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Old 08-18-2010, 12:53 AM   #1
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Default Misfure under cruise

Recently I've been having odd misfire issues. My car is a 1990 w/ 1.6L and MS1. Running Toyota COPS set a 2.5ms. It's for the most part only under med cruise, and tip in from med cruise to WOT. It's like a hesitation/misfire.

I've tested all my coilpacks and they are all well within spec. The plugs are gapped at .040.

Car runs at 11.2/11.5:1 under WOT.
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Old 08-18-2010, 01:08 AM   #2
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Would you happen to have a log of the event occurring?
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Old 08-18-2010, 01:22 AM   #3
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Hrmm... not. But I can go drive around tommorow with my laptop. Main proplem here is my laptop is piece of **** that needs to be plugged in at all times.

I read your thread about the COPS, but not sure if it's the same thing?

There was zero misfire for the first 3 months when the car was turbo'd. I raced it and everything. Not a hiccup. No all of a sudden it's happening all the time.
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Old 08-27-2010, 01:41 AM   #4
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Ok this is progressively getting worse. I did the 2.5MS to 3.0MS adjustment and it seemed to help... until the track day today. The car runs like ****. WOT in any gear above 4kRPM the engine mis-fires every few seconds... and sometimes a few every second.

I'm going to go log it tommorow. What setting should I log? I'm pretty n00b at this MS stuff and want to make sure I get the right info.

The f'd thing about it, is it didn't do it for a good 4-5 months... all that time I was tracking the car and driving it hard. I don't know what changed.
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Old 08-27-2010, 05:43 PM   #5
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Could the fact that I'm running a turbo map on an N/A car right now have somethign to do with it? Running super rich/can't spark the fuel?

I popped the turbo off a while ago and have just been driving around with the same map.

BUT, if I remeber right it was just starting to do the same thing when it was turbo as well.
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Old 08-27-2010, 05:44 PM   #6
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have you inspected your plugs?

Not unknown for them to require re-gapping.
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Old 08-27-2010, 05:47 PM   #7
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Yes I have. I changed plugs and brought the gap down to .030. it seemed to fix the problem until about a week later and it started again. perhaps they are getting too wet and having a hard time firing?
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Old 08-28-2010, 12:10 AM   #8
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If the car is N/A then 11.5:1 is just wasting gas. Target 13:1 at 100 kPa. Not sure that will cure the misfire though. I mean, the OEM ECU is reported to run pig rich at WOT above 4000 rpm too and stock cars don't normally have misfire issues due to the AFR.

Perhaps you have a COP going south?

My laptop also requires constant plug-in power to keep from dying. Get on ebay and spend $15 for a cigarette plug adapter. Ending that grief was definitely worth a few bucks, and that solution will no doubt be cheaper than a new laptop battery.
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Old 08-28-2010, 12:24 AM   #9
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Lol.. my laptop just sucks. I need a new one.

Aside from that... I could have a COP going south. It's gotten really bad lately. How can I test them? I just want to make sure I did it right? They have a warranty. I bought them at a wrecker.

And as for the AFR... a new engine is going in soon so I'm not spending time on the dyno to get this one tuned.
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