Speedtoys

Being off one injector size should still start and run, just poorly even if you change nothing else. You sure the injectors are firing, and spark?

FredR

Tony,

As Jeff rightly says that difference in nominal rating will not cause what you see/report. Remember the nominal poundage rating of the injector is the amount of flow/hr at a specific pressure which as I recall is less than the system pressure used by Porsche in our 928s. Obviously the bigger the injector the more the correction needed. The general idea is to get the "injector sizing correction" such that the deviation from zero is minimal across the board as it were and thus it makes sense [to me at least] that the injector rating dialled in to ST2 may well be a bit less than the nominal rating you understand the injector to be.

When the adjustment is maxxed out [as you report] the correction from zero is 25% in flow terms. Your nominal injector sizing offset is nominally 10% so the adjustment range should more than compensate. If it cannot compensate as would appear to be case then logically something else is wrong- incorrect Temp2 resistance values for instance? I doubt that would be the problem as your ambient temps are currently around 7C so notmuch scope for substantial error but...?

jcorenman

Tony, As noted the difference between 38.6 and 42# is not a lot-- not enough to be completely out of range. But remember that cranking fuel is separate-- "Cranking pulse width" on the fuel-param tab. Nominal is 4.20ms, I believe that gets increased at low temperature (so check coolant-temp on Fuel-Monitor tab) but with bigger injectors you want to shorten that cranking pulse. If the cranking-pulse is too big then the engine can flood before it ever starts.

If the injectors are spec'ed at 42# (at the usual 39.5 psi spec pressure) then setting Sharktuner lower will flow more fuel. The LH calculates the required fuel and therefore the pulse-width, if you tell it a smaller injector then the calculated pulse-width will be longer for that amount of fuel. Again, not a lot, but in the direction of too much fuel.

The other big variable at idle (once the engine is running) is injector opening-time. For stock injectors, this should be 0.94ms but will be slower or faster for other injectors. That's also a hard spec to come up with, it can be extracted from the spec-sheets for Ford Motorports-branded injectors but not most others. For the Ford M9593-F302 42# injectors the opening time at stock 55psi pressure would be 0.99 ms. That's only a small difference from the stock 0.94ms and would result in less fuel, so not likely the issue.

And Fred, you are correct that injectors flow more fuel at the 55psi pressure for '87+ cars, but the ST injector-size settings are based on the nominal flow at a standard test-pressure (2.7 bar = 39.15 psid). So the stock 19# injectors actually flow 22.5 Lb/hr, and the 42# injectors actually flow close to 50# at 55 psi, but that doesn't matter-- Sharktuner goes by the nominal flow-rate compared to 19#.

Brett Jenkins

Which ignition maps should I be adjusting the retard values? I assume WOT, since that's where I'll see +50% load, but what about cruise?

John Speake

You really need to retard cruise as well as WOT. That's because you will be running through much of the rev and load range as you wind open the throtlle to get to the desired rpm and load.

The WOT map is the most critical, but you''ll be surprised how little time you spend there except for that last exciting part :-)

Brett Jenkins

Ok, thanks for the clarification, John.

Brett Jenkins

Trying to get some clarification before I start changing ignition settings. Louie said above to start around 50% load and reduce all RPMs by .8, and increase by .4 for each subsequent row, ending up with 9 degrees retard across the 100% row. I'm not getting anything like that when I do it. Can someone post a picture of the ignition map when they do it as Louie instructs, so I can confirm what I am doing is correct, or to show me where I am going wrong? Here's the initial ignition map for an S4.

jcorenman

Brett, I am not sure why "Edit RPM Axis Points" is circled, but that is not the adjustment you want at this point. Louie was talking about reducing the ignition advance in the "boosted" part of the map. (He was also talking about the original Sharktuner. The ST2 can talk to both EZK and LH via the PEMs-- just select the "Ignition maps" page as you have done).

So start by selecting the 53% row-- click the "53%" cell to the left-- and verify that the entire row is selected (highlighted). Reduce the timing for that row with two clicks of the single-minus button, which will be around 0.8%.

And you are correct, 7 more rows each retarded a further 0.4 deg is not going to get you to 9-deg by the last row. So jump to that last row next, reduce timing by 9 deg, and then go back and retard each row to make a smooth progression. So maybe the lower-right corner (max RPM, max load) winds up 17 or 18 deg instead of 26.7.

This is just a starting point, a wild guess. The point here is to take out some timing so that the EZK doesn't exceed its 9-deg knock-retard limit. And going back and forth between LH (for fuel optimisation) and EZK for timing adjustments is simple.

Then, as you get fuel dialed in for higher loads and RPMs, watch for EZK knock-retards. Sharktuner software will beep if the computer audio is enabled, and you should reduce timing further as needed. Also, logging data and looking at it with Sharkplotter is very helpful, This will show you where the knock-retards are occurring on the ignition map, and how much and from which cylinders the EZK is backing out timing. A few cylinders retarded by a few degrees is fine, but all cylinders retarded by 9 degrees is definitely not what you want to see. Then once you get that dialed in, start adding advance back in for cells that weren't getting retarded by EZK. Basically, you are probing the knock threshold which isn't necessarily max power or efficiency, but it will be close-- and doing better requires hours of dyno time.

Generally, there is no need to shift the RPM axis points with a stock intake and flappy. The scaling is compressed around 3000-3400, that's where the flappy is flapping and the torque peaks are, and timing requirements change over a smaller range of RPM. That can be changed, but get the basic tuning done first and see what the map looks like.

Edit: A further thought on the WOT map: Normally the EZK switches from the main map (the "cruise" map) to the WOT map, whenever the throttle WOT switch is activated. So the WOT map should also be retarded by the same 9-deg as the last row of the main map. However, many folks (including Louie) don't bother with the WOT map and disable it, and use the main (cruise) map for everything (except idle). So IF you leave the WOT map enabled, then be sure to reduce the timing there too.

Cheers, Jim

Brett Jenkins

That was the 1st image I could find of the ignition maps screen, and that was already circled.

Thanks for the clarification. It makes much more sense to me now.

olmann

I can send you an EZK file that has been adjusted for my SC car. It works real well with minimal knock.

Brett Jenkins

That would be great. I'll PM you my email.