RASP pressure fluctuation?

[RMecum]

I only drive my truck a couple times a month. I bought to tow the Airstream and that's what it does, mostly. Today I took it out to run some errands and noticed at freeway speed the fuel pressure gauge (Westach electronic) was fluctuating between 10 and 13 psi. Once it went to 8 for a half second but came right back up. I've only got about 4000 miles on the RASP pump and I suspect the Westach sending unit more than a RASP failure. Have any RASP's failed? I've heard of Westach sending unit problems but I put a snubber on it when I installed it and it's on the grease line hose from Geno's. Anybody have any thoughts?



Mike

 

[rweis]

Are you fp before or after the ff?



I have Westach electronic and have replaced 3 of them. Last about a year when measuring the VP side.



Now have sensor on a long, well away from the Vp and a needle valve that is CLOSED and still get reliable fp.



I have asked Westach for ideas and sent them a verbal discription of system trying to get their ideas as to why the sensors are failing. I even sent them a needle vavle so they could evaluate it.



Bob Weis

 

[Fishin Guide]

Just as a simple thought. Is the belt set to the correct tension?



Dave

 

[paulb]

I agree with you, I would suspect the guage as well.

 

[24V-DSL]

After many miles on my RASP, with consistent readings, I started to get lower readings, but they weren't irratic, just lower.



Bill K told me it could be from a "dirty" regulator, or a weak spring. Sent me a new spring. The regulator wasn't dirty, so I assume it was the spring. Pressures actually ended up higher than they had been originally.



Just something else to consider.

 

[Graphic man]

I too have a RASP with a Auto meter Direct reading gage on the VP side



13-14 psi on start-up, 11-12 in gear hot, cruz 13psi and if i let off the go fast peddle it will go to 15 psi



i have had trouble with air in the gage line,

and it is time for a new filter so i am going to change it

i have also talked to Bill K and did the tricks he told me to and still no better

i have also brought the pressure down a little to around 14 psi i didn't want the VP to think there was something wrong LOL



140,000 and Org. VP still going strong



Scott

 

[RMecum]

I got the big line kit from OPoole and it has the F/P port between the filter and the VP... I kind of suspected the sending unit... I'm gonna keep watch on it and maybe find a mechanical gauge to monitor the pressure for a while and see what it does. I'm a little disappointed with westach... I've flown a few airplanes with their stuff in them and had no problems... . I've already had to replace the trans temp sender and now the F/P is acting up... . I might need to change out the gauges.



Thanks for your responses and comments.



Mike

 

[jeepit]

I got the big line kit from OPoole and it has the F/P port between the filter and the VP... I kind of suspected the sending unit... I'm gonna keep watch on it and maybe find a mechanical gauge to monitor the pressure for a while and see what it does. I'm a little disappointed with westach... I've flown a few airplanes with their stuff in them and had no problems... . I've already had to replace the trans temp sender and now the F/P is acting up... . I might need to change out the gauges.



Thanks for your responses and comments.



Mike

What sorts of readings or problems are you seeing?

 

[RMecum]

jeepit... take a look at my #1 post... . it explains what happened.

 

[Dustdevil]

My Westach fp gauge started fluctuating from 10 to 22#s. I checked and retightened grounding wire and gauge operates smoothly now.