Fulltilt

Ok, I got it all wired in, but it wouldn't fire. There are some obvious things to go after, but some not so obvious. First off, Al, I tried your .cas file and it came up with an error message about an audit and 493 warnings or something like that? Don't know what that was about. I loaded mine again and didn't get the same message.

Sensors: after all that messing around with EasyTherm, the coolant sensor was reading 60 and the IAT was reading 90. Ambient temp in my garage was probably 80? I am using a GM IAT sensor from the intake tube of a LT-1 Chevy. When it warmed up (running on OEM computer) the CTS was still 30 degrees less than the reading from my infrared temp gun aimed at the thermostat housing. When I shut it down, the IAT read 113 and my temp gun on the intake tube read 111. I have read threads about people having problems running the OEM sensor, should I switch to a GM sensor?

Ok, here's the big one. I am not reading engine RPM when monitoring it with the OEM ECU running the engine. I suspect this is why it won't run. I used a 1K Ohm resistor off the ignitor, even though everyone else is using the CAS. Sorry, but I don't know if I'll run spark with mine, and I can't find clear board mods for the V2.2 board and the 1.6 engine that make me feel confident enough to do this. Can anyone help? Should I proceed with the ignitor and add another resistor? In series or parallel?

Also, for more information, while running it on the stock ECU, the MAP and temp gauges were working, the O2 indicator was not.

Thanks in advance for any help you can provide,
Kyle

Al Hounos

The warnings come up because it was made with an old version of the MS code. It won't work.
Which wire on the ignitor are you connected to? It should be the yellow/blue wire labeled TAC. The resistors are only so the stock tach isn't killed when the MS is connected. It should work in megatune no matter what.

Aussie Driver

Check your connections to the factory harness, and check your soldering on your DB37 connection. The different temp readings under different conditions suggest a short in there somewhere.

Fulltilt

I'll check the DB37 tonight. I was hooked to the TAC wire of the igniter. One other question. In the settings sticky, there is a screen for cranking settings. Should that be in my version of MT?

Aussie Driver

Yep, the cranking settings should be there.

Make sure that you have Megatune 2.25 on your pc, then get MSnSE 029q2 from the Extra website. Unzip 029q2, open 'Edit Settings', change the default to # set MSNS_EXTRA,

choose your O2 sensor (do the same thing, # set..., and have the rest #unset...)

Then click on File > Save

Then exit 'Edit Settings'

Then use 'copyini' to copy the current version of MSnSE into the MegaTune2.25 > mtCfg directory.

Then you have to open EasyTherm, change the settings to the ones you want for the temp settings, click on 'Custom' in the Code Version box, change the port to the correct port for your connection, then click on Write .inc and .s19Files, then click on Download to MegaSquirt.

That should get the files set up. If you want a N/A setup then I can send you my .msq if you send me a pm with your email address, and if you are running a turbo setup then one of the other guys can help you out.

Fulltilt

Oh boy, you guys are going to get me running spark after all, aren't you? I'll try that tonight. Thinking more about what you said about different temp readings under different conditions, I'm not sure that is the case. I think I could say that the coolant sensor was consistently 30 degrees below the actual coolant temp. Does anyone know what problems are associated with the OEM sensor when people say they don't have good luck with it?

Fulltilt

Aussie, I can't send you a PM until I have 10 posts. This will make 8.

Fulltilt

9.

Fulltilt

10!

timk

Are you sharing the IAT sensor with the factory ECU? If you are, you need to leave out the bias resistor on the MegaSquirt as the bias resistor is present inside the factory ECU. Here's a couple of pages that might be of use:

http://www.megasquirt.info/v22manual/sharesen.htm
http://www.msefi.com/viewtopic.php?t=19473

If you find out what the bias resistor value is inside the ECU, it would be good if you could post it back here so we can all benefit.

Good luck!

Fulltilt

Nope, I'm using a GM IAT because it seemed that was what most of the threads I read were doing. That and using the stock coolant sensor with R7 changed to 2.2K, as that was what I read on the megasquirt forum. Though now reading Greg Salt's thread it looks like he had some temperature error as well, but it didn't affect him either. I did everything Aussie said, so now I'm running MSnSE code in MT. Last thing about coolant temp, I played with the values in ET quite a bit and kept rewriting the .inc files. The coolant gauge didn't change. But honestly, the coolant temp is the least of my worries.

I checked my wiring. Everything is hooked up according to the MegaMiata Pinout.pdf file pulled from MS forums. TAC is hooked to pin 24, power to 28 (with a 3 amp fuse...enough power?), I've got power, temp guages, and the MS works with the stim. The only good thing that happened tonight is that my 1.8L injectors arrived and I got those put in. Ahhh, wrenches are so comfortable......

Aussie Driver

I'm still running the factory coolant temp sensor. I haven't modded the board (I'm going to run the GM sensor when I do my coolant re-route) but by using Al's temp settings with EasyTherm, it's reading accurately enough that I'm getting reliable first starts in 4 degree C morning temps.

Make sure when you load the 'new' file onto the MS with EasyTherm, that you choose the .s19 _mod file. Otherwise it will just load up the original unmodified file.

(Don't ask me how I know that.......)

Fulltilt

So are you saying you are still running the original 2.49K resistor? Maybe I should put that back. What is this coolant re-route you mentioned? I am looking for better cooling, it was running pretty warm on the track Saturday. My EP Miata had a very different coolant routing that the SCCA guys claimed ran much cooler, but I didn't find anything about it on Miata.net's garage, which surprised me. I've got a new radiator on the way, but I'm always interested in coolant system improvements.

Fulltilt

(I accidentally posted this in my other thread, it belongs in this one.)

Major progress last night. I wasn't reading spark because I was only using the jumper from XG1 to XG2 for using the stim. I was finishing assembly on the other MS I almost had built and going through the assembly process brought me to that decision point on the board and in the past I guess I hadn't planned on running it the way I am right now. I also put the 2.49K resistor back across R7 and my CTS is only about 10 degrees off. Close enough! So I'm reading spark when the OEM ECU is running it, but as you have described, the OEM tach doesn't work. I never got an answer, should I put more resistors in series or parallel?

Aussie, I tried your .msq file, and it says there are 20 warings to the audit file. Any idea why thiss would be?

So I tried running it on MS. It fires, revs, then dies. Revs then dies. But it's running fuel and spark when it does that. I increased cranking fuel by 50% but it didn't help. It's like it really wants a TPS signal, because it doesn't respond at all to the gas pedal. Any more suggestions?

Getting closer,
Kyle

kingofl337

The Megasquirt doesn't need a TPS sensor.

What year is your car? How do you have the fuel pump output connected?
Is the Megasquirt reporting correct RPM readings in the software?

Fulltilt

Hmm, I have done nothing with regards to the fuel pump. The pdf I was using with the connections I need to make said the fuel pump relay connection was not used. Shouldn’t the stock ECM be taking care of this? I hope I'm wrong. No fuel pressure could certainly explain what it's doing.

I have been scouring threads/DIYAutotune's site to make sure I'm clear on how to make the board mods on a 2.2 board. Does anyone know of a clear thread/link that could help? Also, my Radio shack only had 1/2 watt 470 ohm resistors. That just means that they will disapate more heat right? Should that affect anything? Half a year ago I bought an EDIS set-up thinking that's what I would need to do to run spark. Maybe waiting paid off, it would be great to be able to use my stock ignition system.

Thanks,
Kyle

Fulltilt

Oh, and to answer your other questions: the car is a 1990, and the rpm is reading 1700 at idle. It is idling high, but I'm not sure if it is really 1700. I haven't added another resistor to the TAC conection yet to try to get my stock tach working again to find out.

Al Hounos

I would guess those resistors will work fine. Your fuel pump should run normally if your AFM is still connected.
Get that 2nd resistor on there and everything should work.
If it fires and dies, check that your after start enrichment table has acceptable numbers in it.
Asfor the mods, just use the picture on diyautotune.

kingofl337

Do you still have the AFM connected? The AFM has a switch that controls
the fuel pump. You need to take a realy and jumper two of the wires together
to turn on the fuel pump.


Check the forums for my thread on Miata VS Megaquirt. It has all the info you need for the 2.2 Board

Fulltilt

AFM is still hooked up. I would love to get rid of that thing. It probably isn't the fuel pump. It would appear that the picture in DIYautotune site for the 2.2 board isn't there anymore, but I followed these instructions:

<-How to mod a MegaSquirt-I PCB2.2 ECU-

Parts Needed for Input Mod: (1) 1k 1/4w Resistor and (2) 470 ohm 1/4w Resistors (Just ask me for them when you buy your kit - free!)

"CMP Signal" -- Lay a 1k 1/4watt resistor across the bottom of the PCB with one end at pin 11 of the processor (U1) and the other end at the X11 hole. Bend the resistor leads to raise the resistor just a bit off of the PCB and allow a lead on one end to drop through X11 and solder that end in place (while making sure the other end is in place near pin 11 still, and with the resistor still raised a bit off the board so the leads don't short against anything). Then use needle-nose to hold the resistor lead to pin 11 and solder it to the pin. Now to get the 5v pullup use a 470 ohm 1/4w resistor and solder one end of it to the first resistor at X11 (just tie them together) and the other leg of it to the small un-labeled hole just above and to the right of D9 (when looking at the PCB from the top that is). Once again raise this just enough off of the PCB to prevent it from shorting with any of the leads sticking out on the board. (Heatshrink tubing over the whole wire/resistor assembly works nicely)

"CKP Signal" -- We just need a 12v pullup. Install a 470ohm 1/4w resistor between the right side (non-band) end of D5 and the right hole (banded) end of D9.>


I hooked up the blue and yellow wire off the CAS to pin 24 and the white CAS wire to pin 11. I tried to load Aussie's .msq and got the same 20 warnings to the audit file. This time the original ECM won't run the car. Unplug the DB37 and it starts. Grrrrrrrrrrrrrrrrrrrrrr!