X64v

What I meant was during normal street driving (it's my daily driver) I don't hit WOT much anymore with this problem hanging right there. I've tried tuning up through 150-160 ve at 4krpm and above with the same results. And I'll get my current .msq file up in a few hours before I go to work.

Yes, you are certainly correct, I am running lean there. I'm still running the same fuel map that I just stole from someone else to get the car running. I never bothered to tune the rest of the map because it was just hitting that wall really fast anyways, so I'm not under WOT very much anymore (which really blows...I miss dropping a few gears and flooring it to pass people and stuff). And yeah, my duty cycle is way low. I bought these injectors with the intention of adding a turbo in the near future. I only need maybe 180cc or 200cc injectors for this engine running n/a.

Nope, alternating made it run worse. Still did the exact same thing at the exact same rpm, but it wouldn't run worth beans under 2k rpm, either.

Stock 5/16" feed, emissions hardline for return. I'm getting well over double my needed flow through the lines, so they're not a problem. I'm bored, and it's nice out (~78 degrees, gotta love southern arizona), so I'm going to go try out setting injector staging to alternating.

Not on my 72 or 73, that's for sure. They're just stamped steel that close in a half turn, no threads or anything like that.

Two groups of three, simultanious, two squirts; what I saw as the standard for running MS on a stock-manifold L6. Would the engine run on alternating?

I am currently running cleaned/flow tested 338cc ford cfi injectors. It also did the exact same thing with 25 year old 19lb n/a zx injectors as well.

Yes, it is a 240 tank. However, it does it with a completely full gas tank, and also sitting still in neutral. The FPR is giving me 36psi while the engine is not running, and I'm getting that 36psi in between injector pulses (or so I would guess, I couldn't time it to be sure). This happens free revving as well. I wonder what I could find out if I rev it with one hand and then pinch the return line with the other... I will try wiring it directly to the battery, though I doubt this is the problem since the fuel pump wiring is the same now as it was with the carbs, and I never had any trouble then. Otherwise, I'm stumped. Hopefully braap will chime in and tell me why it's not working with two pages of fluid-dynamics...

http://www.ozdat.com/ozdatonline/enginedesign/ wonderful.

Yes, you can do that. I ran one like that for a while. You'll have to block off the cold start injector port and the old return port that come off of that line of rail. Just remember not to cut the ends too short, because if you do, the sharp edges will cut through fuel line like no tomorrow (ask me how I know...).

yards like that make me sad

Alright, I'm about ready to file this under the straingest car problem ever... I just did some flow tests on the system (5 gallon gas can w/full mark, and a stopwatch). Free flow (tank-->prefilter-->pump-->filter-->gas can) I got 60gph (did 5 gallons in 5 minutes spot on) Pessurized to 36psi (tank-->prefilter-->pump-->filter-->hardline-->fuel rail-->fpr-->gas can) I got 49gph (did 5 gallons in just over 6 minutes). The second test is running exactly like the car runs, through the same routing, everything. The feed line did not collapse or even seem weak during either test. So this means there's no blockage, no restriction. The only thing I can think of that hasn't been discussed is that I'm not running a fuel damper like the ones that came on the cars originally. I was pretty sure they weren't necessary, but are they? EDIT: I didn't like the fact that my first free flow test didn't run through the hardline and fuel rail, so I repeated the test, but ran it through them as well... Free flow (tank-->prefilter-->pump-->filter-->hardline-->fuel rail-->gas can) 60gph as well (came within two or three seconds of the original free flow test, which is within my margine of error for shutting off the pump at the 5 gallon mark).

Matt - Thanks for checking the whole log to make sure there was nothing that the untrained eye would miss. Cygnus - That's the conclusion I came to as well. I have been testing and bypassing every part of the fuel system that I can think of. I will try bypassing the 2nd fuel filter when I get a chance, as well as making sure the feed line before the pump isn't collapsing. Bernardd - It's mounted on the intake manifold, with perhaps 8 inches of fuel line between it and the rail.

Yup, that's how it's run. And I will do the visual flow test next time I get a chance. I'm running NGK plug wires. Matt - Here's the whole datalog file. I did the 1st-2nd run, then pulled over and waited for some cars to go by, then turned around and did it again, towards the end of the file. datalog.zip

Yup, I was actually getting a nasty spike while running spark control, so I took that away and just had it trigger off the coil -, no apparant spikes on the tach or on the rpm graph anymore.

Same power source as I ran with my electric carb pump, and I ran for ten or fifteen minutes at a time over 4k. And I thought about that, too, but I banged up the bottom of the tank with a rubber mallet and then drained it, and it came out clean, and then I bypassed the tank feed line by feeding from the drain hole, and the gas that comes out is clean, with no crap in the clear prefilter. But please, keep the ideas coming.

Don't worry about asking seemingly stupid questions, we all make dumb mistakes. Yes, the msd pump is an FI pump. Veritech - That's EXACTLY what it feels like. Climb up just over 4k and BAM feels and sounds like a rev limiter. Except mine's cutting 0 out of 5 sparks at 25,000rpm... On the question of ignition, I'm running fuel only through megasquirt, and this exact same ignition set up ran just fine with my su's. Ah, forgot to mention the temporary fuel pressure gauge thing...when it's cutting lean, the pressure needle bounces back and forth between 0 and 35 as fast as it can (I assume it's dropping to 0 when the injectors open, telling me I have a lack of flow for some reason...). Problem is, I have no clue why I'm getting this lack of flow (that was the reason I bypassed the tank pickup and feed line and used different pumps and all that). And here is the same datalog with the pulswidth...which (as I see it) totally eliminates the electronics from being the problem.

This has been plaguing me since I made the switch from my su's on Thanksgiving. The engine will run alright to 4000rpm, at which point it promptly falls flat on it's face. Even with it floored while out of gear, it won't reach much past 4-5k. My NBO2 sensor (along with everything else I know about tuning) shows that it's just dropping dead lean. Figuring that out was the easy part. The part that's stumped me for the past three months is why is it dropping lean? Every single mechanical component in the fuel system has been tested or replaced. Lets start from the top: Clean tank, gas flowing out the drain plug hole through 3/8" line into a clear fram filter, into a new MSD pump (stock nissan pump was used as well, with no filter before), then through a new fram metal filter, through the stock hardline (have also totally bypassed the hardline with new 3/8" rubber fuel line), into rebuilt 338cc ford injectors (also used oem l28 n/a injectors), through a stock FPR (holds ~36psi at ambient pressure), then back to the tank via the emissions hardline and one of the 1/2" vent tubes. The tank is vented just fine, and as I just showed, every single part of the fuel system has been tested/bypassed/replaced. Below is a datalog of a 1st-2nd gear run of the problem. I floored it in 1st until the problem popped up, then shifted to 2nd and ran wot again until it maxxed out. On the graph, you can see it best climbing through 2nd gear where TP is at 100% with the rpm's climbing, and then O2 just shoots lean. My ve table is layed over the O2 graph, showing that my fuel map is rising through 90-95% ve just fine. I have tried using fuel maps up to 150-160% ve (way too high for an N/A l24) with the same result. If you have any idea as to why this is happening, or have any questions about my set up/what i've tested, please speak up.

Got the injectors a week ago. They're freakin sweet. All polished up, with the correct pintle caps and even a new set of seals. I'll definitely be using motor man for my injector needs in the future.

Yes, it will. The vapor line mentioned will do just fine. I cut it in the back of the car by the tank, and ran the line directly into one of the tank vents.

That's right, it is 5/16". I've just been using 3/8" for so long because my local auto zone doesn't have 5/16" carb fuel line.

an hy35w....

Yes, I did it for a few months on my 73 (bad battery tray corrosion as well). The feed is 3/8". The return is something rediculous like 1/4" or something.

Great mph Clifton. The left lane takes off on you and then wooosh! What psi were you running in that run? Like 1 fast z said, for those of you that haven't seen Clifton's car in person, it's amazing. All that power, and totally driveable on the street.

You surely should be able to find a competent shop in tucson, but if for some reason you can't, I know of a good alignment place here in phoenix that can set up even the most exotic z suspension very well.