Missing

Discussion of technical issues and ideas (engine, chassis)

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rat
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Missing

Post by rat »

Story Time:
car was missing on startup badly, smooths out as it gets hotter. compression in one chamber is a bit low so thought that i had burnt a valve sent the car to my mac Mark (in dec). Head off the engineers said that a valve was not sealing, got that sorted. exhaust studs broke when putting the head back, got the fixed. get the head back cam broke! long story to get a cam. got the car going yesterday, and it is still missing. Mark says it is some thing bottom end like rings but he doesnt want to strip it.

So any ideas want is wrong?
How much to fix it?
And can i drive it as a A to B car?
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Doctor G
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Post by Doctor G »

A miss on a CA can be a number of things.

I still have an intermittent hesitation but I'm ingoring it till I redo the motor and get a management system.

Service the car before you seek further. Get new plugs too.

Then,
Do a compression test on all cyclinders.
Check coil packs. Usually if the miss changes between hot and cold temperatures they are the culprits.
Check earth wires or add aftermarket additional earths.
Flash the ECU (no - not like that :roll: )
Check TPS voltage
Reground the MAF
Check IACV
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Vlade
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Post by Vlade »

I had the oversized cylinders with undersized pistons at one stage and my car didn't even miss... so your mac might just be talking crap, my engine ran less than 600kpa compression and it still ran, not well but it did.

The biggest reason for a miss is always plugs / coils... faulty/dirty injectors can also cause an issue... if it continuously miss pull the plug check it out.. if its dry then its not getting fuel... if its wet then the plug is not firing... Then you start tracing from there... do the compression test... but it will only make a difference if it differs more than 20% from the other cylinders.
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rat
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Post by rat »

on the std management when cold it revs the car to about 1400rpm and slowly brings down as it gets hotter, now it is like 750rpm missing and slowly gets better.

Done :
New Plugs
Swopped the coil packs around and all seem fine
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rat
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Post by rat »

@vlade the car still runs and is drivable, 3 are the same but one is less dont know how much on the compression test.
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WooHaa
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Post by WooHaa »

Just a suggestion.
I changed my plug to a colder plug & that sorted my miss out.
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