help: 3sgte boost / "hesitation" at multiple point

[Inane]

whatever the problem, I seem to be having it too

where did you last get your fuel from??


although my car seems to be running 7psi at the moment...

it only gets above that when I plant the foot and it'll spike up to 13-15 psi...

any ideas with that?

[TWSTD]

last lot of fuel from BP fanshaw st mid to late last week.

[Inane]

== last lot of fuel BP Johnsonville.....

I usually never use bp, I almost always go with Mobil synergy 8000

[HERGTT]

.....last lot of fuel was from MOBIL Wairau Road (Nth Shore), and yes I run it on Synergy 8000 too

I'm pretty sure it's the plugs tho, not the fuel.

[YTWGN]

Havent had any problems with MOBIL on constellation. Havent tried any others.... yet.

[MrBob]

I do have my suspicions re the plugs being the cause however as it is ONLY when im at about 0.3 bar boost or above that this problem occurs and does not seem rev related at all (i can happily rev to 6000rpm slowly without any sign of the problem).

yes, this is exactly how it was with mine. No prob off boost.. under boost the weak spark just isnt doing the job, hence the hesitation and missing.

[vvega]

I do have my suspicions re the plugs being the cause however as it is ONLY when im at about 0.3 bar boost or above that this problem occurs and does not seem rev related at all (i can happily rev to 6000rpm slowly without any sign of the problem).

yes, this is exactly how it was with mine. No prob off boost.. under boost the weak spark just isnt doing the job, hence the hesitation and missing.

id have to agree with that
my old gto used to eat plugs and that was the signal they were $&#$%
i tened to crack the cermic on them :S

v

[anthonym]

I would suggest the rash of GT-T issues as described in this thread is more likley due to a recent significant increase in amibent temperature that fuel octane, although perhaps not for those in (subantarctic) Welly .

The GTT is pretty much on the detonation threshold even on 98 and the air temps over the past few days here in AK will be pushing it even further. Knock-induced retard is hard on ignition components, and as others have noted the symptoms described indicate spark plug problems.

[fivebob]

I'd second Nemesis's opinion on the likely cause of this problem, and add that in most cases I doubt that the plugs are really the problem. Modern plugs are more than capable of the requirement exacted by turbo engines, though TWSTD's plugs seem a bit on the cold side.

Also the stop start nature of the problem described points to something other than a plug misfire. Which, once they start misfiring from excessive combustion pressure, tend to continue to do so, and in most cases would be accompanied by a backfire or two from the unburnt fuel in the exhaust system.

A simple way to see if the ECU is detecting knock is to monitor the signal going to the Turbo VSV.

[Inane]

A simple way to see if the ECU is detecting knock is to monitor the signal going to the Turbo VSV.

please explain

actually fivebob, I'd like to arrange to plug your brain into something I can download all that useful information into....

[TWSTD]

pulled plugs and heres what they look like... distinct rust colour to them - even more than shows in the image... what causes this type of phenomenon?

[Inane]

how old are your plugs?

[TWSTD]

about 6-8 months. Why?

[vvega]

iridiums have quite a massive life more so that platuims
and it is normmally a good idea to change em when you do a cam belt
i guess youve already don that

there still firing as the cleanness of the electrode shows
though id have to say that gap from this perspective looks massive
to me the color just looks like its a old plug with many km's worth of deposits and use
but its not
ive service quite a few fresh imports and they tend to have a redish look as well

i would have thought that it would have looked a little more blackish running on nz fuel though

my thoughts
change the plugs
eleminates one possibile issue
in my experiance iriduims are easly damaged by det

then work from there


factory ecu's are mapped to deal with a wide range of intake temps in hotter conditions than this
and if this is the problem there would be a rash of questions relating to this every year
in fact toyota would be overrun with them right now with unknowing owners wanted ther cars fixed cause there gunna blow up

ive rung teh waikato toyota workshop and they have none in there with your problem

just my thoughts


v

[TWSTD]

thanks for your input vvega - appreciated. Will try other plugs tonite n see how it goes. The gap was 1.1 rather than the 0.8 i thought it was - and now i do recall gapping them up again to the 1.1 that they came set at as it felt better to drive than the smaller gap (unlike my mitsis 4g63/4g93 engines which i found much better on a 0.7-0.8 gap at most).

[anthonym]

thanks for your input vvega - appreciated. Will try other plugs tonite n see how it goes. The gap was 1.1 rather than the 0.8 i thought it was - and now i do recall gapping them up again to the 1.1 that they came set at as it felt better to drive than the smaller gap (unlike my mitsis 4g63/4g93 engines which i found much better on a 0.7-0.8 gap at most).

0.8 is standard for the gen 3 3SGTE. I'm not sure if the coil over plug DFI system is any better, but I've had the exact problem you described when a clown put plugs with a 1.1 gap in my car.

[anthonym]

factory ecu's are mapped to deal with a wide range of intake temps in hotter conditions than this
and if this is the problem there would be a rash of questions relating to this every year
in fact toyota would be overrun with them right now with unknowing owners wanted ther cars fixed cause there gunna blow up

The GT-T is a JDM model mapped for 100 octane fuel, it runs a high compression ratio, has a poor intercooler, and the engine is subjected to high loadings as a result of the AWD system. Running it on 98 (or worse 96) in warm weather will push the factory knock control to the limit, and in some cases past the limit, as evidenced by the (at least) 2 people on this board have detonated GT-Ts to death.

[vvega]

factory ecu's are mapped to deal with a wide range of intake temps in hotter conditions than this
and if this is the problem there would be a rash of questions relating to this every year
in fact toyota would be overrun with them right now with unknowing owners wanted ther cars fixed cause there gunna blow up

The GT-T is a JDM model mapped for 100 octane fuel, it runs a high compression ratio, has a poor intercooler, and the engine is subjected to high loadings as a result of the AWD system. Running it on 98 (or worse 96) in warm weather will push the factory knock control to the limit, and in some cases past the limit, as evidenced by the (at least) 2 people on this board have detonated GT-Ts to death.

nasty

point taken
but at any load ???
thats one big issue they need to adress
i dont know the car inside out i was more just looking in gereral factory terms

v

[anthonym]

but at any load ???
thats one big issue they need to adress
i dont know the car inside out i was more just looking in gereral factory terms

v

The load would need to be relatively high to cause problems, and a sustained thrashing, particularly on a hot day, appears to be required to pop the engine . And Toyota have addressed it partly, IIRC inadequate fuel has been cited as the reason we don't get many of the real performance cars here new, why they think it's OK to sell them Signature class is anyones guess.

[H1S_SUB]

so i changed the plugs in the caldina tonight a may have found the soultion to our common spark plug problems .
when i remove the coil from the engine i notice alot of condensation around the sharft of the coil pulled the plug and it was rusted and wet with water i believe the common problem that we have is there is a rubber o ring around the bottom of the coil which in my case wasnt fully sealed beacuse of general dirt in the rocker cover, some how water probably when i wash the car the other day has tracked down the coil and even down the thread of the spark plug into the bore causing the trouble, so i replace the plugs with a new set of lazer platinums, and all is well. on top of that, another story went to ripco the platinum seem to be the only plug available for the gen iv 3sgte that was on their computers , so me being a know it all said that i knew of someone running irriduims in their caldina (twstd) and he told me that they were in a 1.1 gap and not .8 another funny thing was the plugs in the car before i pulled them out looked like they were copper which aparrently they dont even do for a caldina, he tried to tell me the car was to new he went on a bit to about recomending 5s instead of 6s so here are some pics

its hard to believe that they have only done 3000km