this is from the q and a section of aeromotive's site



5.) My regulator doesn't seem to keep consistent pressure, every time I look at the gauge it reads something different, what is going on?

Chances are good you have a liquid filled fuel pressure gauge. This type of gauge will change it’s reading as the temperature of the gauge case changes. Because it’s sealed to contain the liquid inside, a liquid filled gauge no longer compares fuel line pressure to actual atmospheric pressure, reporting the difference. Instead, it compares fuel line pressure to the pressure inside the gauge case. Unfortunately, as the liquid in the case heats or cools, it expands and contracts, causing case pressure to change as much as 7-12 psi plus or minus. As a result, gauge readings can fluctuate from 40 psi cold to as little as 28 psi hot! Fuel line pressure is NOT actually changing, just the pressure in the gauge case. To confirm if this is occurring, procure a heat gun or blow dryer and heat the gauge from cold to warm and then hot, while running the fuel pump. Observe if the pressure reading drops, if so, you found the problem.



has anyone else experienced this other than just me?

why did you waste money on liquid filled gauge? anyway. their explanation sounds legit. I can see the temp of the liquid causing a problem. especially under the hood of our ******* ovens on wheels

lol i didnt buy it... it was in my car when i picked it up..



well a non liquid filled seems cheap enough, and the replacement seems easy enough.. so thats what ill get

hmmmm i guess there are a lot to choose from, any suggestions?

I have a good ol' autometer. works perfect, cheap.

ok i think my fluctuation is caused by my fuel filter or some other obstruction in the fuel line. i screwed the adjuster all the way down with no change in fuel pressure, then raised the adjuster up and lost fuel pressure.

[quote name='FikseRxSeven' date='Apr 7 2005, 09:40 AM']ok i think my fluctuation is caused by my fuel filter or some other obstruction in the fuel line. i screwed the adjuster all the way down with no change in fuel pressure, then raised the adjuster up and lost fuel pressure.


[/quote]



definatly would replace the filter, but you should be able to "dead head" the pump and the pressure shoot up. If not, i'd be looking for a new pump too.

[quote name='mazdadrifter' date='Apr 7 2005, 04:46 PM']definatly would replace the filter, but you should be able to "dead head" the pump and the pressure shoot up. If not, i'd be looking for a new pump too.


[/quote]





what does dead head mean?



i hope its not the pumps, they're 2 walbro 255s thats only about 2k miles old.

Get an electronic fuel pressure gauge and sensor.

Those under-hood gauges are only to adjust idle fuel pressure.





-Ted

has there been any history of people clogging pumps and filters with premix?



i added a new tank of gas, and added the premix and drove about 20 miles... by the time i got home, the car was sputtering the 1st split second after switching gears, and when i checked the fuel pressure, it was down to 25lbs

replaced the fuel filter and still have the same problem....



disconnected each of the pumps and hey made identical sounds when they were running alone, and the fuel pressure went down to 20psi when alone and 30psi when they were running together. this was when the aeromotive regulator screw was all the way down.



next thing im going to try is to disconnect the feed line to the engine and have it drain into a bucket, and see what kind of sound my fuel pumps make.



to be continued

fuel pump prefilter 'socks' might be clogged up..

another weird observation.... the first 2 seconds that the car is turned on, the car makes a normal sound, on the same fuel pressure... then the hum gets louder. then, when i start the car, the hum gets even louder due to the higher voltage i guess.... then as the car warms up, the hum gets even louder and i start losing fuel pressure

thanks to greygtc for offering his regulator to help me narrow this problem down, and also ordered a couple of walbro's to make sure things are straight... car will be in the body shop while im waiting for the parts to come in.

give me the blue bomber and i'll fix it..

[quote name='rfreeman27' date='Apr 17 2005, 09:43 AM']fuel pump prefilter 'socks' might be clogged up..


[/quote]





you are right it was the socks.. took them off for the time being,



they were black when i took them off.

they can probably be cleaned using carb cleaner or something simliar.

i tried... still black, im gunna find a place that sells just the filter

Premix clogging the pre-filters?

Or was it something else?

If it was the premix, what brand are you using?

What ratios?





-Ted

im using amsoil dominator, at 1oz:1gal ratio



my concern is the filters are black, and the premix is red. i think if it was the prmix that caused the clogging, my fuel filter would be clogged as well.



when i cut the filter open, the cotton? fiber part of the filter is grey with a somewhat sticky powder residue on it, not oily, maybe because i sprayed it with carb cleaner.



i did also notice that the strainer was bent up. from the middle i dont know if that is normal but i can imagine that the bend would be greater when more pressure is applied.



anyone know where i can find a place that will sell me just the strainers?

[quote name='FikseRxSeven' date='Apr 23 2005, 08:22 PM']im using amsoil dominator, at 1oz:1gal ratio



my concern is the filters are black, and the premix is red. i think if it was the prmix that caused the clogging, my fuel filter would be clogged as well.



when i cut the filter open, the cotton? fiber part of the filter is grey with a somewhat sticky powder residue on it, not oily, maybe because i sprayed it with carb cleaner.



i did also notice that the strainer was bent up. from the middle i dont know if that is normal but i can imagine that the bend would be greater when more pressure is applied.



anyone know where i can find a place that will sell me just the strainers?


[/quote]



1oz per gallon is like twice too much!!!!!!!!!!!!! https://www.nopistons.com/forums/pub...1047683785.gif

Hey sorry to jack off your thread Martin, Hey Jon when u had your FDS did u also had upgrade injectors like 1600? I am curious because as much I knew car I can't remember that portions of it. Khris

[quote name='vosko' date='Apr 23 2005, 09:15 PM']1oz per gallon is like twice too much!!!!!!!!!!!!! https://www.nopistons.com/forums/pub...1047683785.gif


[/quote]



i did my research, and according to turbovr6, thats how much he's running too

word from the wise Dragon.



if its black its probably from when the stainless steel lines are cut. just like cutting metal you create fine shavings.



so.. with that said... always flush the lines after you cut them.

What do you mean by that?

The cut portion of the line “should be pressed onto the fitting and technically never come in contact with the fuel. The rubber compound that is used in the SS line is not hydrocarbon soluble, so that should rule out any theory that the lines could be causing any darkening of the filter media. I would think you would find splinters of hose if anything were to come off the hoses if anything at all.



I would assume it is like Ted said. It is probably deposits from the oil. The filter was never designed for a 2 stroke oil additive so it could possibly be that. Even if the oil is a red color this is probably due to a dying agent as opposed to the actual molecules of oil.

[quote name='FikseRxSeven' date='Apr 24 2005, 07:41 AM']i did my research, and according to turbovr6, thats how much he's running too


[/quote]



when i ran that much, my car smoked way too much. it should be about 8 oz for a full tank



and khris my old car had 750cc primary and 1680cc secondary injectors