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Turbo 13B w/MS3Pro: Fires up for a second then dies after fixing MAP signal

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Turbo 13B w/MS3Pro: Fires up for a second then dies after fixing MAP signal

Old 01-11-19, 10:44 PM
  #26  
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due to the video its a lot more clear to me that its at least partly the TPS signal. You cannot have it jumping around like that. You are engaging flood clear.

also I think the reason it will start without the map plugged in is because it seeing 100 kpa is preventing it from going into fuel cut. to enter fuel cut you need a low kpa and a descending rpm reading. but i may be wrong about this one..

also.. it looks like you're using an old firmware.. would probably be a good idea to upgrade as i know they had problems with implementing engine states. (and its still not right completely..)

Last edited by keithrulz; 01-11-19 at 11:01 PM.
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Old 01-12-19, 11:37 AM
  #27  
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Yeah the s4 tps is really biting me. It seems there’s no way to disable flood clear. Maybe I can manually input a sensor count while calibrating to a number that the tps cannot reach?

The seems to need some throttle input and prodding to sound like it’s about to start.

Hmmm. I’m pretty sure fuel cut decel (overrun fuel cut? whichever it’s called) is disabled but I’ll look into that.
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Old 01-12-19, 12:18 PM
  #28  
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After looking at your data logs which I could not do yesterday it's looking like you have severe noise issues. even your internal ECU temperature is fluctuating. everything is very spastic and you have many sync loss counts that climb as you're cranking. Poor grounding or unshielded CAS wiring or both need addressed.
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Old 01-13-19, 12:55 PM
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Yeah, I noticed that the sync count seems to increase slowly during cranking. The ms3pro harness had shielded cas wires, the only unshielded portion I suppose is right where the wires connect to the weatherpack connector. I have the ECU with dual grounds to the engine as shown in the attached photo, which I figured should be sufficient.

I think I'm going to try and seperate the CAS wiring from the rest of the wires. Currently it is all traveling within the same split loom. I figured the shielding would take care of any issues, but maybe not.

Engine Grounds
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Old 01-13-19, 02:10 PM
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How is the engine grounded? Are there grounds from the battery to those rotor housings as well?. The way I have it set up: Each rotor housing has its own ground wire to the battery. I then grouped each individual (6) ECU grounds and crimped them together with an eyelet connector at the same point as one of the rotor housing grounds. As for power I made sure nothing else is feeding off of the ECU power supply. As for the shielded wire being in the same loom as everything else i don't see that being an issue.. However, I would make sure nothing is ran near the coils. Here is my question. Are your signals still noisy on ACC without cranking and without the engine running?
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Old 01-14-19, 02:54 AM
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The engine itself should be grounded via the starter grounding wire that grounds the starter as well and is attached to the driver side shock tower. I recently redid that cable and ring terminal and replaced all of it. So that should be good.

Those two grounds on the engine in the photo I posted go to the fuse panel. I donít have a great photo so I found a photo from my build and circled where those two wires end up



All of fhe ms3pro ground wires from both connectors are grouped together and attached to the ground panel via one ring terminal.

My battery is relocated to the passenger bin. 12v from the passenger battery goes to the fuse panel. The battery itself is grounded to the chassis within the passenger bin.
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Old 01-14-19, 08:28 AM
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Originally Posted by keithrulz View Post
Are your signals still noisy on ACC without cranking and without the engine running?
Could you address this?
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Old 01-14-19, 09:49 PM
  #33  
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It looks like there is still some noise when the car is just sitting on ACC. ECU fluctuates about 0.5 degrees here and there. I attached a log as well.

Semi related, should I be installing some sort of restrictor pill on the vacuum line to the MAP sensor ?
Attached Files
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Old 01-30-19, 09:22 AM
  #34  
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I had similar problems when i first installed a megasquirt. My cas was wired wrong. triple check that. It still kinda works when wired wrong.

Ive never had the noise or grounding issues everyone talks about. I honestly think noise and grounding become the scapegoat. No offense meant to anybody.
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Old 02-05-19, 04:45 AM
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Ground the ecu straight to the battery
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Old 03-19-19, 09:59 AM
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Alrighty. Been awhile because I've been busy.

So here's an update of where I'm at and what I've looked at.

-Re-cleaned fuel injectors. Also realized I needed some resistors for low-z secondaries (not that it should matter right now since only primaries are used when trying to start iirc). Installed said needed resistors.

-Replaced fuel tank strainer. Replaced fuel filter and fuel lines.
-Went through assembly photos and was able to confirm timing marks on pulley were correct.
-Verified spark and fuel injectors worked via testing in tunerstudio.
-Created a vacuum leak tester. Basically used my air compressor to lightly pressurize intake to find vac leaks. Turned out I forgot to plug the two holes where oil injectors used to be. Fixed that. No vac/boost leaks.
-Checked CAS connector. Wired Properly

So I fix all that and.... Still no start.

So I start messing with the req_fuel a bit more.... and just kept adding until I got to 16.0ms. And it fired up! and stayed on (albeit with prodding from the throttle to keep it on at ~2000rpm). It's never stayed on before while the MAP sensor has been hooked up so this is a big success overall for me....

For the life of me I cannot figure out why my req fuel has to be twice of what it should be. I've attached a megalog.

The .msq should be identical to the last .msq I posted except that it read 16.0 req_fuel instead of 8.0 req_fuel.

Again for reference I've been following Aaroncake's guide to megasquirting a rotary. That's where I got the 8.0 from. The built in TunerStudio calculator gives me 7.9ms when I input 4x550cc injectors and 1300cc engine.

I'm hoping I just have a setting somewhere that needs to be fixed. I do still need to try and ground ECU to battery ground @ chassis rather than the engine ECU. I'll be getting to that.
Attached Files
File Type: msl
2019-03-18_19.27.57.msl (551.1 KB, 2 views)
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Old 03-19-19, 02:09 PM
  #37  
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Congrats! IIRC, the required fuel changed with a firmware update since Aaron wrote that writeup. I'm not positive, but you may need to use 2600cc since the rotary fires twice as often as a 4 stroke. If you're able to idle at normal VE numbers, I would leave it at 16ms and move forward. Setup and startup is by far the hardest part of a new MS install.
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Old 03-19-19, 02:18 PM
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I think Aaroncake's guide had 2600cc, but based off of what I've read, the newest firmware should only need to see "1300cc". I am running the newest firmware on my MS3Pro so I went with that.

That all being said... I am just gonna try and run with this for now. 16ms req_fuel and the "base" VE table.

Did some more googling... Evidently the 1300cc vs 2600cc only affects the build in calculator for getting Req_fuel... not the tune itself.. hmm

Last edited by ApexHunter; 03-19-19 at 02:22 PM.
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Old 03-20-19, 09:46 AM
  #39  
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Going back through my .msq ( I really need to upload them before heading off to work), and it turns out I last used 18ms... Not 16ms.

I'm starting to think that despite my injectors spraying when I manually pulse them with a connector attached to a 12v battery, they may be bad. Or not spraying to their full capacity..
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Old 03-21-19, 10:19 AM
  #40  
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So either my RX-7 really likes fuel... or something is up.

Attempted to do a start-up with 38ms req_fuel. Which is insane.... And it fired right up. Like easiest fire up I've had my entire experience since rebuilding the engine. Idle was a little rough, so I upped it to 40ms and it definitely ran smoother. There's some footage of the engine at 38ms req_fuel and you can see how it was a bit rough.


But yeah... it runs almost "normal" like with a super high req_fuel setting. I inputed the deadtime table I could find for the rc engineering sl9-550s. So that's correct. I cross checked all the other inputs with Aaroncake's guide as well. Those look good.

I imagine it has to be the fuel injectors then? I guess they are so blocked that they have to be open for a ridiculous amount of time to get fuel into the engine?

I've attached a zip with .msq and a datalog of the engine running. AFR's look decent, and not far off target IMO.

Duty cycle and pulsewidth is insanely high for low rpm and no load.

Attached Files
File Type: zip
2019-03-20_rx7tune.zip (306.8 KB, 0 views)
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