FAST EZ EFI questions

[Bygblok]

hope to be running gas through the lines later today to set my pressure and have a few questions for those who have used this setup. Number one, when I set my fuel pressure @43psi, how much pressure)if any) is in the return side of the system and would it be safe to let in run in a loop for a little while to clean the new fuel lines out from any trash that may not have exited when I blew out the lines with air prior to installing them? I used a spectra tank with the internal pump so I hope adjusting the pressure doesn't give me any suprises. Number two, I want to set my a/f up to run as efficiently as possible for the motor I have. It's a zzz sbc with a set of dart 200cc iron eagles. Lift at the valve will be around .512 with duration [email protected] on a 114 lobecenter. Fairly mild but should bump pretty good idling. Was thinking idle @13.1 and set most anything above idle @ 12.1? I can go leaner if need be for cruising the highway but looking for the best all-around for a baseline. Oh, and using an MSD HEI for a dizzy and will start with an AC Delco R44ts plug if it makes any difference. Just hoping I don't have any fuel leaks when I put pressure to it. Don't want any of my new powdercoated stuff to get messed up!!! Thanks in advance, Bill

[Mr Nick]

I installed my EZ EFI system this Spring. I'm not sure how much pressure you'll have on the return side, that's probably dictated by the size of your return lines, elbows, restrictions etc... It's ok to run it for a while, but I assume you're going to run it with the return emptying into a secondary container, to flush out the lines? When you go to key on, the pump runs for about 10 seconds. This was not enough time for me (working alone) to set the regulator. But if you ground the correct wire, you can run the pump continuous for setting pressure and checking for leaks. I ran mine like this for 10 minutes, with a battery charger hooked up, to visually check every fitting for leaks.

My SBO makes about 425 hp, and I have my AFR's as follows: Idle 14.4, cruise 14.2, WOT 12.2. My idle is fine, no misses, no smells, no overheating, no hesitation off idle. My cruise is ok except an occasional lean miss at steady cruise, more noticable up slight hills. I may go to 14.1 or 14.0 and see how it reacts. Your guess of 13.1 at idle seems rich to me. But one thing to remember, which I've read all over the place online, is don't get hung up on a number for AFR. Give the engine what it wants. I was hoping for a 14.7 cruise AFR, but the engine just flat out runs better in the lower 14 range.

Also, one you get some miles on it, don't forget to then go to advanced options and play with accel enrichment. Mine is best at 1 or 2. I tried 8 just for kicks, and even in neutral revving the engine wasn't smooth, was slower to rev, and sounded bad.

[72BBSwinger]

Definitely agree on those settings. I could feel a difference between 12.4 and 12.2 wot.

[Bygblok]

I was thinking that with the cam specs I'd have to run it a little fatter and the last time I messed with a/f was on LSx based motors which seemed to enjoy the extra fuel. I' was used to seeing factory(lean) settings at 14.1 or higher. Thanks for the info. I can play around with a baseline from there. Almost ready to fire it for the first time.

[Mr Nick]

Sounds great! I'll keep an eye on this thread, post some updates and any more questions you have. My install went smooth but took a fair amount of planning. I used an in-tank pump and wanted all the lines and wiring to look nice. If I ever installed another, it would go much quicker.

[Bygblok]

well, got the motor fired and have spent two days now trying to get this damned thing to tune. I set a tune(even a base tune) and it will start fine and everything seems to work. Try driving it down the road and the furthest I've gotten was about 5 miles without problems. It seems to go full rich or start hunting for AFR at different times once it's warm. CTS shows anything from around 185 to 210 warm, the fans are set at 200 and shut off at 180. The last run on it only netted around two miles before it went pig rich at cruise and almost didn't get me home. Once I got home it would idle but surged between fat and lean with a 300-400rpm surge as well. When it pucks back up the idle it puffs black smoke for a sec and then cleans out. Less than a week till cruising the coast and I may throw this $2k sack of crap in the can to go back with a carb. I knew I shouldn't have sold my holleys....... damnit. Back to the garage tomorrow now that I'm furloughed!!

[Anthony k]

I'll get in line if your actually going to sell it

[Bygblok]

I'm still fighting it right now. Dropped my fuel pressure down to 35(instead of the recommended 43) and REALLY leaned it out.....WAY lean. Drove it about ten miles today without it leaving a black trail of smoke behind it. It used eight gallons of fuel in two days and only fifteen miles or so. Gotta get better than that or cruisin' the coast isn't happening for us.

[Mr Nick]

I'll start with the obvious... something isn't right. Not to be a smart ass, but there must be something set wrong or hooked up wrong.

Keep in mind it runs open loop till it hits 140* I believe. So it may run ok before 140* because it's not paying attention to the O2 sensor, then once it hits closed loop, it runs like crap? Do you have an exhaust leak before the O2 sensor? Leaking header flange gasket, header collector, cracked manifold, rusted pipes?

It took me a few days of tinkering to get mine all set up, and I'm still playing with the fine tuning each time I take it for a cruise. But it's a great little system, keep at it and you'll be happy.

[Bygblok]

No offense taken Nick. No exhaust leaks(soap bubble checked it even) all the targets seem to be happier now that I dropped the fuel pressure back to 35psi. Went lean on some more afr's. Going to drive it today if its not raining. Seemed a lot happier yesterday after I did all the crazy stuff. The only code I see now and the is a tps code. When I scan it I see nothing wrong as far as % in tps travel. Seems pretty linear to me, no dead spots or jumping around in readings. Wiring and sensor pins all appear good.

[Mr Nick]

I have learned the TPS setting and also IAC count at operating temp idle is very important. It took me a couple shots to get it right, but even so I don't think it would cause the odd fueling issue you seem to be having.

Maybe your pressure gauge isn't accurate?

[Bygblok]

spent some time on the tech support site with Matt(a big help, thanks to Matt) at F.A.S.T. today. After finally getting it through my head that this is just an old GM takeoff design I started checking voltages and grounds. Turns out that yes, the TPS was bad. Could only get it to adjust up to a little under .3vdc at closed throttle and it should be closer to .4vdc. Also, depending on how long it was run and what movement/shaking the motor was doing, it would short to ground internally making the car think it was at WOT so that explained the random fuel dumping and full rich condition. It got to where it would just go full rich at idle and die. It's a wonder I didn't wash some rings and foul plugs. I replaced the Chinese-made sensor with a Canadian AC Delco one, adjusted it as much as it would allow without slotting it, recal'd the TPS and it ran pretty damned good at idle. Was only able to get about 10 miles out of it this afternoon though before I was out of time. Hoping for no early tropical storm rain tomorrow so I can get it out and let it learn some more. Tossed no codes today after the replacement which is a sure improvement. Changed my fuel curve a little more too. Will see how it works

[Mr Nick]

Update?

[sebtarta]

Any updates on this? I am looking into buying this kit for my SBC, but not so sure anymore.

[Bygblok]

Sorry I haven't updated this. Got the car running good enough to do cruisin' the coast and ran pretty good the whole week. I've retuned it several times since and it gets a little better every time. The only issue I have is the pig-rich cold start. Until it gets a little heat in it it farts and snorts black smoke unless I pop the loud pedal a few times to clear it out. I hear that FAST may have a newer cold start program but I think I have to send my pcm back to do it. Other than that the motor seems pretty happy. I just don't have enough time to enjoy it!!

[Mr Nick]

Glad to hear of a positive update. My cold start is the exact opposite, it runs lean at 15.0:1 or worse till it hits 140* and then goes into closed loop. I've heard raising the fuel pressure at the regulator, but leaving the computer still think it's at 43psi may help me. You may try the opposite? Leave your regulator at 43 psi, but tell the computer your regulator is set at 48 or so.

Cold start ignores the O2 sensor, it's all a predetermined guess on how much fuel the engine needs while in open loop. So for you, the computer will think you're at a higher psi, and open the injectors for less time, in an attempt to get the same end result. Once it goes into closed loop, it may have to "relearn" things a little bit. Worth a shot, only go a few psi at a time and see what happens.