[DStage]

Yep, there's no pull-up on IAC input in ETC as it was rather intended for direct control from MCU without another transistor in between. But also if there would be a pull-up and someone does not use IAC therefore no PWM it would interfere with the intention of using only gas pedal input and keep the throttle partially opened unless IAC input is intentionally grounded. OK, cold be done this way but I think external pull-up on such occasions is easy enough and doesn't hurt too much

[Izzy46]

Update, after a few days and a few mistakes I've got the IAC valve functioning well. Thank you once again for everyone's advice and recommendations. In the end I went with PSIG and DStage's suggestion of installing 5v pullup resistor to the idle out pin. I now know what a pullup resistor is

For some reason Speedy lost the coolant sensor calibration and was reading -40*, it took me a lot of trouble shooting before I realized the sensor needed to be recalibrated. Once that was done she fired up right away. The other thing to note was the IAC input on the controller has an inverse effect on the butterfly opening. It took me a few starts and some high revs to realize this

So, no I'm finally on to getting a solid base tune before using the WBO2. As it stands, the lowest PWM setting only puts the RPM down to around 800. I think I'll need to get lower than that to give me more of a buffer?

I've never tuned a car engine before so any input on my next steps would be appreciated.

1) Adjust the butterfly so that when the ignition is on it's 100% closed. When the ignition is off it sits at 95% closed, ignition on 98% closed. I think I can get another 2% out of it to bring the idle down a little further.

2) Turn the idle off and adjust the VE table to get minimum MAP and the lowest idle possible.

3) Turn idle to open loop and adjust for a smooth idle around 750 rpm

4) Once the idle is right I start adjusting the VE table so that the engine can transition from low to high rpm smoothly.

I guess I should leave the spark table as is?

[apollard]

Congratulations on another milestone
I would leave the spark table as is. It replicates the marine curve in the delco module- exactly what a carbed version of your engine had, and at best will be a degree or two different in a few places than your previous efi system. Long experience with marine engines has shown its a bad idea to mess with this much without the benefit of equipment and expertise. Well known high performance marine engine builders run basically the same curve, although the slope might change some. Some top out at 36 instead of 34, but the difference in boat performance is not noticeable unless you’re trying for 450+ hp out of that 5.7L

In my experience the next tstep is WBO2 and tuning on the water. On the hose is only good to tune unloaded idle and starting.

[PSIG]

+1, you are on a good path. Tune to best performance, not an AFR. Just as with idle to best MAP, tune higher regions in slow steady increments for best performance indicators, and then note the AFR to target at that cell. After some spots are good, then you can target that whole similar section to the same tested AFR.

Once the table is pretty darn close on steady-state tuning, then you can do your injection angle testing, verify injector latency (dead-time), accel enrichments, hot-start priming, cold-start priming, cranking enrichment, warmup enrichment, etc. One additive after another, all on the base tables you created.

After all that's done, you should be zipping around with a big grin. All that remains is advanced tuning. Now you can begin idle stability timing mods, and cruise power economy fueling with coordinated ignition timing required to get max power with economy in the same tune. Sweet.

[apollard]

Just one modification from the above based on the use of the engune - ie, marine. Tune for best performance, but do not go higher than 13.2 afr. 13 is safer; some builders go to 13.4 to even 13.6 on midrange, but again they have the expertise and equipment- you don’t. 14 afr will run well, but at some point it will lift a ringnland ( ask me how I know) or ventilate a piston.

Marine engines are at light load at idle and no wake speeds. Getting on plane, cruising ( especially a wake boat like yours) are high load. Obviously WOT is too. Google AFR on sites like www.offshoreonly.com fir lots of real world experience.

There’s a reason 2.5 - 3 miles per gallon is considered good fuel economy for a boat.

[apollard]

Google search - ignore anything that is discussing turbo or superchargers. And don't think your family boat with lots of people in it throwing that big wake is under less stress than a speedboat:

https://www.google.com/search?q=afr+tar ... nt=gws-wiz

An example from an engine builder I know and has an excellent reputation and lots of experience. Frankly, I would let him tune my engine to mid 13's, but i won't do it myself.:

I tune for mid to low 13's at 70/75 map/2800-3200 cruising, low 13's to high 12's at 80-85 map (3200-3400 cruising harder at 5-7" vacuum), high 12's in the 3600-4200 range and mid to low 12's in the 0-2" vacuum 4400 up hard to wot. A carbed motor will be a little harder since it doesnt have rpm/map based tables like efi but tune for mid to low 12's at wot, play with your power valves for cruise,you might end up a little fat somewhere to get the wot where you want it. This is all based on assumption motor made best power in mid 12's at wot on dyno and is NA,

[Izzy46]

So.... I've been having some "fun" over the last 4 days trying to get the engine to idle nicely.

On Monday I was working with the IAC and idle but couldn't get it to run smoothly on 'open loop'. I put a multimeter on the IAC pad on the DStage TC and notice that the voltage was fluctuating only slightly 1.2 down to 0.8v every few seconds. The idle was OK but wondering a little. The engine would only seem to run for up to 5 seconds before dying.

When I switched over to no idle input the voltage at the IAC pad would sometimes read 0v and sometimes read 5v. It scared the hell out of my wife when she started the thing and it went right to 4000 rpm

Tuesday I desoldered the connection from pin 37 to the DStage IAC pad. I spent the day trying to work out why the boat would stall randomly. Sometimes it would run for 5 seconds then stall other times it would run longer then stall. It didn't seem to matter whether I had it idling fast at 1200 or slower at 700 rpm. At the end of the day I threw up my hands and imported Apollard's VE table. To my surprise she ran fine! I could go inside get a coffee, come back and she was still running. I was so excited I saved the tune as Tuesday Great.msq

Wednesday I thought I was ready for the next stage but I was back to square one. The engine would start, run for a little while and then die randomly. I decided to buy 6 new cables and rewire the TPS to ECU, this was the last thing on the boat that I haven't rewired yet!

This morning (Thursday) I finished the new TPS to ECU harness, started her up and she ran like clockwork. I could have her idling at 550 without any issue. I went to work, came home, started her up and she ran well again the first time but the second time onwards she has been diabolical. She starts well (as long as it's primed at 2.1 seconds) but only runs for a second or two then dies.

I have a fuel pressure gauge on the fuel rail and it always reads 60 psi.
The air intake is clear and the butterfly responds accordingly.
The plugs have been cleaned.
I have a constant 12v to the computer when the engine is running.

I've noticed that the Inlet Air Temperature sensor will read 0. As I don't have an IAT I'm wondering if this should be turned off somehow? Could this be influencing how the ECU is delivering fuel?
Since rewiring, I've recalibrated the TPS with the ECU but not with the controller. I didn't do this as the difference in the ECU calibration was very minor. I should go out and do this to make sure it's spot on.

I also noticed that when the engine stalls if the ignition is not turned off the injectors will remain open filling up two of the cylinders. I've removed my fuel rails to test that the injectors hold pressure without leaking and they seem to be fine.

I've tried to get a log but can't keep her running more that a second or two at this point.

The bluetooth connection is also acting diabolically, only slightly better than my direct usb connection. Sometimes it will connect fine other times it will disconnect and only connect again through the communications settings. I have a Mac, is there a way I can improve this...?

At the moment I must look like a lunatic to my neighbours. I connect through bluetooth, start the boat, run to the hose, run back to the boat to turn the ignition off when the boat stalls then run back to turn the hose off.

Anyway, I'm out of ideas for now. I guess I'll get after it again tomorrow.

Any thoughts would be appreciated as always.

PS I tried uploading my tune but it says submitted form invalid. I will try again in a few hours.

[apollard]

To run a speed density system, you need IAT. Without one connected, you won't get accurate fuel metering, and that could be causing the issues you see. OEM systems even have failsafe to use if IAT fails. For example, my Dodge truck substitutes the battery temp for IAT if it fails; if that fails it uses ambient and goes into limp home mode.

All EFI needs to know the mass of air in the cylinder to calculate the mass of fuel and then the pulse width needed. Some measure mass directly, but speed density measures manifold pressure (MAP), RPM, and IAT, then uses gas equations to calculate mass of air. This is simplified, but close enough for most users.

IAT is vital to all calculations. You could substitute a fixed value in the code, but I would not recommend it. Right now, you probably have a 35-40C ambient, and reading zero is causing over fueling. Then, perhaps sometimes the reading (since it isn't connected and can 'float' with interference) is closer to the actual temp and it runs OK. Since you likely haven't calibrated it either, who knows what the readings might be?

You also need to get your throttle to a fixed position near idle and then tune the idle VE before trying to use idle control. Jumping ahead is tempting, but running w/o needed sensors and skipping steps is causing you lots of time and headaches IMO.

[Izzy46]

To run a speed density system, you need IAT. Without one connected, you won't get accurate fuel metering, and that could be causing the issues you see. OEM systems even have failsafe to use if IAT fails. For example, my Dodge truck substitutes the battery temp for IAT if it fails; if that fails it uses ambient and goes into limp home mode.

IAT is vital to all calculations. You could substitute a fixed value in the code, but i would not recommend it. Right now, you probably have a 35-40C ambient, and reading zero is causing over fueling. Then, perhaps sometimes the reading (since it isn't connected) is closer to the actual temp and it runs OK.

OK, another lead, this is good. Do I need to install an IAT, do you recommend it, is there a way I can get around it in the short term? I'm always 2 weeks away from car parts in this country How does the original computer run without an IAT...?

You also need to get your throttle to a fixed position near idle and then tune the idle VE before trying to use idle control. Jumping ahead is tempting, but running w/o needed sensors and skipping steps is causing you lots of time and headaches IMO.

Yes, I did jump ahead on Tuesday's tune. I'm back now with the IAC disconnected with the throttle at a fixed position.

[apollard]

OK, another lead, this is good. Do I need to install an IAT, do you recommend it, is there a way I can get around it in the short term? I'm always 2 weeks away from car parts in this country How does the original computer run without an IAT...?

You could use a fixed resistor to simulate an IAT sensor, giving a fixed value close to the correct ambient as a temporary fix. But it would be a kludge and you'd have to fine tune again when you get an IAT, especially since temps morning and night there probably vary quite a bit. In other words, it would allow you to play, but not really finish tuning. Are there no wrecking yards there? I got GM sensors with connectors attached for $4 each at the local junkyard.

I don't think they are using a MAF sensor, so Indmar is using an ambient temp sensor that reads engine compartment temp. Alternatively, some MAP sensors have a temp sensor in them so maybe yours does. I'd try to find out if the MAP has more than MAP in it (4 terminals would indicate this), or make absolutely sure it didn't have a IAT before I added one. IATs can be hidden quite well sometime, even under the manifold. Also, sometimes a CLT is screwed into the manifold as the IAT (GM CLT and IAT use the same resistance curve).