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The mkiv Supra Owners Club

Misfire on start up


supraman382

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Apologies if this has been covered elsewhere, had a look at the search and all the other misfire problems happened at different times to mine...

 

On start up when the engine is cold it's definitely running on 5/4 cylinders (sounding like a Subaru), the smoke from the exhaust is thick and the fuelling smells very rich. Then as the automatic choke lowers idle and the engine warms up its fine, drives with no problems. The first time was Last night and it did it again this morning, misfire only lasting for a minute or so....

 

Is it simply the start of the plugs going?

 

Thanks

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Its a TT...no engine warning lights/codes etc.

 

Has been smelling rich for sometime on start up but idling has been healthy...coilpacks known to work themself loose?

 

Not the coil packs per say (but they do fail over time), but the two wires that connect them up have a habit of getting a bit brittle and the connector doesn't make a good contact.

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I'd like to hear how the idle air control valve can cause a misfire on one or two cylinders on cold start :)

 

Have you got any fuelling modifications - AVCr, E-manage, aftermarket stuff etc.? Probably plugs though, how old are they, what type etc etc?

 

-Ian

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I'd like to hear how the idle air control valve can cause a misfire on one or two cylinders on cold start :)

 

Have you got any fuelling modifications - AVCr, E-manage, aftermarket stuff etc.? Probably plugs though, how old are they, what type etc etc?

 

-Ian

 

That will teach me to read the post fully:blush:

 

No it definitely wont be idle control valve, could be a plug, or leaky injector, or injector driver stage in ECU or piggyback, but unlikely.

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I'm voting plugs.

 

Agree, most likely cause will be plugs, it would be the first thing I'd change. I'd replace all the coil pack connectors at the same and also fit 2 new breather hoses, as they are likely to split when you try to remove.

 

If that doesn't solve the issue then next step would be to check the coil packs.

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Thank you for the info and advice chaps, I shall definately start with the plugs, they have been in for nearly 3 years and 9000 miles so wouldnt surprise me if thats all it is.

 

No Ian the car is standard other than Blitz Nur spec..which is now thick black inside due to the smoke its been emmiting on start up.. Plugs are most likely OEM as it was imported 3 years ago and iv had to do nothing to it (other than oil and filter change)..which leads me onto my other question;

 

I checked the coolant - well my dad did as im colour blind and red and brown are the colours i struggle with most :blink: - and all looks fine, along with transmission fluid and diff oil levels but as mentioned I have had it for 3 years and done 9k miles and technically not had a service...im a strong believer if its not broken then dont fix it..not sure if the car would still benefit from full 'fluid service'..especially if i look to sell as there is technically no UK service history.... any thoughts??

 

Thank you Nic, its a standard J spec TT, can you send my quote via PM for all you mentioned (plugs, connectors and breather hoses, and delivery to cornwall) thank you very much, also if the car I got a cooler grade of plugs with the intension of ever going BPU how wud that affect the running of the car having them fitted now??

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First off using one grade colder plugs when still completely STD will be OK but they will fowl up a lot quicker, so i would stick to STD for now.

 

As for fluids, the first thing i did when i bought my Supra was to change and flush the cooling system, i was surprised at the amount of sediment that came out, which is one of the reasons i was put off the Toyota red for life antifreeze, which had been used previously, but not changed regularly.

 

The gearbox and diff oil in theory should be fine, but depending on mileage, if the car has over 40K on it, then i would also change both.

Apologies for the earlier misleading reply, i obviously wasn't paying attention, think i may have been thinking about another post wen i replied:senile:

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Haha thats ok mate, any advice is helpful at the moment! :)

 

A standard grade of plugs it is then, any recommendations on make of coolant if not the red for life..and yes its on about 70k so I guess it wont harm to do the oils, im sure there are guides on here somewhere :)

 

...I dont know if there is any connection to the 'plug problem' but quite recently the wastegate/actuator has sounded a lot louder, not when under load but when stationary, and gently reving up to about 2k...it only did it after a fitted my new alternator and belt so im wondering if I have left anything loose.... wen it rains it pours eh?!! lol

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A lot of people swear by the Toyota stuff, and i dare say its fine when changed frequently enough, but any proprietary antifreeze is fine, i just object to paying Toyota prices, but then I'm tight:)

 

Not sure just what you mean by "the wastegate/actuator has sounded a lot louder, not when under load but when stationary":blink:

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I use the Toyota stuff because it's a drop in the ocean compared to the other stuff you spend on the car, I think about £18 for a full load that lasts x years. But I do tend to re-use it if I drain it out and it's still fairly young, as I'm a different kind of tight :D

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Thank you Nic, its a standard J spec TT, can you send my quote via PM for all you mentioned (plugs, connectors and breather hoses, and delivery to cornwall) thank you very much, also if the car I got a cooler grade of plugs with the intension of ever going BPU how wud that affect the running of the car having them fitted now??

 

If standard then no need for exotic plugs, probably just as cheap to get them there once postage is added from here.

 

See FAQ section here http://mkivsupra.net/vbb/showthread.php?t=41927

 

I can get the breather hoses and connectors but would need to order which would take a few weeks. They are cheap so you're probably better off getting from your local Toyota dealer in this case.

 

These are the part numbers

 

6pcs 90980-11246 Coil Pack Connector

12264-46010 Breather Hose 1

12263-46010 Breather Hose 2

 

How to refurb the connectors http://mkivsupra.net/vbb/showthread.php?t=61141

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