Re: qtc@4800rpm details

[MICHAEL ZAMIKHOVSKY <mikez755@sprintmail.com>]

Tom Juliani wrote:
> 
> Thanks for the tips so far -
> OK, here's the full story on the cutout/shutdown @ 4800rpm in my '83qtc ­
> 
> Location: Firebird Raceway, Phoenix, AZ.  Clear weather, 70 degrees F.
> This track is all 3rd gear in my q, except for the final 180 left hander in
> 2nd which opens onto the straightaway (3rd, 4th). Entrance into the final
> turn is a downshift into 2nd @5500rpm, drops to ~5000rpm at the apex, up to
> 6000rpm and then shift to 3rd as I enter the straight.
> 
> Each lap while accellerating down the straightaway, once I reached 4800rpm
> in 3rd gear the motor would shut down (quite abruptly!). Lifting off the
> throttle momentarily would restore operation and I could continue along
> past 4800rpm to 6000+rpm and shift into 4th gear.  If I did not floor the
> throttle, but maintained approx 90% pedal deflection down the straightaway,
> all would be fine (but a bit slower).
> 
> I disconnected the WOT switch, and it made no difference. I was running a
> quarter tank of fuel, so to eliminate pick-up problems as a possibility I
> filled it to half full. Same results.  I ran the susequent sessions at 90%
> throttle to make the most of my tracktime.
> 
> So gang - overboost?  Why only in 3rd gear?  I can run to redline in 2nd
> with no problems - less load therfore less boost perhaps? Sticky wastegate?
> Temp issue?  Boost check at the shop produces consistent 1.90 bar on
> calibrated test gauge. I have never experienced this problem on the highway
> or street during, um, spirited driving.
> 
> THE GOOD NEWS - My '83 qtc is bone stock, has 117k miles, and at 90%
> throttle still kept the 3000GTVR4s, VTEC Preludes and Mustang GTs behind me
> on every lap!
> 
> Cheers, tj
> 
> Tom Juliani                             tomj@emerald.net
> Dir Sales & Mktg                     520-887-7001 x15
> EmeraldNet                              http://www.emerald.netMy 83TQC does the same thing and many people pointed out fule starvation
possibly do to inadequate pump output or line constriction. The pump may 
be turned down by the ECU or it may be not pumping out enough volume. 
This will still give normul pressure reading, but in high demand 
situation will cause lean minture. I replaced my pump 2 years ago when I 
got this car. Bruno told me that there is a way to test output by 
disconnecting return line near the tank and measuring output over 
specific period of time. I have not done that yet. But I have a Hallmeter 
and I hope that this will verify the mixture problem. I checked output of 
all sensors at the ECU plug according to Supplement service manual and 
all was well. Since than I removed my turbocharger and cylinder head. The 
head was plained, valves reground, guides replaced, valve heights set 
springs shimmed, and all broken studs removed. I replaced my turbo w/ 
watercooled K26 and had custom turbo oil supply hose fabricated to mate 
new tubo to old oil thermostar/filer housing. I am about to get it 
running again and work on old cut out problem.
                 Mike Z