jblake00

Hello everyone, I apoligize in advance for such a long post, but I am needing some help on this one. I just recently bought an 89 4runner V6 with 228k miles and had the head gasket give up on me a week after purchase. My father in law and I ended up tearing it all down and replacing all of the gaskets from a napa h/g kit. We were able to get it put back together and running, but it isn't running as strong as before, and it idles and accelerates rough. It doesn't have the power to make it up hills in anything higher then third gear. Oddly enough when I am in first and second gear the 4runner roars to life at 3k rpms. Below that and you can feel the engine strugling. Other things I have noticed is at cold start the engine won't idle at 1200 and then drop down to the normal 800 once warm. It will just start at 800 and stay. Things we have checked are; TPS, timing, timing belt, vacum lines, plugs, wires, and o2 sensor and everything seems to check out okay. Don't really know what else to check. Oh yes, and I have been throwing the codes 25, 26. (too Lean, too rich). I have been reading through the forum a lot over the last month, but I think I might need a little more help then what I am finding. I can post pictures and video of the engine running if that would help at all. I have already learned a lot about the 4runner from this site, and I don't doubt someone can't help me out here, so thanks in advance.

91ToySR5

check to make sure all your grounds are secure. the first thing listed in the FSM for both those codes are "engine ground bolt loose" hope that helps and keep us posted

jblake00

Is it the ground on the block that needs to be checked, or should I look for all of them such as head, intake manifold, and others? One thing I found when double checking my vacum lines was that I have neither of my BVSV lines hooked up. When I tried to reattach them (from the charcoal canister and TB) I found the two connections to be broken off. I have two question on this. One what is the BVSV, and two could I posibly just attach both ends of the vacum lines without using the BVSV? I doubt it would work very well if at all, but like I said I don't know what it is for. ^^ Thanks for the advice on the grounds, I will check them soon and keep yall updated.

neilan

i had a similar probelm wit hfuel injectors. Mine were clogged and one leaked. Your vodes point to this in the fact thta the fuel injectors coudl be partially clogged and cause the engien to run lean. Throwign the code. Then the computre dumps more fuel trying to get ti up to spec then it goes to rich and will ocnstantly teater like this. I had the same idle problem and accleration/ power was horrible til lhgih rpms.

seanathan

hey i had the same thing i had to buy a new tps and that for the most part fixed it i still need to get it professionaly tuned but for the most part that wat the main prob

jblake00

I can't se it being my TPS because I ran through the resistence checks and it was within specs. Could it still give good readings and not work properly?

jblake00

I was really leaning in this direction once before and gave my injectors a visual check along with trying to turn each one while seated. My #1 injector did have gas built up around the base of it, but it was all contained within the black seating in the minifold. I replaced all 5 of the O-Rings and gromets with new OEM ones and the leak went away for about 2-3 days. It does seem to be back now however.
I was having trouble finding the connection to pull power from the sending unit to depressureize the fuel lines, so I just gently covered the area with an old tshirt to catch any spray from the banjo bolts on the fuel rail. Strangly enough all it did was leak out with as much pressure as a cold coolant line... Would that be a sign of low pressure in the fuel lines?

keithguts

Fuel Injectors AND OR INJECTOR . I would tend to belive that this is your problem.

Yotapup

Try adjusting the TPS. Resistance readings will tell if TPS is good, but you still have to check resistance while adjusting.There are several posts on adjusting TPS. If it was removed or you possibly bumped it then it will need adjusting.

Yotapup

Did you remove the TPS ? Or maybe bumped it during procedures? If so you will have to adjust the TPS.

jblake00

I never removed the TPS from the TB, but it could have been bumbed. I did try taking readings while the throttle was pushed down at increasing intervals to see if the resistance went up, and it did. Was I wrong in checking like that? I thought the purpose of the check was just to make sure the resistence increases as the throttle was opened farther and farther. Is this not right?

motoriderbc

Check your valve timing again, sounds like its off. Idle engine vacuum reading would be helpful as well.

jblake00

Just a little update, I ended up replacing the BVSV valve back behind the intake plenum, which really helped smooth out the engine. I also went ahead and pulled outmy injectors and sent them to Witch Hunter for a cleaning. Once everything arrived I threw everything back together. My CEL was out and the truck run much better, but still under powered below 2700 rpms. And now about 30 miles later, the same two codes have come back up.... It's getting a little old now. Anyways I haven't looked at the TPS in a while because I was so sure the injectors being clogged/dirty was my problem. Any other ideas?

em3e3

I've heard where a problem with the knock sensor would kill the power. Did you replace the pigtail to the knock sensor when the HG was done?

jblake00

It looked fairly new when I was in there. Is there a resistence check I can use to check it?

CEbeling

Check for vacuum leaks. Make sure you check the EGR valve. Hesitation from 2,000 to 3,000 RPM was disappeared when I did the resistor trick.

Ebin

My bet it is a vacuum leak.

jblake00

Is there a better way to check for a vacum leak other then by sight and listening? I thought about holding a lighter up to some of the hoses while the truck was running to see if any leaks might pull the flame toward it. But I am not so sure about this idea... Other wise, I check and have checked for leaks everytime the hood is up. (about 3 times a week for at least 20 minutes.)

keithguts

They make a spray that you can spray around all air lines. If there is a leak, you will here it whem the spray hits the liking spot. I'm not quite sure of what type of spray tho. Maby someone here can answer that question.

jblake00

Okay, update #2:

After checking for leaks again and not findaing any, I went ahead and dove back into checking the timing belt. Found that my passenger side was 5 or so teeth off from its mark!! (I couldn't believe it still ran!) So it looked like my problems were almost over.... almost...

Wanting to double check which one of my cam gears was off, I looked at the bottom mark, the lower one that matches up to to oil pump, and realised I couldn't see it. So I turned the crank, with the belt off of the two cam gears, until the stamped lines matched up. Perfect. Now all I had to do was line up the cams and button everything up. Not so apparently...

I happened to look over at my timing mark on the crank pulley and it was pointing almost straight up! This is with the lower timing mark on the gear BEHIND the crank still lined up! Is this even possible? Can the crank pulley and the lower timing gear not match??? It was then that I had a great idea. I figuered I would just check the #1 piston and see which mark, gear or pulley, lined up with #1 being TDC. Well it was the pulley that lined up perfectly with #1 being TDC. The gear, when properly aligned, left the piston about 1/2"-1/4" from the top of its stroke. How is this possible?? Any help on this would be GREATLY appreciated...

I spoke with one of the techs at my local Toyota dealership and he didn't really know what to think, but he is going to ask around in the morning. Do you guys have any thoughts/ideas?