Supra holding back a tad????

Hi

I have a j spec TT auto on a 93 and when i floor it and the second turbo comes online it seems to hold back like a heartbeat, it'll go fine for 1 or 2 seconds then a quick hold back and same again and again, this happens very evenly through out the revs upto a high speed....

Imagine when your heart beats that is the hold back, then it goes like a train again then holds?????.

No smoke that i notice, no lights on dash, it only has a cat back exhaust and is running on the cheapo premium unleadedas my lass drove it to ists and filled it with the cheap crap????

Drives great and is nice and smooth sounding when driven normally...

ANY HELP WOULD BE GREAT...

its probably the transition between first and second turbo where the first drops boost levels slightly to prespool the second then wallop both together.. normal

This happens from 4000rpm right upto 6000rpm plus, its like fuel starvation????

A rolling road should show this shouldnt it??

could be detonation due to the rubbish fuel.. Or a slight missfire, plug, coilpack, etc

check the basics before you get a rr though

What boost are you running? If it's over 1 bar do you have a FCD?

Stock ecu fuel cuts at over 1 bar, you will need a FCD (fuel cut defender) to get around this....

Running stock apart from a cat back exhaust so the guage reads .9 bar ish...

What should I try first before rr

Running stock apart from a cat back exhaust so the guage reads .9 bar ish...

What should I try first before rr

It might be the drag off your overfenders and graphics I still gotta make the small run over to you check the obvious before putting it on the logs as already advised

Test all the VSV's and vacuum pipes.

This sounds very like what my supra was doing a couple of month ago.

I got plugs all regaped & there was a few coil pack conectors needed replaced. All sweet now.

I take it was filled with normal 95 Unleaded? Dry it dry then fill with VPower.

Failing that I suggest you check pipes Ash has mentioned above.

I had much the same issue. Have you changed the O2 sensor recently? I had a non-Toyota O2 sensor fitted for about 3 months and it went like this. Got a proper Toyota one and re-placed it. Not had a problem since and mixture seems spot on.

Maybe its needs renewing or possibly cleaning? (Lemon Juice and all that) however that did not work for me.

So what pipes do I need to check???

It did squeel a tad earlier at full boost like a high pressure air leak?????

all the skinny ones on the left hand side above the turbo's and follow the big pipe through the intercooler, also check the intercooler.

If engine is running will these be loosing air???

Cheers

dan

mine was doin it a few months ago.... i tightened the boost pipe that the dump valve bolts onto and didnt seem to do it again

If you have a boost leak you won't notice it unless your boosting.

Which makes it a bit of a poo to diagnose.

I was reading your first post again, your not getting one flat spot, your getting loads every 2 seconds... right?

This isn't boost leak, I'm the king of boost leak and this isn't it.

This sounds more like fueling or ignition.

If it does it every time, it should be relatively easy for a competent garage to diagnose.

Thor is in Warwick which is only an hours drive from you unless there is someone closer, who knows their stuff.

i had this with my old black supra.

Its always been run on v-power but one day there wasnt a shell garage open, so i had to use esso supreme s**t.

Worst mistake going, made the car run terrible.