Required fuel and Injector dead time

[ozzyrulez]

Hey guys I had a few questions about required fuel and injector dead time. I'm 99% certain that they are both incorrect. The car is running, and running pretty well. However when I go into boost IDC is getting 120%+ it was even worse until I got the AFR's down where I want them. This is leading me to believe that dead time and required fuel are off. Currently dead time is 3.6ms and required fuel is 17.2. I will note that Shadow dash shows much more realistic IDC's than Tunerstudio is, I'm not sure what the difference is there.

I have Bosch 850cc injectors, the paperwork that came with them from the company I bought them from state dead time is .672ms at 13v. The Tunerstudio required fuel calculator is calculating 4.3ms. Both numbers are a far cry from what I have, and what is working. When I change these numbers to what the paperwork states and Tunerstudio recommends the car is so stupid lean it won't start. If I jack up required fuel I can get it to start with .672ms dead time but it is still lean and runs terrible. I'm not real sure what I'm doing wrong. Other than this the car is running and idling nicely.

[grom_e30]

your baro settings are incorrect leading to a baro correction of 200% at all times. and in the msq the dead time is set for 0.9ms and required fuel is 4.3. what is idc? do you ve?

Currently dead time is 3.6ms and required fuel is 17.2

is that in a different tune?

[ozzyrulez]

Yeah I thought the baro correction settings were wrong too. If I mess with them I end up with a no start situation too.

Let me get some screen shots from the laptop I use, I swear required fuel is 17.2 and dead time is 3.6ms. It makes no sense.

Shadowdash shows shows 1.4% IDC at idle and was at 59% with AFR's in the 9's where Tunerstudio with a corrected VE table is showing 5.4% at idle and 125% with AFR's in the 12's

To say I'm lost is an understatement.

[ozzyrulez]

This is what Tunerstudio in my laptop show, and the car will not run unless it says this. I've come across exactly what you are saying though. A friend of mine sent me a modified tune from his laptop with .900 and 4.3 and the car left me stranded. Luckily I had the running tune on the tablet.

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[grom_e30]

hmm i see. i have always found the calculator for required fuel pretty much spot on, so something must be a miss. how about trying with the calculated required fuel (4.3) and dead time to 0.9 and setting the baro to correct settings as well. are you sure the injectors are 850cc/min.

[ozzyrulez]

Well I have suspected that they might not be because these settings don't make any sense. I've tried the baro on 147, -47 with 0% correction and 0,0 with 100% correction. Both end with a super lean no start situation. Same thing happens when I change required fuel to 4.3 and dead time .9 it results in it being super lean and not starting/very very poor running.

The curious thing is though IDC was much higher when the AFR's at 5000+rpm were in the 9's. That tells me there is plenty of injector there because when I got it down into the 12's it IDC dropped to 125%. AFR shouldn't change if the injectors are maxed out.

[ozzyrulez]

Well I just went and pulled an injector. It is stamped BR3E-E5A which is a part number for 5.0 Coyote engines 32lb injector... I'd say I got screwed pretty nicely. The vendor is adamant they are 80lb injectors and I can get them flow test for my satisfaction (on my dime of course). They were little help when their fuel rails were leaking all over the place too so I should have taken that as a sign I guess.

[grom_e30]

ah that may do it. to be honest your fuel ve table is a mess as well 40% ve at 6000 rpm. and flow test your self using test mode on the megasquirt.

[ozzyrulez]

So I went out and set the baro settings to 0,0 and correction to 100% across the board. I then set the injector dead time to .672 but that was proving way to low so I ended up with 1.5ms and required fuel of 30.5. I redid the VE table real quick with the VE table maker and with some small adjustments in the 35kpa area I was able to achieve idle... The injector size in was 120cc, as much as I think those people hosed me, I'm not sure that they hosed me that bad. So I'm curious if something else is up. Here is the "test" tune.

[grom_e30]

still seems odd, low fuel pressure possibly? if they are 32lbs you seem to need 3x the required fuel id expect.

[ozzyrulez]

I have fuel pressure set high due to this mess. It is at about 52psi right now. It holds steady at idle.

[grom_e30]

And they are high impedience injectors? 1 injector per driver to the ms3x card?

[ozzyrulez]

They are supposed to be high impedance I guess I'll need to check that tomorrow too.

They are one injector per MS3X driver wire each. I do have 1 power wire feeding each bank though instead of having 6 individual power wires.

[grom_e30]

Sharing the power feed has not given me problems in the past

[ozzyrulez]

I found a shop that will flow test them this week for $50 so I pulled them out. When I got them out I noticed that the last portion of the Part # has been buffed off all 6 injectors... I wonder what they are trying to hide. I'll find out in a few days.


I also pulled a data log today when I went out to meet a friend for lunch. My idle was surging but otherwise it ran good. If someone could have a look and give me some feedback I'd greatly appreciate it. One thing in the log I noticed was EGO cort1 was all over, I'm not sure if that is normal or what.

Log is on my google drive as it is 18MB
https://drive.google.com/file/d/0B6JOnD ... sp=sharing