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The mkiv Supra Owners Club

Aristo problems


legendswraith

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Having problems with the car atm, to outline it after i turned the boost up to 1.2 it started blowing pipes off all over so after playing replace the hosing for a while everything seemed alright apart from a fuel cut issue.

Come the other week i thought the car had done the same again it started running sluggishly, but it wouldn't give any power under WOT and i needed to gently bring the revs up to keep the car moving any sudden movements with the throttle and it hesitated.

I've looked all over the car for split/loose pipes and i have jsut changed the plugs as well, but i still have the problem.

While parked if i rev gently i can take the engine thru the rev range, if i plant my foot and try to use WOT then the car jsut stutters and struggles to get above 1200rpm. Its also running very lumpy at idle as if its not picking up the revs on cold starts but it sits quite comfortably at 600 when warm, and on top of all this it seems to be running extremely rich.

I'm at a bit of a loss on this one apart from changing the coil packs and possibly the lambda.

If anyone can shed some light on it or say yes its coilpacks etc it would give me some peace of mind, ATM i can see it being expensive and i am missing the first set of dry roads i have seen since i got the car.

 

Cheers

 

Austin

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the aristo has a flyby wire control on the throttle body , if it senses something is wrong with one of the sensors it will not let you bring the load on. check the following :

 

1:maf sensor- where the air intake it

2:put the boost controller back to normal, stock boost

3:reset the ecu

4: bov is not broken - fully open.

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the aristo has a flyby wire control on the throttle body , if it senses something is wrong with one of the sensors it will not let you bring the load on. check the following :

 

1:maf sensor- where the air intake it

2:put the boost controller back to normal, stock boost

3:reset the ecu

4: bov is not broken - fully open.

 

 

Not looked into the maf yet although i did read that could be an issue, i'm not making boost atm as this is just done free revving with no load, i've reset the ecu and the bov is a new HKS ssqv.

 

If it wouldn't let me bring the load on why does it let me bring it up to 6k rpm but stumble at WOT? Is that a system inhibit that prevents fully opening within x amount of seconds?

Is there a bench test for the maf at all

 

*Edit* Its jsut got new NGK plugs in there that was the first thing i changed start at the cheapest and work up lol

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I know on Soarers the low idle and not revving thing are due to the fuel pump ecu not switching over from 6v to 12v, but thats due to lack of fuel, not too much. Might be a stuck injector? On idle theres not much demand or pressure but once you rev it youre dumping fuel into it? Just an idea.

Maybe run it for a bit and pull the plugs agaim, see what they tell you.

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i had a few issues with the MAF on my old UK spec supra, try some electrical contact cleaner on it, if you still have an issue just replace it. Worth a shot.

 

Cleaned the maf up last night put it in this morning and got full WOT revs again for about 5 min before it went dodgy again, so now trying to acquire a new one from toyota

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Right still no cure for this, took it out today to roadtest the car drives but any massive inputs on the throttle and its a no go massive hesitation. Also pulling off it feels like its in the wrong gear shuddering and jumping slightly. Putting it into tiptronic made things slightly better rather than letting the car change but not alot.

If i floor it i now jsut get hesitation and alot of fuel dumping into the exhaust by the sound of the booms.

If i take it slowly i can get the car up there but i can feel it holding back on power and it does not want to hold the high revs to generate power.

 

As i know the MAF is ok now i can only think it is either the o2 sensor completely buggered, the coil packs or the wiring where i took the FCD out but i am not sure if any of the FCD reconnections would affect the fuelling. I now have an OBD2 reader on order to get teh codes out as i am at a loss to me it feels like its overfuelling, especially due to the vulgar nose of the exhaust fumes.

Never was going to be easy was it.

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work backwards, take the FCD out of the equation then set the boost to stock , do you have a resistor ring on the 1st decat pipe ?. have you taken the cats out ? if so have you connected the O2 sensor on the second cat . Do you have a FMIC or the standard SMIC ?? have a look at the SMIC if you still have it , see if its falling apart , if it is then the SMIC may be split.

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FCD is removed completely and the stock wiring reconnected, i was planning on using the emanage to control boost cut but i have unplugged that atm as well to remove it as a cause. Car is decatted and came as such so i can only assume it has a restrictor ring in there due to never overboosting. It has an aftermarket HKS intercooler on it rather than the stock SMIC too.

I turned the boost controller off during the road test to see if that was having an effect but it made no difference and i have already run it in True Twin to see if it was any of the sequential parts causing an issue.

 

edit* atttached a sound file to try and get what i am explaining across better first part is a slow opening of the throttle, second part is WOT condition

eng.zip

Edited by legendswraith (see edit history)
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  • 2 weeks later...

Running out of options with this still have the same problem and i have changed the MAF, the ECU water temp sensor and the TPS. At a complete loss with it car will start run and idle in neutral fine but if i take it on the road it won't accelerate withot feeling like its choking and constantly feels like its in the wrong gear.

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put it in manual mode and see if it accelerates ,use the triptronic to go up and down the gears. If this works, put it back to auto mode and try to determind which gear you are in. it could also be your thottle body, the flyby wire unit is controlled with an electronic gizmo, this could be faulty.

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