Burrows1372

I just rebuilt the motor and did some performance while I was in there now its running rich and i dont know how to adjust it. I added a cool air intake, Pro Street Head from LCE and pro tourqer cam, Headers, and full exhaust. But now its dumping fuel somewhere. Its rough when it starts but smooths out when it warms up. Also it seems to bog down from so much fuel being pushed in. IDK what to do or where to start so any suggestion will help. Thanks alot

myyota

Make sure the TPS is properly adjusted, and also check or replace the 02 sensor, if its original or has a lot of miles on it then just replace it. if you still have the stock cat it could be plugged and not letting the engine breathe. You can also call LCE and and tell them whats happening and maybe they can help you out.

BrianJE

check the cold start valve make sure its not stuck on.

Burrows1372

Alright will check that today but... How do you check/ adjust the TPS. Also how do I check to make sure the cold start injector isnt stuck on. Dont know much about EFI components.. Ill research it as well today

tim a.

fuel pressure regulator not hooked up?Hooked up to wrong port?Did it run rich before you worked on it?

Burrows1372

I belive it did run rich before. But not real sure. It was a real peice of work before i tore into it soo there was so much wrong its hard to remember but i think it did run rich before

Burrows1372

By the way i went and ordered a new O2 Sensor today. Ill hvae it on tommorow after work and see how that works out. The Fuel pressure regulator is hooked up and has a plug with a black and a white wire coming out of it. I have a "extra" plug that would reach it, it is grey and has a green and yellow wire coming from it. I have looked at truck before and it seems like they all have that plug tho. Which connectiong should the vaccum line be hooked to tho just to make sure thats on right

Burrows1372

Yeah when I say it seems to be getting bogged down. Its like when I get it to about 2-2500 rpm it just takes off like no other. But its just kinda boggy when its in lower rpms. IDK what to do

myyota

With the cam, head and headers that your now running have you tried advancing the timing a few degrees to see if that helps ?. With your set up you are no longer stock so setting everything to stock specs might be holding the engine back. What about the valve adjustment, did you set them to stock setting or did you go with what the cam specs recommends ?. I`m just trying to throw out ideas that might help you.

Burrows1372

I set them to the cams specs. idk can anyone give me some pics of where the FPR vaccum should go or is there a bypass for the VSV that I can do

myyota

You can bypass the fuel presure regulator VSV, ive done it on my 86 4Runner. Unplug the VSV for the fuel presure regulator from the intake and then run the vacuum hose straight from the fuel presure regulator to were the VSV was connected and thats it, then unplug the VSV and remove it from the valve cover.

Burrows1372

Alright Im pretty sure i know what your talking about but there isnt any other lines ill have to plug off or anything. Also could you post a picture of the VSV i need to unplug and what will this do? If I do that it should make it quit bogging down correct, that is what ive been told anyway. Im just trying to make sure before i try it.

Colombo

Bump....

Burrows, I'm having the exact same isues and can not for the life of me figure it out!
It runs rich all the time, and runs like a dog till it gets to about 3K rpm and then takes off like a rocket!

Pleeeeeeze let me know if and how you fixed this thing!

Thanks!

Relyks

bump

I am curious about the O2 censor is there a upstream and down stream?
where are they at?

also my truck is running rich it is a 91 22re i think its the cold start but all this conversation about the fuel pressure regulator has me wondering so if you could post pictures on this i would highly appreciate it

edit ahh this pots is old just realized dates and he doesnt seem like a very active user sorry for bumping this.

James Woods

iTrader: (1)

The O2 sensor measures oxygen and hydrocarbons in the exiting exhaust gas, hydrocarbons are unburned fuel, and the computer receives these signals and attempts to keep the air fuel mixture to about 14.7 to 1 which means for every one molecule of fuel, the engine needs about 14.7 of oxygen.

When the O2 sensor starts to fail, usually the reason is that it is just coated with soot from years of exhaust gas, when it gets covered, the sensor cannot intake all the information it needs from the exhaust gas and usually determines that the engine is running lean so it will apply more fuel. When more fuel is applied, the combustion chamber cools and gets a less efficient burn resulting in the vehicle having that fall on its face feeling when accelerating from a stop.

You have in most cases on these trucks, just one o2 sensor upstream of the cat and right after the exhaust manifold.

The fuel pressure regulator will be at the end of the fuel rail and is a disc shaped metal object that will have a vacuum hose attached to it. The reason for the FPR is that when the pressure builds in the fuel rail at idle, it has the same pressure as if you were WOT. Of course you cannot burn all of that fuel at idle, but your fuel pump is not able to compensate as it puts out one steady pressure, so the pressure overcomes a spring inside of the FPR and is allowed to return back to the fuel tank. The vacuum hose will adjust the opening of the FPR depending on engine speed to compensate for the engines need for fuel.

Sometimes when the seals leak in the diaphragm for the FPR causing fuel to leak past the seals and into the engine via the vacuum hose.

Hopes that long boring post helps some understand how these systems work.

abecedarian

True, for the most part. The ECU ignores the O2 sensor at idle and at somewhere around 2/3-wide open throttle. Bear in mind that is only true if the Throttle Position Sensor is operating properly.
Generally true- when an O2 is failing, the ECU will most often compensate by making the fuel mix rich. This is a "fail safe" design so that you don't damage the engine: rich-running engines don't run lean, detonate and implode.

Unless it's a California model after 1990 and most other US after 1991 which have two sensors- one before the converter and one after.
I can say with certainty that my 91 Cali 22re has 2 sensors, as I described above.

Huh?
The fuel pump is capable of supplying fuel at a higher volume than the engine requires. To do this, the fuel pump supplies fuel at a high volume and a high pressure. The fuel pressure regulator allows the system to maintain a relatively constant pressure behind the injectors so they can spray a relatively constant amount of fuel into the cylinders.
The vacuum line attached to the fuel pressure regulator allows the regulator to compensate for the vacuum in the intake manifold: with high intake vacuum, less pressure is needed to inject fuel and with low intake vacuum, more fuel pressure is required to maintain a somewhat linear injection rate.

So, at high vacuum, the injectors see lower fuel pressure, and at low vacuum, the injectors see higher fuel pressure.

Yeah, I suppose that's possible.

Translation:
At idle, the O2 sensor is not doing much to affect your fuel mixture.
If you seem to be running rich, as evidenced by checking your spark plugs, it could be a faulty fuel pressure regulator causing full fuel pressure to the injectors when it should be limiting fuel pressure.
It could be faulty injectors, i.e. bad spray patterns.
It could be a mal-adjusted or faulty TPS.
It could be a weak ignition coil, faulty wires or spark plugs.
It could be a dirty air filter.
It could be a mal-adjusted air flow meter.
It could be a plugged up catalytic converter.
It could be worn piston rings, low compression or excess blow by.
It could be valve adjustments aren't right.
It could be you need to adjust the air-flow meter for the new cam (oops, I already said that).

But I do have to ask, how do you know it's running rich?

James Woods

iTrader: (1)

Post deleted

Relyks

this is great stuff im 18 and worked very hard for my yota and my grandpa is a yota man he has 2 4runners 22re and v6 and a 22r pick up i have a 91 2wd pickup 22re and wanna know everything i can so thanks a lot (: for posting back at this i actually have another post on this same page if you guys could take a look and place a opinion it would highly be appreciated.

abecedarian

If I remember correctly, I said you were correct "for the most part".
I said...
- the ECU doesn't read the O2 sensor at idle
- the ECU doesn't read the O2 sensor above around 2/3 throttle
- O2 sensors generally fail in a way that makes the ECU go rich to protect the engine
- the fuel pressure regulator lowers the fuel pressure at idle (high vacuum) and raises fuel pressure when the throttle is open (low vacuum).

You said I "...pretty much just reiterated everything I [you] had already said..." And then complain about me doing that. I clarified some things, and corrected other errors, and you complain?
If you have an issue with me and how I post information, you are more than welcome to discuss such with me via private messages instead of on the forums here.

Thank you.