Quote:
Originally Posted by RedArrow
Dealing with issues one by one is tons easier and it makes much more sense than changing multiple setups of several components at the same time, then not really knowing what mod resulted having a certain symptom(s).
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Well said, agreed.
Quote:
Originally Posted by jpliddy
when got the car back the plastic cover over the smoke screw was missing , they found it and put it back on ! so do they have to wind the screw off to release the throttle shaft? so they have to reposition it ,
your description seems right . so i woud be willing to try the slight adjustment of the smoke screw with your guidance
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Yes exactly right, the smoke screw gets removed (or at least screwed a long ways out) in order to disassemble the top of the IP/throttle control system. So they would have had to do this during the service that was performed, and then they would have had to get it reinstalled to the same setting it had been.
Normally the way to do this, if one is working on the IP still installed on engine using "seat of the pants" methods, is to very carefully note the position angle of the smoke screw before disassembly, and then count the number of turns required to remove it from the pump upper section housing. Then one tries to reinstall it in exactly the same position and with the same number of turns, so as to have the system work as it did before.
(This is as opposed to the ideal scenario of bench calibration off the engine, where the pump settings could be configured precisely based on fueling/advance measurements.)
If the folks who worked on your pump didn't use this "count the turns" method, or didn't manage to get it just right, then it is very much possible that the setting is off from what was intended. Or even if they did use it, since there are new parts in the pump and there are lots of other little fine variables that can affect how the pump operates (eg minor changes in the installed position of the upper cover section onto the main pump body), it could still have resulted in a change in the relationship of accelerator position to injected fuel quantity.
All this to say, it would be a good idea to carefully experiment a little with the smoke screw and see if that can get the engine back to running like it did before. It sounds like you know where the smoke screw is on the pump, and how it works. You can try turning it inwards (clockwise) in small 1/8th turn increments (loosening and tightening the jam nut each time), then go for a drive after each change and see what the difference is in terms of response, power, transmission shift points, and exhaust smoke.
Your target with the adjustments is to improve throttle response and power, but not get to the point of excess exhaust smoke under load. If you floor the pedal from a stop and see a steady trail of dark smoke until the turbo boost rises, then you have turned it in too far. It's OK to have a small visible puff of smoke during the transient moment just as you snap the pedal to full load, but it should not do more than that and should clear up as soon as the car is in motion. That is the result you're looking for. Any kind of steady state operating condition should have completely clear exhaust. Excess visible smoke is wasted fuel, and causes very high exhaust and cylinder head temps and is hard on the engine. Don't be tempted to allow it to smoke, even if the power feels good.
If you see smoke, you can back the screw off until you get to the sweet spot.
Let us know how that goes. Also be aware that changing the setting of the smoke screw will also result in minor changes to the engine idle speed. After you reach a satisfactory setting for the smoke screw, you may need to then make some final adjustments to the idle stop screw and/or the turnbuckle type linkage rod from the throttle spool to throttle lever and/or the position of the ball stud on the throttle lever to bring the warm idle speed back down to specified range. If your adjustments to the smoke screw cause a big increase in idle RPM, then you will want to make those other adjustments before test-driving the car, so as not to damage the transmission by engaging a gear with the engine racing.