MS3v3 System for CNP and EFI/Turbo "Beetle"

[kangaboy]

Alright, got the plugs replaced with some more BR6HS (w/resistor) NKGs and gapped them to .02". Took it on a short trip down the road and gave it time to warm up. I was being optimistic but I didn't think I felt any of the previous issues I had been describing.
Fast forward to an hour later and my buddy came over and wanted to get his feet wet with the Tuner Studio and the EFI scene, as he is putting a MicroSquirt setup and my unused MexiFI kit on his rail buggy. We hopped in the beetle and got to tuning.
New plugs seemed to still have done the trick at the time, so we made sure the AFR table was some what conservative and let Autotune do its job. I previously had a kinda screwy VE table because of the spark issue, and the fact that I was having misfires and the Autotune was trying to make up for it by adding/removing fuel during those events...so Autotune was kinda out of the question until I got the issue fixed, which seems to be solved. We drove around for an hour or so trying to hit all the drive-able cells on the map, from flat out pulls, to 2nd gear 4k rpm hill climbs, and still everything seemed great. We got a nice smooth tuning session with none of the issues I had been describing in the most recent posts. The real test will the next time I have to go to work. If I can do the 64 mile round trip with no issues, I'll consider it fixed.
I will say from personal experience, having a co-pilot with a general understanding of tuning was 10x better than ever trying to tune by myself. I know we have the ability to do it solo with logs and all that, but having someone be able to change your values on the fly and then testing the new set points with out having to pull over and do it yourself is a real treat. Looking forward to more of that.

26981

[Schweg]

Glad you got it sorted hopefully! It’s hell chasing gremlins!

[Piledriver]

Cool, delighted you have it sorted.
No matter how good the software or hardware is you cannot tune around broken.



Usually,
(you can to some extent but you must know exactly what is broken and what to tweak)

[kangaboy]

Annnnnnnd it seems to have reverted back to its poop head ways. Just as bad as it was before, if not worse. Tried to drive to work on Tuesday and it was spitting and sputtering and not wanting to drive. I figured it was because I had messed with the AE settings the day before and it was just acting a fool. I switched cars and headed to work, telling myself I would try again next time. Well next time was today. I removed all the AE settings that I had put in previously just so I could get it back to where it was and hopefully drive it. Nope. Still acting like crap. I drove it anyway hoping I could get a better feeling and understanding of what may be going on. I know the VE and spark tables are good, as it was running perfect (by my standards) following the last tuning session with the spark plug change. So here are my questions:
-Could a leaky/loose/cracked vacuum like cause this much issue? (The MAP signal is nice and constant without any fluctuations to it, so I don't think this is actually the issue, but worth an ask)
-When I actually go into boost (which is rare with the current condition), everything seems to work. It has good AFR with no surging or sluggishness. Could this point to something in the tune that is causing issues down in the lower (less than 100kpa) areas?
-How in the crap could I go from a perfect tuning session (over an hour of driving around with autotune) with a super stable tune and no noticeable issues to it running like crap...again? It makes no sense to me at all

What is going through my head right now:
1. Start a brand new tune and copy my VE and spark table over and tune from there, seeing if the issue goes away, which would point to something that I did in the tune to make it act up.
2. Start replacing fuel/spark things randomly until it works.

[Schweg]

Did you pull the o2 sensor?

I know you said you didn’t have one in before the tune.

Any big temperature swings?

Have you triple checked all your grounds? I had an o2 sensor ground starting to come loose and it played hell with how my car was running.

How is your cold start table? Could it just be that it never thinks it’s warm so it always adds fuel?

Any points in the harness that could be rubbing on the body?

Sorry if these are redundant questions you’ve answered before.


Sent from my iPhone using Tapatalk

[Clonebug]

Have you been saving tunes as you let autotune do it's thing???? If you have a tune from a couple days ago....load that and see if the problem goes away....
Then you can see what changed....

You should go to Youtube and watch a couple videos by Andy Whittle. He is one of the main writers of Tunerstudio I think. He has a great video on Accel Enrichment that will help out setting it up. Also DIYAutotune has some good videos to watch. Here is one of DIYAutotune's video to give you something to ponder.

https://www.youtube.com/watch?v=HSE3CxaWF-I

You should turn off accel enrichment and let the VE map take care of most of it.....it's in the video. When you blip the throttle and it goes straight up in the VE map you want those numbers to give the enrichement...not the accel.

[kangaboy]

I didn't pull the o2 sensor, but I will, just to rule it out.
No real temp swings.
I have double checked grounds, but will again, just to rule it out.
Cold start table is great, and I know its turning off because I can't Autotune while it is in warmup mode
I'll look over the harness to make sure all wires are still coated and not grounded.

I have been saving tunes...which is the wild part. I had a whole day (Thursday) of tuning which was great (including the AE tweaking), put the car in the garage that night, five days later (Tuesday) I tried to drive it to work...dud. Only thing I changed from Tuesday when it wasn't running well to today (Thursday) was set all values in the AE table to 0 so there was no added fuel. That's it....which is why I'm super confused why it ran great when I put in into the garage, to the next time I went to drive it.

I'm looking forward to checking out an learning more about the AE once I get this gremlin worked out.

[buguy]

Mine does weird stuff when my lights are on. Maybe check your voltage?

[jimmyhoffa]

Didn't we start last Thursday with the AE table at 0 as well, and all it really did was the lean stumble going back into the throttle on gear changes, and the usual lean spike when you went wide open in gear?

I do remember we had the thresholds for TPS derivative set reasonably either way, so it wouldn't even get onto the AE graph in the conditions you're describing the problems, so I agree it really doesn't seem like the AE is playing into your current situation.

I'm quite inclined to really study injector pulse width, both "commanded" by the MegaSquirt and ACTUAL, like with an oscilloscope at the injector.

[kangaboy]

Voltage is quite stable the entire time, but I have thought about electrical connections a little more, mostly in regards to grounds.

As far as the AE, yeah the way we started tuning on Thursday is the same way I currently have it set up, which makes me think it has nothing to do with that aspect of the tune. It may be time to get in there and check injector flow and have them bench tested.

While the lean spiking is ever prevalent, I am still leaning towards a spark issue as Piledriver spoke of initially. I parked the bug in the garage last night after driving home from work and my wife was getting on me about it smelling like gas in the garage...which makes me think major misfires.

[Piledriver]

Start a thread over on msextra.com forums, you can post your tunes & logs there so we can all eyeball what is really going on.

I wish we could do that here...

[Piledriver]

fuel pump cavitating? starting to die? check pressure (preferably logged)

[kangaboy]

No good updates from me. Posted my issue in the MS Forums as Pile suggested...nothing to really note regarding their replies.
I have spent several hours just going through leads and grounds and cleaning things to no avail.
Cleaned battery terminals, trans ground strap, sensor grounds, MS grounds, went through and pulled on a bunch of crimped connections and actually found a couple that were suspect. Put new crimp connectors on and it didn't help anything. Re-calibrated my O2 sensor, checked wiring harness connectors to actual ECU, looked at fuel pressure which stays constant and acceptable, checked plug wires, checked coil and injector wiring...and the beat goes on.
At this point I may have to pull the injectors and send them in to get flow tested. After that doesn't answer my question, I guess I'll switch out the coils.
I guess one test I can do regarding fuel is hook up the computer and put the fuel pump to "ON" with the key on. Right now after you click the key to on, the fuel pump runs for 2 seconds to prime. I need to see if i can just turn the pump on and have it stay on without the car running and see if the pump makes some weird noises or the pressure drops off at all. I'll try to get a log of it as well. Obviously not going to be in a running condition, so results may vary.

[kangaboy]

More testing this morning. Removed IAC and plugged plumbing (just a wild hunch it may have been stuck open), disabled flex fuel sensor (maybe not reading correctly)...no difference during test drive.
Went into test mode and tested and listened for all coil and injectors. All tested (audibly) fine one at a time.
Ran fuel pump in test mode and pressure was constant 47ish for several minutes with no anomalies noted in pump sound or performance.

[Schweg]

Do you have a Jim Stim or a way to check your ECU other then individual? Maybe you have a cracked circuit board or driver overheating?