I have a 1990 Lancer and a few months ago it started to have this slight miss (irregular idle) thought it may have been fuel filter block so replaced then one day it would not go it took a while to start and when it did it was really missing i heard a cracking coming from under bonnet found the coil shorting out, replaced coil, still the same miss cleaned the distributor of all electrolysis, no difference, changed spark plugs now it idles way way high on first start up eg; when motor is cold. Once motor is warm it idles reasonably high but can live with that so why would it idle so high that you don`t even have to use the gas peddle to take off it only got worse after i changed the plugs and yes the are the right ones (Spark plugs) in need of a tune up ? of could be a blocked jet in carb? Thank you so much for help in advance
intrade,
Jan 6, 11:37pm
now considering that a 1990 should have the computer repaired by now. they used to fit one-hung-low capacitors in computer leaking on to circuit board when they pood them selfs. High idle most probable cause is dirty throttle body causing the iac =idle-air-controller to be maxed out or sticking . something like this would be the first thing poping to mind .
kazbanz,
Jan 6, 11:43pm
Mihgt be as simple as the idle got wound up to compensate for issues. Now issues resolved idle needs dropping down
intrade,
Jan 6, 11:49pm
so is it a carburettor? carb wont have ecu for fueling also is it nz new or not if its nz new carb it probably never even had a cat either carburettor often ne4ed cleaning fit old plugs to clean carb down then refitt new plugs again, plugs will get dirty if a carburettor is extreem dirty from the wash-down of carb cleaner thru engine.
intrade,
Jan 6, 11:54pm
if its even older system it will also need to be timed with timing light to correct ignition point and vaccum addvance checked usually advance disabled when timing distributor with light. dont waste your time to tune it if you have a worn out distributor cap and old plug leads that should be replaced since years. Your coil probably crakced open because it could not fire the plugs no more so the spark when back to the coil instead of thru rotor cap- leads and plugs.
intrade,
Jan 7, 12:12am
Quote
why would it idle so high that you don`t even have to use the gas peddle to take off
you changed the burn time with new plugs . so it ignites the gasoline now better so the piston speed up= higher idle no magic trick on a scope you would see the burntime difference http://images.picoauto.com/privsec_1-1.png
B is the burntime 1 milliscecound your plug one or more probably had almost 0 burntime with all the resistence in the ignition system. your eyball update rate is 100 millisecound anything faster you wont see and 100ms is only when your young 16 jear old +- its why one needs a oscilloscope and why the old allenscope was good but you probably would not have seen a miss with naked eye and a 100ms update rate when it happened in 1milli secound one in 100 chances to spot it at all with naked eye. stuff like that is what to know there is no magic trick its logical reasons behind everything
2014isanewstart,
Jan 7, 2:13am
the leads have been replace i`ve even started up and cheeked in darkness for signs of any sparks off them, it has electronic ignition, NZ New 1300 Cyclone engine, Timing cheeked all good there, the rubber tube from manifold was disconnected but have since reconnected as for distributor cap looks in very good condition
2014isanewstart,
Jan 7, 2:16am
Yes i had to do this once engine temp got up and have it idling down as far as i can, it only idles too high from cold
poppy62,
Jan 7, 2:20am
There is a solenoid that fits into the carb, just follow the wire. This is probably the culprit and is either sticking or kaput. Unscrew it and earth the body and power up the spade fitting and see if it is operating. Chance are that it needs replacing.
2014isanewstart,
Mar 16, 9:17am
just been out to find wires right at back of carb hmm thats a mission in it`s self looks like a weekend job coming up Thanks everyone for input
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