94 auto trans problems...

[ratio411]

Here's what I got:
1994 Mustang GT, 5.0 w/AOD (E?) and 2.73 gears out back.

The tranny acts perfect at all times, except when you get on it.
If you floor it, when it comes time to shift, it doesn't. The stupid
thing will run up to the redline and bounce on the rev limiter all
day long rather than upshift.

If you take your foot off the floor, for a split second, and jam it back,
it will shift finally. Makes for a very rough upshift though. It also
is very late to upshift when you drive more aggressive than grandma...

Anything more than putting around town, and the rpms go higher
than they should before upshift. Full throttle has no upshift.

What is the problem?
TV cable adjustment?
TPS?

 

[Bullitt95]

Your tranny is electronically-controlled (AODE) so there's no TV cable. Check the tranny fluid level first of all. If it's low that could be causing your problems. You might wanna change the fluid anyway if it's old and change the filter.

 

[toyman]

Here's what I got:
1994 Mustang GT, 5.0 w/AOD (E?) and 2.73 gears out back.

The tranny acts perfect at all times, except when you get on it.
If you floor it, when it comes time to shift, it doesn't. The stupid
thing will run up to the redline and bounce on the rev limiter all
day long rather than upshift.

If you take your foot off the floor, for a split second, and jam it back,
it will shift finally. Makes for a very rough upshift though. It also
is very late to upshift when you drive more aggressive than grandma...

Anything more than putting around town, and the rpms go higher
than they should before upshift. Full throttle has no upshift.

What is the problem?
TV cable adjustment?
TPS?

Besides the shift problem something else is not correct here. The PCM will not allow the AODE car to rev past 5450 rpm (rev limiter set point). How long have you owned this car and is this just a recent event? Check fluid levels.

 

[ratio411]

Yeah, 5500 rpm is pretty much where it stops accellerating and stutters.
If I have my foot to the floor, it will sit there at the limiter, literally, until
I let up. It absolutely will NOT shift until I let off the gas. Then it shifts
really hard, neck snapping shift. Will do it in any upshift, no matter which
gear it is going to. At lesser throttle positions, it is very similar, but it will
eventually shift, just obviously later than it should. The only time it seems
to shift at the proper rpm is when I am driving very sedately.

I have had the car 3 months or so. It has done this since I have had it,
and the previous owner confirms that it shifted late for him too.

Fluid level is clean and full. A large aux cooler is in place.

I have no way to check codes myself, but I know it throws them on
occaision. If you drive 'spirited', the check engine light will come on
for just a moment after hard accelleration, 9x out of 10.

I doubt it is related, but I also cannot run regular fuel in the car.
Anything less than 93 octane will ping like a b!t#h, and 93 will
on a hot day. The timing is set stock and I put new plugs/wires/
cap/rotor/air filter. I am currently treating the car with injector
cleaner to hopefully remove any extreme carbon buildup in the
chambers that might be causing the ping issue.

Will a 'worn out' O2 sensor cause a lean condition? I was thinking
that might be a ping issue... Or if the TPS is out, it might cause lean
AND send faulty readings to the tranny... which would explain both
problems. ???

Is my thinking correct?

 

[Bullitt95]

Bad O2 sensors almost always cause a rich condition so I think you can rule those out. A faulty TPS is a possibility and you can easily test it with a digital voltmeter. Backprobe the middle wire of the three coming from the TPS connector and check the voltage between that and ground with the ignition on, engine off. It should be 0.95-0.99v with the throttle closed, and ramp up steadily as you open the throttle until it reaches about 4.6v with the throttle fully open. If there are any voltage spikes or troughs while you're opening the throttle, replace the TPS.

 

[ratio411]

Bad O2 sensors almost always cause a rich condition so I think you can
rule those out. A faulty TPS is a possibility and you can easily test it with
a digital voltmeter. Backprobe the middle wire of the three coming from
the TPS connector and check the voltage between that and ground with
the ignition on, engine off. It should be 0.95-0.99v with the throttle closed,
and ramp up steadily as you open the throttle until it reaches about 4.6v
with the throttle fully open. If there are any voltage spikes or troughs
while you're opening the throttle, replace the TPS.

Good info! Thanks!

TPS: 1.03v at idle, smooth operation to 4.65v

I bumped up the fuel pressure from 40 psi (no vacuum) to 45 psi.
This made the car run much better at idle and around town.
The jury is still out on the 'ping', but I should know soon, I stepped down
to 89 octane. I do notice some cat stink lately. I wonder if my cats aren't
shot... ??? When money allows, I think an ORP is in order.

That brings me to another question...
How does the bone stock exhaust sound with an ORP?
Does it add any sort of aggressive tone while you still have stock muffs?

 

[gcomfx.com]

Have you checked to see if there is a chip in the back of the computer?

Honestly, you REALLY need to find a way to pull codes. Try any local auto parts store to see if they will do it for free. I highly recommend a scan tool for at home. It's saved me countless times.

 

[Bullitt95]

I do notice some cat stink lately. I wonder if my cats aren't shot... ??? When money allows, I think an ORP is in order.

Sounds like you're having trouble. You could just have the catted parts of your stock H-pipe replaced with straight pipe if you want to save some money. Then gut the cats that you've removed and recycle the insides as kitty litter.

 

[HISSIN50]

You can pull codes with a jumper wire or paperclip.

 

[earleys94gt]

When my car had a clogged cat, no matter when, it would only rev to about 4,000 and no more; and it wouldn't ship either.

Check the fluid level/condition, and try and find out more about the cat condition.