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TBI HELP! adjustable fuel pressure regulator

So i pulled it all apart and it seems that everything is indeed correctly installed and seated (at least by what i can tell) I installed the smaller spring and reassembled to test it and the PSI is now closer to 17 psi but, that is with the smaller spring backed all the way out!

At this point things are really starting not to make scene.

Are the diaphragms specific for application sort of?
Could it be that when i replaced the diaphragm the new one is stiffer???

I did notice it was not the same material but rubber but all the new ones are rubber
 
So something else i noticed was that the fuel pressure drops slightly when the gas is applied like 2psi maybe. This should not be the case tho if im not mistaken it should be a constant correct?
 
I'In my thinking manifold vacuum drops as throttle opens, so with it not hooked up, it should run X PSI (say 20PSI) which would be the same as with the FPR hooked to vacuum, but under heavy acceleration. At idle, with vacuum hooked up, I would *assume* fuel pressure should decrease.

I have never seen one of those things disassembled, is the vacuum just pulling on the back side of the diaphram?

If changing the spring made a difference, I guess you are on the right path. Only adjustment I see at this point would be to cut the spring in very small increments, so that you can still adjust it. But you would have to know how vacuum affects the idle fuel pressure before doing that.

Whatever port you connect it to, it needs to be manifold (not ported/timed) vacuum.
 
So below is an idea of what im working with (not the same exact one ill try to get a pic of mine later) pretty simple though and everything is the same except the shell on the right.

Ya so the manifold port looks like what im looking for then at idle i need the most vacuum as it will be pulling the diaphragm open and less vacuum at wide open

as for the spring i was thinking about doing like what the Mexicans do around here for there low riders and heat the spring to reduce the springs constant and thus pressure

TBI.jpg
 
I'd be careful about heating the spring, you can completely ruin a spring at even oven temperature. Might get away with doing a part of a coil near the end, but its going to be hard to control.

In any case going to be a pain to get it where you need to be, doing a bit at a time. Once you go too far, the spring is ruined.

I've never watched the fuel pressure with a gauge. I suppose with two large injectors, getting into the throttle initially might drop pressure, but as long as the injectors weren't flowing more than the pump could supply, the pressure loss should be momentary. Someone with TBI and a pressure gauge would have to comment on whether that is normal or not.
 
Show us a picture of the inside of the regulator cup. What is the spring seating on oposite of the diaphram? Make sure that when you back out the adjustment screw that the spring seat is moving along with it and not binding in the cup.
 
Is the adjuster screw really hard to turn?

I can BARELY turn mine by hand. If it turns easy, something is probably wrong.
 
the adjuster screw is not hard to turn i can not turn it with my fingers tho but light pressure with an allen wrench works just fine and i can kind of feel the pressure in crease with each turn. But keep in mind this is all with the screw back all the way out so i am not even adjusting it yet and the pressure is to high

I will get pictures of everything shortly. made a run to the parts stor and hardware stor to see if i could find different springs
 
Ok so here are some pics of what im working with... First one shows the side of the diaphragm that goes face down into the pod lid. second show the diaphragm set in the pod lid with spring pad facing up and how it only installs one way. Third shows the opposite spring end with the spring perch assembled how it go into the regulator.

diaphragm2.jpg

diaphragm1.jpg

spring end.jpg
 
This next set of pictures shows that assembly in the first one final assembly in the second one and the last one is of the two washers. Originally the reg just had the washer on the left in there as the spring purch but my old reg had a better perch and so i put that one on in replace and it seems to work better

assembly.jpg

assembled.jpg

washers.jpg
 
So as of today:

I pinched the return fuel line and there was no change in the pressure.

I put in the smaller spring and the pressure dropped to 17 psi but when i pinched the fuel line still no change in pressure.

I ran compressed air through the return line and it was clear. i ran compressed air through the regulator and it to was functioning properly.

As of this moment i think im going to use the link provided to try and find a lighter spring. I am really thinking it might be my fuel gauge although it is my second gauge i have put on there recently and they are Both reading the same.

one fuel guage was a cheap $20 one and the other a $40 dollar one. Should i be investing in a more quality gauge?
 
Use ONLY the parts that came with the new regulator, DO NOT mix your old parts with the new AFPR parts and i'll bet your problem goes away.
 
I tried using the ONLY the parts that cam with the new regulator and no such luck. The instruction for the new one say to use the spring it came with if you want higher psi and to reuse the stock spring if you want lower psi. either way it did not fix my problem
 
Brians1990Blazer said:
I tried using the ONLY the parts that cam with the new regulator and no such luck. The instruction for the new one say to use the spring it came with if you want higher psi and to reuse the stock spring if you want lower psi. either way it did not fix my problem
Click to expand...

Will in that case I would suspect a bad gauge. What is the range of the gauge you're using? If it goes high enough i would suggest testing it on an engine oil pressure port and see what it does.
 
one of them reads 0-15 but the other which is in their now reads 0-30?

Where might i find an oil pressure port?
 
Brians1990Blazer said:
one of them reads 0-15 but the other which is in their now reads 0-30?

Where might i find an oil pressure port?
Click to expand...

I would not use either of those gauges in an oil pressure port since they are both too small of a scale.

If the rig runs and you're comfortable driving it here i'm sure we could check and fix it. Just let me know.
 
O she runs and seems to run ok. Would love to drive to you for some help but unfortunately time dose not permit me to do so currently. Working two jobs and school kind of kills any time i have but if i get a day that opens up or something and i haven't fixed it by then i will defiantly hit you up! Thanks!
 
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