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Oil Pressure Sender Ground

RVbySDI

RVbySDI

Well Known Member
I have been troubleshooting Instrument configurations for a while now. I do believe with the help of Sandy and Carlos at GRT I think I have found most all of my gremlins. However, I am still dealing with one last (at least I hope it is the last one) item.

It looks like I have not properly grounded my Oil Pressure sender unit. The sender unit is mounted on the firewall on the manifold supplied in the Van's firewall forward kit. This manifold is also housing the fuel pressure sender unit. My question is: How are you guys grounding this sender unit? Where/how on the unit are you grounding and where is the ground wire running to (engine, firewall, or somewhere else) in order to provide adequate ground? Any pics would be appreciated.
 
I just clamped a fast-on tab under the hose clamp that mounts the oil pressure sending unit. My Fuel pressure sending unit had it's own tab. I grounded each individually back to my common ground terminal block on the FWF side, but you could get away with one ground wire for both if you wanted to...

Sorry, on the way to OSH. no photos...:eek:
 
I've struggled with this too on both the fuel pressure and oil pressure senders. I suggested to GRT at Sun N Fun that they switch to the VDO sensors that have the ground post.

On my senders I soldered a wire onto the housing which helped the oil pressure one but did not fix the fuel pressure sender. My fuel pressure reads high. I just remounted it in a Van's manifold thinking that would take care of the issue, but it didn't. I'm not sure what to do.
 
Thanks Terry and Bubblehead for the information. It seems in the world of RV's, this issue should already have hundreds of resolutions and the manufacturer(s) of these units should provide for a simple way to ground their unit if it requires it to be grounded. So, I guess I have to just EXPERIMENT with a solution to ground this oil pressure sender unit.
 
The sender is designed to ground through its threaded case connection. Works fine if you connect it to the engine with a steel braid-sheathed fluid line. However, don't put any anodized aluminum fluid fittings in the ground path, and clean off any coating on the threads of steel fittings before assembly.
 
DanH said:
The sender is designed to ground through its threaded case connection. Works fine if you connect it to the engine with a steel braid-sheathed fluid line. However, don't put any anodized aluminum fluid fittings in the ground path, and clean off any coating on the threads of steel fittings before assembly.
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Interesting Dan. I have the VA-102 Stainless Steel sleeved hose from Vans installed that is running from the manifold to the engine. I did use aluminum AN fittings on the manifold and steel fittings on the engine. I also have some coating material on the pipe threads on the engine side. So I suppose this coating could be stopping the ground?
 
RVbySDI said:
Interesting Dan. I have the VA-102 Stainless Steel sleeved hose from Vans installed that is running from the manifold to the engine. I did use aluminum AN fittings on the manifold...
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Try replacing the aluminum fittings with steel or brass. The anodized surface finish is an electrical insulator.
 
Measure the resistance between the engine ground and the transducer case. If it is less than 0.5 ohms then this is not your problem.

I have an error with the oil pressure on my EIS4000 - it turns out the EIS was incorrectly configured for the HPS01 (VDO 360004) sender. I am using another oil pressure gauge until I get a chance to remove and return the EIS to GRT for rectification.

Wire a 100ohm resistor in place of the transducer, if you see about 25psi* on the EIS then it is misconfigured.

My HPS01 has about 70psi when its resistance is 103ohms.

Doug Gray
RV-6 VH-UDG flying! Currently 1hr on the clock.
 
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DanH said:
Try replacing the aluminum fittings with steel or brass. The anodized surface finish is an electrical insulator.
Click to expand...

At one time Van's was sending out their manifolds anodized blue....... :eek:
I see they changed that in a hurry.
 
RVbySDI said:
Thanks Terry and Bubblehead for the information. It seems in the world of RV's, this issue should already have hundreds of resolutions and the manufacturer(s) of these units should provide for a simple way to ground their unit if it requires it to be grounded. So, I guess I have to just EXPERIMENT with a solution to ground this oil pressure sender unit.
Click to expand...

Steve, I mounted my senders with adel clamps on the motor mount close to the firewall. What I did to ground them was to purchase two brass 1/8' couplers. I soldered push on tabs to the side of the couplers and screwed them to the senders. On the other end, I screwed in the 1/8" pipe to flair fitting to connect the pressure supply line to. The ground wire goes all the way back to the "field of grounds". YOU NEED A GOOD GROUND if you want your gauges to work properly.
 
Doug said:
Measure the resistance between the engine ground and the transducer case. If it is less than 0.5 ohms then this is not your problem.

I have an error with the oil pressure on my EIS4000 - it turns out the EIS was incorrectly configured for the HPS01 (VDO 360004) sender. I am using another oil pressure gauge until I get a chance to remove and return the EIS to GRT for rectification.

Wire a 100ohm resistor in place of the transducer, if you see about 25psi* on the EIS then it is misconfigured.

My HPS01 has about 70psi when its resistance is 103ohms.

Doug Gray
RV-6 VH-UDG flying! Currently 1hr on the clock.
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Doug, I am starting to believe this is my issue also. Last night I installed a metal hose clamp around the housing and ran a ground wire to my ground terminal (that is very well grounded). This did not make any difference on the oil pressure readout. The readout was continually showing 84-85 psi at 2300 RPM, 27 MP. I just refuse to believe this was a true reading of my oil pressure on an IO-340 engine that was otherwise running normally.
 
Oil & fuel pressure sender grounding

I am working with the placement of the oil and fuel VDO pressure senders. I intended to mount them with adel clamps on the engine block and use 1/8" copper tubing for pressure lines. I thought I could use the pressure lines as ground for the senders but reading posts on the forum I no longer so sure. Is it possible? The fuel pressure has two push-on tabs. Which one is for ground and which one goes to the Dynon EFIS?
 
RVbySDI said:
Doug, I am starting to believe this is my issue also. Last night I installed a metal hose clamp around the housing and ran a ground wire to my ground terminal (that is very well grounded). This did not make any difference on the oil pressure readout. The readout was continually showing 84-85 psi at 2300 RPM, 27 MP. I just refuse to believe this was a true reading of my oil pressure on an IO-340 engine that was otherwise running normally.
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Why not just go purchase a 150 psi gauge at auto parts for about $10 and connect it to your line and get a true reading?
 
hcccs said:
I am working with the placement of the oil and fuel VDO pressure senders. I intended to mount them with adel clamps on the engine block and use 1/8" copper tubing for pressure lines. I thought I could use the pressure lines as ground for the senders but reading posts on the forum I no longer so sure. Is it possible? The fuel pressure has two push-on tabs. Which one is for ground and which one goes to the Dynon EFIS?
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Mounted to the block is a bad idea. Too much vibration.......

Don't use a copper line for your oil pressure. Too much vibration.......

You can check with an ohm meter. Touch the case and each tab. When the needle jumps, that is your ground.

Why don't you use two adel clamps and mount it to the top motor mount near the firewall? You can then run the wires right there through the firewall.

Go to a local speed shop and purchase a stock braided fuel/oil line, the smallest that they have for your line from the restricter in the motor to the sender.
 
hcccs said:
I am working with the placement of the oil and fuel VDO pressure senders. I intended to mount them with adel clamps on the engine block and use 1/8" copper tubing for pressure lines. I thought I could use the pressure lines as ground for the senders but reading posts on the forum I no longer so sure. Is it possible? The fuel pressure has two push-on tabs. Which one is for ground and which one goes to the Dynon EFIS?
Click to expand...

Do not mount the senders on the engine block. Do not connect them to the engine with copper tubing.

Senders may be mounted in a manifold block on the firewall, in a location which allows bolting the block through a firewall support angle. The alternate mounting is a padded -8 adel clamp on a motor mount tube attached to a padded adel of the appropriate size for the sender diameter.

Either way, plumb to the engine with a high quality flexible hose, with firesleeve.
 
One more data point...

I had a high fuel pressure reading with the standard senders from GRT. I measured the ground path resistance and it measured as a dead short (correct) on all three senders, tried three different senders, tried different grounding schemes and finally bought the more expensive 3 wire sender from GRT. Problem now gone with the higher quality sender, but only after a lot of time and a bit of expense.

Jeremy Constant
 
I've had the same problem. Do you have the item# for the 3-wire sender?

With 3 wires one is ground, one is signal, and what is the other one?

I've looked at catalogs full of senders and it seems that lots of them are available with ground wires. I wish GRT and others would just supply one with the ground wire connection and then we could use it or not as we see fit.
 
On Grand Rapids' site it is listed as:

HPS-SS-01

and they now say "recommended for fuel injected engines".

It is 0-100 psi


Jeremy Constant
 
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