trying to get my car started with the new MS2
My MS2V3 built by Reverant has a problem or two. The car doesn't start. There may have been a problem with the transistors running the injectors but that is probably fixed by Braineack who was very helpful.
I recheked the injectors with a test light, they work fine. I did not test the spark plugs to see if they fire, but previously they did. One big problem seems to be that it does not run the fuel pump. I thought before it did, but this time, I hooked up my friend's fuel pressure gauge and there was no pressure at all. The MS does not operate the fuel pump. It works fine with the OEM computer, the car otherwise runs perfectly with that. We jumped FP and gnd and ran the pump. There was some ignition, but it was irregular and the timing seemed way off. The car pooted and chugged a little and almost backfired. But no start. So there seems to be both a hardware and software problem, but now there is actual information. :) I think I recorded a data log, but I haven't done that in a while and I need to look at the laptop later to see if that came out right. I will upload it if it looks usable. So...Dimitris...you might have to talk me through repairing the fuel pump driver circuit, but for future tests, I can run it through the diagnostic port. |
Well lets check the ignition again, do the spark test through the output test mode.
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Hmm. Today I found time to run in diagnostic test mode. Coil A ran plug 2 and coil B ran plug 1. The output test did not run the fuel pump at all, but it did work again only when jumped at the diagnostic port. So far these are promising leads.
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Coil A should run plug 1 and 4; Coil B should run plug 2 and 3. So you definately need to swap these around.
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I switched the wires and manually ran the fuel pump. The car had some combustion here and there, an occasional chug without really coming close to catching, and I smelled some unburnt gas. It did not start. I did a datalog, but I can't seem to recall how to locate it to upload. It's odd, because I looked at it. I need to figure that out.
Not sure what the next step here is. Is this ever going to work? |
Now that you switched the wires around, can you confirm you have spark on 1&4 when testing coil A, and spark on 2&3 when testing coil B?
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Hey! Success!! I fiddled around with it this morning, and keeping the fuel pump on and with the spark plug wires switched, I was actually able to get the car started! It wouldn't idle, but it started! As soon as my foot released the accelerator it stalled. But it started a couple times!
The timing must be off as when I ease off the gas to 1000 rpm it runs roughly and stalls at about 800 rpm. This is good news! |
There are couple things you need to dial in to keep it happy and idling - like calibrate the TPS, give it enough air at idle (either through the bypass screw or through the idle valve), give it enough fuel - it may also be lean at idle, so give it some fuel as well (start by adding 3-4 units in the cells below 1500rpm and below 50kPa).
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Excellent, yes. (The TPS was already calibrated by the way.)
Does the autotuning feature help that? I am still running basic tuner studio, it seems time to buy the full featured program. Unfortunately I need to use the car now, so I will have to put things back, unless it is fast to adjust and I could actually drive it right now. |
I wouldn't recommend doing things in a hurry.
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:) Good advice! Or in the dark, I have made several mistakes that way.
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(zack morris's phone)
Swapping fuel injector at night without a flashlight is simply humorous |
I did exactly that not long ago. Leaked a gallon and a half of gas until I had time to fix it. I had put in the 4th injector a little awkwardly in darkness and tore the tiny gasket at the top.
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yep exactly what we did. lol! started the car and fuel sprayed all over the damn place.
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Any suggestions on fixing the fuel pump issue? I would like to get that running before I start tuning. I am only able to get it going with the diagnostics port jumped to ground.
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Scott did the fuel pump work on your stim?
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Pretty sure it did or I would have noticed it if wasn't, but not something I really took notice, so I can't say that with confidence.
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Originally Posted by SleekBlackBeauty
(Post 750260)
Any suggestions on fixing the fuel pump issue?
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Yes. Everything is correct and attached to the right place in the harness. I opened up the plug and looked at it, and could easily trace the violet wire from one end to the other.
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Hey gents, I'm all geeky excited, have the MS installed and I'm driving. It's running pretty well, still needs some tuning. Working with ts and am experimenting with ve live. So... I'm pretty happy overall. Except, I really want to deal with the fuel pump circuit. Multimeter confirmed that the wiring harness is ok. How shluld I go about approaching the ms unit itself? Point me in the right direction and i will look into it and maybe get help from engineer friends I have. Not having built this thingy myself i could use a couple more hints about the picture and correlating with the wiring diagrams.
Thanks again to Reverent all who have helped me so far! |
I'll take a picture of what components need to be where and you can double check the board for errors.
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Thanks Dimitris, I think that's what I need.
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I've adjusted afterstart enrichment a bit and it idles much more smoothly from cold (it had been stalling after a couple seconds) and using VE live to smooth out the running. It still bucks and stumbles some at low speed rpms, but less. Working on it.
Still would like to fix the fuel pump circuit. |
Pm me your mailing address and I'll send you the components you need to change.
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6 Attachment(s)
I'm back from vacation.
Here's some photos of the MS2V3. Perhaps you could point out anything amiss? Maybe point to the offending transistor? Not the greatest pictures, but I can take more if needed. |
I need a better pic of the the area just behind the big black disc-like component on the second picture.
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4 Attachment(s)
Moar:
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4 Attachment(s)
And:
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Everything seems to be in order...have a look at the two black transistors in there (labelled Q2 and Q19). Q2 should be a "ZTX450" and Q19 should be a "2N3904".
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2 Attachment(s)
Oh wait...this resistor here is probably the culprit:
https://www.miataturbo.net/attachmen...1&d=1314028434 Replace it with a 1.0Ohm (one ohm), 1/2W resistor from Radio Shack (or temporarily remove it and replace it with a wire to test) and it should work. |
looks like 270 in there. why you trolling!
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Which would explain why it would work on the stim (which as a 30-70R relay) but not in the actual car.
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:yippee: OK!
So, how hard would it be to switch the coil outputs while I'm at it? |
swap the green and brown wires on the bottom of the board. why would you need to?
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well...just so I don't get confused if I take off the new unit in the future and go back to stock. not important otherwise.
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did you have to swap your coils to get running or something?
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Yes. Coil output is reversed on the megasquirt, and the fuel pump didn't run, so it took a while for me to get it right as I would work on it a little while off and on when I had time, then put the OEM computer back in as it's the DD, etc. I meant to get this going a long time ago, so it will wait until colder weather for me to start working on the turbo hardware--I just like to drive the Miata in good weather, and my daughter is driving my Acura until school starts anyway.
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the MS outputs look okay, it must be reveresed on the harness if anything.
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Is that 1k Ohm, 1/2 Watt or 1 Ohm 1/2 Watt Resistor?
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Good read. Good luck to getting all straight, there are some very knowledgable moderators up here
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1 ohm.
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Does Radio Shack even sell resistors any more? What a crap store now. I tried googling 1 ohm and came up with 1k and 1M is why I asked. OK, cool 1 Ohm 1/2 Watt.
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i can mail you the correct one. looks like 10ohm might be all radio shack sells.
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Originally Posted by sickmiatabra
(Post 762363)
Good read. Good luck to getting all straight, there are some very knowledgable moderators up here
Originally Posted by Braineack
(Post 762381)
i can mail you the correct one. looks like 10ohm might be all radio shack sells.
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1 ohm, 1/2 watt. I deliberately wrote both the number and the word in my previous post to avoid confusion.
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Originally Posted by SleekBlackBeauty
(Post 762384)
Well, that would be pretty excellent! I assume you buy in bulk....
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Originally Posted by Reverant
(Post 762564)
1 ohm, 1/2 watt. I deliberately wrote both the number and the word in my previous post to avoid confusion.
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i have your resistor in my pocket, just remind me to actually head off to the PO at lunch.
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Hey Scott! Don't forget to go to the post office at lunch today! :)
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good timing. im hungry and should be heading off now. after my day[9] vid is over.
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2 Attachment(s)
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what if i mailed it exactly like that...
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fine! with the proper address of course. might it not just go in a letter envelope? send me an invoice or whatever and I can paypal you.
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but what if i stuck it in mail just like that?
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fine, good! thanks!
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(zack morris's phone)
I don't think it would be fine |
Originally Posted by Braineack
(Post 762838)
(zack morris's phone)
I don't think it would be fine |
there's no mailing address.
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Check your pms I sent it to you yesterday! :-p
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Originally Posted by Braineack
(Post 762896)
there's no mailing address.
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