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Hopefully Solved, maybe not :(- Kangaroo hopping....


listy

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JSpec NA-TT

 

When accelerating sometimes the supra will kangaroo hop at 2000rpm, if I lift off and go again, it tends to sort itself out, but not all the time.

 

This happens in 2nd, 3rd and 4th.

 

As I said, its not all the time, so I'm thinking something is sticking somewhere. It's almost like its in limp mode.

 

Sometimes it also idles a bit rough, dropping really low, and borders on stalling, but never quite gets that far.

 

Could it be a sticky ICV?

 

Any other opinions? Really want it sorted before JapFest.

Edited by listy (see edit history)
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Where is the vsv in the bay? From the link I can see its turbo side, is it easily accessible without silly amounts of work?

 

After reading the vsv description, it sounds like it may well be the culprit, as when it "hops" it's kind of like the engine is struggling to breath, so kind of fits with the vsv maybe sticking closed.

 

Hopefully it will be a simple fix :)

 

If anyone around the Bristol/South Wales area wants to come and give me a hand next week, the misses makes a good brew, and has started baking cakes (and they are GOOOOOOOOD :D)

 

Thanks for the link dude :thumbs:

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Where is the vsv in the bay? From the link I can see its turbo side, is it easily accessible without silly amounts of work?

 

After reading the vsv description, it sounds like it may well be the culprit, as when it "hops" it's kind of like the engine is struggling to breath, so kind of fits with the vsv maybe sticking closed.

 

Hopefully it will be a simple fix :)

 

If anyone around the Bristol/South Wales area wants to come and give me a hand next week, the misses makes a good brew, and has started baking cakes (and they are GOOOOOOOOD :D)

 

Thanks for the link dude :thumbs:

 

Photo's here, good luck.

 

http://www.mkivsupra.net/vbb/showthread.php?35926-The-sequential-system

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Problem 4: I can't get any boost on the first turbo, it oscillates around a low boost pressure.

A rare one this, your IACV is stuck open, and every time turbo #1 makes boost it takes pretty much the easiest way out - via the non-spinning 2nd turbo and back out to the air filter. It's like Problem 2 but happens all the time, not just at the transition point.

 

This sounds like my problem, which is maybe why I couldn't find anyone else with the same problem when I searched for it.

 

Thanks for the help mate, seems like I should be able to get it sorted pretty easily, be it a hose (have checked, but may have missed something) or a new IACV/second hand from Keron. :)

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I have had a look at the IACV and both hoses are in tact and in good condition. Could it just be sticking? If so, how can I fix that? Or is it a new/refurbed/second hand IACV?

 

Also, I have noticed my throttle cable is slightly loose. Could this cause the same symptoms?

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Tightened the throttle cable, its still a little slack, but cant go any tighter, is that the way it should be? :search:

 

I also noticed a slight clicking (not tapping) noise from under the Spark Plug Cover.....is this a tell tale sign that my problem may be coil pack / coil pack clips related?

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Anything is possible mate, it gets to be a process of elimination sometimes. But certainly if the is a poor connection to a sparkplug resulting in a weak spark in one or more cylinder then I can imagine there might be no or poor ignition/combustion in the chamber when the boost starts to increase.

 

Just out of curiosity, has the fuel filter and pump been eliminated from the list of possible suspects, or are you just starting at the front and working your way rearwards?

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Starting at the front mate. ;)

 

From the link TomGeer posted, it suggested the IACV being stuck open, but dont know if they are easily "unstuck" or if it requires a replacement?

 

Also, as a bit more info on the problem, the 1st turbo boosts to around 6psi and then it gets groggy. It feels as though the engine is struggling to breathe, which also makes me still think it may be a sticky IACV, as air is being forced back towards the air filter, (from the linked thread) which would make perfect sense to how the car feels when it happens.

 

It was happening a while ago too, but then sorted itself out, and now its happening again, also pointing towards something sticking I guess.

 

Is it normal to hear a feint clicking from the spark plug area? Is it just the plugs sparking? You have to listen carefully for it, just something ive never noticed before, but this is the first time I've had my ear that close to that part of the engine as far as I can remember.

 

Fuel pump is something I want to upgrade to a Walbro anyway (gives me an excuse for the misses I guess:)) and fuel filter is an easy one to change, but dont want to be buying things I don't need right now, as I have a few things going on at the moment.

 

I hate seeing her poorly :(

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Thats good to know then, it is a very regular click, not intermittent, so thought it was ok, but thought I'd check anyway :)

 

Thats the plan mate really, if I can refurb/unstick the IACV (if that is the problem) then all is good. If it's not the problem, I'll move on to coil packs, and clips, plugs, then fuel pump and filter.

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Right then, hopefully (fingers crossed) problem solved :D

 

Changed the coil pack clips (they literally disintegrated when I removed the old ones)

image

I know there's only 5 there, the other one was in the house as I thought I'd show the misses why they needed doing. She likes to "show an interest" :)

Also changed the spark plugs, first time I've done it on this one, and there was one BKR7EIX, three BCR7EIX, and two BPR5 something. Interesting mix :rolleyes: Now all 6 are BKR7EIX NGK Iridiums.

image

 

She is now idling beautifully where before it was a bit lumpy, and that clicking sound seems to be gone too.

 

Hopefully the problem is solved, but I'll find out tomorrow when I take her out for a drive.

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

Ok, so today after a short (less than a mile) trip to work (had to take some stuff in), parked up, and two hours later, drove home and she had a misfire again :(

Same story as before.

Now dreading it may be the coil packs. Clips and plugs changed, so that's the only other thing I can think of.

Going to check all the plugs some time this week, to make sure nothing untoward is going on there.

 

Only other thing I can think of, is that on a very short journey, if excess fuel is being left in the chamber, stopping the plugs sparking properly? Is that possible?

Since I changed the plugs and clips, I've only done 25+ mile journeys until today, and there hasn't been a hint of a misfire, only after today's short trip, hence thinking of a bit of over fuelling. Think I smelt petrol earlier when I got out too, which could also point that way.

 

Any other ideas?

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Did you take the 02 sensor out and clean it up listy?

If not, remove it, clean it up and stick it into a lemon over night, try it again once its been cleaned if it works temporarily then starts misfiring a day or two later my guess would be it needs replacing with a new one.

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You'd smell petrol with an ignition based misfire regardless of the fuelling, as it's not burning the petrol it injects :)

 

If it's just fouled plugs then it should clear up in a few minutes just at a fast idle as normal running burns up the excess. Try that before having a heart attack :D

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Did you take the 02 sensor out and clean it up listy?

If not, remove it, clean it up and stick it into a lemon over night, try it again once its been cleaned if it works temporarily then starts misfiring a day or two later my guess would be it needs replacing with a new one.

 

I didn't no, as the clips and plugs seemed to solve it, I forgot :innocent: I'll give that a try :thumbs:

 

You'd smell petrol with an ignition based misfire regardless of the fuelling, as it's not burning the petrol it injects :)

 

If it's just fouled plugs then it should clear up in a few minutes just at a fast idle as normal running burns up the excess. Try that before having a heart attack :D

 

It idles fine to start with, but then bounces between 800 and 600 rpm, which is what it did before.

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Hope you get this sorted, if you don't have any luck with the above stuff I am fairly local to you and we could swap my coil packs (only 3 years old) into yours as a test if you want, save you spending money you may not need to spend. Did you replace all the parts of the coil pack clips? I had a really irritating stuttering problem that I was struggling to sort for ages, turned out there was a break in the coil pack pin. Bit of speaker wire packed in until I got replacement leads and never troubled me again.

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