fuel pressure testing

[ed hess]

With vac line disconnected i get 55psi on liquid filled auotmeter fp gauge. with the line connected i get 45psi. I am sure i didnt reverse the text pressures wwriiten above. This seems backwards to me. I expected the base to be lower with the vac line disconnected. It has a stock regulator which i dont know if my syclone buddy mechnaic (his is faster) (and he knows what he is doing) made an adjustment years ago when he put the chip in.
Is this ok given stock injectors? i.e. can you run too high a base fp?
I understand the regulator just send the unused or unneeded fuel right back to the tank.
I will be adding the atr 7th injector later to see if it helps with top end detonation over 14.7 psi.
The ultimate chip and 3 bar sensor is planned for after that. But i know to take it only one small step at a time so as not to confuse what the results are.

ed

 

[Daron]

Re: fuel pressure testing

With vac line disconnected i get 55psi on liquid filled auotmeter fp gauge. with the line connected i get 45psi. I am sure i didnt reverse the text pressures wwriiten above. This seems backwards to me. I expected the base to be lower with the vac line disconnected. It has a stock regulator which i dont know if my syclone buddy mechnaic (his is faster) (and he knows what he is doing) made an adjustment years ago when he put the chip in.
Is this ok given stock injectors? i.e. can you run too high a base fp?
I understand the regulator just send the unused or unneeded fuel right back to the tank.
I will be adding the atr 7th injector later to see if it helps with top end detonation over 14.7 psi.
The ultimate chip and 3 bar sensor is planned for after that. But i know to take it only one small step at a time so as not to confuse what the results are.

ed

Boost pressure raises the fuel pressure via the rubber line you are disconnecting. Vacuum reduces the fuel pressure with the same hose. The hose is attached to your intake thus it is affected by what load your engine is under.
Pulling the hose off the regulator brings the fuel pressure regulator to a known state (atmospheric pressure) and allows you to set the pressure to a specific value, referenced to atomospheric pressure.
A stock regulator is not adjustable, unless you crush the top.
55 psi may be a bit much for a stock cal, but works well for me on the ultimate chip. The injectors arent your limiting issue, as much as your fuel pump will be...

 

[ed hess]

Just went back and looked a the receipts for the 1st mods done 11 years ago (everything goes into the notebook for reference) Line item says "Adjustable fuel regulator" guess thats one item i wont need. But I will be looking at the pump. I wonder where i can find install instructions for those walbro's i keep reading about. atr told me they no longer stock the double pumper set up, but they can make me one if i want.


ed

 

[Daron]

Just went back and looked a the receipts for the 1st mods done 11 years ago (everything goes into the notebook for reference) Line item says "Adjustable fuel regulator" guess thats one item i wont need. But I will be looking at the pump. I wonder where i can find install instructions for those walbro's i keep reading about. atr told me they no longer stock the double pumper set up, but they can make me one if i want.


ed

So, it already has an adjustable regulator? You mind describing it? Some of the old ATR adjustable regulators sucked. It may behove you to verify that your regulator is indeed raising the fuel pressure a pound, for each pound of boost.
Dookycat felt in necessary to PM me, suggesting I was saying to adjust the FP by crushing the stock regulator. If you have been around a bit you'd know how opposed to that method I am, but I felt compelled to mention it as a possibility for your elevated pressure since you are not the original owner. Poor Dooky........

 

[ed hess]

I am the original owner, probably one of the 1st people to buy a syclone vin is no 00045. The top of the reg is black with a silver threaded tube sticking up that has the adjusting screw inside, the vac line is off to the side of the cylinder about midway sticking out at 90 degrees. It is an early atr unit installed 11-12-92. You suggesting i change it for a newer one?

I would assume to test it you power brake to bring up boost while having someone look at the gauges to compare boost to fp? I assume this is how this is done since the boost gauge is inside and the fp gauge is under the hood?

ed

 

[Daron]

I am the original owner, probably one of the 1st people to buy a syclone vin is no 00045. The top of the reg is black with a silver threaded tube sticking up that has the adjusting screw inside, the vac line is off to the side of the cylinder about midway sticking out at 90 degrees. It is an early atr unit installed 11-12-92. You suggesting i change it for a newer one?

I would assume to test it you power brake to bring up boost while having someone look at the gauges to compare boost to fp? I assume this is how this is done since the boost gauge is inside and the fp gauge is under the hood?

ed

There I go assuming... I figured since you were unsure of which regulator was on there, that you were not the original owner, and since you mentioned your truck had the stocker on it and that it had been adjusted I suggested the possibility that it had been crushed. Anyhoo...

Building boost with your buddy watching the underhood gauges could be dangerous. The prefered method would be to move your underhood gauge up to the outside of your front window for testing. I used a length of stainless fuel line that had the proper adapters on each end and just zipp-tied the gauge to my wiper, so I could watch what the fuel was doing at all the various parameters for testing, to include WOT.
However, we have digressed from your original question. Id get Datamaster before any more mods.

 

[ed hess]

Yesterday bought a used ibm thinkpad w color tft for 300, then downloaded datamaster, my diacom software is from 1991 and last night i rediscovered it didnt include the sycone file. since the diacom has gone thru a number of upgrades and feature additions monday i will order the cables for datamaster. The old diacom cable uses the lpt port thru an adapter. Rather than post questionshere using diacom it makes more sense to use datamaster so that i can speak the same language here on the board.
The unknowns with the fp regulator is because up until a few months ago year ago when i started redoing the truck i had not taken the time to learn how anything worked in the truck (heck i just figured out where the map sensor was while redoing vac lines.
As for moving the fp gauge to the wiper, i redid the body in 2001 and rather than chip some paint for the ss line, i think i will add a isolated 2nd or electric gauge into the gauge panel i built which mounts uder the ashtray with my tcc switch, ic pump switch, and manual fan & man pump switches. I was going to use the extra space for the ulitimate chip controller box but i can always mount that in or under the glove box.

Gimmie a few months and i wont sound like a newbie anymore.
Funny since i been working i the business my whole life. I own a pace called Auto Dogz Inc. www.autodogz.com
We do viper alarms, rhino linings, sunroofs, tint and all kinds of truck and car accessories just no motor or suspension stuff.... ya might say we do the gravy end of the business.
Go to the site and click on the products page, check ot the dog wearing the tux. You will laugh your ass off when you see it.
thanks for the help!
ed

 

[ed hess]

just ordered boost memeroy guage which will work wilth my existing vac boost gauge and electric fp guage with hi lo memory. when the goal is 11.99 it might pay to be able to look where your are going and check the guages afterwards lol not to mention the added diagnostic capablities.
ed