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The mkiv Supra Owners Club

Misfire at cold startup


jza800

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I have had the engine out of the car over the last 1.5 years, and have finally had time to put it in the car again. when i did start it up, it misfired and did not run on all 6 cylinder, and if i did give it a little throttle it stalls and go out , but after 20 to 30 sec it runs on all 6 cyl and i run smooth and can take the throttle with no problem. and i can shot it off and start it up, and i run like normal, i didn't run it long, as i have no water in the system, as i am still missing a sensor..

when it did not run right i smells a lot of unburned fuel, so maybe a spark plug..

 

 

 

things i have had apart.

 

Intake

 

Fuel rail

 

Injector (Did change all the o rings)

 

Can it be because it have been sitting so long and i have had the fuel system apart, so it will be better when i have been running for some time? i did run fine when i pulled the engine

Edited by jza800 (see edit history)
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was it just that once or does it do it every time its cold?

 

i don't know, i have just got the engine in the car, i have tried where it have stand 1 day, it would start up fine. it have stand for 7 days, and it did it now.. but only for 15 til 30 sec. then i will run fine..

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which sensor is missing? i broke the ECU water temp sensor once and it ran like a bag of spanners and stunk of fuel.

 

i have changed the plugs on the water temp and ecu sensor at the water neck.. the sensor i need it the one to the a/c fan.. on the bottom of the radiator.. i have no intercooler pip on the car jet, i don't know if that could mess up the signal to the map sensor.. or because there are no water in the engine, that the sensor gets the wrong signal ??

Edited by jza800 (see edit history)
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what fuel pump are you running I had a issue with the walbro 400 would not flow when the stock fuel pump ecu was giving it the 9v for idle and needed to do the 12v relay mod

 

stock fuel line and fuel pump..

 

i did not have any problem before i took the engine out..

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Does it still do it today if you started it ?

It could easy be due to it sitting ,moisture, and still.getting fluids to parts that stuck. That being said there is a connector in the passenger foot well for the injectors 1and 6 are on o e pin and 2-4 on the other which I had problems with . Take the passenger side foot mick panel off and give the plugs a wiggle when running and see the misfire comes back

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Hi

 

No this morning everything was ok, it startet on all 6 and run smooth.. yes i have had that thought too it is about 2 years old, so maybe that could be the reason.. all o rings are new and i have tried prime the fuel by the diagnose plug in the enginebay, bridge fb and b+.. no leaking..

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