Unresponsive Throttle

[XJoshua]

Alright Specs-
1986 AW11
Naturally Asprirated
5-Speed

Alright I thought I lost my EGR bolt on the exhaust manifold so I stuffed a huge bolt in it to make it sounds normal instead of a Harley. Well when replacing my O2 sensor I found the hollow bolt and replaced it. Now sometimes in 1st and 2nd gear when at 1500 RPMs I can go wide open throttle and it will respond like Im only slightly pushing the gas in.

Really annoying specially in rush hour traffic, because I have to clutch and throttle to WOT several times just to get it to respond.

Help me please. I want to accel fast again.

[ebouwman]

well being a 1.6 litre engine, the 4age isn't really known for it's torque at 1500 rpm...

Check out your t-vis though, make sure all the vacuum hoses are plugged in right, and maybe take the intake off and test to see if it actually works.

Maybe it's time to replace the spark plugs, distributor rotor, and spark plug cables, this can actually make a world of difference.

On my brothers fj40 after switching from rotten points, over to a semi-electronic setup (very similar to the mr2) and doing spark plugs and spark cables, there was a WORLD of difference in terms of power at the bottom end.

Also in it's ability to start!

EDIT: what does WOT mean? I always see that but don't have a clue what it means.

[vipfal]

WOT= wide open throttle

[ebouwman]

Originally Posted by vipfal

WOT= wide open throttle

Oh, that makes so much sense...

Thanks

[XJoshua]

Originally Posted by ebouwman

well being a 1.6 litre engine, the 4age isn't really known for it's torque at 1500 rpm...

Check out your t-vis though, make sure all the vacuum hoses are plugged in right, and maybe take the intake off and test to see if it actually works.

Maybe it's time to replace the spark plugs, distributor rotor, and spark plug cables, this can actually make a world of difference.

On my brothers fj40 after switching from rotten points, over to a semi-electronic setup (very similar to the mr2) and doing spark plugs and spark cables, there was a WORLD of difference in terms of power at the bottom end.

Also in it's ability to start!

EDIT: what does WOT mean? I always see that but don't have a clue what it means.

I have a feeling its EGR releated. Because when I replaced the bolt, it does this. The bogging only happenes once in awhile. Usually at 1500 rpms it has some power. The power I get when this happens, is like the car went from weighing 2300lbs to 8500lbs.

[ebouwman]

Originally Posted by XJoshua

I have a feeling its EGR releated. Because when I replaced the bolt, it does this. The bogging only happenes once in awhile. Usually at 1500 rpms it has some power. The power I get when this happens, is like the car went from weighing 2300lbs to 8500lbs.

I don't know how the whole egr system works, but not much is based on that bolt itself. Do you have a service manual or anything? Because if you do, use it to follow the steps to test it out, and also pull the egr valve apart and clean it out.

As long as it's hollow, and has the hole drilled through to the the exhaust through it should be fine, the egr VALVE on the other hand could be the cause of it.

When was the last time you changed your plugs distributor cap/rotor and all that other fun stuff? Just check pop off the distributor cap and take a look, if it looks terrible replace it, if not, well whatever.

[ebouwman]

oh ya, does it misfire a bit, or run rough when you have the lack of power issues?

[XJoshua]

Doesnt really do anything. Runs fine, except when this one gremlin shows up. No missfiring. I think the EGR valve might just be getting stuck open from time to time. I remember on the Cherokee when you pushed the egr valve in itll die. But mine doesnt seem like itll die, just no power. Feel like I only have 3HP.

[ebouwman]

i kinda just re-read you post, and i realized what you were saying a bit better.

I have had that happen to me, but only at something like -30 degrees Celsius or colder, and went away as soon as the car warmed up. But even in neutral it wouldn't rev over 4000.

I just never thought anything of it though because temperature does all sorts of nasty stuff to the way almost any car works.

The best way to find the problem is to start ripping things off the car and inspecting them. Not big things, but for instance the egr valve you're blaming, or the spark plugs, or anything like that. Have you taken anything off to inspect it yet?

[XJoshua]

Originally Posted by ebouwman

Have you taken anything off to inspect it yet?

That comming this Tuesday after class. Most of my tax returns are going to bringing it back to tip top shape.

I need to check out the TVIS aswell, because when on the highway once I get to 4k it doesnt go further, and read thats a good culprit of not being able to rev to 7K. Couple other things Im going to be replacing are the fuel filter, valve stem seals, and a new exhaust. Im sure the catalyst converter is plugged up and might be another problem, seeing I have to down gear alot just to pass a person on the interstate.

Ill keep everyone posted on this mater.

[ebouwman]

Ya, the t-vis very well could be sticking if you're having that problem, i've seen dyno's where some guy was testing the t-vis, and when he kept it shut through the whole rev range the car lost something like 25 to 35 horsepower at where it's peak should be.

So the power difference is massive.

You're doing the valve stem seals though?

Doing that yourself or having the shop do it?

I had mine done when i was doing my head gasket, i brought the head in to have that and other things done to it.

[Jackstand Queen]

VACUUM LEAK.

[XJoshua]

Originally Posted by ebouwman

You're doing the valve stem seals though?

Doing that yourself or having the shop do it?

Doing it myself. Actually going to be doing three toyota's at once. My MR2, my buddies 90 Corolla SR5, and my other buddies 92 Tercel. Its going to be as 4A Engine Party.

Dont worry, not the first time Ive done valve stem seals. Did it on my 5M-GE, and on my Jeep Cherokee's 4.7L. Also Im the only one in the group with a garage filled with tools.

[ebouwman]

Originally Posted by XJoshua

Doing it myself. Actually going to be doing three toyota's at once. My MR2, my buddies 90 Corolla SR5, and my other buddies 92 Tercel. Its going to be as 4A Engine Party.

Dont worry, not the first time Ive done valve stem seals. Did it on my 5M-GE, and on my Jeep Cherokee's 4.7L. Also Im the only one in the group with a garage filled with tools.

Lol

i probably would have done mine myself (to learn and what not) but the rest of the head was pretty bad, the valves were just nasty, and the seats were bad, so ya, most of the stuff was a little over my head, with valve reconditioning as such

[iceNine]

I've had this sort of problem with a couple of Toyotas. On my MR2 it was the cat. A big piece of the matrix had broken off and was blocking off most of the flow when I got over a certain rpm. At low rpm no difference but at higher there was enough exhaust flow to drive the loose piece into the exit. The tipoff was that my A/F meter was going crazy and the ECU could not get the fuel mixture right. When I replaced the cat I also realized that the backpressure and excessive heat had killed the O2 sensor. On my Camry the lack of power turned out to be an extremely dirty throttle body. A can or two of TB cleaner and a lot of paper towels to clean out the nasty stuff that came out and it was back to normal.

[ebouwman]

^

i just replaced my nasty O2 sensor, and had my header put on, and new 2 inch exhaust built, and between those things, i get WAY more power at the top end and my fuel economy essentially doubled, seriously, the difference is massive.

I also went and cleaned my egr, because i suspected it was sticking a bit or something sometimes, and that stabilized my idle.

I'm kind of amazed at how much difference little maintenance items can make sometimes.

I still need to get my t-vis vsv though, cause i don't have any bottom end power

And i have heard lots of good things about cleaning out bad TBs, thats a good point iceNine