SCCA RX7 RACER

Hi Ken,
Your idea helped with smoother start up and idle. I set the CAS to the third tooth set the timing and it started with out a pop. My big sticking point is still the solid miss fire at 6000 RPM and at 4000.It reacts as if the ignition is shut off and then turned back on at 4000 and 6000 RPM. The timing light reflexes this as well. My last runs it pulled strong until 4000 then stuttered ,pushed passed that and hit 6000 then stuttered, then strong to 8000 or more. I change the CAS pick up tonight; swap out the trailing coil tried a new set of plugs and wires again (You know new some time can bite your ***). Still hits 4000 bang on cuts out goes to 6000 cuts out then continues on with out no problem. I have no clue at this point but strongly believe it is some thing in the programming telling it to not ground the leading coils at those RPM spots. Any one have this problem please toss some ideas my way.Here are the last runs.
Thanks,
Kim

SCCA RX7 RACER

I use the missing tooth system with the MS 1 chip and V3 board. I had the chip flashed with the latest version (029n4). Is it possible for this to be a problem? If so should I reflash or play it safe and use an older flash that does work (Proven). If so what is the older one and can some one send me the link to down load it?
Thanks Guys.

muythaibxr

I don't think it's the flash version, I think you're probably getting some noise on your VR sensors. I'll take a look at your logs and settings again tonight.

SCCA RX7 RACER

Thanks Ken, You’re a few hours ahead of me so if you see something let me know I'll check the forum every hour or so tonight. I can still adjust the set up on the front end of the car and load up the trailer tonight. I have hopeful plans to leave on Friday to Portland.
Thanks

SCCA RX7 RACER

Hi Guys
Thanks for your help . After you explained things to me I set my data logger to show the primaries and secondary performance. What it is doing is. At the 5800 to 6000 rpm range the Duty cycle and PW for the primary injectors go up to 85-90% and the secondary drop to 10 to 15 %. One set is working harder than the other so at that point it jumps around and causing a fuel mix problem for a split second. I have no problems at the 4000 Rpm range the adjustment to moving up the secondary when it come on cleaned it up. What could the problem be with the jumping of the injectors like that? Before and after that RPM range both injectors run even.
Thanks
Kim

muythaibxr

I've never seen that happen....

West-se

PW2 and DC2 mean nothing unless your running the dual VE tables which you are not. I looked at your logs and your not running rich enough from 4700 - 7000 rpm. You need to fatten it up. Your log shows you lean way out 16.666 around 6k but then you richen it up and it levels out after that point to ~14.5. You need to adjust your VE table and run some more logs to see if your secondaries are infact capable of keeping it rich enough under load at high RPM's if you haven't already swapped them for the larger injectors.

muythaibxr

west-se: when viewing his logs, did you make sure you're set up for his wideband?

West-se

sure did, he's using an LC-1 0-5 AFR.

I've seen Kim's motor first hand its quite extensively modified, its a street port with an extremely ported intake both upper and lower with 2.5" (i believe) header into 3" exhaust. Needless to say the thing is a monster and it can really breath. Initially when I first saw the car I thought that his stock 460 x 4 injectors wouldn't be able to provide enough fuel at the top end and after viewing his logs its hard to saw if that is exactly the case or he's just not allowing enough in his VE table. After soem thought and reviewing his logs, it looks like his injectors should work but will be ~90% since his duty cycle drops down after his VE rises after the lean spike around 6000rpm. I wish I've had more time to help him but you know my engines out, its actually sitting in Kim's shop and I had more time to help with some hands on but between work, and finding another vehicle and the rest of life its tough.

muythaibxr

yeah, I haven't looked at the datalog yet, but if he's really going lean at 6000, then that's his problem. It could be his staging settings or it could be something else.

PW2 does actually show the correct value with staged injection though, at least in my experience.

renns

Kim,

With newer extra codes, pw2 does show correctly. From looking at the log, you are running very lean as soon as the secondaries come on line. Your VE table looks reasonable, so I don't think it's entirely a tuning problem. This leads me to believe either: 1.) The secondaries are not the size you think they are (should be equal to primaries according to your staging settings), or 2.) They are not functioning properly, either due to wiring or injector problems. I wouldn't run under load until you get it sorted out, as you are really lean up at the top end.

Also, there is an oddity that appears as a pulse width spike that occurs after the staging transition is complete. I've checked the datalog, and I can see no reason for this spike shown in the log file. See time 456.397, 459.794, 494.533. Ken, you may want to take a look and see if there's some issue with the staging mods. He's running max transition cycles of 255. It'd be interested to see a datalog with that dropped down to 50 or so.

West-se

thanks for the info renns, I was unaware that the PW2 and DC2 where now accuratly recording.

I also noticed the oddity, also noticed that there is a dip in his spark timing as well during the PW spike his timing goes from 18 and drops to 16 for 1 recording cycle then back up to 18. I know Kim was running stock 4 x 460cc injectors but has swapped the secondaries for some 800's but didn't adjust the scalling factor and it was still at 255 when he did his last run and said it wasn't responding well to his adjustments. I told him to change it to 187 and try from there. So far all his wireing seems to be 100% accurate so I'm doubtfull he's miswired his secondaries, i'd lean more towards possibly a bad or dirty injector but now that the 460's are out we shall see.

muythaibxr

Yeah, I'm not sure what will happen with it set to 255... Most likely it'll just have to round on the calculations, and it'll take 20-30 events anyway.

I'm sure that the code works as I test it each time James does a release... so I'd suspect electrical problems (wiring, etc...) or the injector size.

That pulse-width spike could be evidence of a noisy CAS signal. The problem I'm having on my corolla shows up the same... sometimes I'll get PW spikes or drops without rpm spikes or drops, sometimes I'll get rpm spikes/drops without PW spikes/drops.

I'll go over those settings and the datalog when I get a chance.

This is with a modded CAS... so try adjusting the hysteresis resistor inside the megasquirt to see if that helps any.

Ken

SCCA RX7 RACER

I am going to skip the run to the track at this time. I am planning to make more data runs here at the shop on Saturday and Sunday. In this way the data should be more accurate. I will post them as sone as I can so you guys can veiw them. Thanks Again,
Kim

SCCA RX7 RACER

Hi Ken,


You mentioned a hysteresis resistor, Location, how would I adjust it, in which direction and how much??
Thanks
Kim

renns

Kim,

Adjustment of those potentiometers is detailed in the manual here:

http://www.megasquirt.info/ms2/vradjust.htm

I'd suggest logging at the highest rate you can. To do this, zero out the delay in the Communication Settings page. With a decent computer you should be able to get up to 20Hz or so. For track use, buy an old Palm for $20, and velcro it to the dash.

Roger.

muythaibxr

Thanks renns, sorry about that. This is what happens when I post from work.

renns

I can't see how the noise signal would result in a huge jump in pulse width. If rpm spikes to 15k or some nonsense, MS will fuel according to the VE entry where it left the table. Kim's table values don't change much at the top end, so the calculated pulse width would not change much. More fuel could be injected due to more frequent squirting during that mode, but that wouldn't be seen in the logged pulsewidth.

I need to check that V3.0 box I built on the bench. If I get a chance, I'll do some further testing.

Roger.

muythaibxr

OK, just saying I've seen weird things happen during noise situations. I've seen the exact same behavior in my car, and occasionally I'll see pulse-width spike along with rpm, sometimes with no spike in rpm.... and my VE's are actually LOWER at 8000 rpms than they are at 6800 where I see my spikes (which I've pretty much gotten rid of now BTW).

muythaibxr

As your secondaries phase in, the AFR gets leaner and leaner. I do see some momentary dropoff in pulse width though when it shouldn't be dropping, and this could very well be caused by the 255 cycle transition time you set up. I never tested with a number that high, so I don't know what it'll do. Try a more sane number, like 25 or 50, and see what happens there. Every time you stutter, your secondaries are shutting off a bit, and you're getting a lean spike. This could probably be caused by a signal dropout or spike, and I don't think my code will do anything stupid with a number that high, but it's worth a try.

If the wheel decoder loses sync due to noise, it'll briefly drop to zero, which would explain it going back to all primaries before the secondaries come back on.

You do have some SERIOUS noise issues. Take a look at your CLT and MAT during the same areas... CLT especially bounces up and down like crazy around these points.

Ken

SCCA RX7 RACER

Hi all,

West-se lives not to far from me and has helped me a great deal. To be honest I know there is no way this race car would even run with out his help. I know the car inside and out mechanically but when it comes to all the stuff you guys are talking about it’s like a different language to me. West-se has been a great help in this area.
I’ll change from the 255 to 187 and make about 10 to 15 first and second gear passes. Each time I will clean up the AFR so that the 5800 to 6000 RPM problem will hope fully stand out on its own. Better yet get corrected. From West-se advice in the early part of the set up to get the car to fire he asked me to turn both R56 and R52 potentiometers CCW until they clicked. At this point the car had spark. So now I will turn the R52 pot clock wise if it is required. I will check in to what Ken was saying about my CLT, MAT spiking at the same time as my problem then look at adjusting the R52 pot (Hysteresis). Also to note my ajustable fuel pressure regulator is set at 45 LBS.With all the stuff that I am doing may be one day I’ll have enough experience to jump in with my own ideas on these matters (I hope LOL). I’ll post my best and cleanest run hope fully on Saturday.
Thanks again all
Kim

muythaibxr

Don't forget to adjust your Staged Injection Settings. Change the Staged injection delay to 25-50.

renns

That makes sense. Still seems odd that we capture the pulse width effect in the log, but never the erroneous rpm. Also, with Kim's setting of 255, we should be tranistioning over 255 cycles (squirt events?), which if once per rev would result in a transition time of ~4 seconds at 3800 rpm. The log shows a much shorter transition time, around 1/2 second. That 255 value is way too large for sure. That value should be as low as possible to avoid reaching the high duty cycle points prior to having staging complete.

SCCA RX7 RACER

Ken you mentioned to Stage injection change delay to 25-50. Is this the same as changing my stage scaling factor from 255 to 187 as west-se told me earlier? I look through all the tables and can not find what you say is a Stage Injection Changesetting with a value of 25 or 50.
Kim

renns

Kim,

The one to drop down to 25 or so is the 'Injector staging delay (cycles)" setting under 'More staging settings' page.