Erratic Westach Fuel Pressure Gauge

[dpuckett]

About a year ago, maybe a little more, I bought a used Westach fuel pressure gauge from a fellow TDR member who had upgraded his supply system and needed more than 16psi on his gauge. I hooked it up in my 92, and it worked fine for several months. Recently, it has been erratic, enough so that I hooked my boost guage into the outlet for the fuel pressure to see if it was the lift pump or the gauge/ sender. It turned out the pump is fine, and doesnt drop below 5psi unless I am on it pretty hard at higher RPMs (stock style 1stGen pump- diaphragm, made for 6-7psi, and no more than 100cc fuel and 2800rpm. The fact it pulls down when my hopped up pump demands more fuel does not put the pump at fault, but rather, the owner, who needs to upgrade his supply system). I have checked my grounds and wiring connections, and they look good.



The gauge will read 0psi for a while, then matbe 4, then 7psi, then whatever it wants to read, without rhyme or reason. Throttle and load have little effect on the reading, (to a point, about 30psi boost and 3000rpm, then it will drop), which leads me to believe it is electrical. How can I test the sending unit and/ or gauge? Can I even test them? I dont mind buying a sending unit, but dont want to buy one if the gauge itself is the problem.



Daniel

 

[Thomas]

. . . How can I test the sending unit and/ or gauge? . . .

All Westach Resistive Senders are 240 ohms @ 0psi and 30 ohms @ full scale (page 37 of their catalog: http://www.westach.com/ ).

A meter will allow you to check the sender. Resistors of the proper value plus a 12-volt source will allow you to check the zero and full-scale points of the gauge.

 

[glhs]

I have two of them on my truck and one lasted about 1 week, the other 2 months. These are sold by Genos garage and they are NOT compatible with Diesel fuel. Call Westach. They will tell you. The repair is hundreds of dollars. Good luck.

 

[WTBurke]

Daniel,

If you wish to do it once and end the hassel go to Hewitt Industries for a mechanical gauge and go to Eric at Vulcan for a "floral-carbon" diaphragm isolator and you will have a bullet proof telemetry system for monitoring your fuel delivery devices. You could read nuclear-slag in a closed pressurized system with these inexpensive components. No kidding!



William

 

[jwilliams3]

No problems out of my Westach's here. Ran them for years on diesels... since 2002/3.



Check the grounds...

 

[Gary - K7GLD]

I've had mine on my truck since it was new - about 55K miles now - always worked great, no problems. Here's my sensor mount - I take the PSI off right at my VP-44:



#ad

 

[Eric Lee]

I ran the electric for quite awhile - but when I got accustomed to ignoring erratic readings and having to carry a portable gauge to plug into the fitting on pump to double check it - well - nuts.

I went with a mechanical I ordered from Piers. It was not cheap but if I ever see the needle dive I feel confident it is a true reading. The whole idea is to know when to shut down immediately. The electric cried wolf so many times - it was worthless. The Isspro gauge is super quality and I believe, made here in the States. It comes with an isolator that is charged with antifreeze for the line going to the gauge so there is no fuel in the cab.



- Eric

 

[kschitoskey]

Same problem...

I too had erratic readings with my Westach FP gauge - took the dash back apart, rechecked connections (especially ground), problem resolved. I think I had a shaky connections in the back of the gauge. I have read numerous accounts of the sending unit going bad; the above mentioned diagnostics sound very helpful. Good luck.

 

[FYarcho]

Westach makes 2 types of senders. When I bought mine they recommended the more expensive ones saying that they were not compatible with diesel fuel. But being the penny pincher I am I bought the less expensive ones. Had them on for over a year and one is just now starting to fluxuate and leak. I can't remeber how much the better one's were, but I am thinking they were over 100. 00 each.



But I think if you continue to use the less expensive ones it will just be an ongoing problem. I would call Westach direct and get them.

 

[WTBurke]

Eric,

You're dead right, I work in the pump industry (closed high pressure systems) and telemetry is critical. NO ONE in my industry uses electric isolators to transduce true pressure readings. There might be electronic pressure management systems but, the technicians must use mechanical glycerin filled instruments to set the critical operating parameters and verify that all is correct before operating or releasing the systems to end users. I have to laugh every time I see some dude wondering what he is looking at when I see that he relies on electrical devices to provide critical liquid pressure readings within a closed system. Besides, the fact is mechanical systems such as what we deal with in feeding our beloved ISB's can be monitored for much less investment and have greater reliability when proper mechanical instruments are chosen.



I have NO electronic telemetry devices added to my platform, I have chosen NOT to do so because of my professional disciplines. I don't really care what others do... besides... they make me laugh:-laf



William

 

[turbo torque]

My Westach sending unit also developed a leak at the terminals. Took it apart and applied a light smear of black silicon and the leak is fixed. BUT , the gauge reads 7 psi @ idle. My snap-on mechanical reads 15 psi @ idle.



Neither reading is ever eratic though.



It looks to me that this sender is not reliable enough to protect our VP44.

 

[Eric Lee]

It looks to me that this sender is not reliable enough to protect our VP44.

Plain and simple.



The last issue of TDR - or one of the last, stated inside ANOTHER article on the VP44 and it's accompaning gauge, that the mechanical is too expensive and hard to install to be a smart choice. Did any one else catch that?



- Eric

 

[WTBurke]

I just glanced through Issue #57 and could not find that article. I would like to read that and find who the author was. As for difficulty to in stall I find that hysterically funny:-laf and cost factor... . well that too is absolutely misinformation.



The telemetry devices I've chosen are not only superior they are also considerably less expensive. Also, all the new gauges from Hewitt have the new cool look of light emitting diodes embedded on the rear of the face plate. Cosmetic priority shouldn't be the reason you choose a telemetry device... it should be the design of the internal movements.



I'm not affiliated with Hewitt Industries, I'm just highly discriminatory when I dissect and disseminate what I'm looking at.



William

 

[Eric Lee]

The article is '24-Valve - What to do?' in issue 56 page 72. The reason the author does not recommend a mechanical gauge is it's complexity. The writer actually says - "the mechanical gauge is not recommended".



We have guys (and gals) putting in their own injectors and pumps but the capillary tube is too complex.



Hook up is as easy (or difficult) as the electric - easier if you have an electric already. Isolator goes where sender was - tube goes where wire was - and the electric gauge and sender goes in the trash can.



- Eric Lee

 

[WTBurke]

Eric-

I just reviewed issue 56 page 72. I respect the written articles within the pages of the TDR journal. I can't identify who wrote that particular paragraph but I must concur with you that it is mildly misleading.



Daniel Pucket started this thread lamenting his experience with an electric transduced pressure sensing abnormality. I have seen dozens of simular threads over the years by many different members sharing their frustrations revolving around the electric transducer and I don't think this points to any particular manufacturer. I'm under the impression that all the manufacturers have had their share of end users returning transducers for replacement or correction.



You are so correct in the term of difficulty in the process of installing either device chosen by an able bodied individual. I belive this "Cummins Cult" group (we are members of) has a vast majority of mechanically inclined individuals. It is the understanding level of how a device works that may elude some individuals momentarily. This may lead them to select a device or component on less than a solid understanding of what they are getting.



This simple subject of pressure sensing has been kicked around quite a bit. Reliability is the key issue when any of us chose to make, modify or purchase a device or component for our CTD's.



Honestly, regarding this simple subject... simplicity is the best choice. Cost... well I've stated before from my own experience, mechanically based instruments are less costly if you research the vast suppliers. Some "overly distributed" suppliers have a higher price tag because they have earned that through name recognition. Aggressive marketing and vast printed presentations cost money... and the end user pays for that.



Now as for performance... . I appreciate the immediate subtle changes in telemetry that I observe with my mechanical instruments. The sensitivity and reaction time are real-time and not logarithmically smoothed (or slew-rate) as you would observer with electrical devices. Mechanical transducers in particular floral carbon diaphragm units have no difficulty surviving in rapid-pulsation environments. Additional snubbers leading from the VP-44 are not required and keeps the installation very clean and simple. Diesel fuel, additives,solvents or any normal liquid that we use in our diesels have no effect on the diaphragm's composition. Reaction of heat and cold on a closed capillary system containing a glycol base has a very good expansion/contraction coefficient. Op-amps used as balanced comparators in electronic pressure sensing systems require drift compensation to track correctly on thermal curves.



OK... I'm going over board here... sorry.



I would hope all who might be considering placing telemetry devices in the cabs of their CTD's would consider simplicity as the basic theory first.



In closing and to add a bit of levity... on your last trip to your Doctor what device did he or she slap around your arm to take a pressure reading? I'll bet it didn't have electric power



William

 

[PToombs]

Wrong! The nurse put the cuff on, and pushed a button! The machine did the rest, and she wrote down my BP. (well, maybe she held my pulse a little )

 

[Eric Lee]

Wrong! The nurse put the cuff on, and pushed a button! The machine did the rest, and she wrote down my BP. (well, maybe she held my pulse a little )

Maybe if she left it on there and then every time it gave a false reading she threw you on the gerny and hit you with the paddles... .....



In Jest - Eric

 

[WTBurke]

Oh yeah... I forgot about them new-fangled devices... I'm out in hay-seedville where they still wrap your arm and pump it up by hand to get the BP level. Boy all you big city fellers got all the new stuff :-laf



William

 

[BJonesUSA]

erratic gauge...

Yup, check your grounds... . mine was driving me crazy for 2 months with all that bouncing around until I finally found the loose wire under the dash...

 

[PToombs]

Maybe if she left it on there and then every time it gave a false reading she threw you on the gerny and hit you with the paddles... .....



In Jest - Eric

Eric, don't threaten me with a good time! :-laf

Oh yeah... I forgot about them new-fangled devices... I'm out in hay-seedville where they still wrap your arm and pump it up by hand to get the BP level. Boy all you big city fellers got all the new stuff :-laf



William

Big city? I think my village has 3000 residents! We aren't too far from Syracuse, which is a moderate sized city. I prefer Hayseedville! :-laf