Injectors too Big?

[Olds442FI]

OK guys,Now that i have the car running and i have had a chance to play with some tuning I am starting to think that maybe having injectors that are to big cannot be compensated for. As some of us know i purchased the system for TurboS10 (IE Chris), and He had some 50lbs injectors on the system. Now that i realized that i must have moved my distributor and knocked the timing off, I cannot seem to get the fuel quite right. I am either running Fat at the bottom and lean up top or vice versa. I finally have it idling decent but it still seems eye burning rich, and it kinda crackles through the exhaust if i accelerate too hard.the only way that seems to go away is increasing the pulse to over 9ms but it still isnt right even then. Mathematically, it calls for a 35-37lbs injectors.am i just spinning my wheels here trying to get it right? On top of that i think i may have killed my WB02 sensor  . it doesn't seem to register anything in the real time view .

[gunni]

Have you tried tuning the VE table ?

[Olds442FI]

well, first i tried using the VE table builder but that seems to argue with me a little. it does not allow my hp to be greater than my torque. i tried several configurations that just didnt work out for me. Then i went to the fuel setup guide from Antach. Obviously, that base configuration doesn't seem to work to well for me either. Outside of that, i really dont have such a good picture of what it should actually look like in my situation. 2 things i should probably mention. 1. my vacume is kinda low generally especially at idle (about 70-80) gets better at a cruise. 2. The trotlle body i have is a little different then standard. Its like a 4 Barrel carburetor.Up to about 60% TP only 2 plates open but the rest of the way 4 plates open. Obviously after 60%throttle my need for fuel is much greater. Building a VE table just isnt my specialty yet. Can i get this to work knowing the injectors are to large?

[gunni]

Yes you can make it work even if the injectors are large.

You need to do things in stages and not attempt to tune a whole map and then see what happens.

Get it to idle steady at as lean as possible or lambda 1.

Then for the area after idle, put in VE  numbers that are +10 on the idle numbers, make the rest of the table like these numbers.
Then attempt to drive slowly and log while doing so, you should be able to drive around slowly and collect enough information to read through and re-calculate the correct VE numbers for slow driving (2000-3500rpm, 50-60kpa). Then you attempt to go up by 10kpa each time and rev out most of the rpm range while monitoring the mixture for healthy numbers, If they are not then just let go and check the log. Do this until it´s all done.

This assumes your by yourself driving, if your not then you just do it live while somebody drives it slowly and then a little more and a little more.

[Olds442FI]

ok. this kinda makes sense to me. i have a few questions to get me through here.

1. To start off, should i be using the normal PW calculations for the injector?

2. In the VE table, your saying i should get the idle good and to Lamda 1 (or as close as humanly possible) by plugging in #s around where the idle is hovering on the VE table. then in the areas on the table that would fall under acceleration i should add 10 (then fine tune tune by 1's) until i get the lamba to, or as close to 1  as possible. then follow these steps going faster and faster ultimately until i can go fast.

3. If i am using the VE table to control the injector flow, then where does the Lamda table come in?

4. As i said in my original post, i think my WBO2 sensor isnt working. I do recall getting readings when i initially hooked it up but nothing now. Does this necessarily mean its fried? is there a way to test it or do i simply get a new one?

I realize this is alot to answer but there is alot i need to know. i am staring to understand alot of this but the tables were probably the most confusing to me with the exception of the spark table. The thing that helped most was probably getting the car to actually go and physically watch the tables as its running.  just one mre question since i am asking so much anyway. When i make a change of a number on the VE and Lamda Tables,exactly what parts of the system does  it effect? Is it just fuel?

thanks for the help

[rob@vems.co.uk]

1. You will have the PWs worked out by way of the Req_fuel, VE and lambda tables.  Just tune the table where the ECU is reading from, by pulling out a load of fuel - you dont need a wideband to tell you that its too rich if the exhaust is making your eyes water.

2. You need to avoid acceleration as much as possible - let the RPM increase with small throttle openings at this stage - then you will find that you are tuning across the RPM scale of the Map.  Turn off accel enrichment, its throwing even more fuel down the ports and thats the last thing you want.

Also check your oil - it may be awash with fuel now.

3. Lambda table is a divider - at idle and part throttle the lambda table should be 1 as PW / 1 is PW  (e.g. 2.5 / 1 = 1).  When you get to the power range of the map then you lower the lambda values to richen the mix: PW / 0.9  ( 3.2 / 0.9 = 3.56)

4. It should be giving some form of reading, any value.

You need to give more information about the readings you're getting, or we can't tell what the problem is - its a good move for you to do this as you will start to think about what the readings mean and how they are changing with your adjustments: "Are my injectors too big, as I have a PW of 1.2ms at idle and its still pig rich" has a very different answer to "Are my injectors too big as I have a PW of 4.6ms at idle and its still pig rich".

[Olds442FI]

originally my thread was based on the fact that there are indeed calculations to chose a correct injector for a specific application. I may have complicated the question to more than what it truly was. I should have said " If my engine calculations call for a 35-37 lbs injectors, is it possible to get it to run correctly with 50lbs injector with VEMS? everything i have ever heard about fuel injection says that you shouldn't have an injector that is too large, but i figured everything i heard was based a much less tunable ECU and apparently i am right, and i did get that answer. I simply wanted to know whether or not i was wasting my time trying to do something that cannot be done or get an answer like, "with VEMS it isn't a problem because you have the ability to tune your fuel unlike a factory ECU". ultimately, that was the reason for the lack readings because i already know they are going to be wrong because i have no idea what im doing (but im learning) .

Now Back to the solution (again no readings cause we are going to pretend i never started the car). lets say i have my spark curve table set so lets forget ignition  for the time being.

 Base settings - i understand the MAP, TPS, Fuel Cuts, And rev Limiters. As far as the PW Setting, according to Phat Bobs pw calculations i should be req_fuel = 6.49 * (D / N / I).or in my case, 6.49*(5850/8/496)=9.56. then apparently it is common practice to half this # and double the values in the VE Table for better tun-ability.  I am assuming this is the base or where i should be starting hence the term base settings. Now, Is this value my equivalent to Lamda 1?  after this i assume my next step would be what we discussed in the last post with the Lamda Table.

I am just trying to get a beginning. So far i seem to be asking all of the wrong questions and i think i am getting solutions the middle of a problem that has a terrible beginning so of coarse my ending is going to have sad results. Its just really frustrating because it's not like there is a set manual going through the steps but a forum that has the answers but, they are all over the place and really hard to find. i am getting it, and understanding. The whole Lamda definition is coming to me but i have a feeling it isnt that time yet.

Anyway, thank you for dealing with my frustrations. I promise i will include more information in my future inquiries.
 

[gunni]

I never double the VE table and half the req fuel, I don´t see the need for that.

[Olds442FI]

Ok, so what im am led to believe here is that i am entering my the original calculation of 9.56 PW in the req_fuel as i will be able to pull back on this through the VE and Lamda tables correct? So Now i want to Kill My accelerator(Just set to zero?) enrichment so i can tune primarily through my Map and RPM range without outside interference or super excessive fuel. Now should i use the Lamda or VE table to lean out the idle area?

on a side note. I know pw/1=pw so 9.56/.5 (lamda on the table)=4.78pw ultimatly cutting my pw for that area on the table in half as a simple example. so on a VE table, how exactly does a .90 affect the mixture as opposed to a 80 or a 70? in simple terms its being able to take 100 cc of air and getting into 100 cc of space so a 90 would be the only 90 cc of air into 100cc of space right or 90%VE? this seems to me like its just another way of playing with the mixture. how are the effects from the VE table different from the Lamda tables?

on another side note: based on all of my stupidity through all of this so far do you think it would be safe to say that my WBO2 sensor is dead or do these thing come back to life?

[rob@vems.co.uk]

You're asking the right questions, and what you're trying to do is actually quite difficult because of all the variables and it being your first time around.  I can guarantee you that the next ECU you do (and there will be more as you'll be the guy who knows about them, and you'll be addicted) will have just as many problems, but will be much easier because of what you've been doing now.

The VE table is designed to model the engine's fuel requirements, so once its off idle you'll find that its pretty flat.  The Lambda table defines what the power requirements for fueling are, in normal life you will have 1.0 at idle, going to 0.85 in the areas of high power (and possibly in the low power areas for extra cooling on trailing throttle - but we'll not worry about that for the moment), in extreme cases caused by turbos, nitrous and what have you lambda targets go way past 0.8, for example 0.7 is the value you'll be wanting for nitrous, turbo cars run 0.85 to 0.7 depending on the level of boost and subsequent cooling needs.

So, for the time being set your VE table to 1.0 across the map, for now when you are tuning with a lambda sensor, you'll be tuning to get the lambda at 1.0 at all the RPM and KPa sites you'll visit.  Then, once you have that, you can leave the VE table alone and use the lambda table to add the fuel you need for power and cooling requirements.

If you're getting a decent idle at 50% of your PW, then set the areas of the VE map visited by the ECU to 50 and see where that gets you.  You should be able to tune idle mixtures without a wideband, by ear and by smell.  Double check your wiring, and check t again - you may have killed your wideband with execess fuel - you might just have a bad connection.
For the moment though ignire it and concentrate on the idle fueling.

[Sprocket]

I never double the VE table and half the req fuel, I don´t see the need for that.

I had to double the VE and halve the req fuel to get a far better idle resolution. I now have 190s on the top line and 40s in the bottom line. THis is with Alpha N and a fixed 3.5bar fuel rail pressure. Idle pulse width was 2.5ms. Max duty cycle was 65%

[Olds442FI]

alright, i have a decent idle. My lamda table is set to all 1's and my acceleration enrichment is all set to 0.  In park, a idle at about 1000-1100 RPM with MAP kpa of  about 62 and PW @ about 2.4ms. The hit areas of the VE table are set at 35. still seems a little rich yet ,but i have no cats and it was kinda always like that. I expect it with a little rumpity rump of the cam.
After putting it in gear, here is how its working out. I set the VE table to 40 in these hit areas, idles between 700-900 RPM with a PW of between 3.1 and 3.4.  Idles a little bit low but ill correct that yet. I always did like a good low cammy sounding idle though. MAP KpA is at 78. Very low due to the really low idle. She does stay running with no problems however.So Now, where do i want to go from Here?

[rob@vems.co.uk]

Nows the time to get your wideband problem resolved.
And while you're doing that have a read of these:
Open Loop tuning - the traditional way of doing things - http://www.vems.hu/wiki/index.php?page=TuningSession%2FOpenloopTuning
Closed Loop Tuning - using the Lambda sensor as a guide - http://www.vems.hu/wiki/index.php?page=TuningSession%2FClosedloopTuning

[Olds442FI]

OK, so closed loop is running without the use of the wb02 sensor and open loop is the opposite, correct? well this may or may not be the reason my sensor is not working. obviously i had no idea about open or closed loop. Anyway, My EGO settings are as follows,
Lean limit (%) 1
Rich Limit (%) 1
Step size(%)  1
Speed limit (or PID kp) 64
engine cycles before changing 21
conditions for enabling\warm up time (sec)  60
Max TPS 100
Min RPM 1600
Max RPM 7500
Max MAP  200
Min Temp 42
EGO NBO2 connected Disabled
EGO NBO2 Config Enabled
Target voltage (grayed out) .49
PID window (also grayed out) 255

I dont know if i needed to give all these readings but since i dont really know what they do i figured i would put it out there. If this is what determines open and closed loop then i figure i may already be in closed loop. Also i notice on my real time display Accel flashes on and off ALOT. I get the funny feeling that this is way off and that getting this screen right may help me out as well.

[rob@vems.co.uk]

Your wideband will give a reading (if its working) regardless of what tuning strategy you choose.  Closed and Open Loop are control theory terms, open means that the control system will do what the tables tell it to do, Closed will make adjustments based on readings fed back from sensors.

But, just to give some meat to the settings you've posted there, as it stands:
The controller will only richen or lean the mixture by 1%, so if you're lean with a PW of 4.3 it can only richen the PW to 4.34.  It will wait 21 engine cycles before making the change and then it will do it in a single step (1%).

It will make corrections even when the throttle is 100% open.
It will only start making corrections from 1600rpm and will make them to 7500rpm.

These are not good settings.  But - we don't want to worry about that part next, you need to get the wideband working, and start tuning using the open loop method.