2nd Gen Non-Engine/Transmission Fuel Sender, Capacitance Type Install Notes

[BarryG]

Nutter

Yes it is still working fine and hopefully it will last for the life of the truck. Time will tell on that.



Bob

I need to hook up with you. Will give you a call in a day or two.

 

[Pliska]

We are now working on adding a standard unit for this. Does anyone know if the tank is the same on a 1997 QC LB? I want to use my dad's truck (already on its 3rd stock fuel level sensor) as a test subject.



Thanks,

Michael Pliska

 

[BarryG]

Michael:

When I was researching this originally (I didnt want to have to drop the tank to measure) I found that there were a couple of tank variations. I was only concerned with one area which is the area I used to drill out. Not all of the tanks have that stepped up area. I cannot remember or not sure I ever even knew what years were different. If it would be going in the stock cannister location I think those are all the same.

 

[Pliska]

Barry,

Thanks! I'm just trying to "pre-engineer" things a little bit so my dad's truck is off line as little as possible. I may try to buy a junkyard tank for this project.



Does the fuel level go all the way to the top of the new sender on your truck? I am wondering if that extra "hump" places the sender above the normal max fuel level. We need to know where to place full and empty along the length of the sender.



Thanks,

Michael Pliska

 

[BarryG]

Michael:

I go less than 50 miles before the needle is below the full mark. It starts out approx 1/16-1/8 inch above full ( iirc I think the stock sender I could go 100 miles before it moved below full). So the fuel must be above the high mark on my sender. My sender does have an adjustment for both full and empty but I honestly havent played with it because the way it works seems pretty good to me. I do think that the fuel does go up in that humped area, at least when you fill it up good. When setting the empty level make sure and give yourself some cushion. Dodge sure felt it needed it. They left at least a couple inches of fuel below the empty mark of the gauge. I know when my low fuel light came on with the stock gauge I could put in approx 24 gallons which meant there was a solid 10-11 gallons + left at the point it was supposed to be 1/8th tank. Now when my low fuel light comes on I can put in 29-30 gallons. When my guage reads zero I know I have approx 1 inch of fuel remaining in the tank as I have about an inch from the bottom of the sender to the tank.

 

[nutter3]

I just installed this gauge about a month ago. I mounted it in the hump area.

I had to calibrate the gauge, and I did it in a 5 gallon bucket as i did not want to have to fill the tank with it on the ground and then empty it to reinstall the tank. But now, with the tank completely full, the gauge only reads 5/8. (I dont think the fuel is going up into the hump)

I would suggest lifting the bed off and installing the gauge and calibrating it with the tank installed and as full as you normally fill it.

 

[DShore]

I installed a Centroid fuel sender about 6 months ago and was told that I could recalibrate the full mark on this sender. After many emails with different methods used to accomplish this, I finally convinced them that this was not going to happen. I shipped this sender back for a replacement. Evidently Centroid thinks all tanks are flat on top. My tank looks just like Barry's picture with the sender mounted in the same area. These senders are calibrated at the factory with full @ 1-1/2" down from the mounting flange, or so I was told. In order to to recalibrate these senders, the liquid level must be higher than this preset point in order to be reset; in other words, the full level can only be reset up from this point.



If the liquid level does not reach this preset point, the level will NOT reset. Why they do not tell the customer this before the order is placed escapes me. The replacement sender they shipped me was calibrated lower; after filling the tank, the full mark is now just touching the full mark. I can live with that, but the stock gauge is very slow to react, it takes 20 minutes of driving to stabilize. The first miles are on very rough desert roads before getting to I-40. In my case, the jury is still out on this installation.

 

[BarryG]

Guess I was lucky as I didnt have to recalibrate the sensor and I honestly dont think I could get it any closer for me than how it already is.



I also notice the delay as I mentioned in a previous post but for me it seems to take just a few minutes. I also attributed it to the fact that my driveway is very steep where I park and the sensor is in the forward portion of the tank(it reads about 1/8 tank low when I first start it up in the morning until it stabilizes). However after that it seems to react fine.

I did read in the service manual that there is a delay built in to the stock gauge and I also read that there is a delay/damping in the centroid sender (both of the delays are for the same reason to avoid the gauge from swinging) however if both are damped then the reading is being damped by double the time it ordinarily would be with the just the stock or just the centroid sender.



I hope it works out for you as mine is still working good and I have no real compaints about it.

 

[kscheffler]

Has anyone tried the 15 inch sensor in a 2001 truck? Do I understand this full recalibration correctly? So if I take a new sensor and place it in a bucket of fuel and place the fuel level on the sensor at the predicted elevation I can calibrate the guage to read correctly?

 

[BarryG]

Kscheffler:

I have not recalibrated mine as it didnt seem to need it or at least I am happy with the way it is working. I can go less than 50 miles before it reads below full with a very good fill up(previosuly with a good fill it would go 90-100 miles). So that must mean there is approx 2-2. 5 gallons or so above the full level mark on my sensor. Which would mean if I were to recalibrate it I would need to raise the full mark on the sensor which should not be a problem if I understood DShore (poster a couple back) correctly and that seems to be confirmed by what nutter did as well. Seems like you can raise the full level from where it is but not lower it.



Do be careful about letting the empty level be too low. As I mentioned dodge felt they needed quite a reserve. Now with mine when it says empty I have approx 1inch of fuel left in the tank compared to the stock level of 2+ inches left at empty. Should be fine just need to realize when it says empty it means it unlike the stock setup. Obviously it is not quite empty with 1 inch of fuel remaining but hills etc could make it starve for fuel much below that as the tank is very long and at least mine had no baffles at all hence the design of the cannister and the return fuel going into it.

 

[DShore]

My Centroid sender is 14” long. The fuel pickup on my system has been extensively modified. Draw straw was added, OEM fuel canister and all attachments were discarded. The canister was replaced with a stainless steel flour/sugar canister from Wal-Mart 5” diameter and just a shade under 7” tall. I drilled 5/16” hole in the center of the bottom and 8 evenly spaced holes, also 5/16” dia on 1. 69” dia. circle from the center. I cut a 2. 375” dia gasket from 1/32” Viton sheet stock with ¼” hole in the center, with 1” washer and ¼” bolt ¾” long with lock nut fastening it to the canister. All fasteners are Stainless Steel. . This assembly was bolted to the metal slides used to attach the OEM canister. This setup is 13 ½ “ overall length. The bottom of my tank is 15” from the mounting flange. The bottom of the canister is 1 ½” off the bottom of the tank. The draw straw pickup tube is 1/8” off the bottom of the canister, so my fuel pickup is 1-5/8” off the tank bottom.



This setup acts as a reservoir holding just under ½ gal. of fuel, and keeps the fuel from running away from the pickup on uneven ground & sloshing around. I have run this setup down to almost 1/8 tank and the low level light on and not run out of fuel. I like to run it down no lower than ¼ tank range. My return line from the injectors now goes through 3/8” line to a “T” in the fuel filler vent line to keep hot fuel away from the draw straw pickup.



Now about adjusting the Centroid sender. The set points on these senders can be adjusted up or down by using the small screws marked “F” and “E” on top of the sender , with clockwise turns on both screws are toward full mark, counterclockwise moves setting toward “E”. These adjustments are very touchy and must be moved in small increments. This is what I understand from the last info I received from Centroid. Hope this info is helpful.

 

[BarryG]

DShore:

Sounds like quite the setup. Would you by chance have any pictures of that. I have been contemplating redoing my cannister setup somehow and maybe trying to move my sender back towards the center of the tank. I guess I shouldnt worry about moving it since it is set already. I should have done it all at once like it sounds like you did but after 125k of no fuel gauge I just got tired of it and just did it the relatively simple way and decided to save the cannister stuff for another day. I think I can picture your setup in my head but if you had a pic that would be great.

 

[DShore]

This drawing is revised from one I found on an old TDR thread. It fits my application and seems to work for me. I have a large folder in my file cabinet that is used to store the info that I garner from TDR. It is like a gold mine when I start a project.



Long live TDR. Merry Christmas to TDR and all its contributors.

 

[Chief USA]

What is the current cost of the Centroid fuel sender sytem? I guess a better question would be how much do you have into this system and making it work? Thanks.

 

[DShore]

The cost of my entire tank conversion is approximately $100 including the Centroid Fuel Sender. Making the Centroid system work is a whole different story. I am on my 2nd Centroid sender in 6 months and have decided to go another route.



In my case, when I operate my truck on fairly level ground, it seems to operate fairly well until it is shut off and restarted, then it goes to the full mark and stays there for at least 45 minutes. Let it set 24 hrs, on start-up it reads about right, then drive it on steep grades (20% to 30%) the reading switches from “E” to “F” randomly. At this time, I am not a happy camper and am going to call ISSPRO and check on their unit. I have another truck with an aftermarket sender with a small hollow plastic float that works very well. Will post again when I find a sender that works reliably.

 

[kscheffler]

Dshore let us know what you find out. I was about to dive into this project and does not sound good for the centroid unit. Thanks for the update. . kts

 

[Chief USA]

Me too! Thanks for the heads up!

 

[BarryG]

WOW Dshore that sucks.

Mine is still working fine no problems at all. As far as cost goes for the poster who asked when I bought mine the sender was 50ish, misc electrical parts <15. 00, gasket sealer 6. 00. I think that is all I have into mine.

 

[nutter3]

DShore,



I have some of the same problems you're having-- Besides my calibration being slightly off. So with a full tank, when it is reading "correct" it reads 5/8 tank. (I calibrated it in a bucket instead of the tank#@$%!, not thinking about the air gap in the tank hump)

But mine can change from 5/8 to either E or F on startup. Then you can shut off the truck and restart it and it will read "correct". Sometimes it will read either F or E and after driving it a while it will start to read correct. I'm not quite sure if it is a grounding problem or what it could be.

DShore if you ever figure out what causes this please let me know. Once it's warmer out I'm going to drop my tank again and check everything over.



Andre

 

[DShore]

I believe a lot of the problems with this system have to do with the third wire (hot wire), current flow and direction of flow, etc. I get a different reading when ignition is turned on and when the engine is running. I called ISSPRO and they indicated they make a float type sender with the proper OHM requirements that has a metal float. Will check online for a vendor and see what is offered.