Diagnosis

Novice1 · Postby **Novice1** » Sat May 19, 2012 7:16 pm

Last night was the first time I pushed my car on high boost to the max.
I had done so in 1-3 gears went like a train.
Sitting on about 4000 rpm in 4th gear on high boost I put the foot to the floor. Noticeable hesitation jerkiness, jumping around like a kangaroo.
So i tried to replicate it and thrashed it thru gears 1-4. Again first rhree gears awesome, fourth gear at about 4500 revs its like hitting a wall.
Anyone got any ideas on possible causes.
cheers novice1

Postby **NitroDann** » Sat May 19, 2012 7:23 pm

Either boosting past the end of the fuel map, or hitting boost cut, or running out of fuel due to pump failure or blown a hose..?

Dann

JBT · Postby **JBT** » Sat May 19, 2012 7:50 pm

Novice1 wrote:So i tried to replicate it and thrashed it thru gears 1-4. Again first rhree gears awesome, fourth gear at about 4500 revs its like hitting a wall.

What revs did you get to in the first 3 gears?

Novice1 · Postby **Novice1** » Sat May 19, 2012 8:01 pm

First 3 gears 7000 rpm.
novice1 aka ron

gslender · Postby **gslender** » Sat May 19, 2012 8:12 pm

Not the clutch slipping is it?

Novice1 · Postby **Novice1** » Sat May 19, 2012 8:16 pm

Better not be the clutch, just had new one installed.
novice1

JBT · Postby **JBT** » Sat May 19, 2012 8:34 pm

Novice1 wrote:First 3 gears 7000 rpm.
novice1 aka ron

Weird. Doesn't really seem like fuel if the engine will run up through the gears. The only difference would be a higher engine load in 4th. Ignition system breaking down maybe?

Novice1 · Postby **Novice1** » Sat May 19, 2012 9:10 pm

Whatever it is perhaps one way to test is on dyno. Fourth gear on high boost is not something you can do on the streets during normal hours.
Novice1

JBT · Postby **JBT** » Sat May 19, 2012 9:30 pm

Have you got a spare set of plug leads you can try on it?

Postby **NitroDann** » Sat May 19, 2012 9:35 pm

Does your car have stock ignition?!

Dann

Novice1 · Postby **Novice1** » Sun May 20, 2012 5:11 am

As far as i know the ignition is stock.
Novice1

JBT · Postby **JBT** » Sun May 20, 2012 9:51 am

Wouldn't hurt to try a known good set of leads and/or plugs and see if that fixes it Ron. You can always keep them as spares if it doesn't work and you'll have eliminated that part of the system as a cause of the problem.

timk · Postby **timk** » Sun May 20, 2012 10:10 am

Maybe try a plug with a smaller gap, you are running like 20 psi yeah?

I'm doing a Toyota COP conversion in mine because of the fairly weaksauce ignition in the early NBs, I'll let you know how it goes.