my turbo mess- lean? maybe?cant really figure it out.. - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


DIY Turbo Discussion greddy on a 1.8? homebrew kit?

Reply
 
 
 
LinkBack Thread Tools
Old 05-16-2010, 01:36 PM   #1
Junior Member
Thread Starter
 
Join Date: Jan 2007
Posts: 51
Total Cats: 1
Default my turbo mess- lean? maybe?cant really figure it out..

Ok ... what a big mess. I have a 94 M edition turbo w/ emu management. a month ago it was running great... pulled in the driveway and it shut off.. weird.. started back up and drove it in the garage. after this i started getting weird errors - 1 cel was 7 or 8 blinks.. or maf - but it quickly went away - at this same time i noticed my a/f guage (hooked up to the factory o2 sensor) said i was lean..1 or 2 notches even on revs? weird.. engine was still sounding happy though. anyway i replaced the maf anyway and got an extra bar of red on the guage but still lean...

now here is where i messed up - my water pump was making racket so i scheduled a timing belt/ water pump change and did all the goodies along the way... when it started afterwards it sounded terrible.. but they swore it was on time.. anyway they adjusted timing and idle and it actually went smooth.. SOMETIMES.... it still goes back to the lean fallin on itself but then corrects.

so now i cant be sure the timing belt is off by one tooth or not... i did drive it.. and it sucked and stumbled for 50 feet.. but after that as long as i kept my idle up - it was my old car again... (though my guage still read lean and my wideband now showed everything was ok)

so im assuming the belt is ok and accurate.. and i decided to study the stumbles again. it will sometimes just jump from 12-14ish on idle wideband to 22.... and almost die.. but eventually correct. they made it sound vacuum. but everything looks ok on the lineS? and my boost guage looks normal..

so now... the things i have to fix - maybe replace an o2 sensor and or wires to make the guage work again... recalibrate my wideband to make sure its accurate... and figure out why the car randomly stumbles.

would a bad o2 sensor do all this??? or maybe just wiring?

what a mess- im sure the flames can start about now but lesson learned.. dont do timing belt etc if you have other issues:P
molitar is offline   Reply With Quote
Old 05-16-2010, 03:17 PM   #2
Elite Member
 
Join Date: Feb 2008
Location: Victoria, BC
Posts: 2,322
Total Cats: 12
Default

There are so many problems here...
#1 - You are using a narrow band gauge on a mazda miata oxygen sensor. That is so beyond fail it's not even funny. Buy a wideband O2 sensor and get a bung welded into your exhaust. Yes it's worth it. I guarantee right now you have no idea what your afr really is. PLEASE don't try to tell me that you can get a decent reading on the narrow band. I had a narrow band on my stock setup, and the gauge was bouncing around all the time from rich to lean. I changed 02 sensors, same thing. It's 100% useless.

#2 - Sounds like the timing is off. What you need to do is take it apart and verify that everything lines up. This involves removing the PS, alternator, and water pump belts. Remove the valve cover, lower crankshaft pulley, and plastic covers.

#3 - You really need some proper engine management.
dustinb is offline   Reply With Quote
Old 05-16-2010, 05:36 PM   #3
Moderator
iTrader: (11)
 
sixshooter's Avatar
 
Join Date: Nov 2008
Location: Tampa, Florida
Posts: 15,669
Total Cats: 1,560
Default

I think it says he has a wideband a couple of times up there ^^^.

I'm going to say start with the basics and look for vacuum leaks.

Beyond that, I got nuttin', but I'll ponder it a bit.
sixshooter is offline   Reply With Quote
Old 05-16-2010, 06:59 PM   #4
Elite Member
 
Join Date: Feb 2008
Location: Victoria, BC
Posts: 2,322
Total Cats: 12
Default

Quote:
Originally Posted by molitar View Post
at this same time i noticed my a/f guage (hooked up to the factory o2 sensor) said i was lean.
This is where I'm confused. It makes me believe he has his wide band gauge hooked up to the narrow band mazda stock o2 sensor.
dustinb is offline   Reply With Quote
Old 05-16-2010, 09:47 PM   #5
Junior Member
Thread Starter
 
Join Date: Jan 2007
Posts: 51
Total Cats: 1
Default

To help (and thanks so much btw!) I have a narrow band regular o2 sensor in factory location and a wideband for turbo tuning (lc1) at the proper place also i generally use the gauge on the narrow band just for monitoring idle and that sweep as well as to keep track of the narrow bands health but for most/all things tuning i use logworks but later tonight i am going to recalibrate it just to make sure something isn't up with something else and my narrow band is actually reporting a valid problem... \

I drove it a few minutes ago.. and it really has super slow acceleration in comparison to when it was healthy. (didn't drive far but far enough to tell..)

so i guess i have to find out and prove its timing for the lack of power and i guess secondary - why my narrow band doesn't register anything but maybe 1 bar of red (yellow stoich to green ) Would a bad o2 sensor cause the lean?

i am almost positive they aren't dependent issues on each other is the good part i think.

As far as vacuum hunting.. my boost gauge shows normal on the vacuum end - i have gone through almost all of the topside vacuum lines and don't see anything or hear a leak - i pulled one of and the engine rapidly stumbled until i put it back.. also usually when i drive and hit 0-1 psi of boost and shift ill hear a vacuum leak if there is one.. its a very distinct sound.. i didn't hear that this time.


_________edit + additional info

Ok so I marked all the pulleys I and E and turned the crank by hand and it indeed is off 1 tooth on the exhaust cam- so mystery solved there. It still makes a "chushing" sound when turning over but i bet that is what that noise is. (ie its/engine running and from the water pump area there is a chush sound... er there also is a random 1 or 2 per minute metalic whine too... i think i got screwed on this deal lol)

So once I get that fixed... I bet I can replace the o2 sensor and maybe get that part "true'd" up and better investigate the lean a/f on narrow.

BTW I used guides from this forum to get most of this done and suggestions from you guys directly to motivate me in the right direction. Thanks again Ill update Tuesday - thats when Ill redo Tbelt.

Last edited by molitar; 05-16-2010 at 11:56 PM. Reason: updated:
molitar is offline   Reply With Quote
Old 05-17-2010, 11:17 AM   #6
Moderator
iTrader: (11)
 
sixshooter's Avatar
 
Join Date: Nov 2008
Location: Tampa, Florida
Posts: 15,669
Total Cats: 1,560
Default

Narrowband + gauge = wasted gauge

If you have an lc-1, why aren't you running the gauge off its signal? If you have a $70 o2 sensor and a $15 o2 sensor, why use the $15 one? Further, if one is capable of delivering fine resolution and the other is only a half-step better than an on/off switch, why use it?

It is somewhat like using a chisel and a hand sledge to clean your teeth. While it is good that you are trying to clean them, you are likely administering to yourself more pain than solutions.
sixshooter is offline   Reply With Quote
Old 05-22-2010, 04:22 PM   #7
Junior Member
Thread Starter
 
Join Date: Jan 2007
Posts: 51
Total Cats: 1
Default

lol true - I just use a laptop for the other.. though I do plan on getting a better gauge for the wide band - it did in fact turn out to be a bad o2 sensor in the narrow position... so replaced it.. no longer lean however I am having a bit of a tough time getting power back.. but may be needing some tuning.. So i redid my timing belt myself this time.. got it back together.. fired it up.. SOoooo smooth! dead quiet... smooth idle... timing dead on .. 850-950 idle.. wow.. drove off.. tested.. hrm seems to be light on power... may be because ive been driving the e55 for 2 weeks.. but even then the miata used to feel quicker with quicker response.. maybe off a tooth again?

i guess- is there a quick way to know if you are off a tooth? im gonna have to pull the cover off again and just double check onnnne more time..
molitar is offline   Reply With Quote
Old 05-22-2010, 05:01 PM   #8
Elite Member
 
Join Date: Feb 2008
Location: Victoria, BC
Posts: 2,322
Total Cats: 12
Default

If it's running fine I would think that you are not off a tooth. Have you checked your timing with a timing light to see what your base timing is? I'm guessing they super retarded your timing to try and get it to idle properly, and that would take a lot of power out of the car.
dustinb is offline   Reply With Quote
Old 05-23-2010, 02:05 PM   #9
Junior Member
Thread Starter
 
Join Date: Jan 2007
Posts: 51
Total Cats: 1
Default

i did - i had reset it to 8 before running the car - then adjusting the timing with the emanage from there
molitar is offline   Reply With Quote
Old 05-23-2010, 03:58 PM   #10
Elite Member
 
Join Date: Feb 2008
Location: Victoria, BC
Posts: 2,322
Total Cats: 12
Default

Quote:
Originally Posted by molitar View Post
i did - i had reset it to 8 before running the car - then adjusting the timing with the emanage from there
But the car has to be fully warmed up and in diagnostic mode to properly set the timing.
dustinb is offline   Reply With Quote
Old 05-23-2010, 05:03 PM   #11
Elite Member
iTrader: (18)
 
Join Date: Dec 2007
Location: oahu
Posts: 1,720
Total Cats: 2
Default

If you think you slipped a tooth check to make sure you have 19 teeth between the tops of the cam gears. I also think you need to recheck your timing. If it was a tooth off it would be running noticeably poorly.
astroboy is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
WTB MP62 (Hotside) (NB2) Rick02R WTB 3 01-03-2016 08:18 PM
ISO 1.6 turbo cast iron manifold cale saurage DIY Turbo Discussion 16 10-01-2015 12:25 PM
Any pnp megasquirt for 2001 Big_gumby WTB 0 09-30-2015 04:34 PM
why is my car running like pewp? (tune/datalog) itsMikey MSPNP 3 09-28-2015 07:40 AM


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 02:30 AM.