I understand. I was just thinking if I move the #2 injector and the temps also move, and the car still runs rough (which it should given no other things are changed) then the next step, besides checking the injector harness wiring, would be to change injectors, especially since I have some on hand.

Another approach would be to just send the set of injectors to be tested and rebuilt. I've used Marren before. While the injectors are off to Marren, I can be checking wiring. However, those Flow Force injectors are not even two years old. Could an intermittently bad injector could cause the engine to die?

 

I would think that an injector that is bad enough to cause that would have roasted that piston under boost by going lean by now.

 

I've exchanged some emails with Nigel at Flow Force. Great guy. He thinks it might be a bad adapter pigtail to an injector. I'm awaiting parts.

Here's a screenshot of the AFR/EGO Control pulldown.

Anything on there I should change?

Thanks,

 

You have controller authority limited to +/- 3 percent. That seems pretty small to me, the wideband loop is barely allowed to do anything. I'm not sure what's normal, but mine is set at +/- 30%.

--Ian

 

Alrighty then... I assume the car should be tuned with that set to Zero, and then some correction percentage is chosen. Is that right? I read the book by Matt Cramer, "Performance Fuel Injection Systems", and I reference the MegaSquirt website often, but I haven't found the kind of help I usually need. Here's my tune.

Is there anything in the AFR or VE Table that's heinous--that would prevent me from progressively increasing the EGO correction after I get the car actually running right?

Thanks much,

 

You don't need to change that value to tune -- just turn on VE Analyze Live and let it do its thing. It can read all of the current fuel data from the megasquirt, back out the correction factors, and figure out what to put in that cell.

The EGO control authority limit is to stop the MS3 from doing something truly stupid if the wideband sensor fails. Arguably, 30% may be too large a value for it (since if you were at 11:1 and knock off 30% of the fuel, it's now dangerously lean). I don't know what most people run it at, and I'm not sure where the 30% in my table came from, I don't recall changing it, but I might have.

I don't think the control authority limit is causing the problems you're seeing here, it's just something I noticed when looking at the table you posted.

--Ian

 

I was referring to an initial dyno tune. It seems to me you'd want that Off. Regardless, I've posted my tune before for other reasons. You are not he first person to comment that 3% was low. But, I assume (although I could be wrong) that value has never been changed.

 

Typically people tune fuel on the street and then use the dyno for doing timing. Dyno time runs about $2-3/minute, and there's no real advantage to doing it there if the car is streetable.

--Ian

 

This is what I use. 15% in idle is to work out hot restart. Still, it is likely more than I need.
Small numbers in boost make that region practically open loop, which is OEM common. I may make them a bit bigger in the future, as I did have an unexpected AFR fuel cut yesterday. Then again, my AFR Error table is pretty tight.
The low kPa are small because, when trailing throttle, where's the danger, AND, i was tuning that section manually and did not want any confusion.




So, my philosophy, not yet compete, is that 30% is too much and 0% is too little. It also may be, that if one wishes to set VE and leave it alone forever, then you need the EGO to account for crappy winter gas (low BTU) vs good summer gas, and that can need either long term trim activated, or more range on the EGO correction. I'm under the impression that winter to summer is about a 3.5% differential.

Another safe thing to do is to tune on winter gas and let things run fat in the summer, but that will give poorer gas milage. Track car, you probably don't care.

 

Sir,

I cannot find that table in my version of Tuner Studio.

 

Oh, yes I see. What Firmware Revision are you running on your MS3?

1.3.4 is pretty good since you are not running EBC. Otherwise Reverant is recommending 1.4.0.

Also, I'm not sure this is your issue.

Your MAT Air Density Table is messed up:



In that you are not at 100% where you likely tune. However, the relative numbers are not too bad, so, though a bad tuning practice, I don't think this is your problem.

Do you have an intercooler? If so, where is the MAT sensor?

I didn't see anything else out of place in your tune.

 

Yes, I have an intercooler. The GM temp sensor is in the aluminum tube just below the 90 degree silicone connector going into the throttle body.

If I were to slide the numbers down so 100% lined up with, say, 110 degrees, would everything get 4% richer than it already is?

Thanks,

 

Yes. Basically, I'm saying that where you tuned (typically around 70F) should have initially been set to 100% along with the rest of the curve. Then, as other MAT temperatures affected AFR, those points should have been adjusted, leaving the base at 100%.

Now that you have tuned everything, it would likely not be worth the effort to redo.

If you were a purist, you would multiply the whole VE table by .96 (or whatever matches the present correction at the temperature where you did most of your tuning of VE), and then redo the curve. I'm not suggesting that, only observing.

Again, these are side issues. I don't see where the actual cause of your problem has been found. Intermittents are tough.

 

Nigel at Flow Force sent an install kit with the newer pigtail version. At first glance, they seem identical to the ones I had, but closer inspection showed the blades in the connectors to the OEM harness are much longer. I don't know if there are other differences. I installed those, as well as the new aluminum spacers that sit atop the three plastic isolators. The spacers add 2.5mm of height to the isolators. I assume the guys at Flow Force figured out the injectors needed a little more room. I repaired the burnt insulation on the O2 sensor wiring, and recalibrated the sensor since I already had it disconnected. I also swapped the locations of the #2 and #3 injectors. (See posts 94 to 101.)

She's still up on jackstands, and it's cold and rainy here. I elected to leave her up in the air and just let her idle. She ran smoother than ever. I ran her till the coolant temp got up to 192 and the fan kicked on. No rough running. I hit the header flange with the laser thermometer when she'd warmed up -- 340, 310, 340, 360. #2 was still and consistently the coolest, and #4 the warmest, but there wasn't the 100 degree difference like there was before. (I have no idea if those numbers mean anything. I had the laser thingy handy, and it gave me something to do while I waited.)

I plan to take her out tomorrow. Wish me luck.

Thanks,

 

I think that did it.

It's 74 here right now. I took her out for over an hour, about 50 miles. Slogging around in my little town, some 6800 rpm pulls, highway driving, traffic -- no issues. Running smooth and cool. I don't know what else I could do. If there were an HPDE tomorrow, I'd go.

I do have one concern. I was reading another thread about issues updating the MS firmware and I checked mine. TS says I'm running 1.2.0. I haven't updated the firmware since getting the box from Rev a few years ago. There never seemed to be a driving need to do it. I'm a don't-fix-it-if-it-ain't-broken kinda guy. Now, I'm running obsolete firmware. If I were 100% sure she was fixed, I'd take on updating. I went to the MS website and could not find any version change notes, so I don't know what I'm missing, but I need to hear back from Rev.

What do you all think?

Merry Christmas,

 

Awesome!

As far as software updates go, there's a big improvement in the EBC algorithms in 1.3.x. If you're using EBC, you'll want this upgrade, but be aware that you'll need to spend an hour or two retuning it once you do.

Personally, I'd wait til you're confident that the car is fixed before messing with a software update. Drive it for a month or so.

--Ian

 

It is the 1.4.x firmware that has updated EBC controls.

I would highly suggest upgrading to the 1.4.1 firmware. There are tons of very good changes that have come over the years. There was a thread recently though about another MSLabs customers upgrade process. I would take a look at that and follow in his steps while upgrading.

 

I've been keeping up with this thread, so congrats for finally figuring it out.

So in sum, it looks like your car had issues misfiring/giving fuel etc, just from one of the injectors not getting inputs correctly. I just got the FF kit in the mail. Hopefully the issue is gone. That sounded like it was nightmarish to diagnose. Hopefully your saga is over.

Wasn't that TorqueZombie?

 

My Friend,

I can neither confirm nor deny it was a single injector. After living with this for a while, I speculate it was sometimes more than one. Sometimes... it would run like crap but run well enough to get me down the road. However, there were a few instances where I thought I would need a tow. Once I was only about three miles from home, but I didn't think she'd make it. I'm hopeful the issues were all related to the injector setup.

I owe Nigel at Flow Force Christmas beers.

Merry Christmas,

 

DAMMIT, DAMMIT, DAMMIT.

She's not fixed. I decided to go through the idle adjustment procedure again and had the car idling in the driveway. Coolant temp was upwards of 180--I have a 180 degree thermostat and the big TSE radiator. I stepped into the garage to grab a beer and the car just stopped running. There was no indication of anything wrong. One second she was running, the next she was not. I restarted her and she was running like crap, just like before, like she was out of balance.

I would have bet a month's pay she was fixed, and would have gone to an event if there were one this late in the season. I was sure the problem had been solved.

I took a couple of logs afterwards. They're not long and probably don't reveal anything.

Thanks for taking a look and best wishes for a Happy New Year to everyone here,