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View Full Version : 81 Toyota Corolla won't go faster than 50 mph



stevedmc
05-22-2014, 09:03 PM
So I am getting ready to sell the Toyota again. The new title showed up today.

The guy who was supposed to buy the car knew it wouldn't drive faster than 50 mph and was cool with it. Unfortunately, as you guys know from my other thread, the deal didn't work out.

So I am going to try to fix the issue before selling it again.

A few nights ago I did a compression test. All four cylinders came back great, 150 pounds on each cylinder (give or take 1 or 2 pounds). Frankly I was shocked to see this.

The next thing I did was inspect the spark plugs. They looked fine but were Bosch spark plugs. I replaced them with the Toyota recommended NGK plugs.

I went for a drive tonight and had the same problem. I'm guessing there is either something wrong with the carburetor or there is vacuum leak somewhere. My plan is to start the car up tomorrow morning, and spray carb cleaner all around the engine bay while the engine is still cold. If the engine revs up I know there is a leak somewhere.

Any other suggestions on what to check? Normally this car has an amazing top speed of about 65 mph.

tom kish vin.4357
05-22-2014, 09:11 PM
Put a KJET on it!!

stevedmc
05-22-2014, 09:13 PM
I want to make it better, not worse.

NightFlyer
05-22-2014, 09:29 PM
Throttle cable/linkages possibly out of adjustment?

Is the trans shifting into all gears?

Hopefully it's not a problem with the rear diff...

stevedmc
05-22-2014, 09:41 PM
Throttle linkage is the first thing I checked. The car is a manual and yeah, it shifts into all gears just fine.

I'm thinking I probably need to replace the fuel filter too. I'm going to spray that engine bay like crazy in the morning to see if it revs up. If it doesn't, I'm headed to Autozone for a new fuel filter.

Boglin
05-22-2014, 09:47 PM
What happens when you hit 50 mph? Does it start choking? Does it have problems revving to redline?

stevedmc
05-22-2014, 09:55 PM
You can feel it start to stutter. I almost wonder if the thing isn't getting fuel. Unfortunately this car doesn't have a tachometer.

NightFlyer
05-22-2014, 10:03 PM
You can feel it start to stutter. I almost wonder if the thing isn't getting fuel. Unfortunately this car doesn't have a tachometer.

That's what I'm thinking - something is restricting fuel flow (or the pump is starting to fail).

If you have a capable multimeter, you could use the tach function on it to determine engine speed.

Best luck! :)

Boglin
05-22-2014, 10:08 PM
I'm wondering if it's also stuttering in 1st gear, but he's shifting without noticing it. I'll place my bet on the ignition coil being bad.

stevedmc
05-22-2014, 10:10 PM
Yeah. I'm not noticing it in the low gears. Are you suggesting just the coil or the ignition module as well?

For what it's worth, I was driving 65 mph a few days ago and in the middle of my drive I suddenly lost power and the car slowed to 50 mph.

Boglin
05-22-2014, 10:17 PM
I've seen this problem on 3 different cars and also a boat, and it's always been the ignition coil. It would be really nice if you had a tachometer to confirm that "it stops revving past 3500", etc. I even had this problem on my EFI car, and it was the coil packs - wouldn't rev past 4100 or so.

NightFlyer
05-22-2014, 10:20 PM
Interesting - I'm liking Matt's idea :)

stevedmc
05-22-2014, 10:21 PM
Crap. A coil is easier to change than a fuel pump. I suppose I could borrow the HEI coil from the delorean to test it out.

stevedmc
05-23-2014, 10:32 AM
I went outside this morning, started the car, and sprayed carb cleaner all over the engine bay. The engine revved up. I found a vacuum line that wasn't connected. I connected it, but unfortunately the car continued to have the same issue. Actually, I think it is even worse today, now the top speed is about 40 mph.

I drove back home and disconnected the fuel filter. I was able to use my air compressor to blow air through it both ways. The fuel filter is not clogged. Just to ensure I didn't have blocked fuel anywhere, I went ahead and blew out the line going to the carb and the line going to the tank. It didn't have any problems pushing air through either line.

I then put the fuel filter back in place and reconnected the fuel line. I hooked up my trusty timing light and verified that I have spark on each cylinder.

While testing for spark, I revved the engine and looked into the fuel bowl. This little carb has a sight glass. The fuel level stayed the same, even when I revved the car up.

I guess it is now time to swap coils with the Delorean. It has one of those fancy HEI coils.

Boglin
05-23-2014, 11:28 AM
Ill accept a peanut butter shake for correctly guessing the problem. :)

stevedmc
05-23-2014, 11:44 AM
I swapped coils with the Delorean about 30 minutes ago and it didn't do the trick. :(

Just for giggles, I also took the low pressure fuel pump from the Delorean and put it on the Toyota. The car continues to have the same problem.

This only leaves a few other things that could be causing the problem.

1. Carburetor (perhaps a clogged jet)
2. Distributor (perhaps cap and rotor are worn)
3. Ignition module

I will inspect the distributor cap and rotor in a few minutes. Hopefully they are corroded really bad.

stevedmc
05-23-2014, 12:05 PM
Well, Steve is running out of ideas. The distributor cap and rotor look great. There is no wear or corrosion. They look so good that I am guessing the previous owner changed them out shortly before the sale.

I also removed the PCV valve and was able to blow air through it, in one direction (away from engine) and it was fine.

My last guesses are either the carburetor, distributor, or ignition module.

Boglin
05-23-2014, 12:06 PM
I swapped coils with the Delorean about 30 minutes ago and it didn't do the trick. :(

Just for giggles, I also took the low pressure fuel pump from the Delorean and put it on the Toyota. The car continues to have the same problem.

This only leaves a few other things that could be causing the problem.

1. Carburetor (perhaps a clogged jet)
2. Distributor (perhaps cap and rotor are worn)
3. Ignition module

I will inspect the distributor cap and rotor in a few minutes. Hopefully they are corroded really bad.

Yeah, if you pull the cap and find chalk dust then you know you've got it.

tom kish vin.4357
05-23-2014, 01:21 PM
i want to make it better, not worse.

see i told you to kjet it!!!!

stevedmc
05-23-2014, 04:40 PM
see i told you to kjet it!!!!

But how do I know if the problem is fuel related or not?

For what its worth, I went ahead and posted the same question on the Toyota forum. It will be interesting to see what those people say.

http://www.toyotanation.com/forum/129-older-generations-1969-1987/801330-1981-corolla-wagon-wont-drive-faster-than-50mph.html#post7190274

stevedmc
05-23-2014, 08:23 PM
I think I have found the problem. Tonight I started the car up and started spraying carb cleaner in the engine bay again. The car never did rev up so I'm pretty sure there aren't any vacuum leaks.

Just for giggles I decided to look under the car. I noticed a bight glow coming from the top of the catalytic converter. That isn't good. So my guess is that I have a clogged catalytic converter that is causing the engine to have trouble breathing.

The catalytic converter appears to be welded in place. I guess this means I will be doing some grinding tomorrow morning.

Boglin
05-23-2014, 08:30 PM
Nice job!

stevedmc
05-23-2014, 08:31 PM
Unfortunately the thing is welded in place. I wonder if I can cut one end off, hammer a pipe inside the cat, and then join the cut end back together with some sort of exhaust coupler.

NightFlyer
05-23-2014, 08:44 PM
Excessive backpressure was going to be my next guess too (even though it always seems like a long shot - after all, it's not very often that Eddie Murphy sticks a banana in your tail pipe).

Time to hollow that sucker out! ;)

stevedmc
05-23-2014, 08:46 PM
https://www.youtube.com/watch?v=6y-pdLyZPJ8

Rich_NYS
05-23-2014, 08:54 PM
https://www.youtube.com/watch?v=6y-pdLyZPJ8


LMAO...holy flashback Friday, Batman!

sedated
05-24-2014, 11:11 AM
Off topic a bit, but this thread reminded me of this: http://usatoday30.usatoday.com/news/nation/2002/05/09/toy-yoda.htm

djdogbone
05-24-2014, 11:54 PM
It could be a flat cam. How many miles? Any oil pump issues?

stevedmc
05-26-2014, 12:16 PM
Car has 181,000 miles. I'm not very experienced with engine work.

I do have good news. I disconnected the exhaust from the manifold and went for a drive. The car has lots of pep. I drove the car up to 65 mph before I decided to slow down.

I'm a happy camper. Now I just need to figure out if I am going to gut the catalytic converters (its a two part system) or replace the section with stainless flex tubing. Choices choices.

Its hot out there right now. At the moment I am just rejoicing that I wasn't stupid enough to sell the car for $900.

NightFlyer
05-26-2014, 04:25 PM
SWEET!

Not sure about inspections/emissions where you're at (we don't have any of that nonsense in MI), but if you do, then hollowing them out will give the car a greater resale value, or at least make it an easier sale by appealing to a wider customer base.

Nice job figuring it out :)

stevedmc
06-07-2014, 10:20 AM
Below is a copy of the message I just posted on the Toyota forum.

Last week was pretty busy so I didn't get much of a chance to work on the car. Today I finally made some progress.

I got tired of messing with stuck bolts so I cut the exhaust our of the car. I cut it into sections and attempted to gut both catalytic converters.

I was able to gut the first catalytic converter. The second one I did not have any success with. It has some sort of metal assembly in it.

I reinstalled the first (smaller) catalytic converter on the exhaust manifold.

Currently the plan is to completely eliminate the second catalytic converter and replace the section with universal exhaust tubing from AutoZone. I plan to clamp everything together.

My only concern is this. There is some sort of oxygen sensor that is supposed to go into the second cat. By removing this cat, I have nowhere to install this oxygen sensor. My car is carbureted so the purpose of this sensor confuses me.

Does it do something like adjust the choke plate? Is there some way I can bypass it?

Thanks guys.
21382139214021412142

Greasy DeLorean Mechanic
06-07-2014, 12:25 PM
O2 sensors in my '85 Trucks only drove the air injection system (smog pump). Don't know if your Toyota may be similar.

Do be advised: there are electronic controlled carbs, such as late model Quadrajets. Even the venerable 2100 received a electric valve in its later years (used to think it was part of an idle system, but after getting my hands on one it appears only to control a variable air bleed). See if your carb is electronic feedback only, such as TPS, or if it actually responds to an onboard ECU.

Autozone flex tubing is fine for a car you plan to sell, but don't use it on a keeper -- it'll rust out in a couple of years. Stainless flex tubing from McMaster is only more expensive one time for life.

Also, if you gut a converter on a keeper, I recommend running regular tubing through the middle, leaving the old converter housing as a decorative shell. Hollow cats make a funny resonate sound.

Bill Robertson
#5939

stevedmc
06-18-2014, 07:23 PM
The exhaust job is officially complete. I've been real busy lately and haven't had much time to mess with it. Clamping the pipes back together was a bit difficult so I decided to drive the noisy thing to a place that does welding.

I'm not allowed to say who did the work but they welded me a nice pipe from the front catalytic converter (gutted) to the muffler in the back. The rear catalytic converter is no longer part of the exhaust system.

The car runs perfect now and isn't noisy either. It cost me $100 and I am a happy camper.

Boo
06-18-2014, 07:28 PM
Does it go over 50 now?

stevedmc
06-18-2014, 07:47 PM
Yep. I didn't do much speeding with it but I did take it up to 60 mph on a state highway. I had to slow down because there was a car in front of me. I have a feeling this car could get past 70 mph but 65 is the fastest I want to go in this car.

When I got home from work I changed O rings at the back of the compressor and pulled vacuum. Its been sitting for about two hours now and so far the pressure seems to be the same.

I also replaced the bad fuel sending unit about an hour ago. I'm currently debating whether or not to let the car sit overnight or to dump a couple cans of r134a in it and go for a drive.

Boo
06-18-2014, 08:08 PM
Nice! Congrats man!

NightFlyer
06-18-2014, 08:31 PM
Sweet - glad that problem is solved! :)

Are you still aiming to sell this one?

stevedmc
06-18-2014, 09:50 PM
Yeah. Its a fun little car but I need to sell it.

NightFlyer
06-19-2014, 01:24 AM
Who closed this thread and why?

stevedmc
06-19-2014, 06:34 AM
Wasn't me. Whoever closed this thread should have their admin rights revoked.

stevedmc
06-19-2014, 08:16 PM
I went for a drive in the 81 Toyota this afternoon. I had 40 degree vent temps (on low setting) with r134a. Life is good.

NightFlyer
06-19-2014, 08:22 PM
Yeah, yeah - rub it in.

I'll be re-doing my R-152a charge within the next week or two - this time I'll be certain not to introduce any air into the system during charging...

stevedmc
06-19-2014, 08:28 PM
My tires are about 20 years newer too.

Dead Lesbian Goat
06-19-2014, 08:32 PM
Yeah, yeah - rub it in.
I'll be re-doing my R-152a charge within the next week or two - this time I'll be certain not to introduce any air into the system during charging...

I think I know why Josh is hung up on using 152. He wants to walk on sunshine!
http://youtu.be/3g99h4qaCio

stevedmc
06-19-2014, 08:38 PM
I'm not a proponent of alcohol but in this case I think she needs to put down the air duster and pick up a six pack.

NightFlyer
06-19-2014, 08:44 PM
I think I know why Josh is hung up on using 152. He wants to walk on sunshine!
http://youtu.be/3g99h4qaCio

Well of course! Why do you think I was unable to get it charged right the first time - cause I was walkin on sunshine, baby!

In all seriousness, the use of R-152a to get high is quite disturbing, and because of such assholes, it now contains a bitterant, which may very well slightly lower the efficiency of the product when used as a refrigerant...

sedated
06-19-2014, 09:24 PM
Reopened thread. I assume someone just got click happy and accidentally closed it or something.

NightFlyer
06-19-2014, 09:32 PM
Reopened thread. I assume someone just got click happy and accidentally closed it or something.

I spent a half hour trying to figure out how to do that earlier and still couldn't figure it out - good thing we have smart computer savvy young people like yourself around here, otherwise we'd have to constantly lean on good ole Tom Kish to help us out :)

sedated
06-19-2014, 10:46 PM
I spent a half hour trying to figure out how to do that earlier and still couldn't figure it out - good thing we have smart computer savvy young people like yourself around here, otherwise we'd have to constantly lean on good ole Tom Kish to help us out :)

I've been a network engineer for my entire teenage/adult life so it's always been my thing. FYI at the top of the thread you'll see Administrative with a drop down. That will allow you to close or reopen a thread. I assume someone accidentally checked the box under the quick reply form though.