Ric Herber

I purchased a pre-built and programmed MS1 and boomslang harness a couple months ago. Yesterday, I finally got around to installing the MS in my '93 but I have run into a problem. On the first power-up, it wouldn't turn on (no LEDs lit). So I checked all of the wiring but found nothing wrong. I then checked continuity on the DB37 harness. It checked OK but I did notice pins 7, 8, and 9 are not connected to ground. I then plugged everything back together and the MS powered up fine (2 outer LEDs were lit) but the car wouldn't start. It cranked and fired for a few seconds and then stopped firing. I tried repeatedly but it would not start. I can hear the fuel pump running when I turn the key on (it's jumped in the diagnostics box).

It then occurred to me that the LC-1 was powered from the 12V takeoff behind the left side headlight, which is not powered during cranking (it worked with the original ECU). So I rerouted the positive wire to the 12V power wire powering the MS. The LC-1 is grounded to the engine block. Now the MS won't turn on again. I've verified 12V between pins 28 and 10/11 but it will not turn on.

I work with computerized control systems everyday at work, so I am not totally clueless when it comes to wiring and troubleshooting. Any help would be appreciated.

N3v

When you say it cranked and fired for a few seconds then won't start again, in my mind that points to two possible things:
1. msq setup incorrectly
2. no fuel

I use an AEM wideband, so I can't help you with the LC-1 issue, but even if it didn't stay on while you crank, that shouldn't affect the car starting.

try undoing whatever wiring you did with the lc1 and see if it will boot the ms like that. Then, since it sounds like your engine setup is mostly stock I doubt its a fuel feed problem, so check that your injectors are working. The easiest way to do this is if you have a spare injector, unplug one of yours and plug it into the injector harness and just hold it in your hand while someone cranks and see if you can hear it clicking. Checking for spark also wouldn't be a bad idea, and is much simpler. If you pull your spark plugs and they're soaked in gas, then yep, its a case of no spark, yes fuel. If its not quite as obvious, just pull one plug, hook it into the plug wire, and make sure the threaded area is touching your grounded valve cover, then crank and look for spark.

However, I think its slightly more likely that you just have issues with your msq, as its your first attempt. So, upload that msq!

Ric Herber

Well,

I found out why the MS wouldn't power up. The 12V pin in the boomslang harness has two wires soldered to it, one goes to the existing ECU and the other goes to the MS. Evidently, there was a bad solder joint on the wire going to the MS because I found the heat shrink covering that pin was hiding the broken joint. When I cut it off, the red wire fell out.

Now that the MS powers up, I tried to start the car again while logging it. The LC-1 is completely disconnected. The engine acts like it's trying to start but just never catches enough to continue running. At least it continues to try to start as long as I turn the key now. Here is a copy of the log. Please let me what if you see anything.

Ric Herber

Here is the msq file that was loaded in the unit.

Offline 55

Im not sure if its relevant in your case but ive read it can be a common problem with similar symptoms that you need to swap 1&3 and 2&4 HT leads round?

Just an idea so listen to me at your peril

N3v

I can't view the msq for some reason, its giving me warnings (ms gurus, why does this happen?) but that sounds like it might be an ignition timing issue if its 'trying to start' or it could be wishful thinking. Either way, in your spark settings, if your spark angle addition (the drop down between 0 and +25) is 0, change it to +25 or vise versa and see if the engine sounds any different when you crank it. If this is the issue, it'll be pretty obvious as the car might then actually fire and then run like crap. You're going to have to use a timing light to dial it in perfectly once you get it running.

again though, make sure you have the simple stuff looked after first. if changing the spark settings doesn't work, verify spark and fuel before you continue to wear out your battery

Edit:
-if your ignition wires are switched and firing at exactly the opposite time, your engine will pop and backfire and never start.
-if your fuel wires are switched, it would probably fire after cranking several times, spin for a sec, then die. or run like hell.

Ric Herber

I tried reversing the plug wires (1/4 with 2/3) but it would hardly fire and sounded like crap. With the wires in the correct places, it fires just like it's about to start but won't. I can smell gas afterwards if I stick my head under the hood. Right now I have the battery charger hooked up since I have done alot of cranking over the last couple of days.

I'm going out again to see what I can do with it.

Ric Herber

I just tried changing the spark angle addition to 0 but I couldn't tell much, if any, difference. I also tried advancing the CAS to see if that would have any effect but it didn't. Thanks for the ideas.

If any of you know Braineack, have him reply to my PM asking for help from a couple of days ago. This is the preprogrammed MS package he sells and I can't get him to respond.

musanovic

iTrader: (2)

are the coils firing i know zabac had couple blown ignition coils with the ms dont know it is just an idea his was running like ***** as well

Ben

iTrader: (33)

Just a few suggestions

1. Check plugs for fouling
2. Rotate the CAS both ways and attempt to start
3. Attempt to start with open throttle

What injectors are in the car? What other mods are on the car? Do you have CA emissions? (don't assume that you do not based solely on location)
I don't know if Scott loads firmware, sets up configurator, and loads a base map or not.

The LC1 power location has nothing to do with your no start problem.

N3v

did you pull all of your plugs and check that you're getting spark on all four? Also, if it "would hardly fire," I don't understand. does it actually fire up on the other configuration? Cause if you're getting some kind of combustion with the wires switched, that might be the right setup but the timing might be way off.

I had trouble starting my car for the first time, and when I switched my ignition wires to test that, it would just crank and go pop-pop-pop-pop-pop. It would never pick up or act like it was going to start like that. Btw, seconding the 'try starting it at partial throttle.' When I finally got my car running my idle wasn't working right so it would only start on partial throttle and only stay running if i kept on the gas.

Ric Herber

The next chance I get, I will pull the plugs and check for spark. I'll also have to check it with the CAS in both directions. The car currently does have all of the CA required smog equipment (had to pass visual inspection & test when purchased) with stock injectors and no engine mods.

Yes, Scott does load the firmware with a map based on my engine configuration. I was supposed to be able to install the LC-1, wire the fuel pump, install the AIT, install the vacuum line, and start the car. If it were only that simple....

jsisco

iTrader: (7)

Until Braineack responds a few places to work from:

If you make any changes to your Megasquirt make sure you are making backups as you go.

I'm guessing you have a laptop hooked up while you are starting. Do you get a reading from all the gauges in Megatune while you are cranking? The two big important ones right now are coolant temp and rpm.

Make sure you are getting spark from your plugs.

Check the base timing in Megatune and make an adjustment if necessary.

Also check your req_fuel and maybe even run the req_fuel calculator. I think your injectors are 230cc but you might want to verify that. I don't know some of the details of the pre-94 cars.

If all of that doesn't help there is a section in the Megamanual on getting your car started:
Tuning Your MegaSquirt

Work through some of their suggestions. I wouldn't worry about changing any major settings in Megatune though.

Ric Herber

jsisco, any changes I tried in MS, I changed back to the original settings after testing. All of the gauges read correctly, except the AFR gauge since the LC-1 isn't connected. I'll check the MS fuel and timing settings. I hope to get a chance to check the spark in the next couple days.

I really appreciate all of the help everyone has provided.

Ben

iTrader: (33)

so did you tell scott that you have a freak car when he built the MS (93 CA emissions)?

Joe Perez

iTrader: (8)

Does this mean it's a CA car?

Some history:

The US-spec 1.6 Miatas ('90-'93) had banked, two channel injector drive. Injectors 1 & 3 are paired onto a single line, and 2 & 4 are on another. So there are two injector wires going to the ECU.

In '94, they changed to fully sequential injection, with each injector on its own line, thus, four injector wires at the ECU.

Except that CA-spec cars got this change a year early. '93 1.6s built to CA emissions are unique in that they have four injector drive wires at the ECU. Thus, they require a slightly different wiring configuration from all the rest of the 1.6 cars.

Easy way to check: Have a look at the ECU harness. They'll all have a pair of heavy wires, yellow and yellow / black, at positions 2U and 2V. These are near the edge of the larger of the two connectors. If you also have a second set of heavy wires, green and green / white one space over from these, then you have a CA car and only half of your injectors are firing.


However, it sounds like you need to check a few other things first. Like verifying ignition timing. Mark the notch on your pulley with some white paint, lock the timing on the MS at 10, disconnect the fuel injectors, and have a friend crank the engine while you observe the pulley with a timing light clamped to the #1 plug wire. Make sure that the notch is at least somewhat close to the 10°BTDC mark. If you can't find it at all, move the timing light to the #2 plug wire and try again. If the notch is now near the correct position then you've got your ignition wires backwards- swap 1/4 with 2/3.

Ric Herber

Joe,

I checked the ignitor wires in the ECU plug and I only have the yellow and yellow/black wires. I verified there is spark on all the plugs. I also noticed all of the plugs were black, #1 and #2 more than #3 and #4. I had checked the plugs prior to beginning the MS install and they all looked very good with no black deposits.

Prior to beginning the MS install, I found and marked the timing mark on the pulley. I also verified the timing was correct. Regardless of this, today I tried several adjustments of the CAS without success. There isn't much difference in trying to start with the CAS retarded or advanced. I ran out of daylight before I could check the timing with a light.

Ric Herber

Today I went out again to try to get the car to start and I got repeated and constant beaping from the MS (this is without touching it since the last attempt). I think this means it is repeatedly booting. So I put everything back to stock and the car started right up. I put the MS back into the circuit and I got repeated and constant beeping again and the car still won't start. I found I could cause the lights on the MS to flicker by pushing and pulling on the power pin in the boomslang. I rechecked the solder on the boomslang male pin but couldn't find anything wrong. I tried lifting up on the lower part of the female socket in the car's harness. The situation has improved but I still get intermittent beeping from the MS. The MS lights stay on and do not flicker while it is beeping.

Any suggestions on what to do?

I know this setup is supposed to work but I'm beginning to have my doubts about having a reliable, and usable, MS.

3barboost

iTrader: (1)

the other possibility is the firmware on the ms is corrupt - I had this and had no idea - it aint gonna do anything (except cause frustration) with duff firmware

the other thing - you mention all the gauges work 100% - does the laptop display of engine speed / rpm seem reasonable ? like 200rpm cranking ? and does the cluster agree with the laptop ?

Joe Perez

iTrader: (8)

Beeping (from the PC) generally means the processor is resetting. This is indicated in Megatune by a little Reset counter in the bottom-right of the screen.

If wiggling the BS harness causes this, then you need to fix it. I wish I could tell you exactly what to do, but wiring problems of this sort require patience and elbow grease.