A-dub5513

I posted this in H-T's Integra Forum. It was buried and forgotten within days:

JRSC runs fine, but would benefit with a few less psi's at the low-end. I'm already using the largest orifice (1 of 3 interchangable discharge ports) with the set screw backed all the way out. According to AEM, the range is 20 psi. (min.) to xxx psi. (max.) of whatever high performance pumps can dish out. Granted, they don't specify whether that figure is static or not. I'm seeing 30 psi. @ idle (38 static).

Thought about drilling out one of the three ports I have. It'll work and is easy to do, but want to know what other possible causes can be. I'm sure things like clogged filter, clogged fuel system (teflon tape from in-hood gauge atop the fuel filter), stuck diaphragm in FPR are all possibilities, but unlikely, in my opinion.

Are there any other likely causes? Thanks.

A-dub

PS. I do have 310's if it matters any.

Tony the Tiger

To get a typical Walbro 255 pump down to 20 PSI base pressure, the regulator is not at fault. In order to bring the pressure down that low, the factory Honda 1/4" fuel return line is not sufficient.

A cloggged fuel filter will only lower fuel pressure, not increasing it.. Any restriction on the pressure side will only drop fuel pressure. Any restriction on the return side will raise fuel pressure.

If you really need to bring the pressure down that low (it's probably pointless because most injectors don't even work well below 30 PSI anyway), you will need to upgrade the fuel return to a 5/16th or -6AN. Don't drill anything unless you want to break something and make your AEM FPR worth nothing when you want to sell it.

EARLdaSQUIRREL

why not get a proper tune and not worry about trying to do things a ghetto way

JDogg

yeah.. there is NO reason have the fuel pressure that low

A-dub5513

Thanks Tony, for clarifying the situation. Actually guys, I just wanted the pressures down to 28 psi idle (about 34 - 36 static). Currently, it's set @ about 30 idle (37 - 38 static), with the set screw backed full CCW.

So you see, I just wanted to lower the FP's by a few psi's (about 2 tops), and wasn't sure why I wasn't able to do so with the largest orifice.

So you still think switching to a 5/16" hose will do the trick?

Thanks for your time guys.

A-dub

ralph11sec

2 psi lower is not at all significicant.

A-dub5513

Umm, I respectfully disagree...it'll be significant enough to get rid of the slight bog from a stand-still. The ballpark idle FP's should be @ 28 psi. for my setup. I'm currently around 30 - 31, so it's a bit rich right now. And from experience, a quarter turn on the set screws of the FPR or FMU here or there does make a difference. We're talking as much as one to two full turns here.

JDogg

any particular reason you are 10 years behind the times in your tuning methods?

have you tried adjusting the FMU? I know those cartech fmu's are tricky and can sometimes keep you from lowering the base pressure. They have sort of a base pressure adjustment as well.

A-dub5513

Hey JDogg. I figured this subject would come up again sooner or later. It's usually much sooner.

Many have wondered or have been baffled (and in the extreme, downright offended!) about why I'm even asking about such antequated equipment and setup. Thing is, I bought my 'Teg in '99 and pretty much SC'd it after, but not before doing extensive research on all the best mods; what works and what doesn't for a reliable setup available at the time. For the first few years, 6 psi worked almost flawlessly with the addition of the FMU and JR's BTC. But I got bitten by the boost bug and wanted a little more. So again, I waited to see what mods were tried-and-true for 8 psi. and ignored the rest of the BS. That takes time (and even more patience). Then in went the pullies, J&S, injectors, etc. But it left the install shop in a horrible state of tune (more on that later). Almost immediately after, I quit my job and went to art school. This was in 2002.

I woke up one day, 4 yrs. went by and I had graduated. I had free time. I started tinkering with the car again. On a complete fluke, I realized why my car ran like crap for so many years and the guys at the dyno couldn't lower my FP's: I needed to reuse my check valve in the vacuum hose to the FMU now that I have 310's!!! My car ran noticebly better for the first time in years. MPG's were up and, more importantly, engine didn't die while RPM's dropped when taking corners. Although it was far from optimal, I knew I was on the right track and got back in the game. Only now, EMS's are in. They're the new trend. "Band-aid" mods became the equivelant of homes in the U.S., you couldn't give 'em away! Why? Because the same "car guys", back then, who didn't have a basic understanding of how their cars worked (or cars in general) or how their mods worked; who bought (and bought into) the latest mods are the same "car guys" to later join everyone in calling them junk. I don't, by any means, consider myself an auto guru, but let's be real, there are some straight poseurs out there. But you know what? They're learning. Isn't that the universal noob defense: "I'm trying to learn. That's the point of the forum and posting!"

My point is: it took me a whole decade to learn, to install, to understand how my setup mostly works. MOSTLY. Call me sentimental, hell, call me stubborn, but I'm getting a little too old, too broke, to be dumping ten years of effort into my setup just because there's a newer way to achieve the same thing.

Don't get me wrong though, if my car was a virgin 5 years back, I'd be here with the same setup asking the same questions. I see just as many varied questions now with EMS' as I did back then with piggy-backs. And the answer to these questions is this: There are no magic buttons. It's all about tuning. Careful tuning. The basic principles remain and must still be applied. The only difference is the execution in which to apply these basic principles.

JDogg, honestly, this is not directed to you personally, or to anyone in particular for that matter. And as unbelievable as it sounds, I'm really not bitter. But if I had a nickel for everytime I asked a tech question (and I do try to be as specific and technical as possible), not just here, in other forums as well, only to get a response like: "Why are you using this or that? That's junk." or "Nobody's using that anymore. Why don't you just dump that setup and go with xxx or yyy and forget about it?" or "If you don't take our advice and go with standalone A, why do you bother?", I'd probably have enough nickels to pay someone to invent me a teleportor!

Cheers,

A-dub

JDogg

Thats cool.. I figured it was either that or you wanted to keep the stock ecu for emissions mess.

at least you have a good FMU, there are tons out there that wouldnt last a year.

The fmu/j&s setup does work, however dont kid yourself by calling it the "Samething" as having a proper tune with either a chipped ecu or a standalone.

I would take the fmu out of the return line and make sure thats not the reason the fuel pressure wont go low enough.

HiProfile

I'd just call you ignorant. Nowadays, tuning is as much about the right hardware as it is the person tuning -- no ifs, ands or buts. Its not a 'fad' to do what race teams and OEM's do -- use the right hardware. If you were to sell the AEM & FMU, you'd have half of what a cheap street tune would cost ($100-150). Yes you'd have to drop ~$150 for a harness/ecu/chipping, but it will be the best horsepower & drivability gains for the money. That tune would also pay for itself from the gasoline saved. All that can be acheived with a day's worth of time.

If you really claim you can learn, re-read the posts above. Injectors are NOT designed to work with low fuel pressures like that. You will end up with a worse spray pattern and less atomization of the fuel - both are bad for power and economy. Then you'll be right where you were before -- with poor economy, power, and throttle response.


Just FYI, in the last 4 years Honda ecu's have seen some incredible changes. Full-feature electronic boost control entirely controlled by the OEM ECU, secondary fuel maps, analog inputs, general purpose outputs, etc.

A-dub5513

Yeah, I know next to nothing about stand alones, but from what I've read thus far, about swapping ECU's and harnesses, my personal choice was to not tackle that.

Even back in the day, there were so many stories of folks breaking open their FMU's and rebuilding 'em till their hair fell out because they either thought it was stuck or leaking. Even mines was rebuilt twice by the tuners who installed my 8psi upgrades, but as mentioned above, it was the missing check valve. That, and luck, perhaps.

I happily retract those words as I'm fully aware that with a good tuner and the right equipment, EMS' will get your setup running its optimal and with pinpoint accuracy. Rather, for myself personally, I have faith that with my existing setup, once the bugs are worked out, should (and would) run close enough to, say, "proper" without my starting from scratch to gain that extra inch (or HP) to be "perfect".

In doing so, what am I looking for exactly? Also, in a previous post, you mentioned the FMU's having a "base line adjustment"? I'm interested in hearing more. As far as my understanding, setting baseline is done adjusting the set screw on AEM FPR first, vacuum hose off and capped (with the FMU's set screw backed out all the way). Once done, reattach FPR's vacuum; then disconnect and cap vaccuum on FMU; then adjust set screw accordingly (to desired FP); then reattach.

And JDogg, thanks for bein' classy even after my rant...a refreshing rarity.

EARLdaSQUIRREL

for the amount of money you could sell the fmu and aem fpr you could almost get a good street tune with a jumper harness and a chipped ecu, i know you don't want to hear this, but the gains in gas mileage alone will be worth it, let alone the fact that you know the tune is spot on and your motor will last much longer

good luck either way, but with that low of a pressure your asking for horrible gas economy and a tune that you have no idea where it stands (a/f wise)

JDogg

Earl.. actually his gas mileage should be close to stock as long as he keeps his foot out of it with that setup.. I was tuning things before there were aem's and chipped ecus too.. lol

On some fmu's they will increase the base fuel pressure. If the cartech fmu is the one im thinking it is there is a little **** on the side that allows you to adjust it. That could be keeping you from lowering the fuel pressure, the easiest way for me to tell you to check that w/o seeing the fmu is to completely take it out of the loop, check the pressure, then you can put the FMU back and adjust it properly.

Most of the time fmu's are "rebuilt" to change the rate that they increase the fuel pressure. When i had one break/leak we threw it away and put a cartech on it.