View Full Version : AFPR tweaking, i need help ? plz...

06-12-2004, 07:43 PM
i just redid my fuel rail hoses with all new 6 an gauge braided hose and use hose clamps real tight, swapped out some injectors, and put in my billet AFPR from MN12, did front supercharger seal, changed inlet hoses to braided, and i started my car and it read about 12-13psi at the fuel rail (i have an autometer ultralite pro comp electrical fuel pressure gauge on the fuel rail), could this be possible ? can the AFPR be that restrictive when its almost closed ? i dont smell fuel ? am i suposed to go counter clockwise to open for more PSI or clockwise ? i just got this tonight all back together, just put in new heater braided hoses and eliminated going to the firewall with them, and bypassed my heater core. plz if someone with an AFPR can help me out on how to get more PSI i'd appreciate it ? it was set to this adj from rich i didnt move it, thanks Alex L

06-12-2004, 07:45 PM
i forgot to add, i was getting before at the fuel rail at idle about i think 25-27 psi... so now its about half that..

06-12-2004, 07:49 PM
another thing i have a 255lph pump from SCP maybe 3 yrs old, and i replaced my fuel filter maybe 2 yrs ago.. i put all new o-rings top and bottom on the new used injectors from Victor @ Spinnning Wheels, they look really good..

06-12-2004, 08:28 PM
the regulator needs to be set at static pressure. This is.....remove the vacumm line from the reg and then make any adjustments. With stock injectors you should get 39psi at static. Once the line is put back on you should get around 29ish at idle. The regulator needs to be set, and it isn't set right out of the box. DO NOT drive the car unless you get the right pressure. Like i said, make sure it reads 39psi static and you'll be all set.

99% of the time you dont need a regulator and they are really a waste on our cars. People say they fail all the time, but i've had no problems. I have one, but i'm running 42lb lucas injectors which run their best at around 43-44psi. I learned that adjusting the pressure doesn't give any performance gain, and it was really a waste of money until i purchases 42's a month after.

06-12-2004, 08:32 PM
thanks alot, i'll try that tomorrow then, no i didnt drive it yet, just reved it a lil and i seen the a/f gauges go to the stoch , but thanks again.

06-12-2004, 08:41 PM
fastsc92, i'm not wanting to stay stock, just for now to drive it this year, i have a 4 dr civic i'm trying to finish up this yr for my daily driver, but i want to be at least able to drive my SC the way it is, i thought mayeb my injectors could off needed to be replaced, because i never did them, and also the fuel pressure regulator i didnt either, and i was told that a "leaking injector" could cause late engine start, to i said what the hell, newer stock injectors for now (i want 50lb MSD, look ay my member page for future plans, i want extreme :) ), AFPR for now, and i used braided hose for the fuel rail, AFPR top hose piece, plenum lines, intake to drivers valve cover, overflow line, i made a line that went from the left fitting on the oil cooler to the waterpump so i could remove that junky line i had, and i made another line that went from the right side of the oil cooler up on the side of the engine straight to the inake manifold, totally bypassed the heater core, and took those bulky lines out today also. i spent about 180-190 in braided hose and clamps. but everything was easily acceble and i had some stock lines on my car and i upgraded before to some yellow silicone lines and wanted to get rid of them. maybe i'll take some pics of it all tomorrow. Alex L

06-12-2004, 08:53 PM
sounds good to me, however dont even bother looking at those a/f ratio gauges. Those autometer or any narrow band sensor is basically useless. The only way to monitor your ratio is to get a wideband set-up. I just purchases a wideband kit and it was $509!! However this will give me 100% accurate measuments and it also data-logs ect ect ect.

A narrowband meter is only designed to be accurate around a 14.2-14.8 ratio. This is where you drive 90% of the time, and the computer monitors the readings and makes any changes. If you are running rich, you wont know exactly how rich or how lean you are, because there is a lot of slop in that sensor. It just wasn't designed to be used for tuning.

Just for example...a buddy of mine had one of those blinkying a/f ratio things and we headed to the dyno for a wideband reading and hp numbers. That autmeter guage said it was running rich, when in fact it was running dangerously lean. At WOT the ratio should be 11:1 if its a stock program. A perfect mixture at idle and cruising should be 14.7:1, but that autometer gauge will go rich lean etc while driving. At WOT it should go as rich as the leds will let you, and never got to stoch. Anyways the bottom line is i wouldn't trust one of those things in a million years.

06-12-2004, 08:59 PM
yeah figures after i bought 2 of them and wired them 1 to each O2 then i hear people telling me there not accurate and not good for tuning, but that why i updated my member page on the future plans, but i'm wondering, is a autometer pyro meter good for tunning ? or is that the mid grade thing to do ? i thought i read someone mentioning u really have to know the car to be able to tune with a pyro meter ? or is the wideband the only way to go ? Alex L

06-12-2004, 09:18 PM
well a pyrometer measures the exhaust temp. Generally the hotter the gasses...the leaner the mixture. This isn't always true though. Overly hot exhaust doesn't mean lean on all cars. Some cars will run 1300 and other will run 1600 and still run a 12:1 or 13:1 ratio. Once you get a reading from your gauge, you'll need to know what ratio is at what temp, and makes things more confusing. So you are right that you need to know how your car reacts at different EGT's.

In my opinon, a wideband is the easiest and fastest way to know your exact ratio on the spot. My unit has a digital display for easy monitoring all the time. The unit also can data-log an hour of time. The unit can take in many other inputs such as MAF voltage, TPS voltage, RPM, MPH, temp, baiscally anything. This is used so that you can download the data via wireless connection onto a lap-top or computer and compare your ratio to all of those above inputs. Its a really nice feature when you are writing your own eec tuner file and need to know the exact instead the engine is getting lean and fine tune. (like me).

On a final note, I guess the "best" way to tune, would be to have a wideband and a pyrometer at the same time. However it isn't really practical. Widbands are so cheap now that they pay for themselves in 2 dyno sessions. Mine was more expensive only because it has data logging, but their basic model which is still top of the line was around $330. Like i said i think its a worth while investment. At first it might seem like a hard blow on your wallet, cause once it's tuned....you shouldn't have to touch it, and that investment is just sitting there. But i figure i rather spend the money on this than a new motor because of improper tuning, and dynotime.

06-13-2004, 03:00 PM
<fastsc92> thanks i adjusted my AFPR this morning, did it to the way u said, i was going on the highway and opened it up and hits 50 psi ? is that ok ? i hope so.. Alex L

06-13-2004, 03:51 PM
that sounds about right. If you set your static PSI to 40, then every PSI of boost gets added to that. So at WOT if you are pushing 12psi...then you should have 52psi pressure. This is because the regulator is hooked up to the intake, and it is vacumm and boost controlled. I hope that all makes sense.

06-13-2004, 05:57 PM
i also noticed i was hitting 14-15 psi (in 5th on the highway) on my autometer electronic boost gauge, i was suprised ? is it possible with my setup to hit that high ? (can check my member page) i was messing around with a SL600 V12 convertible mercedes benz red, looked like a 00 style, sick car, he just kept up behind me, and stayed on the side of me, and i'd get on it and he was right behind me keeping my same speed (going a lil quick sometimes, but he never like floored it on the side of me) and then i was just cruising and hittting the gas a lil and he'd pull up on the side and he was smileing, pretty cool, i should of had my friend take my camera out and take a pic of it, he was some older guy had a computer i think stapped down in the passangers seat, and he had that like screen window thing up in the rear, dude must have some serious money :) i was suprised he didnt blow by me, at first i seen it was a mercedes then i got on the side of it and the fender said V12, i said dam, then later on i got stuck in traffic and i seen him go by and i seen 600 SL, i said wow.. all on the way to the mustang unlimited car show in manchester, because i got an e-mail from molley i believe from TCCOA CT chapter and they said they were going to try to get t-birds to enter, but i called this morning and they decided not to i guess, just took some pics of the cars there, was fun..i wonder how fast a mercedes 600 SL V12 would of been ont he highway at WOT :) .. here is a pic of my engine compartment...Alex L

06-13-2004, 06:10 PM
Here's some pics of my set-up