inside and needed an adjustment. Maybe yours was knocked out of cal also.
The Zero and Full Scale adjustment are in one place. Put the screw driver in one slot and you can adjust the Zero Position. Turn the screw driver 90* and you can adjust the full scale movement. The pin and meedle mechanism is the same as the OEM guages. THe screw on the side is for adjusting the regulator. It has a funky screw so you don't accidentally mess up this adjustment.
Irregardless of how the adjustments work internally, the procedure is still the same as above. If you can't get the gauge to work properly after all this then I would recomend you send them back and get another set. THere have been some "Quality issues" with the vendor.
For more information on Gauges and stuff, See my sig
The regulator adjustment will help you match a new Gauge with on old one. I normally never have to adjust this unless the movement is slow or bumpy.
Done deal! Sorry I couldn't afford the lifetime supporter but got you a premium membership for a year. Again I can't thank you enough for the help you provide to the jeep community, PRICELESS.
This is great to see!
They Cant Stop Me, Even If They Stopped Me.
Car History from 1st to Present:
-1997 Mustang V6 (Sold); -1999 Chevrolet Blazer (Sold); -2001 Chevrolet Silverado Z71 (Sold); -1999 Chevrolet Z28 Camaro; 1982 Jeep CJ-7