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85 automatic shifting into gears too fast

S

step

Guest
This site is great for info! I have been reading it for a few weeks now and love it. So, here's my first post:

I have had my 85 for about 13 years and it has always shifted into each gear to quick (unless I am nailing it.) If I drive normal it shifts from 1st to 2nd too soon and bogs down unless I give it a little more gas. And when it shifts from 2nd to 3rd it is even worse! When it shifts to 3rd, the RPM goes down to about 800 and really bogs down. It sounds just like when someone shifts a stick into gear way to early. Is there any way to change when it shifts into each gear? I would love to have 1st and 2nd gear shift at about 1800 or just shift when it can go into the next gear and not be below 1100 or so.

Anyone else have this problem or have a solution?

Another problem I have always had is, when my car is warmed up, and I am stopped and it is idling at 500-550, if I hit the gas and then immediately let the gas off, it will stall. It drops down to about 400 and then stalls. It does this every time I am getting on a freeway if the onramp has a stop light that lets cars go one at a time. Or if I am at a fast food drive-through and moving forward 1 car at a time. You know what I mean... Is there some way to adjust the idle to say 600-650 so when it drops down it doesn't hit 400 and stall? Or better yet, is there a way to fix this and leave it at 500-550 idle?

Thanks a lot to all you smart people out there who give so much help to everyone!

Bryan
 

vigman

Motor head!!!!
Joined
Feb 13, 2001
Messages
3,471
Location
Valencia, CA,USA
Corvette
88 Convert ( SOLD ) /1973 coupe 4 speed/1964 Vert!
Trans & Idle

Welcome to the CAC

Corvette
Addicts
Center

Ok..
How many miles on the tranny and how clean is the fluid? you might want to do a service on it first, drop the pan..change the filter observe the junk in the tranny pan etc.

WHATEVER YOU DO DO NOT GET A FLUSH!

The TV( throttle valve ) cable which contols the internal pressures of the tranny controls how HARD the shift is.. which MIGHT control your perception of the shift points. The tighter the cable, the harder the shifts.

WARNING,,If the TV cable is adjusted to loose your internal pressures will be off allowing clutch slipage so proceed with this knowledge.

Mark where the cable is currently ( scribe the plastic shell with a SHARP awl) .Next to the base of the TV cable bracket is the adjuster
mechanism with a half moon piece of metal facing out..press that in and push the cable nose in a couple of clicks. Did it change things?

Idle
Do you have a service engine soon light on?

If not you can try the IAC trick.

DO NOT RUSH THIS JOB
Go to the parts store.. buy the 2 hoses that go up & back from the throttle body & and a throttle body gasket kit.

Disconnect battery..this will reset the ECM.

CAREFULLY remove the wiring to the throttle position sensor( 3 pin connector) & the Idle Air control motor( 4 pin connector )

Remove the coolant hoses on the throttle body.

Remove the MAF sensor ( the thing on the black tube going to the air cleaner)

Remove the Accelerator cable.

Remove the the TV cable.

Remove the cruise control cable.


Remove the 4 10 mm bolts attaching the throttle body to the plenum.

Put the Throttle body in a vice ( with some wood to protect it)

Remove the IAC valve ( the motor looking thingy with the 4 pin connector)

The nose of the IAC has a thing refered to as a PINTLE. This pushes in or pulls out to control the air flow for idle & is controlled by the ECM.

Do not try to move the IAC shaft.. it should have about a 32nd of end play, and do not loose or break the round gasket for the IAC.

DANGER If you use Carb cleaner DO NOT LET IT RUN DOWN THE SHAFT OF THE IAC SOLONOID IT WILL RUIN THE DEVICE.

Spray carb cleaner on a rag or a small brush, and work the skank off the pintle holding it pintle down, clean it as best you can.

Now take the throttle body and clean the IAC port where the pintle would seat into the casting.

Clean out all the other ports, holes, butterfly plates etc..WITHOUT GETTING CARB CLEANER ON THE THROTTLE POSITION SENSOR.

Take some sand paper & remove any rust/pitting on the water intake & output tubes.

Put it back together.

Try to start.. the second it fires shut it off, this will force the IAC motor to relearn it's position.

The car should idle hi and work it's way back down.. let it do it's relearn procedure.. It might not be perfect yet.. drive the car around ( over 40 mph ) this will force the IAC to be shut off( closed ).

If it's still not right as far as idle goes then the IAC is KAPUT... electrically it might be fine but the shaft might be gooked or the surrounding case might be melted internally.

Electrically if the coils are OK it will not throw an error code.

DO NOT BUY AN AFTER MARKET IAC... get a GM...

Ta DA

Mike
 
C

c4ever

Guest
I found this to be a common complaint for the 85. Mine also shifts quickly at slow speeds. The manual even suggests not driving in O/D when in slow traffic, hilly roads etc. I did find marked improvement when I installed the Stage II chip and stat. I must say even without the chip the gear changes were never really a concern to me.
As far as stall, when I had this occur a good tune-up was in order . Wires,plugs, timing check etc. Never had the problem again.
Good Luck:cool
 
D

Drewser

Guest
chips & Dip

I found that with the old chip my shift points were not what I wanted but with the thermomaster (stage 2) it did what I wanted. In fact, the main difference in changeing the chip WAS the shift points.
--Drew:w
 

vigman

Motor head!!!!
Joined
Feb 13, 2001
Messages
3,471
Location
Valencia, CA,USA
Corvette
88 Convert ( SOLD ) /1973 coupe 4 speed/1964 Vert!
Ok really confused here!!!!!

How does the Chip in the ECM control a 700R4?

It was my understanding the the TV valves and other internal valving controled the shift points.

As far as I know the ECM controls the TCC lockup & the OD shift..That's it.


Or am I in LA-LA land ( ok I do live in CA..no jokes puleeeeze!)

Mike
 
C

c4ever

Guest
Mike,
I hear ya and I don't know why but shift points at slow speed have changed on the 85, not drastically, but enough, and it makes a difference. Go Figure.:confused
Then again, I'm always confused:eyerole
 
D

Drewser

Guest
Chip Chirps

I don't know why either but I think it may have something to do with the tps. At different throttle positions the trany shifts at different points. Smoother with the chip in it, and it really winds it out at WOT! I get some good chirps too.:D
--Drew:w
 

vigman

Motor head!!!!
Joined
Feb 13, 2001
Messages
3,471
Location
Valencia, CA,USA
Corvette
88 Convert ( SOLD ) /1973 coupe 4 speed/1964 Vert!
Stimpy..my brain is HURTING

The TPS is for FUEL management.....

Arrgh.. I don't get it

The chip should have nothing to do with the tranny in a 700r4

Mike
 
M

mb6970

Guest
Hate to add to your confusion Vigman, but I put the same chip in my 84 and the shift points did change.... for the better. I noticed no other advantages from installing the chip (hp/torque) but left it in because the shift points were "a little better" plus I didn't want all the blood rushing to my head again to get the chip back out!!

Mike
 
D

Drewser

Guest
That's my story and I'm stickin to it

My points changed and very little else. Here's something that will really tweak yer mellon. My exhaust note changed too. It doesn't resonate as much when boggin down in 4th gear. I like the way it sounds now better than with that other chip. I really like the way it winds all the way out at WOT and I blew a Jaguar away today and even got rubber a few times.:D Vig, I think you have issues with that headache and all. Maybe we need to ask Dr. C4C5. :L
--Drew:w
 
D

Drewser

Guest
By the way...

I didn't seem to have nearly the problems changeing my chip and getting the ECM in and out as some other people here. I didn't have to get on my back or do any strange contortions, just stick my arm under the passenger side and pull the bolts and wireing harness. No big deal, but then I pull door panels for a living. Just try to get the lock out and back in a Fiero. Now THAT is a pain in the arse!
 

vigman

Motor head!!!!
Joined
Feb 13, 2001
Messages
3,471
Location
Valencia, CA,USA
Corvette
88 Convert ( SOLD ) /1973 coupe 4 speed/1964 Vert!
I now understand

Those chips access the torque converter lock up.. and modify the lock up times so it appears
( and does in real life ) to modify the shift points in the tranny... not quite true.

But if you dont lock the converter.. the converter acts similar to a gear when the fluid is up to full pressure.

Quote
Jerkiness is caused when the torque converter lock up clutch ( which is controled by the chip)
is engaged at low speeds. A power chip DELAYS the lock up until High gear( where torque multipilication is much lower than in 2nd or 3rd gear. All of the jerkyness is elimated.If you notice "lock up"at all it will seem like a smooth shift into another gear.

Many people buy POWER CHIP for this feature alone.

end quote

Ahhhhhhhh weed hopper you now understand?

Yes oh blind one

Mike
 
M

mb6970

Guest
Vigman,

For some reason I knew you were going to investigate this and lay out the facts for us "wannabe motorheads" Thanks for the info. :upthumbs

Mike
 

vigman

Motor head!!!!
Joined
Feb 13, 2001
Messages
3,471
Location
Valencia, CA,USA
Corvette
88 Convert ( SOLD ) /1973 coupe 4 speed/1964 Vert!
Smarts Quest

The more information you have the better decisions you can make.

So

The cheaper things get ( so ya don't get ripped off).

To wit

I can afford my addiction.

Mike
 
D

Drewser

Guest
vigman said:
I can afford my addiction
I can afford this one. :) I want a ZR1 so we shall see if I can afford that one too.

Does your head still hurt Ren?
 

vigman

Motor head!!!!
Joined
Feb 13, 2001
Messages
3,471
Location
Valencia, CA,USA
Corvette
88 Convert ( SOLD ) /1973 coupe 4 speed/1964 Vert!
Stimpy

No...I'm fine ....really
You EEEEiiiiiiiiiidddddooottttttt!


Ren
 

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