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The mkiv Supra Owners Club

Stalls when starting with warm engine. Why?


bodilx6

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Every time I start the soop with a warm engine (everything from a few minutes after a drive to 1 hour) it runs really bad, like only on a few cylinders or so @ 300 rpm or so going a bit up and down. If I "help" a bit with the throttle lifting revs to 700-1000 it runs as smooth as ever untill I let go of the throttle again.

If I go for a short drive and stops it idles fine again so its only just at startup.

 

The car is BPU, stock intake, no known leaks and genrally pulling nicely.

Only thing is it's got Toyotas Iridium spark plugs gapped to 0,5mm which can cause a misfire at idle once in a while, but that doesn't seem like thats to prob at all

 

Any thoughts?

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This what it says in my Supra Workshop Manual, might be of help.

 

Rough idle,

Missing or

Stalling

 

Incorrect curb idle or fast idle speed - Reset idle speed,

Incorrect basic timing - Reset ignition timing

Improper idle mixture - Reset idle mixture,

Improper feedback system - Check feedback system operation

Incorrect spark plug gap - Reset spark plug gap,

Moisture in ignition components - Dry components

Loose or broken ignition wires - Replace ignition wires

Damaged distributor cap or rotor - Replace distributor cap or rotor

Faulty ignition coil - Replace ignition coil

Fuel filter clogged or worn Replace fuel filter

Damaged idle mixture screw - Replace idle mixture screw,

Improper fast idle cam Reset fast idle cam

Improper EGR valve operation - Replace EGR valve

Faulty PCV valve air flow - Replace PCV valve

Choke binding or improper choke setting - Reset choke or eliminate binding

Vacuum leak Repair - vacuum leak

Improper float bowl fuel level Reset float adjustment

Clogged air bleed or idle passages - Clean carburettor passages

Clogged or worn air cleaner filter - Replace air filter

Faulty choke vacuum diaphragm - Replace diaphragm,

Exhaust manifold heat valve inoperative - Replace heat valve

Improper distributor spark advance - Check distributor operation

Leaking valves or valve components - Check and repair valvetrain

Improper carburetor mounting - Remove and remount carburetor

Excessive play in distributor - Replace distributor shaft

Loose or corroded wiring connections - Repair or replace as required

 

Engine Stalls

 

Improper float level - Readjust float level

Leaking needle valve and seat - Replace needle valve seat

Vacuum leaks - Eliminate Vacuum leaks

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Vacuum leaks - Eliminate Vacuum leaks

 

Hmm... Also got a BOV that wont vent at low boost, I have been searching for vacuum leaks and my boost gauge says a stabile -0,7 bar idle boost. Wouln't that be higher if I had a vacuum leak?

 

 

 

 

Compression testing may point out your problem

L

 

Kewl, gonna have a look at that shortly anyway. Hopefully that will show something

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