I use a westech fuel pressure guage and wondering if anybody knows where I can get a replacement electric pressure sending unit--I think mine has gone bad.

stix

 

Speaking from experience the westech electronic fuel gauges are a P.O.S! I probably replaced 3 sending units in the 1yr I ran it I finally bought a Isspro mechanical with a straight fuel line going to my gauge, no isolator just a valve on the line so if I have a leak in the cab I can shut it off. So far it has worked like a charm.

 

I'll second the Isspro EV mechanical gauge! I wouldn't recommend running fuel into the gauge though. I'm pretty sure it's illegal in most states, not to mention a little dangerous.

I would give Eric at Vulcan Performance a call. Everything I have purchased from him has been top notch. He has a new isolator out that looks good and if history repeats itself, will work well and last.

NO FUEL IN YOUR CAB!

http://www.vulcanperformance.com

 

Hey now whats wrong with fuel in the cab just make sure you don't use a lighter for a map light!!

The isolator on this gauge went bad "Law Dog" so I just said the heck with it.Not a great idea but it works

 

Bridleman, I have tried 2 of the Isspros mechanicals, & both leaked almost immediately. The Last time was on a trip across I-10 some 500 miles away from home. I will not ever put diesel in the cab again. Glad I had a plug to put in the fuel filter top cover. I have talked to numerous people who liked the westach. I need to add a fuel guage, so what would you guys suggest? What does the isolator do? Thanks

 

Geno's Garage carries replacement sending units.

 

The senders for electric gauges come in two flavors. There is the cheap resistive type that can’t take the beating from a pulsating fuel source like the Cummins engine creates, and the more expensive solid-state sensors that will take a beating as long as the peak pressure spike is low enough.

The resistive sensors have either one or two wires and change resistance in proportion to the pressure. Their construction is a rubber diaphragm that is pushed on by the fuel pressure with a linkage that slides a contact across the resistive element. The life of the sensor is determined by the wear created by the wiper sliding on the resistive element. It is not unlike our fuel level sensor located in the fuel tank. With fuel sloshing, the resistive element and wiper wear out causing that annoying “Ding” every few seconds along with the fuel pump symbol. I have to keep my radio up load.

These sensors benefit from a snubber to lessen the pressure pulsations, but will still fail. In critical applications like aircraft, these resistive sensors cannot be used.

The more expensive solid-state sensor, which is approved in critical applications, will have three leads running to the gauge. Its construction is a hard membrane that is connected to a strain gauge element. The electronics amplify the signal from the strain gauge and use this to indicate pressure on the gauge. About the only way to kill this sensor is to over pressure it, so a snubber may still be required to limit peak pulse pressures. The reliability is greatly improved over resistive type sensors because there are no moving parts to wear. The hard diaphragm does flex but these have been tested for 10s of millions of cycles without failure.

Unfortunately the two types of sensors are not interchangeable.
Westach makes both type of gauges and senders. If you google Westach and find their catalog, look for the following:

387-15KV is an electronic 15-psi sender
387-30KV is an electronic 30-psi sender

387-16V2 is their resistive 16-psi sender
387-30KV is their resistive 30-psi sender

People with mechanical fuel pressure gauges also use snubbers to quiet the vibrations. The Cummins engine low-pressure fuel supply is a hostile environment. Ask any Carter lift pump.

 

Bent, thanks for the good info. Stupid question: If you are going to have more than 15 lbs of pressureanytime, some of the time, or all the time, is it better to go ahead & get the 30 lb sender? It is a shame they don't make a 20 lb unit, that should be just right for most of us. The 15 may be. The 4601 HP is supposed to make 18 PSI under perfect conditions. I don't know if mine or perfect or not. I doubt that I can hold 15 lbs at WOT, but I don't know. What do you suggest? How about this SNUBBER? Is that something Westach makes?

 

18 psi should not kill a 15 psi sender but spikes will. The VP44 can generate pressure pulses of 50 psi. Many people use a valve to choke down these pulses. A search should bring up lots of info or look at http://www.mcmaster.com/ for a place to buy a snubber. 3820K12 is one I recommend. Westach does not offer a snubber.

 

Thanks BentV for your info. Would you use the brass or stainless steel?

 

BIGHEAD,
In my opinion you should never run a pressure gauge over ½ scale be it mechanical or electrical. If I were in your shoes running 18 psi of fuel pressure, a 30-psi gauge is needed. It is expensive to toss out the 15-psi gauge you have now, but it is the best solution. Another option is to use the 30-psi electronic sender with a snubber and your 15-psi gauge. This will read only 9 psi on your gauge with 18 psi of pressure, but the math is easy. Brass is cheaper than SS.

 

My 15 mechanical is only used for a tool. It is not hooked up, for fear of it busting again. I am looking to do the Westach electrical. That brass snubber was only 7 b ucks, a steel one was 10, I think. That is no big deal. Will the steel handle vibrations better or the brass? Does the snubber reduce the fuel pressure or just regulate it?Thanks Bent for the info.