.500 boost valve pressures?
02-27-2002, 02:02 PM
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.500 boost valve pressures?
I have installed the .500 boost valve and the pressure was 71psi (low TV) and 163 psi (full TV).
Before it was 57 and 140, with the original boost valve. (.391")
Seems to me that these pressures are on the low side, is my pump shot?
What's normal with the .500 valve?
Before it was 57 and 140, with the original boost valve. (.391")
Seems to me that these pressures are on the low side, is my pump shot?
What's normal with the .500 valve?
02-27-2002, 05:47 PM
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That doesn't sound right to me but then again, I don't know what you have!
You see the pressures vary with year and model. The earlier units had @60 PSI at idle and the later ones were @75 PSI. However, I don't recall any of the 60 PSI ones having the smaller boost valve and if it did I just tossed it anyways. That being said, unless you changed something else and didn't tell us then you should still have the same base pressures. OR you might have the TV cable set tighter than it is supposed to be and it is partially open at idle. Anyways, that still doesn't sound like a heck of allot of boost for a .500", I would expect it to be @200. You may have other problems. How about this: To adjust the TV Cable skip the book method and do this: Press the 'D' shaped lock button on the adjuster and loosen the cable setting (The black housing that the metal cable is in will move forward). Now, have someone floor the gas pedal while you check to see if the throttle plate is open all the way. Usually they are off a little and will wiggle. Do whatever you have to do to get it open solid. Now, with the pedal still floored, press the 'D' button and pull the cable casing (the black tube) back as hard as you can (putting maximum tension on the metal cable) and release the button. You now have the engine, tranny and gas pedal all in sync at WOT. Mark the cable casing so if for some reason it gets moved you can know where to put it again. The problem with the 'self adjust method' is that it bends things and puts them permanently out of whack. It is also the full TV setting, which is theoretically what the GM method does. Try that and get back with pressures in ALL ranges at IDLE, FAST IDLE, and FAST IDLE W/MAX TV. Oh yea, a little more info too!
You see the pressures vary with year and model. The earlier units had @60 PSI at idle and the later ones were @75 PSI. However, I don't recall any of the 60 PSI ones having the smaller boost valve and if it did I just tossed it anyways. That being said, unless you changed something else and didn't tell us then you should still have the same base pressures. OR you might have the TV cable set tighter than it is supposed to be and it is partially open at idle. Anyways, that still doesn't sound like a heck of allot of boost for a .500", I would expect it to be @200. You may have other problems. How about this: To adjust the TV Cable skip the book method and do this: Press the 'D' shaped lock button on the adjuster and loosen the cable setting (The black housing that the metal cable is in will move forward). Now, have someone floor the gas pedal while you check to see if the throttle plate is open all the way. Usually they are off a little and will wiggle. Do whatever you have to do to get it open solid. Now, with the pedal still floored, press the 'D' button and pull the cable casing (the black tube) back as hard as you can (putting maximum tension on the metal cable) and release the button. You now have the engine, tranny and gas pedal all in sync at WOT. Mark the cable casing so if for some reason it gets moved you can know where to put it again. The problem with the 'self adjust method' is that it bends things and puts them permanently out of whack. It is also the full TV setting, which is theoretically what the GM method does. Try that and get back with pressures in ALL ranges at IDLE, FAST IDLE, and FAST IDLE W/MAX TV. Oh yea, a little more info too!
02-28-2002, 10:52 AM
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Thanks transfixleo!!
The 700R4 is from a 1987 Caprice (with aux. body).
The TV cable is adjusted as per your instructions, but I think you may be right about having partly open TV at idle.
The pull length of the cable using the standard QJet bracket is 1.38". Which is identical to what I measured at my 1987 TPI (to be installed later).
Total cable pull length is 2.21" and the plunger starts to move at 0.32" pull.
The pressure readings for the 0.500 valve is taken with the TransGo shift kit installed, the original readings is without the kit.
I'm working alone for the moment so I cannot do the rest of the measurements.
The 700R4 is from a 1987 Caprice (with aux. body).
The TV cable is adjusted as per your instructions, but I think you may be right about having partly open TV at idle.
The pull length of the cable using the standard QJet bracket is 1.38". Which is identical to what I measured at my 1987 TPI (to be installed later).
Total cable pull length is 2.21" and the plunger starts to move at 0.32" pull.
The pressure readings for the 0.500 valve is taken with the TransGo shift kit installed, the original readings is without the kit.
I'm working alone for the moment so I cannot do the rest of the measurements.
03-01-2002, 03:55 AM
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Get back with all of the readings when you can. Either your gauge is off or you have a problem since the TransGo PR Spring will give 78 PSI at Idle. The Idle/Fast idle will give better indication of pump condition (do when hot) as that can lower the reading but usually it will come up with RPM's. Still you should be above 163 (or 170 if you figure the gauge might be off).
03-05-2002, 04:22 PM
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I've done some more measuring, these are the low/full TV readings at ca 1000rpm:
P 73 156/170
R 188 256
N 73 156/170
O 73 156/170
3 73 156/170
2 202 202
The needle was fluctuating widely at full TV between 156/170 in all gears except R & 2 .
(I don't have the 1th gear position at my shifter)
If I loosen the TV cable it goes down to ca 70psi before it start to rise (safety function). I get immediate pressure rise when cable is pulled from low position and plunger is fully seated at max TV.
In idle (ca 600rpm) the reading was similar to high idle in Park, but dropped to 114/128 in Reverse. Then my assistant had to leave...
Do these values tell anything more?
P 73 156/170
R 188 256
N 73 156/170
O 73 156/170
3 73 156/170
2 202 202
The needle was fluctuating widely at full TV between 156/170 in all gears except R & 2 .
(I don't have the 1th gear position at my shifter)
If I loosen the TV cable it goes down to ca 70psi before it start to rise (safety function). I get immediate pressure rise when cable is pulled from low position and plunger is fully seated at max TV.
In idle (ca 600rpm) the reading was similar to high idle in Park, but dropped to 114/128 in Reverse. Then my assistant had to leave...
Do these values tell anything more?
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