Misfires Disappeared with Cold Weather
#451371
October 17, 2016 10:31 pm UTC
October 17, 2016 10:31 pm UTC
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Joined: May 2010
Posts: 608 Toronto, ON
Chris Browning
OP
Serious Member
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OP
Serious Member
Joined: May 2010
Posts: 608
Toronto, ON
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So I was attempting to cure the small misfires that I was getting at idle this summer, I installed new exhaust gaskets, a new O2 sensor, and sealed the engine up tight for vacuum / boost leaks but I still had a misfire that would show up after the car had been running for awhile. By that I mean not just after it got up to temperature but after drives longer than half an hour or so. The only thing that seemed to help was reducing my plug gap from 0.28 to 0.24 on BR7ES plugs, but even that wasn't a huge improvement.
Well fast forward to the fall and my misfires have gotten better and better as the outside temperature has dropped, then today with the temperatures back up close to 20 degrees the car was missing again. So with all that evidence I'm thinking that either the PTU or coil packs must be getting heat soaked with the higher under hood temperatures in the summer (coolant temps have remained the same in the colder weather).
Does this make sense or is there something else here I'm overlooking? I'd like to try to diagnose this without swapping in alternate parts so if anyone can think of a method of testing the components other than trying to get the multimeter on them when they're roasting I'd like to hear it.
Last edited by Chris Browning; October 17, 2016 10:32 pm UTC.
1995 Talon TSi AWD Evo III 16G / FIC 850's / Walbro 255 / RTM FMIC / ECMLink V3
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Re: Misfires Disappeared with Cold Weather
[Re: Chris Browning]
#451372
October 17, 2016 10:55 pm UTC
October 17, 2016 10:55 pm UTC
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Joined: Oct 2010
Posts: 9,968 Caledon, Ontario, Canada
Bryan Lawrence
Senior Member, with Far TOO Much Time on Their Hands
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Senior Member, with Far TOO Much Time on Their Hands
Joined: Oct 2010
Posts: 9,968
Caledon, Ontario, Canada
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Based on what I am reading it looks like you might be right, posts on tuners seem to think it's probably the coil pack or transistor. I would try and replace those and see how it goes.
"Old Blue" 91 Talon TSi AWD "Super Enthusiast" 91 Talon TSi AWD Checkout DSMFAQ.com!
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Re: Misfires Disappeared with Cold Weather
[Re: Chris Browning]
#451515
October 27, 2016 11:28 pm UTC
October 27, 2016 11:28 pm UTC
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Joined: May 2010
Posts: 608 Toronto, ON
Chris Browning
OP
Serious Member
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OP
Serious Member
Joined: May 2010
Posts: 608
Toronto, ON
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Hey guys, Here are some logs from today, it was cold out but I was still getting some misses after my 45 minute drive home. The first log is after 10 minutes of driving around with the coolant temps just coming up to 190+, the car wasn't missing at all at this point. The second log was taken at my place after the 45 minute drive home, the misses appears in the log as rich spots in the O2 signal after which the ecu seems to pull a bit of fuel (probably making the situation worse). I'll try to get another hot log next week, it looks like the temperatures will be a little higher so I can get a more erratic idle. Idle After 10 Minutes Idle After 45 Minutes
Last edited by Chris Browning; October 27, 2016 11:29 pm UTC.
1995 Talon TSi AWD Evo III 16G / FIC 850's / Walbro 255 / RTM FMIC / ECMLink V3
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