Really SLOW acceleration under D
 

I just bought a 1988 Supra Turbo for my 16 year old son.

The car seems to have one mechanical(?) problem: it accelerates normal under R, L, 2, but creeps (really creeks) under D

Motor sounds fine during idle. There is no overheating or apparent head gasket problem.

I'm having the same problem with my 1990 N/A Supra. Feels like I'm giving it tons of gas but it's just not moving. Granted it's not a turbo, but still...

I took it in to have the timing belt checked out and they said it was fine. Next step is just having the catalytic converter looked at, it sounds groggly... So it it's jammed up inside then I'm just going with a all new exhaust (straight pipe).

Anyone have any ideas what else it would be? HG is fine and all pumps are in working condition, no leaks, all hoses replaced.

Either take it to a shop and have the EXHAUST back pressure tested, or unbolt the exhaust pipe from the manifold and drive it to see if it improves. A plugged exhaust can give a NO power situation.

Sounds more like a transmission problem than engine, especially if it runs fine in the other gears.

Russ

Really SLOW acceleration under D
 

I thought about tranny, but I can't understand why it would work normal in L and 2, and not in D.

Isn't L and 2 the same physical 1st and 2nd gears under D?

Well your selector may be out of adjustment and for some reason not starting out in 1st gear when put in D. Or it might be an internal problem. But if it runs pretty good in the other two gears then I would count out the engine as being a problem.


Russ

When you drive the car in 1st or 2nd, if you can rev up to 5k rpm for a few seconds, then the exhaust is not likely clogged. Also, if it does this smoothly, without misfires and stumbles, then the ignition and fuel system are likely ok.

So...if it seems sluggish in D (drive), then likely the transmission is starting out in 2nd or 3rd.

That would be likely be either a ETC (electronic Transmission Control) computer, or shift solenoid problem. It can be diagnosed by a reputable tranny repair shop. There is a very good chance that it can be repair without a complete overhaul.

The problem for you also is....finding a shop/technician that KNOWS how to diagnose. Most just want to rebuild, figuring that it will get fixed along the way.

The same is true with engine electronic problems. Finding a KNOWLEDGABLE tech can be frustrating, and costly.

i know in Hondas some of the Shift soleniods in the auto trannys will go bad and make the trans skip gears and do weird stuff.

take it back and buy a 5 speed

Taking it back isn't the answer, I like having an automatic. For my car, the acceleration isn't abysmal, just a little slow. I'm going to get a new exhaust and we'll see if that fixed it. If not, then I'll have to look deeper in the transmission.

I was just curious about something. If the car accelerates normally in R, 1 and 2 but not in D, what happens if you start the car off in D and it starts its creeping, then you pull the shifter back to 1, does it accelerate normally, quickly again? And if you put it in 2, does it shift twice or just start in 2nd and stay there?



Russ

heh ... here's a good question ... is the MANUAL button pressed ? MANU will glow on the dash. cos if that's pressed it'll select exactly the gear you tell it to instead of climbing through them ... ?

Really SLOW acceleration under D
 

I appreciate all the response.

Will try the various things tomorrow afternoon and provide feedback

^^^^Supras don't work like that. The only button option is OD on/off.

Really slow acceleration under D
 

1. The car revs past 5K, smoothly, without any misfire or backfire. Does not seem like exhaust is blocked, or ignition or fuel problem. In fact it tears away (for an automatic) in reverse.

2. If I start in L and accelerate then shift to D the acceleration drops immediately.

3. In 2 it just stays there, does not double shift.

I guess I will have to take it to a tranny shop and keep my fingers crossed that they know about this car. Most likely I would have to change tranny, in which case I may consider swapping to manual, which I am sure my son would love.

Anyone has a manual tranny, or the necessary accessories for the switch, for sale? I live in the NY capital (Albany) region.

Thanks again for your response and help

shift solenoids may not be the problem. it sounds to me like the manual valve is sticking or the 1-2 or 2-3 shift valve in the valve body. it could also be a stuck checkball to where you are not getting fluid flow to those valves for that shift.

now you say you have 1st and 2nd manual but not 3rd or overdrive. it could be an over running clutch or an actual clutch pack itself. how did the tranny fluid look and smell? if it is dark brown and smells burnt then the clutch packs could be going out.

can you rev it high in D but not get any movement? if so then the clutches are going bad or an actual over running clutch and bearing is going bad. then you would need a rebuild.

if it is the manual valve, try and adjust the manual linkage from the shifter to the tranny and see if you get more movement out of it.

try flushing the tranny first and go from there.

I have a 89 Turbo Auto. i had the same problem is feels like the car is starting of in maybe 3rd gear replace the shift solenoids and fix the problem. i do not remeber exactly which ones was bad. But the solenoid cost me about 115 dollars at the dealer. They use a on off pattern to shift so if they both go bad then it is a fail safe to stay in 3rd gear. It almost felt like you have the e brake on or something its so bad. also you pull it down in first gear manually it dpes better but still didnt seem to have the power it should have./

did the solenoids fix the problem or is it still acting up?

i have same problem with my 1998 camry LE. in D drive its pick up is too slow and its like jurk too me,

if anyone know how to take care of that at home bymyself then plz lat me know about it........i like to done wiht this problem as soon as i can.

I know with GM transmissions a clogged torque converter and/or filter can cause things like that. My monte carlo would stick in first and 2nd gear at the same time when it got hot, (which means the wheels lock violently) cause the TC was clogged up. That usually happens from forgetting filter/fluid changes. It also made the car start in 2nd gear or not shift into 3rd sometimesk,and made the shifts really mushy. And OD never worked anyway. I changed the TC and filter and rebuilt the valve body anyway and it shifted like a manual power shifting, chirped 2nd and all. I have no idea if this applies to toyota trannies, but im sure there operation is somewhat the same.