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86-95 Trucks & 4Runners 2nd/3rd gen pickups, and 1st/2nd gen 4Runners with IFS

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Old 03-26-2013, 03:21 PM   #1 (permalink)
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Talking hesitation. no power past 1/4 throttle when in gear

hello yotatech!! i've been reading on here for several weeks after buying my 1990 4runner 3vze 5speed manual. i've learned so much from searching this site but i think it's time to finally post something myself because i can't find the answer i'm looking for.

ever since i got this runner, it has been lacking power when you really try to step on the gas. i can drive and keep up with normal traffic (barely). i can go on the highway and go well passed 75 despite what others have experienced with this engine. it feels like it has power and compression and all of that until you push the gas peddle more than 1/4. so if i'm in a gear at like 2000 rpm and i floor it, the engine won't get louder or anything, it's almost like i don't have enough fuel pressure or somehow it's not getting air when you mash on it.

i've replaced the spark plugs, sp wires, o2 sensor, all of the small vacuum hoses throughout the engine, the distributor cap and rotor, the oil a few times in one month until it was clean, air filter, fuel filter, i dropped the tank to check for rust, it was super clean, fuel sock was clean so i put it back on. duct taped the cracked intake hose. took off the cat for a week, acceleration was worse, so i put it back on because the honeycomb looked clean. i seafoamed it twice, oil, fuel, and vacuum line.

everything i did seemed to yield a slight improvement but hasn't fixed the root problem.

today i unplugged the tps to see if that would help. it tested fine with feeler gauges and a voltmeter but i read some other people who had theirs test fine but ended up being the problem. i read that i could just disconnect it and drive a while to see if it was the problem. i think it helped a little so i may want to replace that eventually but it still feels neutered. my vafm also checked out fine with the voltmeter.

things i'll try to do this weekend:
adjust timing (still haven't done that :S guna feel stupid if that's all it is)
test fuel pressure
test compression

i do know that i have a valve cover leak on both sides. i don't think it's been enough to leak onto the driveway, but it smells like burning rubber after it warms up, especially when the heater is on. my oil pressure wasn't getting up to the first line on the gauge until i switched from 5w30 to 10w30. it pretty much just sits there at the first line, is it supposed to fluctuate as i give it gas? in the only video i found on youtube of the oil gauge, it was moving as he was driving.

i've read all over this site that people have leaky covers and they just live with it. are mine leaking way too much? could that be the cause of my hesitation problem?

if those tests come back clean between fuel and compression, i'm probably guna take apart the whole engine which i've never done before. a rebuild kit is $300, i have no idea how much it will cost to have the block machined or where i can get it done here in denver. i'd prefer to only have to rebuild the top end but i don't want to do that and then find out i have a spun rod bearing or a bad head gasket shortly thereafter.

so what do you guys think? is there some other sensor i should check first? is there some weird simple fix ya'll know about for these symptoms? after replacing my o2, i have no more cel or codes, just 11111111111 forever. am i at least headed in the right direction?
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Old 03-26-2013, 03:32 PM   #2 (permalink)
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just realized i was spelling pedal wrong.

i forgot to say it revs up fine in neutral and my gas pedal is moving the throttle just fine. but when you are in a gear, it doesn't help or hurt to use any more than the first inch or two of pedal. that's why i believe it's being starved for fuel or air. my gas pedal has two settings, on and off :S
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Old 03-26-2013, 04:26 PM   #3 (permalink)
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x2 Timing and fuel pressure.

Once those are done reinspect the VAFM.

Here are two very good descriptions of it's operation.
http://www.yotatech.com/f116/persist...-fault-263957/
http://www.4crawler.com/4x4/CheapTricks/AFM/index.shtml
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Old 03-27-2013, 05:37 AM   #4 (permalink)
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thanks for the reply

ill check my fuel pressure this weekend. hopefully i can find the right fittings to do so. i've read i need a banjo but i have no idea where to get one.

ill try to do the timing when i get home from work today. i think my dad has a timing light.

if all of that is fine, ill use those 2 links you gave me to check my vafm more thoroughly. a few weeks ago i did move that one cog in the vafm 3 clicks more lean and it smoothed the sound of my engine a lot!

i think i'll do a compression test anyway after all the above. i hear different ticking from the engine depending on where you listen. the one that concerns me the most is what i hear when im behind the front drivers side tire, like when you're about to drain the oil. it's not very loud, kinda sounds like a pcv valve noise but on the bottom of the engine. i really hope i didn't buy this thing with a spun bearing because that means i've been driving with it like that for a while and i keep watching videos of people taking paper thin bearings off of their crank.
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Old 03-30-2013, 07:06 PM   #5 (permalink)
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ok i guess my reply the other day didn't go through. maybe i wasn't paying attention and it logged me out before i hit post reply. why would yotatech boot me so quickly? i can't even finish a message without having to log in again?

i tried to adjust my timing but it was at like 30 degrees and i couldn't get it to even get down to 15 degrees let alone 0. i took off my timing cover and when the crank pulley is at 0, the cam pulley notches line up with their designated marks. did i do something wrong when timing? is there any reason why my timing would be that far off?
the engine was warm, i jumped te1 e1, timed with the front left wire labeled 1, rpm was about 800.

i bought the 4runner with some repaired front end damage that makes the radiator not sit perfectly straight. while removing the rad today, my fan shroud fell to pieces. i'm going to try to super glue it back together until i can go to the junkyard. i'd prefer a new one but they want more than $80 for both parts of the shroud new and only $10 at the junkyard.

also i sheered one of the alternator bolts, so tomorrow i have to ride my bicycle to ace hardware for a bolt, an easy-out, and some superglue, just to get it back to its slow self again. if i get it done early enough, maybe i can rent a fuel pressure test from autozone.

can i get one of those "banjo's" at a store somewhere or do i have to order it online? do i just say "excuse me sir, take me to the banjo's please"
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Old 03-30-2013, 07:26 PM   #6 (permalink)
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Sounds like the distributor was inserted wrong. Go thru the inspections and reinsert it if needed.
http://personal.utulsa.edu/~nathan-b...13distribu.pdf
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Old 03-31-2013, 03:57 PM   #7 (permalink)
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i will definitely do that. thanks for the advice

i super-glued my shroud back together and got it back in there and got the new bolt for the alternator. took me about 2 hours to get the radiator, alternator, and shroud installed and i got a nice sun burn in the process. now im waiting til tomorrow morning to fill er with coolant because the silicone i used on the water outlet takes 24 hours to dry completely. hopefully she runs no worse than when i started yesterday morning. i should have got a faster kicking silicone
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Old 04-04-2013, 12:39 AM   #8 (permalink)
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ok so under the fpr, i removed that 17 mm headed bolt from the fuel rail that goes into a hooped fitting that connects to the other side of the fuel rail. im assuming the hooped part is the "banjo" that everyone keeps talking about. from the pictures i've seen of people doing fuel pressure tests, i need a fitting on that hollow bolt's head. please correct me if i'm mistaken

so i went to the advance auto where i live that shares a parking lot with an o'reilly auto parts, and neither one had what i was looking for. am i looking for the wrong thing? if i got a hooped fitting for the tester, wouldn't that mean not using the hooped fitting that connects the two rails? don't i need to test the pressure while the engine is running? so i would need fuel to get to that side of the engine as well?

i know these are stupid questions but im just not getting it
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Old 04-04-2013, 10:25 AM   #9 (permalink)
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Quote:
Originally Posted by machineslave View Post
...adjust timing (still haven't done that :S guna feel stupid if that's all it is)
Yup.

Quote:
Originally Posted by machineslave View Post
i tried to adjust my timing but it was at like 30 degrees and i couldn't get it to even get down to 15 degrees let alone 0.
...
also i sheered one of the alternator bolts, so tomorrow i have to ride my bicycle to ace hardware for a bolt, an easy-out, and some superglue, ...

can i get one of those "banjo's" at a store somewhere or do i have to order it online? do i just say "excuse me sir, take me to the banjo's please"
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Originally Posted by Co_94_PU View Post
Sounds like the distributor was inserted wrong. Go thru the inspections and reinsert it if needed.
Yes - the distributor helical gear has 13 teeth, so if you're off by one tooth the ignition timing will be off by 28 . It has nothing to do with the belt on the cam (that's valve timing).

Good luck using an "easy-out." If the bolt was stuck tightly enough that you sheared a full-sized bolt, the much smaller easy-out could easily snap too. If you do that, you will have a very hard piece of steel in the bracket that cannot be drilled out. Be careful.

Quote:
Originally Posted by machineslave View Post
? don't i need to test the pressure while the engine is running? so i would need fuel to get to that side of the engine as well?

i know these are stupid questions but im just not getting it
The banjo bolt is not trivial to get. This fuel pressure tester kit has the part (with the red cap). Actron supposedly sells it individually (you'd still need a Schraeder valve style tester), but no longer through their website. I've never seen a banjo-bolt-adapter locally.

You don't need the engine running to test fuel pressure, but you do need the pump running. You can jumper FP to B+ in the diagnostic connector (key-ON), and you should be able to hear the pump running.

But hold off a bit on the fuel pressure; the screwed up timing would be enough to cause all your symptoms.

Good luck!
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Last edited by scope103; 04-04-2013 at 10:26 AM.
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Old 04-04-2013, 01:19 PM   #10 (permalink)
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thanks for the reply. the easy out worked but i didn't use the drill side of the easy out, instead i used a black oxide bit, then the easy out, it came right out. i think the bolt only sheered because it was trying to screw farther into the thread than where it was previously and the threads were a bit rusted there.

i think i may have had the tps unplugged while timing it *punches self* i'll have to time it again this weekend just to be sure. if it's still off then i'll check the distributor.

when i changed the spark plugs, they were bosch and really corroded. the corrosion on one of them actually spanned the gap. so im thinking a bunch of other common things may be just as worn. i may have some pretty clogged injectors and maybe a bunch of crud in my intake manifold. i'm going to check them when i do my valve cover gaskets. and i still need to test my vafm with the info that co 94 provided me.

thanks everyone for all your help so far
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Old 04-04-2013, 05:00 PM   #11 (permalink)
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ok i tried timing it just now. i followed the steps that i found here

http://www.toyotanation.com/forum/80...ls-te1-e1.html

the engine was still a little warm from driving home from work so my idle started at like 1000 and slowly dropped down to almost 600 once it warmed up. so i turned my idle screw on my throttle 3 full rotations counter clockwise, til my rpm was between the 800 and 900 lines. then i hooked up the light and jumped the terminals and i was at 12ish, which was a relief. i loosened my distrib and turned it clockwise a little to get it 15 as others have suggested. when i took the jumper off, the timing dropped a degree to like 14. i drove it around the block and there's no real noticeable difference in acceleration. i did notice that this kind of grinding feeling/noise is back. a noise that seemed to disappear when i leaned the sprocket in my vafm 3 clicks. so im wondering why that noise is back. i'll have to record a video and put it on youtube or something. its like a rubbing noise only between 1200 and 1300 rpm when in neutral, that goes away at any higher rpm, and isn't there at idle. and then you hear/feel in first gear when you're in those lower rpms.

and now it seems to be idling at about 1000-1100 rpm. does that mean i have to adjust the idle again and time again?

i must have had the tps unplugged the last time i tried to time it. that makes me feel dumb but it was my first time ever trying to time a vehicle, without any help except for what i gather from reading every night.

i think i'll take it back to 12ish tomorrow after driving it to and from work since it sounded and felt smoother there.

that grinding/rubbing noise has me concerned. i'll record a video tomorrow on my lunch break when it's bright outside. i hope that kinda noise doesn't instantly mean engine rebuild.

at least my timing isn't off super far, i'm just a retard

i think i'll try to do a compression and fuel pressure test this weekend, since the testers cost nothing more than a deposit.
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Old 04-04-2013, 05:49 PM   #12 (permalink)
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and i got a nice sun burn in the process.
Must be nice! HAHA!
Good luck, buddy.
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Old 04-04-2013, 06:14 PM   #13 (permalink)
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sounds like your trying your best!! Make sure your disributor is installed correctly!! Also make sure your fuel pressure is in spec. Also have you checked codes? ck eng light on??
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Old 04-05-2013, 12:31 AM   #14 (permalink)
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You might want to put the VAFM back to factory specs. It's tuned by an old grey beard at the factory and designed by someone with a degree or two.
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Old 04-05-2013, 09:32 AM   #15 (permalink)
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I agree on setting VAF to factory spec.

Toyota's engineers tell you exactly how to set the timing. http://personal.utulsa.edu/~nathan-b...13distribu.pdf Instead, you decide to follow the description by someone named "knj27." (Fortunately, it looks like knj27 was just reading the manual.)

Toyota's engineers (and the sticker under the hood) tell you where to set the timing. (10) But you pick out 15 "as 'others' have suggested."

I'm all for experimenting. Maybe your truck, for some reason, will make more power on the dynamometer when set to a non-factory timing. But your truck is not running right. So I would set everything to factory and get it to where it is at least running well. After you've got that, you can start looking into what "knj27" and "others" (and "scope103") are suggesting you do differently.

But it's up to you; it's your truck.
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Old 04-05-2013, 09:58 AM   #16 (permalink)
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ok i guess my reply the other day didn't go through. maybe i wasn't paying attention and it logged me out before i hit post reply. why would yotatech boot me so quickly? i can't even finish a message without having to log in again?

i tried to adjust my timing but it was at like 30 degrees and i couldn't get it to even get down to 15 degrees let alone 0. i took off my timing cover and when the crank pulley is at 0, the cam pulley notches line up with their designated marks. did i do something wrong when timing? is there any reason why my timing would be that far off?
the engine was warm, i jumped te1 e1, timed with the front left wire labeled 1, rpm was about 800.
Were you checking/adjusting timing with the TPS disconnected? I had the *exact* same problem; No power with WAY advanced timing that I couldn't get below 13*. It wasn't the dizzy, it wasn't fuel, it wasn't the tbelt. I chased those around for days because I'd been messing with all of them when the problem cropped up. It took for ever to realize that I'd left the TPS disconnected. Do this: Connect the TPS, and do a quick half assed adjustment on it (loosen bolts, rotate slowly until the idle *just* drops and lock it down) and re check your timing. If you had it set at 15* advance before you'll probably find it >10 degrees retarded now. Advance timing to 10*, reset idle and test drive.

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Old 04-05-2013, 02:54 PM   #17 (permalink)
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I had to set the timing in a buddies truck to 20 degrees advanced to get it to run properly. Had similar symptoms. Revved nicely in neutral but no power over 1/4 throttle. We determined this was because of the tps idle contacts not working properly. Now runs great at 10 degrees with a new and properly adjusted tps. Also make sure the throtle body is clean and the throttle plate is closing fully
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Old 04-05-2013, 06:41 PM   #18 (permalink)
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wow! so many replies! i guess i just had to admit i'm a retard and then everyone comes out to play

well the runner is my only vehicle atm so with my paycheck today with all this extra overtime ($1400) im guna buy an electric in wheel motor for my bicycle and a lithium ion battery for $700 total, so i can take my time on the engine. i junked my crashed up rusted ford explorer when i bought this runner, but i was working on that explorer all the time. took me over a year to find out that the fuel filler tube was rusted under the rubber hose, and that every time i was putting gas in my car, i was putting more rust in my tank. i went through 3 fuel pumps in a year. thank goodness for warranties. sorry i trailed off a bit. my point was that i spent so many weekends working on my explorer, and every sunday was a mad dash to put everything back together so i could get to work monday morning, and this haste kept me from devoting the required time to each fix.

i could probably buy another car with that 700 but the simplicity of an electric bicycle is more reassuring. plus it has a range of 30 miles per charge, and my work is 3 miles away, so i'm just going to charge it at work only and never pay for the electricity myself

as soon as i get the bike going, im guna do the valve cover gaskets and send the injectors to witch hunter. im guna put the timing back to 10 per your advice, scope. im hoping the valve cover fixes that source of that noise. im wondering if a cylinder doesn't get lubricated enough when the engine warms up, because i have noticed that my oil pressure is a tad lower when warm.

i forgot to take my camera to work to record the noise. ill record some videos tomorrow after i re-time it. i'd do it now but yesterday evening billions of mosquitos came outa nowhere!! i guess it's that time of year again.
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Old 04-05-2013, 07:54 PM   #19 (permalink)
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your oil pressure is supposed to drop when the engine gets warm.....oil thins out a little when warm. as long as your oil pressure is within specs (when warm) you're fine
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Old 04-05-2013, 09:10 PM   #20 (permalink)
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I wouldn't bother with an electric hub motor unless you have to wear a suit to work or something. Just leave earlier and you shouldn't show up wet don't forget to pedal assist, particularly when accelerating or hill climbing nothing will kill your fancy new battery pack faster than overworking it.

Find you a nice used moped and get your on.. I was going to recommend something from Xtream but they don't appear to have recovered from chinese new year yet.
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Old 04-05-2013, 09:10 PM
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