need some help with the adj fuel pressure regulator

[vikingpower]

I recently installed a BBK adj fuel pressure regulator with a Nordskog dig guage, it works ok but it isnt very consistent. I had it set at 38-39 idle, and at WOT it would go to about 42. then it started reading lower, 34-35 idle, 38-39 WOT. I have been playing with the adjustment but the pressure wont stay put. I still have the stock 19#, but also have a 255 pump. Does anybody have any suggestions for what pressure I should set it to or will I have to keep adjusting it?

 

[Ourobos]

Did you set it with the vacuum off (finger over the hose)?

 

[HISSIN50]

you should not have to keep adjusting it. either the pump or regulator is on the way out, from the sound of it.

if the pressure changes are slow enough, the puter will adapt. but if the pressure changes 10 times a drive, the puter is gonna be hunting for a correct injector pulsewidth.

good luck.

 

[vikingpower]

yes, but over time it wanders, sometimes even from day to day. At first I thought it was the barometric pressure changing, but that didnt seem likely...

 

[vikingpower]

what pressure should I aim for? I read in MM&FF or 5.0 the set it to 45 but it was on a 4.6.

 

[HISSIN50]

At first I thought it was the barometric pressure changing, but that didnt seem likely...

if the system was open, then atmospheric pressure could be considered. remember how small atmospheric changes are, day to day.

in a closed system, this is not the case. i would keep looking. good luck.

 

[HISSIN50]

what pressure should I aim for? I read in MM&FF or 5.0 the set it to 45 but it was on a 4.6.

most people are 32-36 stock (at idle, line attached). this is usually ~39 psi vac line off.

remember, the puter will trim the injector pulsewidth to adjust for whatever pressure you set.

good luck.

 

[vikingpower]

thanks for all the feedback, I wish I knew about this site when I first bought my car and started working on it, as I just found it yesterday...

 

[HISSIN50]

thanks for all the feedback, I wish I knew about this site when I first bought my car and started working on it, as I just found it yesterday...

i hear ya - me too! i would have used different parts had i had internet when i got the car.

good luck.

 

[Funanin]

setting proper fuel pressure for your setup

Get one of your buddies to ride along with you. Find a level stretch of road where you can do some testing.
Don't choose a speed range that will make you shift gears, the shift quality & speed will affect your results
. Use 2nd or 3rd gear and do a run from 2000 RPM to 5800 RPM. Call out the RPM as it increases and have you buddy record it and the elapsed time.
If you have one of those cheap digital watches like I do, a stop watch is built in. Start the fuel pressure at 36 PSI, vacuum off and make a run.
Turn it up to 37 and make another. Be sure to reconnect the vacuum every time you set the pressure
. Keep turning up the pressure and making runs until you notice a drop off in time.
If your bud was careful to record the results, you'll have a nice chart to use to find the optimum pressure.

 

[HISSIN50]

Get one of your buddies to ride along with you. Find a level stretch of road where you can do some testing.
Don't choose a speed range that will make you shift gears, the shift quality & speed will affect your results
. Use 2nd or 3rd gear and do a run from 2000 RPM to 5800 RPM. Call out the RPM as it increases and have you buddy record it and the elapsed time.
If you have one of those cheap digital watches like I do, a stop watch is built in. Start the fuel pressure at 36 PSI, vacuum off and make a run.
Turn it up to 37 and make another. Be sure to reconnect the vacuum every time you set the pressure
. Keep turning up the pressure and making runs until you notice a drop off in time.
If your bud was careful to record the results, you'll have a nice chart to use to find the optimum pressure.

hmmmm, that sounds like one of Jrichker's posts.

 

[Funanin]

yup and it works.

 

[HISSIN50]

yup and it works.

um yeah, i kinda knew that. i was sorta trying to be subtle in saying perhaps you would want to reference him as the author, since it looks almost verbatim.

 

[vikingpower]

update

Thanks for the input, although running the car up that high in either 2nd or 3rd gear would give me a reckless driving ticket, seeing as I would be doing about 80 in second or 110 in third (I have actually done it). That is a good suggestion although I dont know anyone that would be able to help me with it with any consistency. I set it to about 47 at idle and 51-52 WOT and it doesnt lean out anymore, even if its a little rich. By the way, does anybody have a reasonable estimate for the top speed of my car? I guess it makes about 50 hp more than when it was stock. Thanks again for everybodys input.