RE: [DML] No power at 4000 RPM

["Scott Mueller" <scott.a.mueller@xxxx>]

I found this message draft that I was putting together after I had power
problems with my car December 2002. The power would drop off above 4000
RPM. I played around with shim thicknesses but I think that I may have just
flushed a piece of debris from the fuel system. The car starts and runs
strong now and pulls up to redline. Perhaps this Winter I will get a chance
to fool around with it some more.

Scott

Below is the test readings I took while trouble shooting.

The injectors are new and were installed during my major tune-up last spring
(2002).

I increased the shim thickness and the new readings are;
1.7 Control Cold 50 F
5.4 Primary
3.0 Rest

2.0 Control Cold 70F ambient temperature
5.4 Primary Cold
3.0 Rest Cold

3.5 Control Hot engine warmed up
5.4 Primary Hot
3.2 Rest Hot

Original Shim
2.0 Control
4.9 Primary
2.9 Rest

Timing
13@Hot Idle
32@4000 RPM Total

The car runs fine now.

I'm not sure if it was the increase in pressure or if I flushed some piece
of trash out to the distributor.

Scott Mueller
002981
RNDOLA


-----Original Message-----
From: dherv10@xxxx [mailto:dherv10@xxxx] 
Sent: Wednesday, December 04, 2002 10:49 PM
To: dmcnews@xxxxxxxxxxxxxxx
Subject: Re: [DML] No power at 4000 RPM


Scott, See below.
John Hervey

<< Recently I posted a message asking for ideas on what could be causing
the drop in power at full throttle once the engine started going past 4000
rpm.
  
I installed a gauge to measure fuel system pressures.
  
All reading were taken on a cold engine, 70 F ambient temperature. ( what 
are your readings hot.)
  
Control Pressure = 2 bar
Primary Pressure = 4.9 bar
Rest Pressure = 2.9 bar
Rest Pressure after 10 minutes = 2.5 bar
  
Looking at my chart, it looks like primary pressure is at the bottom end
of the allowable checking pressure 4.9 to 5.5 bar. I can set the primary
pressure to the setting range of 5.1 to 5.3 bar.
  
My question is;
  
Will raising the primary pressure affect the Control Pressure? ( Yes ).
  
Is there a way to adjust the Control Pressure?( Yes, But by the experts. )
  
How is it done? >> ( Take the fuel dist off and send it to me. )

The fuel pump doesn't create the pressure, all it does is pump volume of
gas. 
The restrictions create the pressure. The primary pressure can only be 
adjusted by a shim in the unit. ( Picture on my web site.) When it's right (

Yes ) it also creates a back pressure ( trying to keep the gas from going 
back to the tank) which will raise or lower the control pressure which in 
turn will allow the control plunger to up or down sending gas to the 
injectors. Speaking of injectors, Have they been cleaned or replaced. You
may 
be starving the car gas at high RPM because the injectors are partially 
stopped up. 
John Hervey
www.specialTauto.com