megasquirt woes

mgb260 · March 31, 2015, 01:22:28 PM

Dennis, Good find. Probably a typo and everything helps.

BlownMGB-V8 · March 31, 2015, 01:36:20 PM

Dennis, you are correct about the 50* (5 teeth). That is not as critical in MS as it is with MegaJolt but it still should be configured correctly as it makes everything else a little easier. Not sure what the 80.0 you are referring to is, but I haven't looked at the file yet either.

Jim, odds are good you are right, or at least that the FPR can be adjusted to compensate. I'm guessing Chris won't be going over 6 grand on his redline, so as long as his injector on time does not exceed 20 ms at that speed he should be in good shape. (actually 19ms, see below) He really won't know that though until the later stages of tuning when he's setting up full power. It's just something to watch out for when he gets to that stage. His redline may have to be set accordingly.

The number of squirts does factor in though since you have to consider the injector turn on time of about a millisecond and subtract that from your total available. For instance, firing twice with 20 milliseconds to use at 6K means you only have an actual 18 ms (or less) to inject fuel and that either cuts into your total fuel delivery or means a 2ms jump from 18ms to 20ms when the injectors are turned on all the time. I'm not sure if MS does that, though so it's safer to assume it does not. Typical injector turn-on time is usually at least 1.2ms and may be over 1.4, it varies by the injector design. Newer is generally better, peak-and-hold are definitely better but require special circuitry. A top notch injector test service should be able to tell Chris what his actual turn-on delay is. It's something you probably have to ask for.

Jim

Moderator · April 07, 2015, 10:32:05 PM

Chris, are you still messing with this thing? Why not post a fresher log file? One thing I noticed in your old one was that your Throttle Position Sensor had never been calibrated. Only takes a second to correct that. Maybe you've fixed it already. I bet we can find more issues like that...

cgill · April 10, 2015, 05:10:17 PM

Hi Curtis,

Sorry, I took a break because it was getting to me. I am back on it.

I checked the coil pulg wiring and found a mix up so I fixed that. The car starts but runs rough. If you give it any throttle it immediately dies. AFR seems to be 10.3. The MS gauge shows that as well.

I don't know how to post the data log and tune on here but it is on the MS forum

http://www.msextra.com/forums/viewtopic.php?f=131&t=58126&p=436816#p436816

cgill · April 10, 2015, 07:05:46 PM

It's running rough because only #2 and 3 seem to be firing based on plug colour (black compared to almost new for the other ones). Why, I don't know.

DiDueColpi · April 10, 2015, 08:56:50 PM

Hi Chris,

You're probably firing on the other six plugs and not 2 and 3. If they are black then they are fuel fouled and won't fire.
Due to the vintage nature of my laptop I can't download your files. But I'll fix that shortly and get back to you.

Live like you mean it.
Fred

cgill · April 10, 2015, 09:20:18 PM

Two plugs for comparison...

Moderator · April 10, 2015, 10:25:17 PM

An inductive timing light will tell you whether a plug is firing. Move it from lead to lead...

You can upload an MSL logfile here exactly the same way you upload a photo here. You might have to clip the beginning or ending off your log to get it down to the 600kb file size limit. The name of the logfile will appear in your message. If someone clicks on that file name, their browser will show the log in text form. No problem. If they save the file (to their desktop for example), they can open it with MegaLogViewer. Okay... that's kinda clunky, but at least the file can be stored here.

cgill-April10.msl

cgill · April 11, 2015, 12:48:43 AM

Hmmm...now to track down an inductive timing light!

BlownMGB-V8 · April 11, 2015, 10:32:55 AM

If you just have two black plugs, check first to see if they are on the same coil. If they are, check the primary side of the coil for a signal and if that is there replace the coil.

Jim

cgill · April 11, 2015, 10:36:46 AM

Yes the two black plugs are on the same coil (#2 and 3).

That's my plan today. Thanks Jim.

So the second plug in that photo looks okay? I thought it would be darker given I have run the engine for two minutes. Sorry, this is all new to me. It's a great dose of reality and very humbling.

Chris

MG four six eight · April 11, 2015, 12:44:19 PM

Chris,

It takes awhile for the plugs to "color in". With new plugs I would check to see if any are wet with fuel.
Also if you do have a bad coil as Jim mentioned, I would replace the 2 effected plugs as well. Sometimes once they have been fuel fouled they will not always fire correctly.

Bill

cgill · April 11, 2015, 02:48:18 PM

It's running finally. It was a plug order issue even though I checked it. I must be losing my mind.

It is running lean. I know I have to adjust the VE table but I am done messing with it. The plan is to get it towed to someone who has experience tuning about an hour away and get him to finish the tuning.

Thank you for all the advice and help!