Is harsh throttle transition common?
#1
Member
Thread Starter
Join Date: Jul 2001
Location: World of Hurt, Va
Posts: 118
Likes: 0
Received 0 Likes
on
0 Posts
Car: 88 IROC
Engine: 305 TPI
Transmission: 700R4
Is harsh throttle transition common?
Whenever I go from on the gas (no matter how lightly) to off the gas, it feels like someone threw out an anchor. Is this common to TPI's, or is it something I should be trying to fix?
------------------
88 IROC with cobbled together (not by me)drivetrain, 86 (?) TPI unit on an '83 305,CE subframe connectors, Edelbrock strut tower brace, polygraphite bushings all around...it handles like a dream, but man is it hard to push!!
------------------
88 IROC with cobbled together (not by me)drivetrain, 86 (?) TPI unit on an '83 305,CE subframe connectors, Edelbrock strut tower brace, polygraphite bushings all around...it handles like a dream, but man is it hard to push!!
#2
Supreme Member
Join Date: Oct 2001
Location: Midwest City, Oklahoma
Posts: 1,712
Likes: 0
Received 0 Likes
on
0 Posts
Car: '87 Z
Engine: 355 in the works
Transmission: 700R4
I'd look into it, my '87 Z28 actually stays up to speed when I let off the gas. My throttle may be sticking though, not sure...
#3
Supreme Member
Join Date: Jan 2001
Location: Brockton, MA, USA
Posts: 1,236
Likes: 0
Received 0 Likes
on
0 Posts
Car: 1983 Z28
Engine: 6.6L 406
Transmission: T-56
That would be because of engine braking. Either OD isn't enaging or you have some tall gears in there.
------------------
I WOULD RATHER PUSH A CAMARO THAN DRIVE AN IMPORT
1983Z28 350w/ edelbrock performer RPM power package , dynomax shorty headers, 700R-4 with shift kit, 750cfm carb, edelbrock 3" exhaust system, 16" IROC rims and ASCD SS hood.
future mods:
completely done over suspension, black paint with flames,
T-56 almost ready to go in, TPI swap coming up
Wifes new car:
95Z28, AT, leather, T-tops bone stock for now.
future mods:
header to tailpipe replacement and a cold air intake. Then I am just going to leave it alone
------------------
I WOULD RATHER PUSH A CAMARO THAN DRIVE AN IMPORT
1983Z28 350w/ edelbrock performer RPM power package , dynomax shorty headers, 700R-4 with shift kit, 750cfm carb, edelbrock 3" exhaust system, 16" IROC rims and ASCD SS hood.
future mods:
completely done over suspension, black paint with flames,
T-56 almost ready to go in, TPI swap coming up
Wifes new car:
95Z28, AT, leather, T-tops bone stock for now.
future mods:
header to tailpipe replacement and a cold air intake. Then I am just going to leave it alone
#4
Supreme Member
sounds like ur Torque convertor isn't unlocking
------------------
- David
88' GTA 5.7L TPI MODS---> air foil, K&N, Shift Kit, 180* therm, TB bypass, Gutted CAT, Flowmaster 80 Series
http://www.geocities.com/david_angel_16
------------------
- David
88' GTA 5.7L TPI MODS---> air foil, K&N, Shift Kit, 180* therm, TB bypass, Gutted CAT, Flowmaster 80 Series
http://www.geocities.com/david_angel_16
#5
Member
Thread Starter
Join Date: Jul 2001
Location: World of Hurt, Va
Posts: 118
Likes: 0
Received 0 Likes
on
0 Posts
Car: 88 IROC
Engine: 305 TPI
Transmission: 700R4
Yep, it is engine braking, but an excessive amount (IMO). Does the torque converter normally unlock when you let off the gas? Or just when you apply the brakes?
------------------
88 IROC with cobbled together (not by me)drivetrain, 86 (?) TPI unit on an '83 305,CE subframe connectors, Edelbrock strut tower brace, polygraphite bushings all around...it handles like a dream, but man is it hard to push!!
------------------
88 IROC with cobbled together (not by me)drivetrain, 86 (?) TPI unit on an '83 305,CE subframe connectors, Edelbrock strut tower brace, polygraphite bushings all around...it handles like a dream, but man is it hard to push!!
#6
Supreme Member
mine stays locked when im at highway speeds, 50+ but i think its something with my ECM. braking is supposed to unlock it, but it doesn't on mine.
------------------
- David
88' GTA 5.7L TPI MODS---> air foil, K&N, Shift Kit, 180* therm, TB bypass, Gutted CAT, Flowmaster 80 Series
http://www.geocities.com/david_angel_16
------------------
- David
88' GTA 5.7L TPI MODS---> air foil, K&N, Shift Kit, 180* therm, TB bypass, Gutted CAT, Flowmaster 80 Series
http://www.geocities.com/david_angel_16
#7
Supreme Member
Join Date: Mar 2000
Location: Orland Park, IL, USA
Posts: 1,468
Likes: 0
Received 0 Likes
on
0 Posts
Car: 88 IROC-Z
Engine: L98
Transmission: TH350
Axle/Gears: 3.45
my car used to do the same thing when id get an SES light for my MAF. On the gas the car would run normal but when u let off it felt weird loike something was draging it down. changed the MAF, havent gotten an SES light since and the problem hasnt happened since either. try and see if you can pull any codes.
Trending Topics
#8
Supreme Member
Join Date: Mar 2001
Location: The State of Hockey
Posts: 2,047
Likes: 0
Received 0 Likes
on
0 Posts
Car: 1987 Trans Am GTA
Engine: Miniram'd 383, 24X LS1 PCM
Transmission: TH700R4, 4200 stall
Axle/Gears: 9", 4.33:1
The TCC solenoid will keep the torque converter locked (if it is already locked) when you let off of the throttle until it hits it's unlock threshold. This figure is stored in the EPROM as the speed in mph when the TCC solenoid should release the TCC. There are actually two different thresholds. The threshold is usually around 16 mph in a stock EPROM for first, second, and third gears. The unlock value for fourth gear, is usually around 35 mph (stock-ish EPROM). Any speeds above those thresholds, in their respective gears, will keep the torque converter locked until it sees a brake signal input or some other event (like WOT, at certain speeds) that triggers the TCC to unlock.
------------------
1987 GTA L98 MD8
355, TFS Heads, LT4 Hot Cam
My GTA
The Minnesota F-body Club
------------------
1987 GTA L98 MD8
355, TFS Heads, LT4 Hot Cam
My GTA
The Minnesota F-body Club
#9
TGO Supporter
Join Date: Jul 1999
Location: The Bone Yard
Posts: 10,907
Likes: 0
Received 3 Likes
on
3 Posts
Car: Death Mobile
Engine: 666 c.i.
Matt's correct about the eprom controlling the locking of the TCC on deceleration. On SD eproms, there is actually a switch for "locked/unlocked TCC on deceleration". I'm not sure if there is a similar switch on all eprom types for MAF cars. The TDFs for the MAF cars by TunerCat (my BIN editor) are not well defined.
#11
Supreme Member
iTrader: (1)
Join Date: Oct 2000
Location: Pasadena, MD
Posts: 1,062
Likes: 0
Received 0 Likes
on
0 Posts
Car: '87 Camaro IROC-Z
Engine: 385 HSR
Transmission: 700R4
Axle/Gears: 3.42 posi
It'll also lock up in 2nd gear, but not in 1st gear. My TCC also stays locked up when coasting/decelerating unless I hit the brakes. Breathment, if your TCC isn't unlocking when you hit the brakes, then you either have a mechanical or a wiring problem. What you can do is press the brakes with your left foot just enough to feel the car slowing down a little, then press the gas down a little (while braking) to see if the engine revs climb. If the TCC is unlocked, they'll climb a few hundred rpm or so, more if you keep on pressing down the gas pedal. If you're on the brakes and gas at the same time and the revs aren't climbing, then you know you have a problem...
------------------
Greg Westphal
'87 IROC 355TPI/A4
------------------
Greg Westphal
'87 IROC 355TPI/A4
#12
Member
Thread Starter
Join Date: Jul 2001
Location: World of Hurt, Va
Posts: 118
Likes: 0
Received 0 Likes
on
0 Posts
Car: 88 IROC
Engine: 305 TPI
Transmission: 700R4
Can anyone confirm 88blkiroc's findings? My MAF sensor is a fair weather friend at best. I just can't lay my mitts on one of those Wells units, and I don't want to drop $200+ on a stocker.
------------------
88 IROC with cobbled together (not by me)drivetrain, 86 (?) TPI unit on an '83 305,CE subframe connectors, Edelbrock strut tower brace, polygraphite bushings all around...it handles like a dream, but man is it hard to push!!
------------------
88 IROC with cobbled together (not by me)drivetrain, 86 (?) TPI unit on an '83 305,CE subframe connectors, Edelbrock strut tower brace, polygraphite bushings all around...it handles like a dream, but man is it hard to push!!
#13
Supreme Member
iTrader: (1)
Join Date: Oct 2000
Location: Pasadena, MD
Posts: 1,062
Likes: 0
Received 0 Likes
on
0 Posts
Car: '87 Camaro IROC-Z
Engine: 385 HSR
Transmission: 700R4
Axle/Gears: 3.42 posi
I'd replace the 2 MAF relays (power and burn-off) first, clear the codes from the computer, then see if the problem comes back. The relays are a lot cheaper than the MAF sensor itself.
------------------
Greg Westphal
'87 IROC 355TPI/A4
------------------
Greg Westphal
'87 IROC 355TPI/A4
#14
Member
Thread Starter
Join Date: Jul 2001
Location: World of Hurt, Va
Posts: 118
Likes: 0
Received 0 Likes
on
0 Posts
Car: 88 IROC
Engine: 305 TPI
Transmission: 700R4
Already did the relays... I had to redo the electrical connections to them, too. There can't be many sensors left I haven't done besides the CSI temp switch (which is bad) and the MAF.
------------------
88 IROC with cobbled together (not by me)drivetrain, 86 (?) TPI unit on an '83 305,CE subframe connectors, Edelbrock strut tower brace, polygraphite bushings all around...it handles like a dream, but man is it hard to push!!
------------------
88 IROC with cobbled together (not by me)drivetrain, 86 (?) TPI unit on an '83 305,CE subframe connectors, Edelbrock strut tower brace, polygraphite bushings all around...it handles like a dream, but man is it hard to push!!
#15
Supreme Member
Join Date: Mar 2000
Location: Orland Park, IL, USA
Posts: 1,468
Likes: 0
Received 0 Likes
on
0 Posts
Car: 88 IROC-Z
Engine: L98
Transmission: TH350
Axle/Gears: 3.45
are you getting any codes? does this happen every time you drive the car or just sometimes? does the car idle rough at stops when the problem is occuring? another problem that i had that you may want to check out is the EGR system. I fixed that at about the same time. mine was a mess but i put a new EGR valve in an reconnected all the vacume lines which were disconnected. the car ran MUCH smoother afterwards and another bonus is that the car runs much much cooler as well. I have not gotten a SES light since i fixed the MAF and EGR. I also tried doing relays but that didnt help. See if you have somebody close to you that has a MAF 3rd gen and if you could possibly borrow their MAF to see if the problem keeps happening. good luck man.
#16
TGO Supporter
Join Date: Jul 1999
Location: The Bone Yard
Posts: 10,907
Likes: 0
Received 3 Likes
on
3 Posts
Car: Death Mobile
Engine: 666 c.i.
<font face="Verdana, Arial" size="2">Originally posted by Bjase:
There can't be many sensors left I haven't done besides the CSI temp switch (which is bad) and the MAF.
</font>
There can't be many sensors left I haven't done besides the CSI temp switch (which is bad) and the MAF.
</font>
#17
Member
Thread Starter
Join Date: Jul 2001
Location: World of Hurt, Va
Posts: 118
Likes: 0
Received 0 Likes
on
0 Posts
Car: 88 IROC
Engine: 305 TPI
Transmission: 700R4
CSI is "cold start injector." It has its own temp sensor next to the CTS.
I haven't monkeyed with the EGR yet, but I sounds like I should. Thanks!!
------------------
88 IROC with cobbled together (not by me)drivetrain, 86 (?) TPI unit on an '83 305,CE subframe connectors, Edelbrock strut tower brace, polygraphite bushings all around...it handles like a dream, but man is it hard to push!!
I haven't monkeyed with the EGR yet, but I sounds like I should. Thanks!!
------------------
88 IROC with cobbled together (not by me)drivetrain, 86 (?) TPI unit on an '83 305,CE subframe connectors, Edelbrock strut tower brace, polygraphite bushings all around...it handles like a dream, but man is it hard to push!!
Thread
Thread Starter
Forum
Replies
Last Post
Pac J
Tech / General Engine
3
05-17-2020 10:44 AM
gixxer92
Engine/Drivetrain/Suspension Parts for Sale
9
05-18-2017 11:20 AM
Fred SS
Engine/Drivetrain/Suspension Parts for Sale
5
10-12-2015 11:27 AM
Damon
Tech / General Engine
8
09-26-2015 04:29 PM