RPM lags MAP by 0.4 seconds

[panel]

Jim great looking car and video......sounds good! Just wondered if have your MAT sensor hooked up yet? I thought I read in an earlier post there was not a good spot to mount it or something ?

[billr]

Since I bugged the OP for some idea of how "big" the intake volume is, I did a similar gross estimate of that on my 427 BBC. It comes out to 900 cubic inches, about comparable to the OP's 1000.

[Jim_Blackwood]

Thanks for the compliments.
The MAT is hooked up and works. Plenum volume from actual measurements is 1340 cu.in plus the volume inside the blower (inlet is about 30) and not including the intake runners (another 160 or so) so realistically only a couple hundred CI short of a Cubic Foot of vacuum plenum volume. Guys, this vacuum drop-off is a red herring. I've measured it with the baro sensor, the boost vacuum gage and a separate vacuum gage, all hooked to different ports on the intake and they all drop off at the same rate. Heck, I can HEAR the hiss as the air flows through the valves to relieve the vacuum after stop. Please stop worrying about that. How fast does your brake booster bleed off when you unplug it? This is a MUCH larger volume. You do realize that during overlap both valves are only slightly open, right? It's not likely more than one cylinder will be in overlap at the same time. It takes time to bleed off. That isn't the problem. There isn't anything to fix here.
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Now I'm not saying that much plenum volume can't contribute to the oscillation. It probably is. But it needs to be dealt with on the control side. Mechanically I can't do anything about it short of removing the blower.
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I just ran a test with that modified.msq, datalog attached. I think it may be closer, hard to tell just yet. The start up was good, no problems there, just revving a little on the high side initially. I missed starting the datalog until right after that but I'll run another.
I did not change anything except for uploading the msq. My IAC is fat bodied and running at 340hz. Photo attached.(still noisy though)

The second datalog shows some promise: As you look at areas where the IAC increases flow like between 160 and 180 seconds, the oscillations decrease. Now I do not know if the IAC can react fast enough to dampen the oscillations or not, but I definitely see damping those oscillations, preferably early on, as the most promising avenue.

I also played with the Lag factors some more but saw only small differences there. Still, maybe the right combination of values would help.

Note, I an still running 2 squirts alternating. My next step is to change that and run the VE table generator, that's on the agenda for this afternoon.

Jim

[ashford]

i widend rpm windows a bit and other small changes. should help out a bit

[Jim_Blackwood]

Ran into an issue generating the new VE table:
"The attempted value exceeds the set maximum for the x axis. (frpm_table1)
Attempted value 17000.0
Set limit 9000.0

Some of you know what this means but I don't. How do I fix this?
I'll run a datalog as soon as I can get it to load.
4 squirts Alternating
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I ran the remodified.msq, it seemed a little better. It's definitely cycling between 600 and 900 rpm at the low point. Datalog attached.

Jim

Edit: Also I just changed the baro definition to MPX4250 and tested. Didn't seem to make any difference.

[billr]

Post the MSQ that goes with that log.

[Jim_Blackwood]

Should be the same as the remodified.msq above but, attached below.
Edit: actually this is the ending .msq and has different lag factors.

Jim

[billr]

I'm going to give up here until the VE values are brought into the real world. Good luck, I'll keep following along silently.

[Jim_Blackwood]

OK, but can you help with the error message?

[jsmcortina]

Sounds like you or the VE table generator set an RPM max of 17000.

James

[Manu]

Ran into an issue generating the new VE table:
"The attempted value exceeds the set maximum for the x axis. (frpm_table1)
Attempted value 17000.0
Set limit 9000.0

Did you change gauge limits in project properties to match your high rev need ?

[Jim_Blackwood]

Stupid mistake, I had 65000 in the HP rpm. Just didn't see it.

OK, well that was interesting.Very hard to start. Hard to keep running. Oscillation still there.

So, 4 squirts alternating with the VE table generated by the tool. That's the first attached .msq and the .msl

Then I went back and started modding the VE map, first just to keep it running, and then to get it to idle. It ain't pretty and a long ways from where the earlier map was but it's a start. Also attached. Sadly the oscillation didn't go away, but initially the map has a more familiar curve. Not that it will be able to stay that way, or even anything close apparently.
The generated midrange was way rich and the idle was way lean.

I went back to my notes, which state that I bought a set of new 42lb. injectors in July 2013 and they show up on the car in the photos after that. Unfortunately I have not yet found my test results from flowing those injectors but if they had not been acceptable I would not have used them. This does indicate that I could be a couple pounds off in my settings, but that hardly seems to be enough to account for the VE table generator results.

Honestly I'm at a loss here. The VE values I need to get the car to idle (cold) are really close to what I had on my earlier map. Around 30 vs 24 or so.

Jim

[billr]

Honestly, I'm kind of surprised the VE generator came up with such a weird table in the lower rpm range. I suggest using the default table from an "example" project would be better than anything you have used so far.

Why was the "req_fuel" cut in half from the calculated value for both those MSQs?

You need to go back and flow the injectors with your fuel system and drivers; that is the only way the req_fuel and VE can be brought into the real world so we can help intelligently.

[Jim_Blackwood]

Why was the "req_fuel" cut in half from the calculated value for both those MSQs?

That was the result from the change from 2 squirts alternating when I changed it to 4 squirts alternating. It halved the Req. fuel when I did that.

I thought the table was weird too. There must be something out of whack there. I'll play with it a little and see what I can do to improve it. The contour is somewhat in the right shape but is extreme in its excursions. By contrast I do agree that my map appeared to be too flat, but at least it works. By the time I get this one to work it will be considerably flatter too.

I'm not trying to be difficult but I don't think I'm set up to flow the injectors the way you want me to, and I can't even imagine just how I could do it.
I can tell you this much. I did flow the injectors, on an injector flow bench, using fuel pressures of 39 and 40 psi and they were rated at 42lbs at 39 psi. At 40 they gave slightly more flow and that is the fuel pressure I am running in the car, so that is the flow that I have entered into the settings. I can adjust that or the fuel pressure up or down if needed, but it should be plenty close enough. I tested their flow in the fully open mode and it was within reasonable tolerances of the specified rate. (Solid pulse train which would be the same as 12vdc.) The only effect the controller could possibly have would be to decrease the flow. I'm not sure what else you expect me to do.

BUT, 24-30 really should be a reasonable range for the injectors at idle, should it not? Maybe even lower? By the time you are getting enough fuel to support full torque or HP it should be up around 80 or more I would think, more with the 5psi boost. If it isn't, particularly if it is greatly lower then the injectors are flowing vastly more than what they are rated for (unlikely in any case but particularly for all 8 injectors to do that, especially with only a couple hundred miles on them) OR, something isn't right in the controller configuration. That's where I'd put my money. So, I'll go over everything again. I don't do this every day like some of you guys so it would not be a surprise to find something set wrong, but that doesn't mean I'll know it when I see it.

Jim

[billr]

"It halved the Req. fuel when I did that."

Did it really halve the "required fuel" value, or did it halve the similar-looking field just to the lower-right of the req_fuel entry; the one with the blue tooltip? That lower-left number is somewhat misleading. You do not change req_fuel to match that other number when changing the number of squirts.

Flowing the injector for rate can be done by just holding them open, as you did; but if your dead-time is way off, then effective flow-per-pulse could be way off. If you use the correctly-calculated "req_fuel", and don't change it, then find VE values are not rational, then other factors have to be considered. Among those are your MAT compensation (looks OK to me), WUE (also looks OK), and fuel type (you are using gasoline, stoich = 14.7?), injector DT, and MAP reading. I"m focused on the DT and MAP because they seem to be the only possibilities. Again, I'm questioning the MAP because of your slow reading-response, a problem I've never heard of here before; and because the idle MAP is so low. I really can't believe it is that low, especially as the engine drags a mechanical blower. You are there an I am not, I get that; just keep an open mind.

As to the low VE values seeming about right, keep in mind that you have "multiply MAP" on. That effectively "scales" the VE for manifold pressure. You could have a VE of 100 and MAP of 30 (kPa) and the fuel pulse would be shortened down from "req_fuel" to provide just "idle power".

Lastly, I urge you to stop clutching at the "bad algorithm" straw. There are far too many installs running fine with the same FW and HW for that to be even remotely likely. Not impossible of course, I can't say that. Far more likely is a problem with your tune, install or MS HW; in that order. So, first step is to correct obvious problems with the tune, like the VE table.

[Jim_Blackwood]

I hope I'm getting closer. But...
Thought I had something. Everything was running so bad that I went back to an older tune, made sure it ran OK, changed to 4 squirts alternating, generated a VE map, kept cranking it up percentagewise until I got it to run, then edited the map a bunch and it was starting to look reasonably good.

Up until I looked at the req.fuel just now after looking at your post. CRAP. Somehow it shows req. fuel at 5.5 and ms at 2.75 (You are right, that's the one that changed.) How the heck did that happen? All that effort for diddly squat. I'm done for the day.

However, this VE map is similar to what I usually end up with on the tunes I do, at least in appearance.

But just for S&G here's the files.

Jim

[jsmcortina]

Somehow it shows req. fuel at 5.5 and ms at 2.75 (You are right, that's the one that changed.) How the heck did that happen?

Why is that a problem?

James

[billr]

Because it calculates to 10.9, based on the engine/injector data entered.

[Jim_Blackwood]

If by injector DT you mean the time required for the injector to open, I have that set to 1ms, same thing that I've always used in every install. All standard injectors, no peak and hold. I had the impression that they generally didn't vary from that much. Anyway, bog standard mid- 1990-2010ish Ford injectors or possibly a little later. I suppose the newer ones might be a little faster.

Getting back to the MAP, let's try not to confuse the time it takes the manifold pressure to rise at shut down with the time it takes to rise when the engine is running. They are very different things. Where the bleed-off might take a couple seconds, I've seen a 4ms/kPa transition while running and I wasn't looking for anything faster. Worst case that'd go from 30 to 90 in a quarter of a second. So it's not as bad as you think and if I went looking for faster transitions they are probably there to be found. It's a huge plenum volume, no question about that, and it's bound to cause some changes. At the very least acting as an accumulator for MAP. At this point I'm becoming convinced that this is the primary cause of the oscillations at idle, but I'm also certain that it can be dampened in the controller, or at least that should be possible. How exactly to do that could be more of a problem.

Meanwhile, I have this VE table to get sorted out. I'm also convinced that I need to give you guys as close to a standard tune as I can possibly manage so that anything unusual stands out like a sore thumb. Like the MAP acting like there's a huge accumulator in the line. Which in fact, there is.

Now normally I don't have a VE map that looks like the one you've been seeing. There is a reason for that, several really, but mainly because I didn't take the time to contour the outlying areas. I was concentrating on the parts of the map that get used the most and pretty much just put in average numbers for the rest that I planned to get back to later, and I haven't done that. Oddly enough the car ran great that way except for idle. I've done a bunch of VE maps over the years, all created manually and I can do it pretty quick, but it's still a good bit of work. I may or may not get done with it tomorrow because I have a big appointment mid-day but I'll certainly try. Getting it to match the engine of course is what creates the work. The one I made today was closer to what I expected to see than anything yet for this engine. The contour and the spacing was dead on. (even the values seemed , well, at least usable.) But...

Anyway, I appreciate you guys more than you know and consider you to be absolutely brilliant. I feel pretty fortunate to have your help on this.
I'll let you know how I make out on it tomorrow.

Jim

[rukavina]

Wild idea... he thinks oscillation is map related. What about trying sd / pure tps load as a test and see if it still oscillates. If you take map signal out of the equation and it still does it.... look elsewhere