RedneckBatmobile

iTrader: (2)

Well I finally got my hands on an 86 4runner back in June and have since done tons and tons of work on it to get it road worthy enough to consistantly make +200 round trips every couple of weeks. I didnt really drive it for 2 months or so while i was doing work on it (its from MA, it needed alot of love. Anyways, when i drove it for the first time it seemed good, but after that i started to notice that the acceleration seemed to decrease and be very poor. I have trouble getting up hills in 3rd gear, and it will decelerate pretty bad on hills on the highway. To go anywhere i really have to floor it and i feel like the last 3/4 of the pedal dont do anything. I've tried to figure out whats wrong but havent been able to figure it out. I'll briefly list the big work i've done recently since June that i can remember:

(all[*]stars were replaced using my 87 parts truck, everything else is OEM or as close as i could get)

-new plugs
-new distributor*
-new alternator
-new O2 sensor
-new brake master
-new clutch master
-all new brake lines
-new radiator*
-new rear end (axle, drums)*
-lift springs in the rear*
-brakes, pads, shoes all the way around
-thermostat
-tires (purchased used with 500 miles on them; 31"x10.5x15 Cooper Discoverer S/T on stock alloy rims)



Things that I have tried:

-timing ajustment

--> the timing was way off when i got the truck (upwards of the 30 range) and i moved it back to the factory setting of 5 which brought me to about a 780-800rpm range but even worse acceleration so i moved it to about 12.

-new distributor*

--> the old distributor contact was worn and wobbly so i figured i would replace it while i was motivated

-new air filter
-new gas lines
-new plugs
-new O2 sensor

Some specs on the truck:

-1986 4Runner SR5 5Speed
-161,000 miles on a factory 22RE Engine
-All stock except a 2"/3" suspension lift and 31" Cooper S/T's on stock rear 3rd member with 4.11
-Compression test was 165+/- 5 on all 4 cylinders
-mpg is about 17.5 and 20 if im really good on the highway

Things im thinking:

fuel filter
injectors
catalytic converter
throttle positioning sensor
subtley blown headgasket?
AFM?
ECU?
clutch?


Am i expecting too much out of a 25 year old runner or am i just crazy? Any help would be amazing!

Nick

dannyreckless

I am in the same boat with my 92 22re 200k miles.

Terrys87

iTrader: (1)

Sounds like you are on the right path. I would change the fuel filter, it gets forgotten alot and have seem similar problems. I really dont know how to check the converter.

I might would try some Sea foam and make sure all of your EGR is cleaned out. Check to see if carbon hasnt built up in the Plenum area and hoses. Check all other hoses and connections for a good fit and seal.

These would all be cheap and easy fixes and most likely need done anyways. If that doesnt help, maybe one of the gurus on here could help you further along.

pruney81

Try adjusting the valves maybe. I did mine at .007", .011" cold.

Levinz11

Loss of power under acceleration/hills is often a cat.

khany2002

Check your AFM for wear. Was a HUGE problem for me (44% increase in fuel economy), and resolved driveability hesitation.

http://www.efinnegan.com/Porsche/Mis...FMRebuild.html

Note: Don't mess with the spring adjustment to throw more fuel at the engine unless modified, you'll do more harm than good.

Regards,
Khany2002.

Mandy Tuning

first thing to check is ignition timing,to check the Cat do a backpressure test,its a pressure gauge that goes in the o2 sensor hole.

RedneckBatmobile

iTrader: (2)

First of all thanks SO much for all the ideas everyone had provided me with so far. I havent had much time considering I just started school again last week, but I've been doing little things here and there.

I bought a can of sea foam like reccommended and tried it out utilizing the large vaccum hose that runs from a port on the right side of the injectors to the front where it ties into the tube that goes to the AFM. I followed the directions on the can and it smoked like crazy out of my tailpipe for a long time which I was excited about. But after i waited a while I drove it again and i didnt notice a change in power.

Still havent had a chance to change the fuel filter but hopefully tomorrow or monday. Plan on testing the AFM and the TPS tomorrow as well.

i dont know how to check the cat really other than to pull it and run the truck without the cat in it. I understand the whole testing the pressure at the O2 sensor port, but wouldnt that require pulling the O2 sensor and altering the running condition of the truck?

Acceleration is getting worse on the highway too, or atleast thats what i think. I did get a chance to readjust the timing (or at least by RPM's cause my timing light is at school). Dropped it down to 800rpms which is close to 750 which is the specified rpms. Thanks for all the help!!!!!

myyota

When you replaced the 02 sensor did you buy an OEM Denso replacement ?, if you bought a Bosch 02 sensor they don`t work well in toyota engines. When you adjusted the timing did you jumper the two terminals to properly set the timing ?. Do you know if the timing chain has ever been replaced ?. Remove the throttle body and give it a good cleaning and also replace the fuel filter.

Im just throwing out ideas and things to check.

RedneckBatmobile

iTrader: (2)

i got around to replacing the fuel filter the other day and i started her up and drove a while and no change, if anything its worse now, but at least i can cross that off the list i guess

and in terms of the O2 sensor i did replace it with a Denso one. Luckily i caught sight of an old post from myyota that warned of using the OEM sensors only. Im really leaning towards a clogged cat but i really dont have the means at school to test this other than taking it out completely, which would be a pain considering its the original cat i think and very rusty. If i go that route it will end up being a one way street and i'll need to get a new one.

If it makes any difference it drove fine the other day for 200 miles+ (besides it lacking acceleration) but i lost response of the Oil Pressure Guage so i dont know how that happened. I also ran it with the TPS unplugged and it didnt help, does that mean the TPS is good?

Also, one more question thats a bit off topic but i recently had been having some issues with the temp guage going all the way up then going down to normal so i assumed a sticking thermostat. I replaced it with an OEM 195 degree new one and it was fine, but now it seems to be sticking again. The radiator is in pretty bad shape, but i would think that doesnt have much to do with it. Any help on that would be great too, but the acceleration problem is priority.

Guerilla Pirate

Like someone said above, if the cat is clogged that would do it. The engine has to get air out of it in order to suck more in, and the cat could be keeping it from doing that.

Guerilla Pirate

Plus there's two O2 sensors fyi - one on the exhaust manifold and one behind the cat. This works with the ECU to control how much fuel you're pumping through the EFI, as well as how much exhaust is being recirculated through the engine. The engine light is also a function of the second O2 sensor, since it is after the cat, and if you're pumping out too little O2 through the cat (meaning too much emissions meaning the cat is clogged).

As for the cooling system, get some radiator flush. Check your fan clutch too.

Zelephant

For my own info, how does one unclog a cat without removing the catalyst in the process?

Guerilla Pirate

you can buy a chemical to add to your gas that can help clean it out

hypertek

what about fuel pump sock? I had a clogged fuel pump sock on my rx7 , would hesitate on hard acceleration and corning until i changed that.. I bet if its original fuel pump than that could be something to look at.

CRogers556

I feel your pain! I took my 1994 SR5 V6 up and over the Rocky Mountains last week for a hunting trip. This was the first long trip (750 miles there and back) that I've taken in this truck. By the time I got home I was so pissed...I would have sold it for a nickle. Now that I'm back home it runs fine. The acceleration has always sucked but HOLY ˟˟˟˟, it really sucks ass going up and over the passes. Going up the long and steep passes it would slow down to 20 mph with the gas pedal smashed to the floor. It would then overheat to the point of the coolant in the overflow tank boiling. It was worst on the way back. We had to pull over 3 times going up Vail pass to let the mother f'er cool down so we could continue on up the mountain. I love my Yota but damn...I'm ready to sell it for an older Jeep Cherokee with the 4.0 strait 6. From what I've read over the past months the 2nd gen 4Runners with the V6 have no balls what so ever unless you're crawling over a rock in low 4WD. Unfortunately I need it to get over the mountains on the highway in high 2WD in order to get to the rock to crawl over. I don't know what I'm gonna do. I'm looking at going with a different SUV. My Yota just didn't do what I needed it to do. And...NO...I won't sell it to you for a nickle!

Zelephant

What chemical is this you speak of?

ChefYota4x4

iTrader: (5)

From all the questions I've asked Putney's, Ted and Tod, etc., etc..... it's usually done with some Citrus Chemical(the CAT has to be removed and placed in this solution) that you buy at Janitorial Supply Stores... NO IDEA if it's for sure, and neither of the above mentioned dudes had done it before.... But I guess it's a "DIY" type thing. I had it bookmarked, but that computer EXPLODED! lol. If I come across it, I'll share, k? lol. NOTHING I'VE EVER heard about Chemicals in the Gas tank, but I'm interested as well. I would HIGHLY recommend removing the 02 while you run this "chemical" through the system.... And then hope it doesn't cause any damage to the top or bottom end? lol.

Guerilla Pirate

Cataclean, or something like it - there's mixed reviews out there about those types of products, nothing is going to be permanent, it is more geared at reducing carbon build up than anything else. The catalyst get used up eventually, kind of like a Brita water filter.

Junkers88

Couldn't he just remove the cat and install a straight piece of pipe and then run it for a few days to see if it gets any better? That might rule out the cat as an issue.