I had my gears changed to 3.73 and since then at wide open throttle the car shifts into second revs all the way up to the redline and literally doesnt move then shifts and moves slowly. I have my superchip tuner comming in a few days that is reprogrammed to the gears. Could this be why this is happening?
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an alternative browser.
You should upgrade or use an alternative browser.
Problem at WOT 98 Mustang 4.6
- Thread starter sanitarium16
- Start date
- Status
- Not open for further replies.
- Joined
- Sep 28, 2002
- Messages
- 39,799
Hmm...have you reprogrammed your VSS?? That is, is your speedo corrected?
sanitarium16
Thread starter
yes the spedo is corrected. Had a speedo gear put in.
Have you disconnected the battery to reset the adaptive strategy for the automatic transmission?
sanitarium16
Thread starter
It only happens at WOT. When cruising everything shifts perfect. There is no lack of power or anything. When i floor it off a light it will shift from first then in second it goes all the way to 6,000 and just sits there. The car literally isn't moving any faster.
So, with the gas pedal floored it never shifts to third gear and just stays in 2nd at redline?
sounds like a vacuum actuated transmission? Surely not in this day and age. but just in case...
At really high RPMs the engine isn't making enough vacuum to shift. This was quite common in old muscle cars with automatics, my college roommates' 69 GT500 had this tendency. You had to back off the gas pedal a smidge to get it to upshift. Normal driving was fine, it was the WOT that did it.
just a thought
At really high RPMs the engine isn't making enough vacuum to shift. This was quite common in old muscle cars with automatics, my college roommates' 69 GT500 had this tendency. You had to back off the gas pedal a smidge to get it to upshift. Normal driving was fine, it was the WOT that did it.
just a thought
No, it's got an AODE in it. No vacuum modulator in that one..last year for the AOD which did use a vacuum modulator was '93.
- Joined
- Sep 28, 2002
- Messages
- 39,799
It still applies in principle. The rev limit isn't matched with the mandatory upshift due to the VSS/MAP/TPS ..or whatever tells it to shift. In the older trans ..WOT would result in the governor pressure dictating the upshift point. This is how the trans integrated vehicle speed ..vacuum, or in some cases (TF/Chrysler) throttle position valve/linkage, indicated the load level.
Either way ..whatever is telling the trans that it's time to shift is out of whack ...or ...he needs to adjust his rev limiter upwards a few hundred rpm.
Does this trans have its own brain ..and is it self contained? ..or does it get input from the PCM/ECU??
Either way ..whatever is telling the trans that it's time to shift is out of whack ...or ...he needs to adjust his rev limiter upwards a few hundred rpm.
Does this trans have its own brain ..and is it self contained? ..or does it get input from the PCM/ECU??
That trans is controlled from the same EEC-V which controls the engine, which is why I wonder if maybe rebooting it will solve the problem.
Ford ditched MAP sensors in the early 90s so that couldn't be the problem.
Ford ditched MAP sensors in the early 90s so that couldn't be the problem.
sanitarium16
Thread starter
The transmission in the 98 is the 4r70w not AODE. It must be a tuning problem because it never did it until i got the gears installed so the rpm range is probably out of whack like stated above. I had my tuner reprogrammed for it and it is in the mail so when it comes that should solve the problem i guess.
I think Ford started calling the AODE the 4R70W. The transmissions are very similar, if not identical.
I looked at the Ford service manual and the vehicle speed sensor (VSS) shouldn't be causing the problem you're having. The only thing the gears changed (as far as the transmission controls are concerned) is what the VSS reads at a given engine speed, so...
Is the check engine light on?
This is what problems it says the VSS can cause:
Vehicle Speed Sensor (VSS) 9E731
ÚÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ¿
³ The vehicle speed sensor is a magnetic pickup that sends a signal to the ³
³ powertrain control module. This VSS signal tells the PCM vehicle speed. The PCM ³
³ uses this signal to modify upshift schedules. ³
³ Symptoms: Shift engagement/disengagement (hunting) on grades. ³
³ DTC: P0500, P0503, P1500, P1501, P0501 ³
ÀÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÙ
I looked at the Ford service manual and the vehicle speed sensor (VSS) shouldn't be causing the problem you're having. The only thing the gears changed (as far as the transmission controls are concerned) is what the VSS reads at a given engine speed, so...
Is the check engine light on?
This is what problems it says the VSS can cause:
Vehicle Speed Sensor (VSS) 9E731
ÚÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ¿
³ The vehicle speed sensor is a magnetic pickup that sends a signal to the ³
³ powertrain control module. This VSS signal tells the PCM vehicle speed. The PCM ³
³ uses this signal to modify upshift schedules. ³
³ Symptoms: Shift engagement/disengagement (hunting) on grades. ³
³ DTC: P0500, P0503, P1500, P1501, P0501 ³
ÀÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÙ
- Joined
- Sep 28, 2002
- Messages
- 39,799
Now let me get this straight (you put the lime in the Coke, you nut).....
You floor it ...it downshifts ...revs up to the redline ...hangs there ..then eventually shifts ..and you've got no power?
The lack of shifting is some mismatch in the parameters for shifting (sorta what brian was refering to) ...there are plenty of transmissions that have mandatory shift points that exceed the engine's ability to reach ..and other parameters aren't yet met.
..but that could easily be tested by merely lifting your foot slightly and seeing if it shifts after this event is in progress. You would then see that the TP or MAP changes effect the event.
Now why you're hitting wet cement when it shifts is some other issue ..or so I'd reason.
So ...we have ...PERFECT pull from idle through 1st gear ...PERFECT pull through 2nd up to the redline ...eventually shifts ..and then is a lead slug plodding through wet cement??
That about it???
What happens at this same speed/rpm/etc. if you don't go to the redline in 2nd? That is, ..let's say you're doing 75 mph in 2nd at the redline (whatever it really is) ..except you're in 3rd and just push the throttle open and progressively accellerate? Do you experience the same lack of power?
You floor it ...it downshifts ...revs up to the redline ...hangs there ..then eventually shifts ..and you've got no power?
The lack of shifting is some mismatch in the parameters for shifting (sorta what brian was refering to) ...there are plenty of transmissions that have mandatory shift points that exceed the engine's ability to reach ..and other parameters aren't yet met.
..but that could easily be tested by merely lifting your foot slightly and seeing if it shifts after this event is in progress. You would then see that the TP or MAP changes effect the event.
Now why you're hitting wet cement when it shifts is some other issue ..or so I'd reason.
So ...we have ...PERFECT pull from idle through 1st gear ...PERFECT pull through 2nd up to the redline ...eventually shifts ..and then is a lead slug plodding through wet cement??
That about it???
What happens at this same speed/rpm/etc. if you don't go to the redline in 2nd? That is, ..let's say you're doing 75 mph in 2nd at the redline (whatever it really is) ..except you're in 3rd and just push the throttle open and progressively accellerate? Do you experience the same lack of power?
sanitarium16
Thread starter
The check engine light isn't on. Where is the VSS located? Is it easy to change out?
The VSS should be located on the transmission. The speedometer gear drives it.
I wouldn't think it to be the problem unless you're getting erratic speedometer readings. It drives the speedometer too.
I wouldn't think it to be the problem unless you're getting erratic speedometer readings. It drives the speedometer too.
I think the box will work to fix this problem if it's installed in the right place. You want it to only alter the signal going to the speedometer.
The output VSS is connected (it's a parallel circuit) to both the computer and the speedometer (and the cruise control,if equipped). If the transmission shifts OK with the original gear, then installing the box between the VSS and the speedometer but NOT between the VSS and the computer will do the following:
1)Provide proper shifts because the computer is getting the orignal un-altered signal
2)Provide proper speedometer readings because the speedometer is getting the modified signal.
The cruise control should function OK with either the modified or the original signal.
I looked at the wiring diagrams last night, this should work fine.
The output VSS is connected (it's a parallel circuit) to both the computer and the speedometer (and the cruise control,if equipped). If the transmission shifts OK with the original gear, then installing the box between the VSS and the speedometer but NOT between the VSS and the computer will do the following:
1)Provide proper shifts because the computer is getting the orignal un-altered signal
2)Provide proper speedometer readings because the speedometer is getting the modified signal.
The cruise control should function OK with either the modified or the original signal.
I looked at the wiring diagrams last night, this should work fine.
Alternatively..you could probably leave the gear that's in there now and install the box only between the VSS and the computer, so it alters the signal back to the way it would have been the the original gear.
Then the speedometer gets the original signal, and the computer gets the modified signal.
Then the speedometer gets the original signal, and the computer gets the modified signal.
hmm, good alternatives, i had not considered that before. you're certain it's a parallel circuit?
-michael
-michael
i'm in the middle of something at work right now and so can't quite wrap my head around this 100%, but i don't think this variant would work. the box can only "slow down" the signal. so, you have to start with a signal that's "too fast."quote:
Originally posted by brianl703:
Alternatively..you could probably leave the gear that's in there now and install the box only between the VSS and the computer
-michael
- Status
- Not open for further replies.
Similar threads
- Replies
- 10
- Views
- 527
- Replies
- 0
- Views
- 484
