when you push the plunger in you drop throttle percent, all the way out is 100. just FYI.

 

Dude, I can't really tell what is going on, the only thing I notice is your tps is at 98 (WOT I presume) and your only hitting like 3 psi? Because of your issue I guess...

Maybe even log the NB 02 sensor.
You can log for a while, not just 10 sec, but like 5 min.

If we had some way to view your fuel correction maps... Are you + correction in boost? Stock timing?

 

As far as correction, the only thing I have done is remove 5% bellow 3300 to compensate for my 550 injectors coming back as 580s. Everything else is stock.

The "issue" is that it randomly leans it and falls on its face. Odd because the few times I have gotten in it during the day I have noticed what seems like black smoke in my rear view...suggesting its running rich. I just don't see how that could be the case since I'm only running 550/710 in the 550/720 setting.

I can try to hook up the nb, but I have a wb, just gotta get a bung welded in. what would a longer log show that one focused in the problem would not?

 

So you're at 64% duty cycle (9.8 ms) 550cc @ 3700 rpm then secs come on at 3800 with 31% dc (4.84 ms) of 1260cc at which your rpm/power take a dive. I'm not sure about this and could be wrong but I believe injector PW is the duration the injector is open during an injection event. In any case 0.0098s of 550 = 5.93 and 0.00484 x 1260 = 6.09 per injection event.
Your pulse width continues to drop to 3.26 @ 3900 rpm = 4.1 = leaner

W/o knowing that your fuel pressure is or isn't dropping off and that you are definitely sure that you're lean, since you have no o2 sensor data I'd say,

Fatten it up! Are you running a stock turbo?

 

fuel pressure at idle is 38-40psi I have an aeromotive rising rate pressure regulator. I don't believe it drops off as I have no leaks and it holds pressure fine.

Yes this is a stock turbo. Whats weird is that I've gotten up to 10psi rolling slowly onto the throttle, but if I get on it quickly .. .well, you see what happens. It just doesn't make sense that it would lean out on the stock turbo @ 3psi w/ larger injectors??? Plus I've seen black smoke when I've gotten on it during the day , which suggests running rich.

As far as the NB O2 it dives into the red/invisible range when this stuttering condition occurs. I assume this means lean, however it is well outside the range of the NB so I don't know for sure.

 

So are these logs at full throttle like the TPS reading suggests (98%)? If you're only reaching ~4 psi, it sounds like you have a large boost leak. The mixture issues should be related if that's the case.

In your first log, you go full throttle at 3150 RPM, but you don't reach positive pressure until 3450 RPM and a full 3 seconds later. I don't know what gear you were in, but that seems super laggy to me.

 

Both pulls were done in 3rd gear. I rolled onto the throttle to try to see how long it would take before the engine would fall on its face. Its not laggy at all actually. It builds boost ...err positive issue quickly, but it seems t that is the catalyst for this unsavory condition. When the tps says 98% it is full throttle.

I'm on the highway right now actually, and I noticed something interesting. The split second the secondary injector flag comes on, that's when the car falls on its face. This less me to believe it's running too rich NOT too lean. Perhaps I don't understand how the injector presets work... I choice sworn they compensate for larger injectors by setting them @ a percentage that would make them equal to 550's

If that's the case, why does it apart that my 710's are dumping fuel like a rain storm. (for the record I am on the 550/720 setting)

 

in the 2nd log you posted, its weird that you are WOT, yet both AFM and MAP sensor signals drop like you are in vacuum and then jump back up. It could be a bad AFM, but its weird the MAP sensor follows it, but that could be because it caused the engine to lean out so bad

 

I've asked before about the presets, and was told that the fuel map is in fact adjusted by the % difference in your injector size. All 4 of your injectors have their D/C reduced by ~15% above the transition point to compensate (2540cc / 2200cc = 1.15, or a 15% increase in total fuel). The D/Cs in your logs look correct. In one spot the primaries are at ~60% D/C, then the secondaries come on and all 4 are switched down to ~30% D/C. Half of the original D/C is what's supposed to happen.

What about your FPR setting? You said it was 38-39 psi at idle, but that's about 10 psi higher than stock. Stock is about ~40 psi at 0 manifold pressure (and 30 psi at idle), so you would be at about 50 psi at the same point assuming a 1:1 rising rate? That extra 10 psi would mean about 20% extra fuel being pushed through under all conditions. It would really be helpful to have the wideband installed to see what's going on mixture-wise. You could just stick the sensor in the stock bung for temporary use. The ECU barely uses the narrow-band anyway.

Fuel calc: http://www.csgnetwork.com/fiflowcalc.html

 

stock fuel pressure is about 2.5 bar (36ish psi) with the vacuum line disconnected

 

The FSM specs are pretty general: 28.4 psi at idle and 34.1 to 39.8 psi with the line disconnected (0 manifold pressure/atmospheric pressure). In practice, I've seen it tend to be at the high end of the range.

 

Ah ha! Now we're getting somewhere. I got my fuel setup from fc3smurray and never bothered to adjust the pressure as I thought stock was around 36psi idle. I have noticed poorer fuel economy since upgrading, but I still get 300/tank highway.

I see about hooking up the wb in the stock location. As fast as correcting this fuel problem would u recommend I turn down the pressure or adjust the map?

 

If you're just going to run off the wastegate spring for now, adjust the fuel pressure down to stock-ish levels, then go from there. You said you've only pulled fuel from below the secondary transition point, right? So the portions of the fuel map under boost should still be stock. Mixtures should be safe or very close to it with a stock turbo.

 

Sounds like a plan... I have adjusted the fuel pressure so it is 28-30psi @ idle w/vac connected. The NB is now always lean @idle (before it was in the upper end of stoich, near rich).

I was going to ask if I should just go to map based timing, but I guess there isn't much point on the stock turbo. Hopefully this fuel pressure adjustment will at least get me to the point where I can run the car to redline, then I can make minor adjustments as needed once I get the wb setup.

 

Hmmm.... tested it out @ stock pressure and its still falling on its face. Its definitely better, so it seems we're moving in the right direction, but instead of falling on its face @ 0psi - 3 psi it now does so @ 4psi - 6 psi.

What could be causing my non ported, stock turbo motor to require so little fuel? Plugs are my next scape goat, so I'll check those this afternoon, hopefully they are fouled to **** w/ rounded nubs for electrodes...

 

if i remember correctly, i had the same problem.... found it:

https://www.rx7club.com/2nd-generation-specific-1986-1992-17/fuel-cut-my-rx-rtek-system-912554/

it was feeling like fuel cut, the 2nds werent making connection.
-if it were me, id check there, then plugs, then wires
-check spark on L&T coils
-check voltage on map
-ANY air leaks
-loose maf harness
-crapped out tps (the one im rocking now, only reads from 54%-100%) and its running good
Kinda shitty idle... but tps are too expensive, and break if u sneeze at it.. so beggers cant
be choosers..
kinda spit balling here, but these have ALL cause issues like this in the past for me

 

have you ever checked your fuel pressure with an actual gauge? your fuel pump might be crapping out on you, and if you're gasing the car all the way, and the TPS doesn't show the computer that you're doing so, wouldn't this lean out the engine since the comp doens't compensate for the increasing airflow?

 

I have a gauge on my fpr, I haven't checked pressure while driving as that would be tedious. I highly doubt its the fp though, as the car runs fine everywhere on the primaries. The problem happens exactly when the secondaries come on line.

I guess I could log airflow sad well, perhaps there's something goofy about that reading....other than the mystery units used by the afm...lol

 

The computer add's fuel according to the AFM and the flow amount in provides, that's why the cars still run with the tps unplugged,but not the AFM.

 

I've had several people with fueling issues lately, all blaming the ECU, and all turning out to actually be a bad or improperly adjusted TPS. Make sure your TPS is working well and adjusted properly.

 

if it is indeed a bad tps, try unplugging it and see if it boosts ok. tps is not used for load calculation, correct?

have you tried cleaning the ground under the UIM?

 

I don't think that is a valid test.

 

I'm not blaming the ecu, I'm just asking in a section of the forum where I feel people will have similar mods and thus be more likely to have specific knowledge relative to the problem @ hand.

I suspected the tps might have been the issue, since it only read to 74 % while I was trying to adjust idle. However during the logs it seems to get to 98% just fine Other than adjusting it to 20% when setting idle I'm not sure what all I would do to set it, guess is time for some research...

 

well i'm taking about checking the fuel pressure with an actual gauge, so you can see it under boost since you need a higher pressure under boost and the fuel pump may not be compensating for the increased flow. the TPS is not a bad idea, since when you have a bouncy idle and unplug the tps and the bouncy idle goes away, then you know it's the tps.. so it could help. i'm having the same problem but only after i start the car again once it's warmed up and only under vacuum, but after a min then it fuel mixture goes back to normal. and i have a wideband so i can check for sure and it read close to what the narrowband is reading also.

 

I guess that came out wrong. I wasn't defensive, posting that stuff here is exactly what the forum is here for. I was just stating some history in the customer support issues we've dealt with over the past couple months.. The TPSs in these cars are getting old and they stop working well. Incorrect TPS readings affect these cars more than you might think so it's important to make sure it's working well and adjusted right..