vegasrunner

i have a 92 4runner 3.slo 310k a/t 4x4 . recently i noticed powerloss on hwy and on mild steep hills and hesitant startoffs on streets. I tested tps,afm with voltmeter all checked out ok fuel pressure test 38 psi vac connected 45 psi disconnected vac and checked egr vlave seemed clean to me. new plugs, wires ,airfilter, fuel filter, timing kit. found and fixed a vac leak and also advanced timing 10 degrees and i did compression test on one cyclinder and that was at 140psi and cat was tested and its ok too. my mpg is bad most of the time i used to make a tank last 2 weeks and now that its running like crap its lasts 1 week 1 1/2 if possible. what the hell can it be?

boneychill

Fuel pump?

FatboyJ

Knock sensor wire.

vegasrunner

fuel pump works but not sure if its fuel regulator or what. knock sensor wire? its come unplugged before and code came back for 52 but no engine light at all right now. toyota service tech manual says psi rating for fuel pump is 31 or 33 something like that. if knock sensor wire what do i do with it? besides see if bad

ksti

First, you need to do a compression check on all 6 cylinders, and 140 is below minimum.
I believe 145PSI is min. Also did you have WOT when performing PSI test on the one cylinder?
310,000 miles might mean she's getting tired.

As for poor mileage, it's possible your up stream o2 sensor needs to be replaced.
If you have a cat, could be clogged.
What is your timing set at know, did you advance 10o or is it set at 10o BTDC?

FatboyJ

I replaced long block on my 914runner. I did not read the forum beforehand. Knock sensor wires become brittle, send a bad signal to the ECM and retard timing. I am with ksti, check compression in all cylinders. 310k is a lot of miles.

vegasrunner

i replaced o2 sensor since it got wrapped around rear shaft when it flooded here. not sure what the timing is set at but a tech set it 10 above where it was at. cat got checked out and it is ok. ill do a check on all 6 my friend did it and said 'its fine for what it is" . is there more then one o2 sensor? i replaced the one right near the cat. and shes my baby and plan on keeping her running i dont mind the 3.0 built to last not to perform

vegasrunner

round 1200 rpm 45 mph it surges like a slight misfire but at 3000rpms 75 mph its fine. it runs okish when i floor it at stops but gentle acceration it bogs and hesitates and fumes at the exhaust are heavy almost raw gas. i did have a flowmaster 40 with 3 turndown installed not sure if that caused the prob thats the only mod done to it for now till i fixed the main problem

ksti

It's possible the that your timing is now at 20o BTDC.
Some run better, some run like crap.
I would put it back to 10o BTDC and make sure you jump te1 and e1 when doing it.

Check for codes stored also, you just might have one.

On compression test, there is a procedure in the factory service manual make sure your friend is following it or you will not get true readings.
Good Luck and post back findings as it helps other people here.

vegasrunner

so just replace knock sensor even if no code? and wires brittle? how far of replacing wires do i need really? shes old but still runs

vegasrunner

when timing was advanced my idle raised a couple hundred rpms at idle before it was a little rough but now its smoother but ill back it down and see

ksti

I don't know what your talking about regarding knock sensor.
Just because the wire is brittle doesn't mean you have to replace it.
That's a bigger job to do also. Not a real fun one either.

Your getting a little off track here, just take it one step at a time.
Get your timing set properly first and then go from there.
You really need a Factory Service Manual if your going to be working on your rig yourself.

TNyota

Getting to that knock sensor wire is what we like to call 'thirsty work' - I would eliminate everything else before diving into that. If it is bad you should be getting a CEL and a code 52 - if you are not getting those look for other things.

vegasrunner

tb has been cleaned also all i know is ive been taking care of the truck previous owner did not care at all. ill do proper compression check and i do have factory service manual pdf so ill go from there if any other suggestions please let me know! yota strong!

ksti

You cleaned The TPS, why and with what did you clean it with?
I hope you just wiped it off.
You can damage them very easily.
Did you remove it to clean it?

Edit: My bad, thought you cleaned the TPS

vegasrunner

removed and cleaned and wiped. tb same way

ksti

Okay, so if you did remove TPS to clean it's a good probability that it is not in spec after installing.
That's could be the problem also.

Maybe unplug TPS and see if there is a change in how it runs. It's not the proper way but it can help to pin down if TPS is acting wonky.
If you do this make sure you clear code afterwards.
So now you got some things to do, go check them and post back.

vegasrunner

how do i clear codes on an ob1? besides unplug battery.p.s thank you all for your input helps alot

TNyota

Pull a battery cable, or better yet just yank the EFI fuse and count to 30 or so.

vegasrunner

thanks.