Raceghost

iTrader: (4)

Hello all, hope this finds you well. Have an interesting issue, and trying to decide how serious of an issue it is.

Car is built, can post build, or you can find it on here --> https://www.evolutionm.net/forums/ev...o-8-build.html

This is a fuel issue, so lets get to the parts that deal with fuel.
Walbro 255, put in back in 2010.
Stock wiring.
Stock Fuel line
Skunk 2 Composite Fuel rail. Same size internal as the AEM one.
Stock FPR
FIC 1350cc Bluemax Injectors. Look to be used, put in by the gentlemen I paid to have tune, who partial tuned it, and kicked it to the curb, selling me used injectors as new... don't ask.
(These are Ignition related, but just incase)
Okada Direct Coils
Magnacore Spark Plug Wires
160 Amp Alternator
Custom Grounding Kit

Ok, so he tuned the car and said it put down 450HP on the Dyno. I looked at the fuel map, and it was ok. I looked at the Injector scaling and this is what I find:

1044 Scaling
Latencies as follows:
4.992
3.264
1.968
1.416
1.224
0.888
0.648

Under this scaling, the trims register pig rich, and are pegged at -12.5 on both Low and Mid. With the STFT adding or subtracting about 20%. Car throws a P code on running to rich. Pulls hard though, no knock, all the way to red line.

So of course, I thought, well he didn't scale them correctly. I called FIC and got the latencies from them, and changed the scaling to this:

Scaling: 1218
Latencies:
5.952
3.984
2.184
1.536
1.200
0.960
0.840

Fuel trims are now spot on, with in +/- 1%. STFT swings between +/- 2%. Verified over a week of trials, and logs.

SO here is the trouble I am having. Both scalings have issues starting. Of course I have been working with the current scaling I have done, and get the car to fire like it should. I utilized Dynatech's ICSV tuning to achieve this. https://www.evolutionm.net/forums/ec...cv-tables.html
However, the car doesn't catch it's idle and register AFR's for a random amount of time. It fires up, gets to 1000 RPM which is the BISS setting, and rough idle for random period, seriously, like 3-4 minutes if I let it. No AFR's on the gauge, no trims in the logs, nothing. Then randomly when it decides to, like the fuel pump kicks in or something, it starts to idle up, and then settle back down to 1000. THen it idles like a champ. Not sure what the deal is there. Both maps do it. Mine and the other guys.

Second issue, more importantly, is the WOT issue. Under the other guys map, remember it is scaled pig rich, you can do a boost pull and numbers in AFR reflect 11.3.ish. Numbers in the fuel map don't match the AFR's, but that would be correct if the injectors are not scaled properly. With my scaling, everything runs nice , try a boost pull, and the AFR's lean out to 12.5 and stay there. I have the WOT section of the fuel map at 8.5:1... Stays at 12.5 AFR.

What the hell? Am I running out of fuel? Am I out of pump? Are my relays going bad, and the fuel pump is shutting off when it should be in full voltage? No fuel leaks. I can verify the relays gong on and off as the pump kicks in for WOT pulls. Read up on the Fuel pump rewire, and found out how to log this now. Of course I shut her down mid pull once I see she is lean in the torque section. I can't make heads or tails of it. New everything, don't want to damage her.

UPDATE:Drove around tonight. First thing was same issue on startup, AFR gauge stayed way lean, for like 2-3 minutes, then everything kicked in, did it's idle up, and settled back down, then struggled swinging wildly lean to rich. I did not notice the pump prime when the key was turned to on, ready to fire... Second thing, once it warmed up, AFr's still erratic, I drove it down the street, and on a road holding the throttle at partial and rpms steady at 2500(45 miles an hour) and it felt like like it was struggling, then ok, then struggling, then ok. Seemed as though the low setting on the pump or relay was messed up. Also in EVOSCAN, the pump switch that MFRED listed to log low to high, kicked in at 40 load. I verified settings for fuel pump switch at 100 load for this speed. I did not do a boost pull or heavy throttle to get up to speed. It rained earlier tonight, and seems when it does, things get worse from a fuel pump standpoint. This suggest a short in the engine bay. or possibly that the relay under the hood is bad, don't know, need suggestions.

As to the second issue, what specific calculations are done with scaling and latencies by the ECU. It suggest that the ECU knows something about scaling size and allowing the pump to flow more fuel. I can't seem to understand, why if I dial in the injectors, even on the other guys map, it still leans out. But if I use his size scaling, it pulls just fine with 11.3 AFR up top. It doesn't make sense, that the only thing you change is the size scaling, and fuel flows. Any one got any ideas or know calculations used by the ECU specifically with size scaling?

Any help would be outstanding. Be great if I could get anyone's help here, would even love to here from the greats.

Thanks in advance,

Ryan

Raceghost

iTrader: (4)

Bump to the top. Help please.

Raceghost

iTrader: (4)

Bump to the top. Help please. Someone has to know something.

roni4g63

iTrader: (1)

If you're on MAF, I believe improper scaling will cause targer afr to be different from actual afr

Raceghost

iTrader: (4)

This I know, but you only scale the MAF when the scaling and latencies are correct for trim readings. This issue happens when the MAF scaling is set to stock while dialing in the injectors. On stock MAF settings, my latencies are LOW +/-3 Mid +/-1. His are -12.5 and -12.5 respectively. Adjust the Maf alittle to bring low into +/- 1% and mid +/- .015. and it still happens at WOT. Again though, if I use stock settings, and only adjust the scaling, since both tunes latencies are almost the same in the 14.07v, his at 14.07 is 1.224, mine is 1.200, his scaling at 1044(trims register maxed out rich) mine 1218 are close to where they should be, his map will show 11.3 up top, mine shows 12.5 in the torque section of 3500/4000 RPM's, so I don't go any further.