Master Trim (fuel)
 

I'm ready to start the car for the first time after installing the new injectors. I have input new cranking fuel numbers that I received from Travis, as cranking fuel is separate from running fuel and can't be trimmed out.

Travis suggested using master trim to see how much fuel (time) I need to remove from my stock injector map to start up and run on the 600cc injectors. I don't know if +trim munbers trim by that percentage or negative trim numbers remove that percentage. I'm guessing subtracting 60-62% of the base map will get me close, 260 vs 600 cc) but is that -60 master trim or +60 master trim?

Also, I don't understand dead time correction and how to find the values to change it to for the new injectors. I assume that I will have to do this before I can tune the car on the new injectors, but will the base map be close enough to get it going?

I still havent heard back from Travis....I guess I'll just wait till you guys figure it out and then copycat lol:)

Alright I got this running pretty well. I'm sending the file over to Stein and Vlad. As soon as we get confirmation on everything I'll put it up on the website, and officially offer the injectors on the website.

OK, I'm in the shop and online, so as soon as I get it I will install and try to start it. So, trim - or trim + to remove fuel?

sweet:D

While we are waiting, it made me think of the carb thread today. Back then it was trial and error, wive's tales, tons of jets, blown motors, tons of time invested.

Now, we are on the internet in the shop, receiving tuning maps in emails, loading them into the ECU in a few seconds and rolling. If there is a problem, you post it on the forum and within minutes you have an answer, or if it works, everyone knows at that moment. If I had a webcam, everyone interested could be watching me do it real time for the ultimate win!

We've come a long way.

EDIT:

While typing my blackberry went off saying that I got a new email. What do you know? New map from Travis.

Your accel enrich is way off by the way stein. Needs a bump! 17.5 on rapid transitions.

Well, no go. Killed my battery trying to start it. I know that my fuel rail was empty when I went into this. Not sure if this is the cause and it's still trying to meter out trapped air, but it never even popped.

I had run the fuel pump for five minutes checking for leaks the other day per the 99 service manual, but on a returnless system, wouldn't it just trap the air that's in the fuel rail?

Charger is on the car-will try again tomorrow. If anyone has any suggestions, please let me know.

Whats the temperature there? It started reliably, fast, and idled flat. I can't imagine what is different.

?

Where is that? I just went through the tabs and didn't see it.

Also, did you address the dead time correction on the new map?

I just loaded the updated map and tried to run with it.

Shop is 64* and has been this warm for a couple of hours so the car should be soaked at that temp - maybe a few degrees cooler.

What is different is that I just installed the injectors and the car didn't have any fuel in the rail or the injectors, I would suspect. All I did from before is swap the injectors. Is there a priming procedure? At least the NA's have a return so they would at least fill the fuel rail with fuel.

ARG! Give me a second that didn't make it onto the NBcrankingmap. Had two files.

Dead times updated, new map sent.

There isn't a priming procedure that I know of, you could set the current cranking temperature time to something like 150 until you smell fuel.

Transient stuff is located over at the corrections tab.

Dude I cant agree more:)

Reloaded the new map.

Changed cranking fuel as above. Got it to start. It fired right away, so I probably was only a couple of cranks from getting fuel to the injectors anyway.

Changed cranking fuel back to normal and it started again. After it started AFR's dropped steadily from 15.5 to 10 (probably lower) over the course of 8-10 seconds. Idle was bouncing between 1000-1300 and back every second. It's too late and the car is too loud to be tuning now as my wife has gone to bed, so I will be back on it tomorrow. It was super rich, though. The shop was filled with fuel smoke in that 10 seconds.

Travis:

Why did you change the fuel maps to the same levels all the way across? Wouldn't it have been closer to finished by scaling the current map?

Those maps did not look right to me at all. They shouldn't have been shaped like that. You can master trim it back a little bit if its too rich.

Hmmm, that was my autotuned map to target AFR. AFR's looked good when driving all across the band.

As an exercise, I tried to make sure to transfer every single item on your new map in the corrections tab to my original map, cell by cell. I'm going to try to run that map tomorrow, trimmed to -58 to see if it is close. The lumps at the beginning were me trying to tune out the tip in problem. I'll knock them down if needed tomorrow. If it doesn't work at all, I'll reload your map and go from there.

Guys, injector dead time is specific to the injectors.

This is important because the ECU uses this value as a known fudge for injector response time. When you want 5ms of fuel from an injector with a .75ms dead time, you only want to send a 4.25ms pulse.

Article:
Yaw Power Products / Injector Dead Times Explained

Call the mfgr before you do much fine tuning if you can.

I've got it for the deatschworks injectors, though we are running them in peak-hold instead of standard saturation. I would think regaurdless the curve would be proportional though.

Well, I started it today. I kept pulling fuel at idle until I got it to idle well in the 15.0 range. The adjacent cells were still super rich so I went to adjust the master trim. I forgot that when you back over the number to change it the ECU sees it as zero. The car died as soon as this happened (would have gone really rich) and will not start or even pop. I don't know if it has something to do with the hot start settings but it won't even fire once. I'll let it cool down and try again. Water was about 60*C when it died.

If anyone has any suggestions, I'm all ears.

The hot cranking numbers need to go up. The dead time is not calculated into the cold cranking numbers like i thought it was.

fwiw, I only used 11% cranking enrichment at 60C (on the hydra)

cranking:
40C 17%
50C 14%
60C 11%
70C 7%
80C 4%

starts fine when warm.

may also want to check where in the fuel / ign map you are at cranking speed and MAP. double check that those cells have valid values.

Occassionally I have starting issues taking two or three times to start - this could be some of my issues. Most of my below 1000rpm fuel map points are bumped way up to help with off-idle tip in.

When you're in the cranking RPM range is the fueling strictly off the "cranking fuel" injector times? Once above the cranking rpm does it transition to the fuel map?

Yes,

The cranking fuel tab is the actual values that will be used regardless of ANY other setting. Dead time, air temperature, none of that gets calculated in. Its just water temperature that determines cranking fuel.

The cranking RPM can be adjusted in the first tab under advanced at the bottom. Once you crank above the cranking RPM then it goes to the fuel map like you were saying.

UPDATE:

Increased cranking fuel to around 30 and it started. Later on, it died and wouldn't start hot. Water was 103*C. Bumped up that range to around 30 as well and it started fine. Now that I know this, I can fine tune cranking fuel and get it down to a reasonable amount of cranking. Even on my old injectors it would have to crank a while before starting cold, but pretty good hot.

I ended up using Travis' new settings on the corrections tab along with my old stock injector map. I subtracted 58% across the board for the whole map. It drove similar to my previous map, but was still a little rich on top. I'm guessing this was due to dead time changes. I did a couple of large scale corrections on sections of the map (-15% for most everything over 3500 and then needed to add back in about 8% on the 140 and 160kPa areas above 4500 and it came in to 13's at cruise and 10.5-11.2 in boost. Close enough to autotune.

Drove to town and back to get fuel and let it autotune. Pretty good map already.

No problem idling 600's but still a bit rich - about 13.5-14. I can work on it more.

It's tough to do everything by yourself. If I had a driver or passenger, at least I could target some of the off cells quicker. Now I have to remember which cells I want to tune, pull over, bump them up or down and then go again.

Took my wife for her first ride since boosting it. She was not impressed, but she could care less about cars. Oh, well.

She did aske me if I was done. I told her that "it's never done". Although, as far as she knows, all future increases and mods will be result of "adjusting the computer".:giggle:

Now to get my EBC in this thing!

:laugh:My wife's reaction; only in Spanish! :giggle: