Mechanics

TOYOTA 4RUNNER ENGINE PROBLEM

1998 Toyota 4Runner • 127,000 miles

I have a 4runner with a 2.7 engine and its lacking poewer, I change fuel filter, spark plugs, plug wires, check cat and muffler all good, check compression and its good 180 to 182 on all pistons, I start cheking fuel pressure and regulator and I find out my fuel pump dont turn on with switch on but when I crank it work fine, check relay and its good, then check fuel pressure 45 psi and it dont move up or down give it gas or not, disconect vacuum hose of regulator and nothing hapen this mean the regulator is bad bud my problem is the regulator hose have no vacuum at all, so im not sure if the regulator is my problem now, the truck idle fine and it runn ok as long as I dont step on gas or jump into trafick lol if u can help me good thanx
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Guest
January 20, 2013.




When you push the vehicle to accelerate, does it misfire or anything? Are you sure it doesn't have the power it should. The 2.7 is a small engine
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No misfires, I know the truck's engine is small for the truck but it dont explane the fuel regulator, I have the repair manual and it say with the vacuum hose disconected of the regulator the pressure shuld be 38 to 44 psi and with the hose conected shuld be 31 to 37 and the pressure with the ignition on not running shuld be 38 to 46 psi, right now the fuel pressure is 48 all the time I runn the truck with the guage on and the pressure didnt move if I snap the throttle the pressure dont change, there is no vacuum on hose for fuel regulator, I look for vacuum leaks but nothing, I think is something wrong cause some times the truck runn good for short time then go back to what it was, do u know how much vacuun shuld be in sensin hose maybe I can put hose in a diferent location, oh and the pressure is 48 psi not 44 like I say before sorry, the manual say if is no vacuum I have vacuum leak but I check no leaks I check vacuum with guage and is normall, if I dont find the problem im sending it to shop and this be the first time I always fix my own car, let me know if u can help thanx


Tiny
Luisbr71
Jan 20, 2013.
It sounds like a problem with the fuel pump regulator. If the pressure doesn't change under different conditions, the regulator can't be doing it's job. Have you traced the vacuum hose back to the engine? Is it connected? You said there is no vacuum at the regulator. There should be.


Yes the vacuum line go to a box between mas censor and throttle body and there is no vacuum to the hose, all simptoms tell me is the fuel pressure regulator but it may be vacuum problems, I took out the box were the hose is conected to see if it was broken or rusted out but it looks good, like I say I thought it was vacuum leak I bought carb cleaner and spray all areas on intake manifold with the truck running to see if I can raise the rpm's cause vacuum leak but nothing, can I be loosing vacuum at head gasket I dont know how but u got the experience and u probably know I dont have water in engine no oil in radiator and compression is good im stuck help if u can thanx


Tiny
Luisbr71
Jan 20, 2013.
First pic is were the vacuum come from second pic is the fuel pressure regulator


Tiny
Luisbr71
Jan 20, 2013.
If you remove the hose at the supply, is there a vacuum?


No no vacuum at all and if I blow through is not glogged


Tiny
Luisbr71
Jan 21, 2013.
That is the problem. Are you able to determine why there is no vacuum at that point?


No like I say before, I took it apart and check it out for leaks cracks and everything looks ok I cant figer it out I think im going to take the truck to the shop and let them figer it out, its almose like is not enought air going through air intake to throttle and yes the air filter is good too, I just like to know WTF is it, thanx for the help, ill check for your reply in case u think of something, thanx


Tiny
Luisbr71
Jan 23, 2013.
Ok I didnt took truck to shop, every one is charging way to mutch just to check it out so I decided to fix it my self with ur help, my girl friend buy the regulator for me, I put it on even when I knew it was not the problem but I thought it help but nop it didnt, do u have any suggestions for me. Im just wondering can the IAC valve be stuck open and using too mutch vacuum just wondering


Tiny
Luisbr71
Jan 25, 2013.

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