Engine/Transmission (1998.5 - 2002) VP input fuel pressure sensor longevity

[rweis]

I have been monoritoring the input fp to the VP for 2 years now. The sensor I use is the Westach solid state 387-30KV 30 psi sensor. The first one failed after about 1 year. Westach thought that was a fluke. The second one just started failing after one year. Westach thinks this is a fluke also.



Westach has replaced them without any questions or problems.



The sensors were on an 18" AN-4 snubber line, and held in place up by the hydraulic hose that goes into the brake boost assist by the fuse box under the hood. The tap for the sensor into the fuel delivery line to the VP is in a AN-6 line mid way from the bottom of the fuel filter to the VP.



I have replummed the fuel system with AN-6 line from tank to VP.



I was just wondering if anyone else has had problems keeping an electrical fp sensor functioning reading the input fp to the VP?



I am trying a different approach this time with a MUCH longer line wrapped in a coil to see if that makes any difference. My thinking is to provide a 13. 25 cubic inch fluid volume to buffer the sensor more and to coil the line so it would make it much harder for any pulses from the VP to reach the sensor.



The Westach fp sensor prefilter has worked flawlessly for two years.



Why am I on the second high quality sensor when I am reading the fp into the VP?



Ideas?



I have wanted to read the fp to the VP electrically rather than mechanically, but how do the mechanical gauges hold up over the years as an alternative?



Bob Weis

 

[RustyJC]

I was just wondering if anyone else has had problems keeping an electrical fp sensor functioning reading the input fp to the VP?

Bob,



I've lost probably 6-8 resistive-type 0-16 PSIG Westach sensors on the post-filter side of my combo dual gauge since installation. My sensors are plumbed with stainless-braided AN4 lines and remote-mounted on the firewall - the post-filter sensor also has a gauge snubber mounted at the inlet of the sensor. I haven't heard of similar problems (at least to the extent that I've experienced) from those who used the grease gun hose to plumb their sensors. I wonder if the AN4 lines are too stiff to dampen the pulsations, and the controlled flex of the grease gun hoses are effective as an attenuator... .



Rusty

 

[dresslered]

I installed an Autometer Ultra-Lite electric fuel pressure guage over three years ago and more than 46,000-miles ago. I am still running on the original sensor. It is installed remotely via a grease gun hose from the bottom of the fuel filter (injection pump side). The sensor is mounted on a custom bracket mounted on the brake master cylinder which is isolated from the vibrations of the engine. It has already saved me from two lift pump failures.

 

[Thomas]

. . . My thinking is to provide a 13. 25 cubic inch fluid volume to buffer the sensor more and to coil the line so it would make it much harder for any pulses from the VP to reach the sensor.

It seems to me that the only way increasing volume would help much would be if the 13. 25 cubic inches were easily compressable - a gas rather than a liquid. If air were trapped permanently in the line you wouldn't need anywhere near the volume you're suggesting. I think a line with a variable volume is the solution.



I'm using the same Westach senders and dual gauge as Rusty. I monitor the inlet and outlet of the transfer pump. The senders are remotely mounted between the PDC and antilock brake controller. I used eighteen inch lengths of 1/8 inch fuel line to connect the senders to the fuel system with zero failures in 60,000+ miles.

 

[rweis]

A more flexable line looks like maybe a better idea than the SS braided type.



What do you think is actually happening?



Is the VP bleeding internal low pressure pump (300 psi) pressure back to the sensor like a slight leakage maybe during a rapid deceleration and the amount is not enough to actually show on the guage but is enough to shock the sensor?



Bob Weis

 

[mhenon]

Would this help?

I'm not sure if these were diesigned for diesel fuel but have a look.



"http://injector.com/fueldampners.php"



If this doesn't show up as a link... just cut and paste it.



Mike

 

[CStewart]

Chemiquip Subbers

I put a AutoMeter fuel pressure gauge on my truck a while back. The first transducer lasted six months before it failed. I contacted Autometer and they said they no longer recomend there fuel gauges for diesel service because according to them the transducer can't handle the pressure pulsation of the pumps on our trucks. I got a new transducer from them and installed it with a 12SE Chemiquip snubber. I have my transducer mounted directly to my filter housing and so far its lasted almost two years without a failure.

 

[darkhorse]

I only have 6 months on my Westach fuel pressure guage. The sender is mounted on the throttle position sensor housing & connected to the schrader valve on the vp44 with Geno's grease gun hose. So far it's worked flawlessly.