Goddammit - another 4l60 build
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From: Texas
Thanks for the interest; I'll update the thread with my review and line pressure readings once it's running, which should be soon (probably a couple of weeks).
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From: Texas
I want to thank everyone for all of their help.
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From: Texas
Okay guys, I finally did a line pressure check on this thing (NOT EASY, for the record*), and I have some questions.
Idle pressures are normal (D- 65 psi, Rev. - 120 psi), but when the transmission is loaded, the pressures will initially raise (D - 200+ psi, Rev. - 280 psi) for about a second , then drop to about 100-120 psi.
Fluid level is good.
I disconnected the main electrical connector on the rear of the transmission to force full line pressure, and I've got 230 psi in Drive, and 280 in reverse. I took it out for a drive, and the pressure in Drive never dipped, so obviously this is a case of the EPC solenoid venting pressure.
Question: Is this normal? I'd expect more than 110 PSI at full throttle.
*There is hardly any room to connect my pressure line; I had to lower the back of the transmission and remove the range selector switch to make enough room.
Idle pressures are normal (D- 65 psi, Rev. - 120 psi), but when the transmission is loaded, the pressures will initially raise (D - 200+ psi, Rev. - 280 psi) for about a second , then drop to about 100-120 psi.
Fluid level is good.
I disconnected the main electrical connector on the rear of the transmission to force full line pressure, and I've got 230 psi in Drive, and 280 in reverse. I took it out for a drive, and the pressure in Drive never dipped, so obviously this is a case of the EPC solenoid venting pressure.
Question: Is this normal? I'd expect more than 110 PSI at full throttle.
*There is hardly any room to connect my pressure line; I had to lower the back of the transmission and remove the range selector switch to make enough room.
Okay guys, I finally did a line pressure check on this thing (NOT EASY, for the record*), and I have some questions.
Idle pressures are normal (D- 65 psi, Rev. - 120 psi), but when the transmission is loaded, the pressures will initially raise (D - 200+ psi, Rev. - 280 psi) for about a second , then drop to about 100-120 psi.
Fluid level is good.
I disconnected the main electrical connector on the rear of the transmission to force full line pressure, and I've got 230 psi in Drive, and 280 in reverse. I took it out for a drive, and the pressure in Drive never dipped, so obviously this is a case of the EPC solenoid venting pressure.
Question: Is this normal? I'd expect more than 110 PSI at full throttle.
*There is hardly any room to connect my pressure line; I had to lower the back of the transmission and remove the range selector switch to make enough room.
Idle pressures are normal (D- 65 psi, Rev. - 120 psi), but when the transmission is loaded, the pressures will initially raise (D - 200+ psi, Rev. - 280 psi) for about a second , then drop to about 100-120 psi.
Fluid level is good.
I disconnected the main electrical connector on the rear of the transmission to force full line pressure, and I've got 230 psi in Drive, and 280 in reverse. I took it out for a drive, and the pressure in Drive never dipped, so obviously this is a case of the EPC solenoid venting pressure.
Question: Is this normal? I'd expect more than 110 PSI at full throttle.
*There is hardly any room to connect my pressure line; I had to lower the back of the transmission and remove the range selector switch to make enough room.
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Joined: May 2012
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From: Poplarville, MS
Okay guys, I finally did a line pressure check on this thing (NOT EASY, for the record*), and I have some questions.
Idle pressures are normal (D- 65 psi, Rev. - 120 psi), but when the transmission is loaded, the pressures will initially raise (D - 200+ psi, Rev. - 280 psi) for about a second , then drop to about 100-120 psi.
Fluid level is good.
I disconnected the main electrical connector on the rear of the transmission to force full line pressure, and I've got 230 psi in Drive, and 280 in reverse. I took it out for a drive, and the pressure in Drive never dipped, so obviously this is a case of the EPC solenoid venting pressure.
Question: Is this normal? I'd expect more than 110 PSI at full throttle.
*There is hardly any room to connect my pressure line; I had to lower the back of the transmission and remove the range selector switch to make enough room.
Idle pressures are normal (D- 65 psi, Rev. - 120 psi), but when the transmission is loaded, the pressures will initially raise (D - 200+ psi, Rev. - 280 psi) for about a second , then drop to about 100-120 psi.
Fluid level is good.
I disconnected the main electrical connector on the rear of the transmission to force full line pressure, and I've got 230 psi in Drive, and 280 in reverse. I took it out for a drive, and the pressure in Drive never dipped, so obviously this is a case of the EPC solenoid venting pressure.
Question: Is this normal? I'd expect more than 110 PSI at full throttle.
*There is hardly any room to connect my pressure line; I had to lower the back of the transmission and remove the range selector switch to make enough room.
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From: BERWICK PA
Seems your max presure disconnected are good so takes presure regulator and pump out of the equation, I would change the presure control solenoid first sounds like its leaking or venting First and easiest thing to do IMO Then if that does not solve it I would look at possible control issues.
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From: Texas
Seems your max presure disconnected are good so takes presure regulator and pump out of the equation, I would change the presure control solenoid first sounds like its leaking or venting First and easiest thing to do IMO Then if that does not solve it I would look at possible control issues.
I've got the OBD II port wired in, but I don't have a scanner that can control anything.
So I figured I could monitor amperage to the EPC solenoid wire, to see if current increases when the pressure drops. I was thinking of wiring my Fluke meter inline with the Pressure Control Hi wire (C2 - 6, Red/ Black) and taking it out for a drive.
Does that sound feasible to you smart guys?
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From: BERWICK PA
Yes to verify current drops as throttle increases and should be near 0 at wot . I have however never looked far enough into the PCM software to see if it calulate or actually measures current, The meter might be a better bet as far as being sure ,
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From: Texas
Okay boys, I took it out on a road test right now, and here's what I found.
Amperage at idle/ minimum pressure was .9- 1.0 amps.
At full throttle, the lowest reading was .5 - .6 amps, which equates to about 150 psi; I could not replicate the 200+ psi spike, nor the 110 psi low that I did last time. I'm going to assume that it should have been closer to .1- .2 amps at full throttle.
I'd like to do more testing, but it's getting dark (Goddam, I hate this time of year), the car has an open exhaust and no plates, and the Texas State Troopers are just itching to **** up the holidays for folks this weekend.
Anyway, the low amount of amperage drop leads me to believe that this is a tune related issue; just to be safe, I disconnected the EPC wire, and the pressure immediately jumped back to 230.
Question: The "tune" for this thing is for the 100% stock '04 Tahoe donor vehicle. Do y'all think that because this car weighs a full ton less that the MAP numbers aren't high enough to command full line pressure?
IE: The PCM doesn't think there is enough engine load to require full line pressure?
Amperage at idle/ minimum pressure was .9- 1.0 amps.
At full throttle, the lowest reading was .5 - .6 amps, which equates to about 150 psi; I could not replicate the 200+ psi spike, nor the 110 psi low that I did last time. I'm going to assume that it should have been closer to .1- .2 amps at full throttle.
I'd like to do more testing, but it's getting dark (Goddam, I hate this time of year), the car has an open exhaust and no plates, and the Texas State Troopers are just itching to **** up the holidays for folks this weekend.
Anyway, the low amount of amperage drop leads me to believe that this is a tune related issue; just to be safe, I disconnected the EPC wire, and the pressure immediately jumped back to 230.
Question: The "tune" for this thing is for the 100% stock '04 Tahoe donor vehicle. Do y'all think that because this car weighs a full ton less that the MAP numbers aren't high enough to command full line pressure?
IE: The PCM doesn't think there is enough engine load to require full line pressure?
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From: Texas
I'll check back on that tomorrow with numbers for MAP, MAF, and TPS.
(Fun fact: if power to the EPC solenoid is interrupted with the key on, it is shut off by the PCM until the code is cleared. I was wondering why I was getting full line pressure and no amperage after connecting the jumper wire, even after cycling the key a few times.
That's why. )
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From: BERWICK PA
I would look at TPS voltage range first . Though most sensor issues that affect line presure should also result in diminished engine performance I would think but TPS MAF and MAP would be the things to look at IMO
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From: Texas
MAP : 30.1 " hg, engine off, 9.7" hg engine idling
MAF: 7.036 grams per second, idling
TPS voltage 1: .8 Volts closed, 3.9 volts WOT (measured at throttle control module, under the dashboard.
TPS voltage 2: .76 Volts closed, 3.46 volts WOT
Do those TPS numbers look okay to you guys? I was expecting a little higher voltage at WOT, but my scanner recognizes 100% throttle when I floor the pedal.
Sadly, there will be no road test today; based on the sounds I'm hearing outside this New Year's Eve, a lot of people are already halfway in the bag.
Thanks guys, let me know what y'all think.
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From: Poplarville, MS
Okay, I got some readings.
MAP : 30.1 " hg, engine off, 9.7" hg engine idling
MAF: 7.036 grams per second, idling
TPS voltage 1: .8 Volts closed, 3.9 volts WOT (measured at throttle control module, under the dashboard.
TPS voltage 2: .76 Volts closed, 3.46 volts WOT
Do those TPS numbers look okay to you guys? I was expecting a little higher voltage at WOT, but my scanner recognizes 100% throttle when I floor the pedal.
Sadly, there will be no road test today; based on the sounds I'm hearing outside this New Year's Eve, a lot of people are already halfway in the bag.
Thanks guys, let me know what y'all think.
MAP : 30.1 " hg, engine off, 9.7" hg engine idling
MAF: 7.036 grams per second, idling
TPS voltage 1: .8 Volts closed, 3.9 volts WOT (measured at throttle control module, under the dashboard.
TPS voltage 2: .76 Volts closed, 3.46 volts WOT
Do those TPS numbers look okay to you guys? I was expecting a little higher voltage at WOT, but my scanner recognizes 100% throttle when I floor the pedal.
Sadly, there will be no road test today; based on the sounds I'm hearing outside this New Year's Eve, a lot of people are already halfway in the bag.
Thanks guys, let me know what y'all think.
Thread Starter
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From: Texas
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From: BERWICK PA
Also remember the TPS voltage is still relative to the Vehical main voltage . Its its lower you will get lower figures, The specs are based on 13.8 as main power voltage So if you are lower or higher you have to account for that as a percentage of the final read voltage on the TPS and the numebr do seem a little low to me also but I dont know the relativity to main voltage and you are showing 100 percent TPS.
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Thread Starter
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Joined: Mar 2012
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From: Texas
Also remember the TPS voltage is still relative to the Vehical main voltage . Its its lower you will get lower figures, The specs are based on 13.8 as main power voltage So if you are lower or higher you have to account for that as a percentage of the final read voltage on the TPS and the numebr do seem a little low to me also but I dont know the relativity to main voltage and you are showing 100 percent TPS.
But wouldn't this depend on the 5v signal coming from the Throttle control module?
IE: As long as I've got 5v at the TPS sensor, the main charging system voltage wouldn't matter?
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From: Texas
UPDATE: I just tested it, and I've got 14.7 volts from the alternator charging stud and battery positive cable, and 5.0 volts at the throttle body (Both TPS sensors).
What now? I was thinking of running a 5 volt jumper wire to the signal lines, to see if it forces maximum line pressure. Does that sound like a reasonable test? Because at this point, I think we're looking at bad TPS territory.
What now? I was thinking of running a 5 volt jumper wire to the signal lines, to see if it forces maximum line pressure. Does that sound like a reasonable test? Because at this point, I think we're looking at bad TPS territory.