Supercharged Car Suddenly Falls Flat, Boost and AFRs Appear Normal - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


Supercharger Discussion For all you misguided souls.
Sponsored by:
Sponsored by:

Reply
 
 
 
LinkBack Thread Tools Search this Thread
Old 09-22-2016, 10:39 PM   #1
Junior Member
Thread Starter
iTrader: (4)
 
Join Date: Jul 2009
Posts: 110
Total Cats: 0
Default Supercharged Car Suddenly Falls Flat, Boost and AFRs Appear Normal

Last night, driving my car home, it all the sudden developed a weird issue where it would drive fine under low load but if I stepped on it and got in to boost around 3-4K, the car would fall flat in terms of power and sound like a brap brap brap. I'd let off and it would run normally again (in cruise and light acceleration). Looking at my boost gauge, boost and vac looked normal both cruising and punching it. Ditto on AFRs. Doing some reading here and elsewhere, I went the bad/clogged cat route as a likely culprit. Just got done pulling it and it looks just fine (not loose substrate, no clogs). Soooooo... any ideas?

I have not logged it yet, as I have not had time between the issue developing and now when I just pulled the cat. Current plan is to reinstall the cat (RTV curing as I type this) and try driving it again and log it and see if that tells me anything. I've heard that every once in a while MS can have issues an need a restart, so maybe it will self fix over night (I know that is not likely).

FWIW, my set up is:
1.6 w/ M45
Non-intercooled 8 psi.
MS2 PNP (AFM delete)
RX8 Yellow injectors
BMW TPS
Toyota COPs

Last edited by Adam777; 09-22-2016 at 11:05 PM.
Adam777 is offline   Reply With Quote
Old 09-22-2016, 11:14 PM   #2
Senior Member
iTrader: (1)
 
Onyxyth's Avatar
 
Join Date: May 2013
Location: Boyertown, PA
Posts: 714
Total Cats: 55
Default

Overboost protection? Unlikely if youve had this tune for a while, but possible. A log will tell you for sure.

Also.. RTV on the cat? wuh?

Last edited by Onyxyth; 09-22-2016 at 11:29 PM.
Onyxyth is offline   Reply With Quote
Old 09-22-2016, 11:17 PM   #3
Junior Member
Thread Starter
iTrader: (4)
 
Join Date: Jul 2009
Posts: 110
Total Cats: 0
Default

No, not overboost for sure. I hit that in the early days of tuning the car and dealt with that issue long ago. This was different. The overboost cut off felt like the car was hitting a wall. This feels way down on power/speed but still climbs very slowly and sounds like ****. I'll report back after the log for sure, as I know that will be the most helpful. Just posting now to get it up in case someone has an easy answer w/o the log. Log will be here tomorrow at this time.

RE: RTV, using copper RTV per Enthuza's recommendation to seal up to the exhaust and header.
Adam777 is offline   Reply With Quote
Old 09-23-2016, 10:24 AM   #4
Newb
 
Join Date: May 2011
Location: Charlottesville VA
Posts: 37
Total Cats: 0
Default

TPS?

Not sure if the MS works without it disconnected or not, stock ecu does.
Andre94R is offline   Reply With Quote
Old 09-23-2016, 10:32 AM   #5
Junior Member
Thread Starter
iTrader: (4)
 
Join Date: Jul 2009
Posts: 110
Total Cats: 0
Default

I'll check the signal on the TPS when I log tonight with MS since it shows a reading. My buddy has suggested perhaps a bad coil(s).
Adam777 is offline   Reply With Quote
Old 09-23-2016, 12:01 PM   #6
Senior Member
 
Join Date: Oct 2013
Location: NorthWest NJ
Posts: 1,042
Total Cats: 42
Default

Sounds like spark blow out. Bad coil, fouled plug, something. But it isn't lighting off in the cylender it sounds like. My friend's car would do this any time the plugs were fouled.

Quote:
Originally Posted by Andre94R View Post
TPS?

Not sure if the MS works without it disconnected or not, stock ecu does.
MS works just fine without a TPS. In fact, if you connect the stock 1.6 switch type up it shorts out and won't run the car...
x_25 is offline   Reply With Quote
Old 09-23-2016, 12:11 PM   #7
Junior Member
Thread Starter
iTrader: (4)
 
Join Date: Jul 2009
Posts: 110
Total Cats: 0
Default

If it were the plugs, that would be great. Makes some sense since I am running rich with high intake temps (for now) and high EGTs (I am assuming, never measured). That certainly would be an easy and cheap solution. If it is a coil, I need to figure out exactly which Toyota PN mine are. Hopefull NAPA has one if that is what I need.
Adam777 is offline   Reply With Quote
Old 09-23-2016, 01:18 PM   #8
Senior Member
iTrader: (2)
 
williams805's Avatar
 
Join Date: Oct 2013
Location: Goleta, Southern California
Posts: 505
Total Cats: 25
Default

Check your timing with a light. I had similar issues and it turned out my key and keyway were waisted. I thought it was spark blow out too. Wish it had been.
williams805 is offline   Reply With Quote
Old 09-23-2016, 01:20 PM   #9
Junior Member
Thread Starter
iTrader: (4)
 
Join Date: Jul 2009
Posts: 110
Total Cats: 0
Default

Oof. God I hope it's not that. Big Nose crank so I hope it is unlikely.
Adam777 is offline   Reply With Quote
Old 09-23-2016, 07:50 PM   #10
Junior Member
Thread Starter
iTrader: (4)
 
Join Date: Jul 2009
Posts: 110
Total Cats: 0
Default

Plug 4 on the left compared to one from the other cylinders (all looks the same). 4 was wet and smelled like gas so... bad coil? Time to test that I guess via MS.



Adam777 is offline   Reply With Quote
Old 09-26-2016, 07:10 PM   #11
Junior Member
Thread Starter
iTrader: (4)
 
Join Date: Jul 2009
Posts: 110
Total Cats: 0
Default

It would appear to have been a bad coil on 4, right where that bad plug was. Thanks for the help!
Adam777 is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Benefits of E85 in a low-power M45 Setup Goingnowherefast Supercharger Discussion 11 11-28-2016 06:11 AM
Megasquirt PNP Pro, Injectors, Fuel pumps and more. Funding my next car! PSS Miata parts for sale/trade 8 11-21-2016 11:17 AM
WTB: Uncut NA 1.6 Injector Harness neogenesis2004 WTB 1 09-14-2016 03:48 PM
1.6 AFM someone in NC Zabac WTB 1 08-04-2016 04:21 PM
Enhanced MS2 + Wideband CAN Module Issues akbloom MS Labs - Miata Accessories 0 08-04-2016 12:56 AM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

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 11:03 PM.