joeytalent
Part of things
ITB Everything.
Posts: 440
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We have revs!  I ended up buying the AXM-100 High Voltage Tach Adapter from DIY Autotune - they are the main Megasquirt company, and I'm happy to support businesses like that.  For the 20 minutes it took to wire in, I'm happy. Worked first time, exactly as I expected. Seems very accurate to what the software displays on the laptop as well. Now I guess I'll be having some discussions with the company that built my ECU however, seeing as there's no way it would've ever worked. |
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joeytalent
Part of things
ITB Everything.
Posts: 440
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Just to prove it moves:  Nothing is mapped above about 3k. I guess that's tomorrow's fun now! The startup is still super rich, so I think next I'll start looking at tweaking the WUE (Warmup Enrichment) curve, and maybe pulling some fuel out of the initial startup. Edit: Bah, that was meant to be a gif. |
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None of the ECUs I'm familiar with are capable of driving a tach that used to run off the negative side of an ignition coil. Wouldn't you have needed a little high voltage tach adapter box even if the company that built your MS2 didn't screw something up? Even higher end ECUs like Haltech require the use of an adapter for that type of tach.
Really enjoying your thread by the way, I'll be going down a similar road with my Fulvia so very interested in all the little tuning details etc.
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joeytalent
Part of things
ITB Everything.
Posts: 440
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None of the ECUs I'm familiar with are capable of driving a tach that used to run off the negative side of an ignition coil. Wouldn't you have needed a little high voltage tach adapter box even if the company that built your MS2 didn't screw something up? Even higher end ECUs like Haltech require the use of an adapter for that type of tach. Really enjoying your thread by the way, I'll be going down a similar road with my Fulvia so very interested in all the little tuning details etc. Yeah, I thought so as well. According to the email exchange I've had with the company, they have it working on other cars without the voltage adapter. I can't be bothered to waste any more time calling BS or anything, but after reading the Megamanual etc, you need some additional circuit to give that high voltage spike like the -ve side of the coil provides. |
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joeytalent
Part of things
ITB Everything.
Posts: 440
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I went out for a drive last night, and the car was definitely bogging down a bit under throttle. The ignition map definitely needs some work, but a few more drives will definitely help me start determining which areas need tweaking. I'm getting a "popping" noise at low throttle - sounds like backfiring through the intake. It's especially worse when you go from closed throttle under load to partially open throttle. This usually implies either not enough, or too much fuel on throttle changes. Ideally you need a solid fueling map first, before you can dial in the acceleration enrichment (AE). My fueling is pretty good under 4k rpm, so now that I have a decent log to work from, I can start to try and figure out what's going on. AE adds in more fuel based on the TPSdot - the rate of change of the TPS%, or MAPdot - the rate of change of the manifold air pressure. TPSdot is generally considered to be the one to use, but you need to figure out how low you can set your TPSdot value without accidentally adding more fuel at idle. I'll go through the process in the next post, as gaps in my meetings today allow for it  |
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joeytalent
Part of things
ITB Everything.
Posts: 440
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Alright, we'll start here.  At this point, the RPM (white line) is pretty steady around 2500rpm. So I was probably cruising at this point, feathering the accelerator (green line). The red line represents the AFR - you can see it jumps SUPER lean every single time I open the throttle. Looking at the green spikes, I didn't open more than 10% throttle, but there are a lot of big red spikes. The yellow line represents the TPSdot. I need to figure out a good value for this to at least apply some amount of acceleration enrichment. Just looking at the values, it seems that around 5%/s seems like a good threshold to at least get some AE happening. Moving over to Tunerstudio:  I've plugged in 5 as my lowest TPSdot value, and also the lower threshold, and some guesstimate added values for now. The max TPSdot value was taken from the max I saw on my last drive, plus a bit extra just in case I can suddenly move my foot faster. Next up will be going out for another drive and seeing if we're hitting any of these. My goal is to have the small throttle openings where I'm seeing the super lean spikes level out by injecting extra fuel. My TPS signal is actually really clean, so I can possibly make the threshold even lower. Of course, this is all guesswork until I get to drive the car next. |
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joeytalent
Part of things
ITB Everything.
Posts: 440
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Installed a new heatshield under the ITBS tonight. I've not seen any heat soak yet, but seems like a prudent move now that I removed the exhaust wrap from the manifold. Started the car up and it sounds awesome.  |
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lebowski
Part of things
Hillman Avenger, Clan Clover
Posts: 488
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Aug 15, 2020 13:33:37 GMT
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I think you will struggle with the accel enrichment at 5%/s activation threshold. Any time you touch the throttle at all will activate it. Think about how slow you would move the pedal to only move it 5% over a whole second.
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joeytalent
Part of things
ITB Everything.
Posts: 440
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Aug 15, 2020 16:47:59 GMT
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I think you will struggle with the accel enrichment at 5%/s activation threshold. Any time you touch the throttle at all will activate it. Think about how slow you would move the pedal to only move it 5% over a whole second. I guess I was trying to use it exactly for that purpose - small throttle changes as the plenums open cause an instant lean spike, which I can't think of a better way to get around. Perhaps I should try the MAP based AE? |
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lebowski
Part of things
Hillman Avenger, Clan Clover
Posts: 488
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Aug 15, 2020 17:27:16 GMT
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I understand what you're saying but it will activate anytime you increase the throttle. Even going from 'cruise' to 'a tiny tiny bit more cruise'. My AE needs work, but for reference I currently have the threshold at 50%/s.
In my understanding, the fuel map alone will take care of light/slow changes in throttle. The AE is needed for bigger or quicker changes.
I would definately stick with tps based enrichment. Do you even have the map sensor setup on your car?
I bet it sounds fantastic by the way!
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joeytalent
Part of things
ITB Everything.
Posts: 440
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Aug 15, 2020 17:56:37 GMT
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I understand what you're saying but it will activate anytime you increase the throttle. Even going from 'cruise' to 'a tiny tiny bit more cruise'. My AE needs work, but for reference I currently have the threshold at 50%/s. In my understanding, the fuel map alone will take care of light/slow changes in throttle. The AE is needed for bigger or quicker changes. I would definately stick with tps based enrichment. Do you even have the map sensor setup on your car? I bet it sounds fantastic by the way! Yeah, I gotcha. I might disable AE completely for now and get the VE tables dialled in more. Yup, I've got a MAP sensor hooked up to the vacuum block. All six ITBs feed into it, it's actually a pretty solid signal (for ITBs). I'm using ITB mode in TunerStudio, so it's already used for the smaller throttle openings. |
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joeytalent
Part of things
ITB Everything.
Posts: 440
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Aug 15, 2020 17:57:21 GMT
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Oh, and it sounds awesome. Never ceases to put a big smile on my face!
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joeytalent
Part of things
ITB Everything.
Posts: 440
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I drove a couple of hours today. Looking at the VE tables, the cells aren't really being changed by much with VEAL, which implies it's getting pretty close. However, it really doesn't feel like it - still lots of awkward popping out of the inlet.
I've decided to go back to Alpha-N and start the process again. I've been successful with this approach before, and in my mind it eliminates the ECU as a potential problem.
The problem normally happens going from closed throttle to partially open (less than 5%). The AFR is completely lean at closed throttle, then as soon as you crack the throttle, you get the horrible clicking / backfiring through the inlet.
Alpha-N will let me add some more resolution below 10% TPS, which will hopefully let me tune the fuelling a little more tightly.
All a learning experience, but still thoroughly enjoying the car.
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Is the firing through the tb's down to timing?
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lebowski
Part of things
Hillman Avenger, Clan Clover
Posts: 488
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I drove a couple of hours today. Looking at the VE tables, the cells aren't really being changed by much with VEAL, which implies it's getting pretty close. However, it really doesn't feel like it - still lots of awkward popping out of the inlet. I've decided to go back to Alpha-N and start the process again. I've been successful with this approach before, and in my mind it eliminates the ECU as a potential problem. The problem normally happens going from closed throttle to partially open (less than 5%). The AFR is completely lean at closed throttle, then as soon as you crack the throttle, you get the horrible clicking / backfiring through the inlet. Alpha-N will let me add some more resolution below 10% TPS, which will hopefully let me tune the fuelling a little more tightly. All a learning experience, but still thoroughly enjoying the car. Have you got too much ignition advance in the areas of the map where it's popping? Mine did that at tiny throttle openings in certain situations such as going downhill. Retarding the ignition in those areas eliminated it. I'm not too familiar with ITB mode on Tunerstudio, but I understand it uses speed density upto a point, then switches to Alpha n. Probably easier to just use Alpha n in your case I imagine. You could always click the 'multiply map' option so it reduces the fuelling under vacuum, but I would think it's probably not necessary. |
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joeytalent
Part of things
ITB Everything.
Posts: 440
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Aug 19, 2020 14:47:22 GMT
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Is the firing through the tb's down to timing? Have you got too much ignition advance in the areas of the map where it's popping? Mine did that at tiny throttle openings in certain situations such as going downhill. Retarding the ignition in those areas eliminated it. I'm not too familiar with ITB mode on Tunerstudio, but I understand it uses speed density upto a point, then switches to Alpha n. Probably easier to just use Alpha n in your case I imagine. You could always click the 'multiply map' option so it reduces the fuelling under vacuum, but I would think it's probably not necessary. Great suggestions, thank you gents. lebowski - you are correct about ITB mode. I've put together a new ignition table and gone back to good ol' Alpha-N. Will give it a go today and report back. |
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Aug 19, 2020 16:42:08 GMT
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Well they look dead pretty even if they're causing you issues!
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Aug 20, 2020 19:29:40 GMT
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Auto tune is great but it’s only as good as your target table. IIRC there is a way to link the target table and VE table so you are effectively making changes direct from the target table. You can do that anyway but it’s quite laggy.
Thanks for bringing the itb mode to my attention - will come in handy when I finally get my ITBs finished and fitted. There have been more than a few changes to available features since I joined the MS family in 2004 (!)
Straight six on ITBs - there’s ear candy 🙂
Nick
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1967 Triumph Vitesse convertible (old friend)
1996 Audi A6 2.5 TDI Avant (still durability testing)
1972 GT6 Mk3 (Restored after loong rest & getting the hang of being a car again)
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joeytalent
Part of things
ITB Everything.
Posts: 440
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Nothing much to report. Work has been manic again, plus we started fostering dogs for a shelter. First one was a 3 month old puppy which was entertaining.  I got more of the interior fitted at least. The cabin is looking quite good now, at least in my eyes. My better half bought a matching Cobra RS seat for the passenger side, and that's really finished it off nicely. The last part is plugging up some of the holes in the rear of the cabin to stop some of the exhaust fumes coming in - for example, I'm missing the two caps that go over the strut tops.   On the tuning front - after doing some more reading and experimentation, as well as considering the valuable advice from here, I've started working on tuning the bottom two rows of the VE table manually. Initial results are good - the backfiring and popping is a lot better, but the trade off is a richer overall drive. |
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vulgalour
Club Retro Rides Member
Posts: 7,285
Club RR Member Number: 146
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Sept 2, 2020 11:59:07 GMT
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That interior is looking really good, especially the matching seats.
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