Begging For Help Now, Someone Please Help Me Fix This!!

[Greddy-Matt]

Ok Guys N Girls,
I’m pleading for help now as I’m at my wits end..
I’m desperately trying to solve a Boost/Power/Hesitation problem with my turbo!

Basically the car is hitting full boost 1.15Bar @ around 3500rpm, its hitting it consistently and not wavering at all on full throttle.

But while the boost hits 1.15 pretty quick the power delivery isn’t smooth, you get a little push, then its flat, little more push, then its flat, then little more and that’s it.

It's even worse on gear change! Full boost, change down @ 6500rpm and nothing, no power, boost is showing 1.15bar but the car bogs down and feels like a wet fart, almost like I’m getting massive turbo lag or slipping clutch (except the revs don’t shoot up!)

I’ve double checked and have no leaks etc from the intercooler piping etc, and the iggy components are all in good shape. The Only thing I can think of is either hole in intercooler or cracked downpipe?? Turbo Isn't smoking and can hear it spooling up like crazy!

Someone please help I’m actually going to cry!!!!

Sorry for the mamoth post!

[Razor04]

Forge BOV leakin under high boost? swap it over for the stock BOV to rule this out. Just had this prob on mine.

[Greddy-Matt]

I hope not its only a few months old I dont have a stocky anymore mine was kaput! Ill have to see if i can borrow one

I just cant get my head around how im making good boost but zero power

[-:[KM]:-]

Dirty air filter?

[Razor04]

I hope not its only a few months old I dont have a stocky anymore mine was kaput! Ill have to see if i can borrow one

I just cant get my head around how im making good boost but zero power

Noticed your in southampton i have a stock BOV you can borrow if you wanna try it My car had the same symptoms when i was runnin a blitz bov feels like it aint pullin but the turbos whistlin away and gague is showin good boost, I narrowed it down to the bov lettin off slightly n bleedin some boost out. No real way of testin this unless you get it on the rollers, Could take it down regal in portswood?

[Greddy-Matt]

Dirty air filter?

Good thinking but brand new Apexi unit on there

Yeah if I could borrow it for an hour of 2 that would be great
Ill PM you.

[Steve-O 2007]

hhmmm when I had this and my car died I did a few things which fixed my car and also fixed that laggy feeling (Turbo spooling like mad but your going no where)

List in order of what I fiddled with -

Airfilter to Turbo pipe - little Loose so I tightened it, car still wouldnt start
Intercooler pipes - bottom pipe on IC little loose tightened it, car still wouldnt start
Earthwires on bottom of Inlet manifold loose - tightened these up, Car started first time and now more bogging down.
Lamba Sensor wire disconnected

Could be one of them four but I think it was the 3 or 4 that sorted mine (Earth wires or Lamba)

[Greddy-Matt]

Cheers for that Ive done the first two, will check the other two tonight

Are the Earth wires on the Throttle body side or the back of the manifold?

[Steve-O 2007]

throttle body side, the area where the IC pipe goes in. You can see them from under the car easier . I think theres 2 on there but theres definatly 1 anyway

[Martin F]

i pressume there are no error codes

could be so many things mate, anything from a faulty knock sensor to ecu detecting overboost / blocked fuel filter to engine problems etc. very hard to diagnose over the internet

have you tried to reset the ecu to see if that helps (even temporarily )

[Driftlimits Performance]

hmm indeed. A faulty knock sensor would let you build up exactly the boost you wanted, but it would seriously retard the timing making it feel very flat. But you'd expect an error code. Maybe worth swapping just as a process of elimination.

[Century Motorsport]

hmm indeed. A faulty knock sensor would let you build up exactly the boost you wanted, but it would seriously retard the timing making it feel very flat. But you'd expect an error code. Maybe worth swapping just as a process of elimination.

I had a motor down here with issues that were similar to yours Matt. No error codes. After a process of elimination it turned out to be the knock sensor.

Suprising as there was no error code.

Other thing to maybe consider is how is the 1.15 bar boost achieved? If its by an EBC then have a look into that to make sure nothing is faulty.

Regards,

Nathan

[stevel]

I have the same problem at the mo, since i fitted a greddy intercooler. Its like the car cant suck enough air in. Checked all hoses. May put the stock one back to prove it. Its just a pain to do it.

[Greddy-Matt]

hmm indeed. A faulty knock sensor would let you build up exactly the boost you wanted, but it would seriously retard the timing making it feel very flat. But you'd expect an error code. Maybe worth swapping just as a process of elimination.

I had a motor down here with issues that were similar to yours Matt. No error codes. After a process of elimination it turned out to be the knock sensor.

Suprising as there was no error code.

Other thing to maybe consider is how is the 1.15 bar boost achieved? If its by an EBC then have a look into that to make sure nothing is faulty.

Regards,

Nathan

Thanks guys, interestng and I suspect correct. I had the intercooler out this weekend and its in perfect condition. Swapped over the BOV with no luck either.

I have no error codes so I wonder if they become intermittantly faulty?

I was saying yesterday it feels like the timing is being pulled, what causes the knock sensor to fail?

Im running a manual boost controller

[lockys96]

check ure plugs,

i have the exact same thing you describe on my supra.

change ure plugs

[salamanzer]

Have you checked your TPS?

I have the same problem as you at this very moment in time, tracked it back to the throttle position sensor.

Boost, no power, then loads of power, hesitates on WOT, when it does make power you can feel it speeding up then slowing down....

Jason

[Greddy-Matt]

Cheers Si, they're only about 3 months old, but ill swap em out for my spare set to be sure

I'm gonna have to go digging to find out how to check the TPS

Good thing Ive got some time off, looks like i might be @ it for a while

[Greddy-Matt]

Just a thought but can someone confirm det / knock is worse @ low revs with the car under load? If it is this the case it could explain why i get "stages" of power as the revs climb and the ECUKnock sensor allows the timing to advance??

[Rogue]

I concur with the guys who are suggesting knock sensor. Do you have a genuine Toyota one or a generic one? All of the non-Toyota knock sensors that we've seen feed the ECU just enough information that it doesn't throw a code, but not enough that it can usefully do anything with it.

The other possibility is a faulty MAP sensor. The signal wire for this is split and feeds both the ECU and the boost gauge on the dashboard. A short anywhere along its length will give you dodgy fuelling.

Patrick

[steve b]

Forge BOV leakin under high boost? swap it over for the stock BOV to rule this out. Just had this prob on mine.

As long as its got the right spring for the respective boost and the bolts that secure the diaphragm are tight the forge item shouldn't leak, its a very simple design with nothing to go wrong.