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

Bad gas mileage/low power/lean?

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Old Jan 10, 2009 | 09:25 PM
  #1  
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Bad gas mileage/low power/lean?

I have an 87 4runner 22re

I blew the stock motor up and had a buddy with an 84 carb block and head so i fully rebuilt the motor and head and put my efi mani on it

the truck runs descent, idles fine etc.

problems.

its getting bad gas mileage...80 miles to a half tank..most likely tps adjustment?

it has a weird powerband, if you step on the gas hard in any gear, it doesnt do anything, it just kinda slowly accelerates, but if you ease into the gas, you can find a sweet spot that will make it accelerate

it still doesnt seem like it wants to cruise at over 60mph though, and at 60 its hard to maintain speed

and it seems like it is lean up top, it does have new used injectors since the 1st motor

im guessing tps adjustment, but i can not get it set right for the life of me, i am constantly trying to adjust it to get it to run better

any ideas? iv been searching and searching, its my daily driver, and i just want it to work right again
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Old Jan 10, 2009 | 09:37 PM
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From: Austin, Texas
Sounds like tps is fubared or something to me...


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Old Jan 10, 2009 | 09:42 PM
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From: Lake City, Fl
how did you blow the old motor up?

the question is relevant by the way... depending on what you did, you may have other lingering effects...
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Old Jan 10, 2009 | 09:46 PM
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i ran it low on oil and the timing jumped and overheated the bearings, a couple months later i was piss pounding it in the mud and it started knocking and then took itself apart. cylinder 1 detonated bad. the piston looked like fresh aluminum from the detonation, i assumed it was a bad injector, so i picked up a set off of ebay
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Old Jan 11, 2009 | 08:40 AM
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From: So MS
Tell me about your VAFM.It must swing freely throughout the entire range of motion.Also the distributor not only controls the ign timing it controls the injector timing.Have you double checked the cam timing?
Bigblock
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Old Jan 11, 2009 | 08:40 AM
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From: So MS
Valve lash?
Bigblock
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Old Jan 11, 2009 | 09:55 AM
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cam timing was one tooth too advanced, so i set it back one, but it didnt change anything

set timing with the distributor with the jumper in to about 0, advancing it doesnt change anything

afm swings freely

the truck ran great before i blew it up, which leads me to believe everything is fine that was already in the truck, the problem lies in this new motor, something is not set right. it has a new fuel filter, new used injectors, and a completely rebuilt engine and head.

something is just not set right, i cant drive it down the freeway, around town cruising is ok if i baby the gas to get it going, hard throttle does nothing.
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Old Jan 11, 2009 | 09:57 AM
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valve lash is set to factory spec

.008 intake
.012 exhaust
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Old Jan 12, 2009 | 07:41 AM
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it runs good in open loop and then starts the hesitation, no power issue in closed loop
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Old Jan 12, 2009 | 07:47 AM
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From: quincy illinoise
id say if u have access to a vantage or scope id scope the tps its probably got some dead spots in it and while your at it check out the afm u can do this with a multimeter but its no where near as accurate
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Old Jan 12, 2009 | 07:53 AM
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From: quincy illinoise
thats of course assuming uve all ready covered the basics vacuum lines air filter manifold leaks egr fuel pressure hook a vacuum guage up should b between 18-22 and steady if its low your leaking bouncing u got valve issues (note main vaccum lines only check valves and such will inter fear

Last edited by darksoldier313; Jan 12, 2009 at 10:03 AM.
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Old Jan 13, 2009 | 09:01 AM
  #12  
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4 Engine Coolant Temperature Sensor signal.
5 Oxygen Sensor.
6 RPM signal (Crank Angle Pulse).
7 Throttle Position Sensor signal.

these are the codes i am getting

its a brand new o2, but the truck ran lean a couple times and the manifold was mildly glowing orange, could that burn the o2 up?

and i dont know what to do about cel# 6
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Old Jan 13, 2009 | 05:10 PM
  #13  
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From: quincy illinoise
oh my glowing manifold not so good id say your lucky this is your only problem but get your hands on a scope u can scope all of those it will let u know whats up with em of course it could b the wiring u dont have ne wires running close to the manifold do u?? if so check em for melt spots
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Old Jan 14, 2009 | 08:37 PM
  #14  
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still runs like ass no matter where the tps is set, bad gas mileage, etc

once it enters closed loop its all over
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