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PostPosted: Sat Jan 31, 2015 2:14 pm 
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Joined: Tue Jul 02, 2013 1:39 am
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Location: Tromsø
Car Model: ST205
The engine does not run smoothly when idling cold, and feels very jerky when at very low load (under 5%)
When revving it slightly in neutral it`s really running uneven. When hot the idle seems to be ok. It makes it almost urdriveable in slow traffic. Seems to run perfectly smooth at higher loads.

This has been a small problem for some time now.
Strangly it got alot more noticeable after I washed the enginebay and changed plugs/oil.
Is this likely to be fuel, vacum or ignition related??
Cannot find any loose hoses, and the ignition system is fairly new except the coil.

Tried to swap to standard ecu but same story.
It may sound stupid but it seems to me like it "looses" a cylinder for very brief moments.
I really need to fix this its f****ng annoying.
Where do I start? any tips?

https://www.youtube.com/watch?v=bOfSaP3eMd8&feature=youtu.be


Last edited by TRDTromsø on Sun Feb 01, 2015 12:31 pm, edited 2 times in total.

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PostPosted: Sat Jan 31, 2015 4:18 pm 
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Joined: Sat Feb 14, 2009 4:32 pm
Posts: 251
Location: The Netherlands
Car Model: None
Reading your first paragraph it could be a broken O2sensor.
To check this you need to get into the diagnistics box and connect T1 and E1. Please wait until someone confirms this, it was a long time ago. :oops: Can't really recall if these are the right ports. Than look at the flashing of the engine light in the dash. Ignition on.

It could be your plugs. maybe the gap is to big and you need to adjust it. This because you mention it starting after sparkplug change.

Tromso, drove through there in the winter of 2012 in my CS. I love Norway!

anyway I hope you can solve the problem.

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PostPosted: Sat Jan 31, 2015 5:24 pm 
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Joined: Sat Sep 02, 2006 3:13 pm
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Location: Bournemouth
Car Model: None
Reading your other thread, I would carry out a compression test. Check for oil smoke blowing out of the dipstick tube.

For information on checking error codes on the standard ecu, click portal above, then 'how to guides' then it's the top one.

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PostPosted: Sat Jan 31, 2015 7:39 pm 
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Joined: Tue Jul 02, 2013 1:39 am
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Location: Tromsø
Car Model: ST205
If it was a faulty sensor the FC commander should tell me. I will do a sensor check tomorrow. Do either of you know what the 02 sensors voltage should be at idle?
Will do a compression test as soon as possible. Do you think its rings or valves? It does puff small amounts of white oilsmoke from time to time. (exhaust, not dipstick)


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PostPosted: Sun Feb 01, 2015 11:11 am 
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Joined: Tue Jul 02, 2013 1:39 am
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Location: Tromsø
Car Model: ST205
I did a sensor check and checked for smoke from the dipstick tube. I made a video of it.

https://www.youtube.com/watch?v=bOfSaP3eMd8&feature=youtu.be

I dont think any sensors are faulty, but I am not sure if the values are within specs.
The o2 sensor read 0.00 until the engine starts to warm up, is this normal?

There is no smoke coming from the dipstick tube. Would it if it was piston/rings/valvedamage?
It would be helpful if you could watch the video and tell me what you think.
Thanks for the help so far :)

Will do a compression test and recheck my igniton system in a few days.

Bu the way I just noticed the fc commander flashed 3SGTE2 in the startup, should it not be 3SGTE3????
*bleep*???


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PostPosted: Sun Feb 01, 2015 5:40 pm 
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Location: Bournemouth
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Ringlands should be ok. It was smooth on all 4 blipping the throttle & no smoke from dipstick.

It does sound rich, can't smell it from this distance unfortunately but does the exhaust smell like a car on choke ? This would also tie in with 100% duty on injectors and smoke from exhaust.

Do you know what mods are done to the engine ? - if it's had different injectors or map sensor the standard ECU may also be unable to run correctly.

The o2 sensor will read 0 until warm, then it should swing between 0.2V and 0.8V at idle (not sure if the commander reads in volts)

Another common problem on these cars is oil seeping from the rocker cover gasket and collecting in the plugs, which then causes random misfires.

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PostPosted: Mon Feb 02, 2015 11:19 am 
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Location: Tromsø
Car Model: ST205
When the coolant is over 50 degrees, it stops running so rich. And yes it does smell like choke until then.
But it has been running like this for four years, with a tiny bit of the same problem. After I replaced the plugs it got 2-3 times more noticeable.
Could it be the coil? Before I cahnged my leads the coil had been running on really bad leads. This could damage the coil right? But if the coil was bad, would it not be worse the more revs?

I think the only mods to the engine is a bigger turbo, exhaust and intake.
Will have to check if my injectors are stock. But I`m pretty sure they are.

There is no oil around the plugs, I replaced the gasket 2 years ago.
Will check my injectors resistance and pulse later this week.

If its caused by faulty injectors, plugs, leads, distributor or coil I will find out later this week.


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PostPosted: Mon Feb 02, 2015 11:31 am 
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Location: Bournemouth
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Did you fit irridium plugs by any chance ?
If the problem was made worse when changing plugs, then it's the plugs themselves or you disturbed something while changig them, maybe damaging a lead.

Normally a coil will either stop working completely, or will misfire at higher boost. Higher pressure gas requires a higher voltage to ionise (nake a spark) and if insulation is starting to break down then the spark occurs between windings in the coil rather than at the plug.

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PostPosted: Mon Feb 02, 2015 2:44 pm 
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Location: Tromsø
Car Model: ST205
Its original Toyota sparkplugs, with platinum tip Denso pk20r8
I dont know if its iridium plugs.
I did not adjust any of the gaps, is that neccesary?
I will try to refitt the old ones and see if it improves.

I asked a mechanic at Toyota, he took a quick look and said it doesnt run on all cylindres. Seems to be ignition he said.
Willl find out as soon as I have an opening at the workshop.
But its abit weird that it runs much better first 10 seconds after cold start.


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PostPosted: Mon Feb 02, 2015 6:08 pm 
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Worth taking the coil off and visually inspecting it, as it's quite common for the casing to crack.


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PostPosted: Wed Feb 04, 2015 12:25 pm 
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Location: Tromsø
Car Model: ST205
Now I`m thinking its more a fueling problem than a spark problem. Because it runs perfectly fine when injection duty is over 5%.
Between 5 and 4% it starts to be jerky. Under 4% its really bad.
And the first 10-15 seconds of cold start when its getting alot of fuel it doesnt miss a beat.


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PostPosted: Thu Feb 05, 2015 11:15 pm 
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Location: Another Shire County
Car Model: ST185
Check Distributor cap and rotor
...remember mine JP? :)

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PostPosted: Fri Feb 06, 2015 9:44 am 
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Good point, the rotor arms have a habit of coming loose if not loctited.

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PostPosted: Fri Feb 06, 2015 11:33 am 
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Location: Camberley, Surrey
Car Model: ST205
Muddy Water wrote:
Check Distributor cap and rotor
...remember mine JP? :)


And mine!

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PostPosted: Sat Feb 07, 2015 7:40 pm 
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Location: Tromsø
Car Model: ST205
Nibbles wrote:
Good point, the rotor arms have a habit of coming loose if not loctited.

You mean loctite on the two small bolts that secures the plastic rotor?

I checked the leads, distributor cap and rotor. Nothing was loose or damaged. The coil seemed fine too.
Does anyone know what the two small rubber "tubes" that bends down from the distributor cap are for?. There is a small opening in each tube. Should these be left open?

The lead from the coil to the distributor had a resistance of 30 Mohm, max should be 25 Kohm. The coil connection on the cap was really corroded. I took a photo, but I dont know how to upload??? All the other connections were spotless so there is definately something going on with that lead. Are the leads directional? I noticed the coil lead fits both ways, but one end has a red plug. Should the red plug go in the coil or the cap?
I cleaned the contact surfaces but it only seemed to make it worse :(

Now it doesnt idle right when hot either. When revving it in neutral it stutters and even stops when releasing the throttle.
I havent changed the lead yet, should have it monday or tuesday.
I really hope its the lead that causes this, but I have my doubts.


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