Zack;
This anomaly developed a few weeks ago and doesn't seem to be related to the engine tick (which has gone away) but the partial loss of compression on #6 is still there.
The problem is that idle speed at start up or any change in throttle setting, hot or cold engine, will only return to the XCal set speed of 900 RPM in two distinct stages, first to about 1300 RPM and then after a second or two settles to tuned idle speed of 900 RPM. This is after coming to a complete stop. If I am coasting, the engine speed will not drop below 1300 RPM.
Engine vacuum is 16-17 inches at idle. Difference between Idle speeds in park or drive is insignificant, less than the width of the needle.
The idle speed was set by the previous tuner years ago, I don't recall if the idle creeped up or was orginally set at 900.
I'v visually checked with flashlite the nest of vacumn lines around the EGR. none are in close proximity to the EGR tube which is still shielded from valve to manifold. I checked the vacumn line from the BOV (or whatever it's called) it's OK
What I have done is:
Removed and cleaned the TB with brake cleaner.
Oiled the blade wind up spring and TB return spring.
Checked to see that blades are not binding and are coming to a complete closed position.
replaced IAC and gasket.
Replaced TB gasket
Resistance checked TPS for full open and closed resistance reading plus observing the change in resistance as throttle is opened and closed, all smooth with consistent return to closed throttle reading.
Removed NOS traction control signal wire from TB output to eliminate loading by the NOS computer - no effect.
Engine vacuum normal 16/17 inches.
Engine RPM at driving speeds seem normal from previous observation
Any advice for me?
Would a defective MAF sensor cause this, I've clean it periodically. This
problem did not develop after a MAF or air filter cleaning but I don't rule it out either.
Thanks,
Pat
The car goes in for head repair in March/April time frame. Since October is car has been dormant except for a weekly start/warm up/drive around the block to keep things soft.
This anomaly developed a few weeks ago and doesn't seem to be related to the engine tick (which has gone away) but the partial loss of compression on #6 is still there.
The problem is that idle speed at start up or any change in throttle setting, hot or cold engine, will only return to the XCal set speed of 900 RPM in two distinct stages, first to about 1300 RPM and then after a second or two settles to tuned idle speed of 900 RPM. This is after coming to a complete stop. If I am coasting, the engine speed will not drop below 1300 RPM.
Engine vacuum is 16-17 inches at idle. Difference between Idle speeds in park or drive is insignificant, less than the width of the needle.
The idle speed was set by the previous tuner years ago, I don't recall if the idle creeped up or was orginally set at 900.
I'v visually checked with flashlite the nest of vacumn lines around the EGR. none are in close proximity to the EGR tube which is still shielded from valve to manifold. I checked the vacumn line from the BOV (or whatever it's called) it's OK
What I have done is:
Removed and cleaned the TB with brake cleaner.
Oiled the blade wind up spring and TB return spring.
Checked to see that blades are not binding and are coming to a complete closed position.
replaced IAC and gasket.
Replaced TB gasket
Resistance checked TPS for full open and closed resistance reading plus observing the change in resistance as throttle is opened and closed, all smooth with consistent return to closed throttle reading.
Removed NOS traction control signal wire from TB output to eliminate loading by the NOS computer - no effect.
Engine vacuum normal 16/17 inches.
Engine RPM at driving speeds seem normal from previous observation
Any advice for me?
Would a defective MAF sensor cause this, I've clean it periodically. This
problem did not develop after a MAF or air filter cleaning but I don't rule it out either.
Thanks,
Pat
The car goes in for head repair in March/April time frame. Since October is car has been dormant except for a weekly start/warm up/drive around the block to keep things soft.
