GODDAMNMOTHERFUCKINGSHIT. (I fixed my misfire) - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


MEGAsquirt A place to collectively sort out this megasquirt gizmo

Reply
 
 
 
LinkBack Thread Tools
Old 04-12-2008, 08:20 PM   #1
Boost Pope
Thread Starter
iTrader: (8)
 
Joe Perez's Avatar
 
Join Date: Sep 2005
Location: Chicago (Over two miles from Wrigley Field. Fuck the Cubs. Fuck them in their smarmy goat-hole.)
Posts: 26,317
Total Cats: 1,915
Default GODDAMNMOTHERFUCKINGSHIT. (I fixed my misfire)

I am so amazingly pissed off right now I'm temped to drive my car into the Pacific Ocean.

Since the initial install, I've been plagued by misfire under high load. Seems like it only happens when I'm in high boost- if I'm just accelerating slowly in 1st or 2nd I can take it to redline with no problems. So I don't know if it's rate of change of if it's really related to boost.

When it happens, the tach drops momentarily (tach is driven by the ignitor) and in the logs it registers as a seemingly random RPM value- sometimes a dip, sometimes a huge spike.

I've tried:
1- Upgrading to HR10G
2- Downgrading to 028y4
3- Replacing coils, wires, and plugs (gapped to .028")
4- Laying a .1uf car across JS8 and GND
5- Replacing said cap with a .47uf
6- Replacing the CMP input circuit with an optoisolator
7- Replacing both the CMP and CKP input circuits with a dual comparator circuit that Abe designed
8- Installing a 1k resistor between +12 and the black/white wire at position 2I of the stock harness

About the only thing I haven't done is install a PCPro...

[/rant]

Is nobody else having this problem?
Joe Perez is offline   Reply With Quote
Old 04-12-2008, 08:23 PM   #2
Elite Member
iTrader: (13)
 
cjernigan's Avatar
 
Join Date: Oct 2006
Location: Atlanta, GA
Posts: 8,147
Total Cats: 6
Default

I had the same issue until i gapped my plugs down to .025. Not sure if it is just the '99 coils or the BKR7E's i'm running but without gapping them down from .035-.028-.025 I was having issues.
I take it you don't have this issue when running the car to redline staying out of boost?
Are you running COPs yet?
cjernigan is offline   Reply With Quote
Old 04-12-2008, 08:26 PM   #3
Elite Member
iTrader: (15)
 
patsmx5's Avatar
 
Join Date: Aug 2007
Location: Houston, TX
Posts: 8,797
Total Cats: 248
Default

Gap plugs to .020 and log it again, bet your problems disappear.
patsmx5 is offline   Reply With Quote
Old 04-12-2008, 08:51 PM   #4
Elite Member
iTrader: (7)
 
samnavy's Avatar
 
Join Date: Apr 2006
Location: VIRGINIA BEACH, VA
Posts: 6,020
Total Cats: 175
Default

Throw your MSQ and a datalog into a zip file and post it... we'll take a look and see what we can see.

I had the same problem and it ended up being my ACCEL ENRICHMENT was kicking in and throwing an extra ****-ton of fuel. You could quick-like post a screenshot of you ACCEL ENRICHMENT PAGE4 in the BASIC SETTINGS window so I could rule it out.
samnavy is offline   Reply With Quote
Old 04-12-2008, 09:52 PM   #5
Elite Member
iTrader: (5)
 
Atlanta93LE's Avatar
 
Join Date: Sep 2006
Location: Marietta, GA
Posts: 2,198
Total Cats: 1
Default

I had this issue as well. Over time, I have done 3 things to try to address it, but didn't keep track of what helped, unfortunately. It's gone now though.

1.) Raised over boost protection a bit higher. I was getting brief boost spikes that put me close to the over boost I had input, which was causing issues. I now put over boost protection at ~5-8kPa above my peak anticipated boost.
2.) Ran an extra ground from the MS to the grounding point on the engine. This helped many issues, including noise in signals, and some misfires under rapid entry into boost
3.) Swapped stock plugs for the BKR7Es, but haven't seen a need for gapping them lower quote yet, as I'm only running 9psi.
Atlanta93LE is offline   Reply With Quote
Old 04-12-2008, 10:08 PM   #6
Elite Member
iTrader: (3)
 
AbeFM's Avatar
 
Join Date: Aug 2006
Location: San Diego, CA
Posts: 3,048
Total Cats: 8
Default

I'd suggested pulling out the caps in the OEM circuit I'd posted, which I imagine will do the trick - but while for me it SEEMED boost dependant, I'm not sure it was.

Quote:
Originally Posted by samnavy View Post
I had the same problem and it ended up being my ACCEL ENRICHMENT was kicking in and throwing an extra ****-ton of fuel. You could quick-like post a screenshot of you ACCEL ENRICHMENT PAGE4 in the BASIC SETTINGS window so I could rule it out.
That's a good point, I've had SO many problems which turned out to be accel enrichment which I thought was something else each of the times....

Quote:
Originally Posted by Atlanta93LE View Post
1.) Raised over boost protection a bit higher. I was getting brief boost spikes that put me close to the over boost I had input, which was causing issues. I now put over boost protection at ~5-8kPa above my peak anticipated boost.
2.) Ran an extra ground from the MS to the grounding point on the engine. This helped many issues, including noise in signals, and some misfires under rapid entry into boost
3.) Swapped stock plugs for the BKR7Es, but haven't seen a need for gapping them lower quote yet, as I'm only running 9psi.
1) Yeah, though that's obvious from the logs. This isn't that, if it's what I've seen, since the tach will do funny things, the logs will do stuff like read 18,000 RPM
2) I did this two, tons of wire. Didn't help me, so I took it out.
3) I'm running 7's now. How would that help you, though??

Anyway, I had gapped mine small long ago when I doubted my coils, as usual, having 5 problems it wasn't obvious what fixed what, then.

When the toyo COP set up, I went back up to 0.35, and I have little doubt I could run 40 or 45 without issue, those things are amazing, even at 15 psi.
AbeFM is offline   Reply With Quote
Old 04-12-2008, 10:16 PM   #7
Elite Member
iTrader: (5)
 
Atlanta93LE's Avatar
 
Join Date: Sep 2006
Location: Marietta, GA
Posts: 2,198
Total Cats: 1
Default

Quote:
Originally Posted by AbeFM View Post
1) Yeah, though that's obvious from the logs. This isn't that, if it's what I've seen, since the tach will do funny things, the logs will do stuff like read 18,000 RPM
2) I did this two, tons of wire. Didn't help me, so I took it out.
3) I'm running 7's now. How would that help you, though??
1) While if boost does cross the boost protection limit, it would be obvious. However, I saw odd things happen as I got close to the over boost limit, both while driving and in the log, including rpm drop-offs and spikes. I think I remember Jerry writing somewhere that the boost protection algorithm was in some way anticipatory, but I don't know more than that.
2) The later cars have more grounds to begin with. The 1.6 cars are sorely lacking, and can benefit from more grounds.
3)The 7's I run now are factory gapped slightly lower than the stock plugs, IIRC, which would help.
Atlanta93LE is offline   Reply With Quote
Old 04-12-2008, 10:22 PM   #8
Senior Member
iTrader: (5)
 
Join Date: Nov 2007
Location: Troy, MI
Posts: 860
Total Cats: 13
Default

Did you try tweaking the coil dwell? Cranking 8 ms, running 5.5 ms?
The_Pipefather is offline   Reply With Quote
Old 04-12-2008, 11:35 PM   #9
Boost Pope
Thread Starter
iTrader: (8)
 
Joe Perez's Avatar
 
Join Date: Sep 2005
Location: Chicago (Over two miles from Wrigley Field. Fuck the Cubs. Fuck them in their smarmy goat-hole.)
Posts: 26,317
Total Cats: 1,915
Default

Ok, lots and lots of ideas here...

1- It ain't accel fuel. First, I'm on TPS accel and second, accel fuel wouldn't cause my tach to drop out.

2- During the original install I ran two additional 16ga grounds direct to the head. Trust me, it's well-grounded.

3- Overboost... Interesting- I'll try disabling it.

4- Dwell- I've tried between 4.5 - 5.5ms running, no difference. (stock igniter and coils)

5- Plugs: Tried BKR7E at .035" and IFR8H at .028" with no difference. Again, a genuine misfire wouldn't affect the tach. I guess I can re-gap my 7Es to .02" before I re-install 'em.

6- Abe, I just nixed the capacitors, and will retry after I get HR code re-loaded.
Joe Perez is offline   Reply With Quote
Old 04-13-2008, 12:43 AM   #10
Elite Member
iTrader: (3)
 
AbeFM's Avatar
 
Join Date: Aug 2006
Location: San Diego, CA
Posts: 3,048
Total Cats: 8
Default

Ain't it time for our hourly update?
AbeFM is offline   Reply With Quote
Old 04-13-2008, 01:09 AM   #11
Boost Pope
Thread Starter
iTrader: (8)
 
Joe Perez's Avatar
 
Join Date: Sep 2005
Location: Chicago (Over two miles from Wrigley Field. Fuck the Cubs. Fuck them in their smarmy goat-hole.)
Posts: 26,317
Total Cats: 1,915
Default

Update: I started drinking with a very nice Barleywine Ale at about 4pm when I gave up for the day (just after you called me.) I continued drinking until I became drunk (there was some Porter, and then a couple IPAs), and then I drank some more. We're on Rum & Coke at the moment.

During this time I have removed the MS, desoldered the capacitors from the comparator circuit, resoldered the five other wires that accidentally popped off when I did that (hopefully in the same places). I then came inside and started going through my MSQ one screen at a time, making various adjustments like raising the overboost limit, going back to earlier, more conservative fuel and ignition maps (just in case) and making a few other tweaks that I've already forgotten but must have seemed logical at the time.

In other words, it will be a miracle if the car starts tomorrow morning.

If it does, we still on for around noon? That beer ain't gonna bottle itself, and I'm dying to taste how it came out. You guys already racked it into the secondary, right?
Joe Perez is offline   Reply With Quote
Old 04-13-2008, 01:23 AM   #12
Senior Member
 
Join Date: Dec 2004
Location: Brisbane, Australia
Posts: 1,272
Total Cats: 32
Default

Ignore this post; I can't read.
timk is offline   Reply With Quote
Old 04-13-2008, 01:28 AM   #13
Elite Member
iTrader: (7)
 
samnavy's Avatar
 
Join Date: Apr 2006
Location: VIRGINIA BEACH, VA
Posts: 6,020
Total Cats: 175
Default

Joe, please post your MSQ and a datalog. Without something to look at, we're all just guessing.
samnavy is offline   Reply With Quote
Old 04-13-2008, 01:53 AM   #14
Boost Pope
Thread Starter
iTrader: (8)
 
Joe Perez's Avatar
 
Join Date: Sep 2005
Location: Chicago (Over two miles from Wrigley Field. Fuck the Cubs. Fuck them in their smarmy goat-hole.)
Posts: 26,317
Total Cats: 1,915
Default

Yeah, sorry. I was debating which one to post, over the past few days I've been blowing through a lot of 'em.

Here's an example from the 11'th. This was after I built the opto-based second trigger circuit, I was running HR10f at the time. If you're wondering why the Spark1 table looks so strange, this one has map-switching enabled for the spark- this is a safety feature. When the WI system turns on, the pressure in the line switches the system to Spark2 which is more aggressive in boost.

The RPM spike at 461.5 is pretty obvious. There's another at 926.4, another at 1106.5, and some little ones from ~760 - 801.

I've done so many test drives the past few days I can't remember exactly where each tachometer dropout / misfire occurred. I ought to hook a button up to one of the inputs so I can hit it to insert a marker in the log every time something odd happens.
Attached Files
File Type: zip 200804110830.zip (380.5 KB, 62 views)
Joe Perez is offline   Reply With Quote
Old 04-13-2008, 02:05 AM   #15
Ben
Supporting Vendor
iTrader: (33)
 
Ben's Avatar
 
Join Date: Jul 2006
Location: atlanta-ish
Posts: 12,689
Total Cats: 99
Default

I used to get those spikes, and Mr. Hoffman advised that grounds needed to be beefed up. He was correct. We ended up running a couple more 18 (or was it 16?) gauge grounds from the MS' board to the back of the cylinder head. Fixed 'er up.
Ben is offline   Reply With Quote
Old 04-13-2008, 02:27 AM   #16
Junior Member
iTrader: (4)
 
Join Date: Oct 2007
Location: santa cruz
Posts: 246
Total Cats: 0
Default

start hijack

Quote:
Originally Posted by Joe Perez View Post
Update: I started drinking with a very nice Barleywine Ale at about 4pm
That barleywine wouldn't happen to be the illustrious Gnarlywine, of Lagunitas Brewing Co., the barleywine of all barleywines, would it? Safeway has 24oz bottles for $3.19. A true gift from the Beer Gods. Maybe your swilling SN Bigfeet?

end hijack
chucker is offline   Reply With Quote
Old 04-13-2008, 02:41 AM   #17
Elite Member
iTrader: (15)
 
patsmx5's Avatar
 
Join Date: Aug 2007
Location: Houston, TX
Posts: 8,797
Total Cats: 248
Default

Another member of the "slight misfire sometimes" club. I usually have a misfire to 0 RPMs on datalogs every 15minutes. I have found one thing oddly strange though. I can push a particular button on my car and the problem goes away. If I run the A/C, it will never misfire. Weirdest thing ever. Have no clue why and how but I guarantee it will occasionally misfire about every 15 minutes, but NEVER with A/C on.
patsmx5 is offline   Reply With Quote
Old 04-13-2008, 02:53 AM   #18
Boost Pope
Thread Starter
iTrader: (8)
 
Joe Perez's Avatar
 
Join Date: Sep 2005
Location: Chicago (Over two miles from Wrigley Field. Fuck the Cubs. Fuck them in their smarmy goat-hole.)
Posts: 26,317
Total Cats: 1,915
Default

Quote:
Originally Posted by chucker View Post
Maybe your swilling SN Bigfeet?
No, I managed to snag a bottle of Stone Old Guardian a few weeks ago, and today seemed like the right time to crack it open. And now that I think about it, their 2008 Imperial Stout was just released- I need to get off my *** and track some down pronto!

But the one I'd really like to find, and call me ******* crazy, is an Oskar Blues Old Chub. A few years ago I was in Denver just after the big annual huzzah, and on the way to the airport I dropped by to see a friend who lives there. He took me to a place called the Falling Rock, where they had about two gallons left from the competition of what may be the most divine oak-casked Scottish Strong Ale I have ever consumed. It was one of OB's entries that year, and from what I can piece together it was essentially just off-the-shelf Old Chub that they aged for 18 months in a whiskey cask. Granted, I'll never experiance that particular beer again, but I'd like to at least see what their "regular" stuff is like.


Quote:
Originally Posted by Ben
We ended up running a couple more 18 (or was it 16?) gauge grounds from the MS' board to the back of the cylinder head. Fixed 'er up.
Already done as part of the original install.
Joe Perez is offline   Reply With Quote
Old 04-13-2008, 04:48 AM   #19
Supporting Vendor
iTrader: (31)
 
Savington's Avatar
 
Join Date: Nov 2006
Location: Sunnyvale, CA
Posts: 14,363
Total Cats: 1,323
Default

Quote:
Originally Posted by Joe Perez View Post

5- Plugs: Tried BKR7E at .035" and IFR8H at .028" with no difference. Again, a genuine misfire wouldn't affect the tach. I guess I can re-gap my 7Es to .02" before I re-install 'em.
Yeah, you'd think that, but the MS works in mysterious ways. My car had the same issue (high-load misfires), and the tach would drop away (sometimes all the way to 0). Gapped the BKR7Es to .024 and the misfires are gone.
Savington is online now   Reply With Quote
Old 04-14-2008, 12:47 PM   #20
Boost Pope
Thread Starter
iTrader: (8)
 
Joe Perez's Avatar
 
Join Date: Sep 2005
Location: Chicago (Over two miles from Wrigley Field. Fuck the Cubs. Fuck them in their smarmy goat-hole.)
Posts: 26,317
Total Cats: 1,915
Default

Update:

The coffee stout spent a total of three weeks in the primary and a week and a half in the secondary. Yesterday afternoon we bottled. Due to the fact that we failed to properly inspect the bottles prior to sanitizing them, we ended up with a large number of sanitized yet very yucky bottles, which fortunately we caught and set aside during the filling process. As a result, we ran out after 39 bottles and put the remainder into a 2 liter growler.

I forget what the final gravity was- Abe wrote it down, but I recall that it worked out to just over 5% expected ABV. We tasted the sample from the hydrometer tube, and despite what might have been called "questionable" sanitizing procedures during the initial brew (Abe, you have to *wash* your hands, with soap, to get all the Miata grease off before you dunk them in the solution) it was wonderful. Just a few more weeks to go as our beautiful little yeast perform their final duty.



Guess I should give an update on the car too...

Yesterday was much improved. I got the misfire only twice (out of a 50+ mile round trip).

Unfortunately, I changed about ten different things, and so I don't know what the fix was. I am hoping that it was the somewhat different cap values that I installed in the CMP/CKP pickup filter. I finally got off my *** and breadboarded that part of the circuit so I can swap values at will. There's something amazingly geeky about driving around with a protoboard taped to the floor of your car next to the case-less ECU with wires criss-crossing between the two. I'm going to try some different values this afternoon at lunch time, and see whether moving lower or higher makes a difference.

It still astounds me that people aren't screaming like hell about this sort of problem. I can't believe that every single one of you either hasn't experienced it, or was content to just fiddle around with random capacitors until it worked right.

Gonna be out of town tomorrow and Wednesday, so that leaves only today, and Thursday through Saturday to get this all figured out and put back into soldered form before the big run on Sunday. The dyno trip will have to wait- I'll be happy if my ECU is fully re-assembled in time. Guess I'll just have to turn down the boost a bit and run towards the rear of the pack...
Joe Perez is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Project Gemini - Turbo Civic on the Cheap Full_Tilt_Boogie Build Threads 58 Yesterday 10:04 PM
Bad head gasket or ? shooterschmidty Engine Performance 8 09-30-2015 11:28 PM
Mystery Engine Trouble. Halp, mt.net! vehicular General Miata Chat 12 09-14-2015 04:17 PM
Missfires on idle and cruising (no load) emarkey DIY Turbo Discussion 2 09-05-2015 07:59 PM
Dumb question about crank and cam angle sensors AlwaysBroken Engine Performance 4 09-04-2015 02:35 PM


Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 11:25 AM.