fuel pressure gauge issues

[WaynesWorld]

Guys,



I installed a Isspro Fuel Pressure Gauge with pressure insulator.

That the good news.

The bad is the needle flutters . #@$%!

I drained it several times to make sure I installed correctly.

It seems something is wrong, Any suggestions?



WAYNES WORLD

 

[PToombs]

I didn't use an isolator on mine, I just sleeved it to the gauge so if it leaks, it runs outside.

I did put a needle valve on at the banjo bolt. I turned it down until I got rid of the flutter. Flutter, heck! It looked like one of those paddles with a ball on a rubberband!

The needle valve was almost closed before it quit bouncing. The other nice thing is if I get a leak, I can shut it right off.

 

[jhoughton]

Only one thing that might help. Did you fill the isolator with anti freeze prior to starting the truck? If not allow fuel pressure to bleed down then properly fill with anti freeze. I also have your same set up and have had no issues.

 

[ToolManTimTaylor]

Yep mine buzzed constantly. I even adapted their isolator to 1/8th common and used 70% antifreeze to slow down the impulses. Have a vibration coil built in and an isolator hose for the isolator. I have the fuel side bled free of air and the isolator at exactly the 50% mark (All connections made upside down so air rose to the top and out) the gauge side I was able to draw air out and replace the void with anitifreeze via 50cc syringe under force. To no avail it still drives me nuts. It's White/Blue numbers too and good luck finding that again :{

 

[WTBurke]

My Hewitt gage and floral carbon diaphragm isolator is Rock-solid stable. Eric at Vulcan, has a new isolator that is cylindrical and black anodized. He reports a better price and same reliable configuration as the floral carbon composition. I strongly suggest always keeping the fuel pressure sensing system designed around the hydraulic capillary basics. Set up correctly there are no errors or fluctuations... snubbers are not required due to the hydraulic capacitance of the system. The old-school method really shines here.



William

 

[WaynesWorld]

PToombs,

Where did you get the needle valve?

I like the rubber ball in the paddle thought.

Does that affect your pressure reading?



jhoughton,

Did you use 50/50 antifreeze mixture?

What about 35 % windshield washer fluid?

Would that make a difference?



ToolManTimTaylor,

Have you considered windshield washer fluid ?

Would the 50/50 mixture of antifreeze make that much difference?

If so would straight 100 % antifreeze be better?

My first attempt went great but I didn't tighten the one fitting tight & it leaked.

Three tries later & no success.



WTBurke,



Can you tell me that in english ?

Where can I talk to Eric from Vulcan ?

the isolator I have from Isspro is the floral carbon diaphragm design. Would the cylinder design make that much difference?



Thanks everybody,

WAYNES WORLD

 

[ToolManTimTaylor]

yep tried washer fluid , mineral oil and have found coolant to be the best so far.

 

[WaynesWorld]

TTT,

I'll give that a try this time.

Just curious, would full strength a/f work any better?

You know the old adage----- if a little bit works, a lot is better?

It seems to work with the bride, oh thats another subject.



Wayne

 

[WTBurke]

Wayne,

If you are already using the diaphragm design then "no" going to Vulcan's set-up will not help.



Vulcan Performance Home Page



Is where Eric can be contacted. Also 866-466-1043



The fluid you choose on the backside of the isolation unit is not critical. I do not know how you are feeding the isolator from the input from the VP-44. I assume you have selected a pick-off point with proper fittings. Now... the thing that is important is the type of line you are feeding the diaphragm with. In general the "grease-gun" hose arraingment is a poor choice. Selecting standard rubber hose is the best. Of course, select a hose that is fuel compatable. I'm using standard 3/16" (Goodyear) line and the length takes me from the VP-44 input, back to the firewall on the drivers side where the diaphragm isolator is mounted. Keep in mind we are only working at sub 30Lbs PSI here. 20,000 PSI burst test grease gun line is not required!



The reason for the standard rubber line compared to the "grease gun" line is the expansion/contraction coefficient of the rubber line. In small terms "it is the additional snubbing" or shall we say the hose will expand and contract at a level that is equal to the oscillations of the "back-pulses" of the VP-44's sipping action. It will reach a point of equalization and provide a nice additional capacitance for your isolators diaphragm to reach an even equilibrium and provide a nice smooth hydraulic force to activate your gage's needle movement.



Grease gun lines are "hard lines" and have little dampening effect to help your diaphragm stop oscillating at the sypathetic resonance of the VP-44.



Good paint stores ( for exact paint tinting) and perhaps a local Veterinarian will have the nice large hypodermic syringes to allow a precision enema feed of your capillary line during the prime up procedure. It is technique and finesse that counts here... don't do the Homer Simpson thing.



I take PSI readings on closed high pressure liquid filled systems for a living. This trick at 15 PSI is a very simple thing... . just take it easy, use the correct components and don't sweat a few small bubbles it won't make a hill of beans of difference at this level.



William

 

[WaynesWorld]

WTBurke,



I appreciate the Vulcan info.

My 12 v is a different animal than the 24v.

I have a fuel gauge supplied line . It came as a complete set up.

I did a gravity feed thru a home made fill line. Is that the Homer Simpson thing. Or is that the sucking on the line idea? I'm still spitting out A/F. Hence the other fill method. Its OK to laugh now.

William, Your job sounds very interesting.

I also think my gauge is too small since it pegs the gauge. I have about 25-28 lbs. at an idle. It hits the stop with a little throttle. AAAHHH

My next step is to call ISSPRO on wednesday for assistance.

Thank You,

WAYNES WORLD

 

[ToolManTimTaylor]

TTT,

I'll give that a try this time.

Just curious, would full strength a/f work any better?

You know the old adage----- if a little bit works, a lot is better?

It seems to work with the bride, oh thats another subject.



Wayne

LOL :-laf yeah it prolly would be good but the ideal dynamics of A/F is 50-50 so I picked 70-30. Why I dunno

 

[jhoughton]

I used strait anti freeze and I also have the grease gun hose tapped directly to the fuel line using the T fitting from Vulcan. I have never experienced any fluctuation with my setup. Originally I had it tapped to the top of the fuel filter housing.

 

[WTBurke]

Oh Gosh... we're talking P-7100 here... I'm sorry Wayne but, some of the info may assist you. Don't sweat the Homer stuff... we gotta do what we gotta do to get the job done. You'll find Eric a very fine fellow and he has great stock of cool fittings.



Merry Christmas

William

 

[WaynesWorld]

WTBurke,

I'll give Eric a call on wednesday.



jhoughton,

I went to the top of the filter housing. Can you snap a photo on your install? I noticed the plastic line still bounces. It would give me a better idea where you put it in.



TTT,

I like the idea of A/F more is better. :-laf

So I tried 100% last night.

It didn't taste any better than 50%.

But the flutter did slow to about 5 lbs. HHMMM#@$%!



MERRY CHRISTMAS TO ONE & ALL,

WAYNES WORLD

 

[PToombs]

WW, I got the needle valve from Graingers, I'd have to hunt for the # , if you want it. And no, it reads fine. I just let the truck run, and closed it gently til it stopped jumping.

 

[WaynesWorld]

PToombs,

It definitely sounds like the way to go. I'm sure the guys at Grainger have an idea what I'm looking for.

I will change to a 50 lb. gauge thou, it will live longer then. I found a boost gauge that will now be a substitute. Who said one man's junk is another man's gold?

Besides, it time for some new Patriot Sun Glasses from them. Try them, you'll like them. I use them at work for safety glasses. Plus, they're great on the Harley.



WAYNES WORLD

 

[jhoughton]

Here are a couple photo's of my isolator install.

 

[Ace476]

Issopro issolator

My Issopro setup just like yours works perfectly. My advice to you would be to move the issolator off of the engine and on to the firewall. My bet would be the engine vibrations are causing your problems. Oo. Oo.

 

[jhoughton]

Ace, Mine works just fine right where it's at. I posted these pics for Waynes World. I have never had any fluctuations at all.

 

[WaynesWorld]

jhoughton,



I like the fact you were successful with the install.



It gives me hope that I will finally figure this out.

Can you tell me what kind of pressure that you have?

My idle pressure is around 23-25, while the slightest throttle pegs the needle at 30.

The last thing is my plastic line moves with the fluttering.

I think I have to slow down the pushes with the new valve for a better reading.



Thanks,

I hope everyone had a MERRY CHRISTMAS,

WAYNES WORLD