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2G eradic idle help me not have to take my car to satan

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Rustic gst

Proven Member
66
2
Sep 14, 2016
las vegas, New_Mexico
ok guys so my car has a bad idle with no check engine light on. i have replaced coils, wires, plugs, as well as the iac and blocked off my egr. i did a boost leak test with my homemade tester and bike foot pump. i found leaks at the biss screw and injector insulators, so i replaced both and am no longer leaking from those areas. whats happening is that when my car is warming up it seems to idle pretty steady around 1300rpms untill it warms up to operating temp and surges between 300 and 600 rpms. if i take it for a drive and do a few wot pulls and my car will start idling around 1500 rpms or 2000 with little surging. i also noticed that if my rpms are low and im in neutral, my brakes only work for the first pump, after that i have to push them really hard to get the car to stop, can i be leaking boost through the vacuum booster? ive been at it for about 3 months and one shop couldnt help. im thinking about taking it to satan aka mitsubishi if i cant figure it out
 
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Alright guys, calm damn. You both seem knowledgeable and have added good points to the conversation. I was unaware that grounding the plug on the firewall also steadied the isc.

None of it was very helpful for the OP I'd imagine LOL.

@Rustic gst sorry for mucking up your thread. GST with PSI posted a link (before we veered off topic again) with the FSM procedure for setting the BISS which is very helpful.
i have to have it back out most of the way to get it to idle where it does
Are you saying you have to screw the BISS almost all the way out to keep it idling all the time? Or do you just mean while the timing connector was grounded?
 
That's funny. Just checked your post history and couldn't find but one post where you vaguely describe the fsm procedure for setting the BISS. And I don't see you arguing with anyone else about the ISC thing? This whole argument started when you disagreed with me that grounding the TIMING connector wouldn't help. You called it an idle connector, and made no mention of the diagnostic pin until I did. Show me the posts in this thread where you've given any kind of clear advice on how to follow the fsm procedure.
And yeah I suppose arguing that shooting for an ISCpos of 30 results in the BEST idle means I have no understanding of how an engine works...

Edit: And the fastidle tables you're referencing, are not a target ISCpos the ECU is trying to achieve.

You just keep proving your ignorance and

I didn't go back very far but I found one from last week, along with this one, and there's one more in there I just don't feel like digging for it to prove a useless point.

Why would I argue about anyone else? You're the only one posting about it adjusting it down.

"I'll say it again though, grounding that connector and blindly adjusting the BISS is not gonna get you the desired results"

I disagreed with this and stated precisely why, since you're struggling to comprehend that. If you read and understood my post, I clearly pointed out that not only does that connector need ground to lock ignition timing (once again, it effects idle) but also the diagnostic pin needs ground to lock the ISC.

The fastidle tables are target idle steps. When the BISS is adjusted correctly the Ecu will shoot for target ISC position when the idle switch is active. That's like saying, the CAS position doesn't matter on a 1g cas because my timing table is set to run 17* of timing. When the BISS is adjusted so that the ISC position matches the target ISC everything works properly. Every single week I have a car come into my shop that either throttle hangs when you step on the clutch, or bogs and has to catch itself. You know why? Because the BISS isn't adjusted to match target ISC. The computer sees the idle switch active, it quickly adjusts the ISC to target idle, it then realizes, since the BISS is out of adjustment it either had too much air (throttle hang feeling) or it doesn't have enough (bog) and has to quickly correct itself. But if you feel like driving your car like that is normal, by all means deal with it and keep adjusting ISC until it's at 30. I like my cars to idle like factory whether it's a 700hp Evo with the AC on, or a stock 1g.
 
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