sweden

I have a 1990 4runner with front end damage thats my new project. Truck was running well untill it was in the accident around a year ago. Now i can get the truck to start but only for an instant, then it dies. If i pump the gas pedal and give it gas i can get it to run, but only at about 3000 rpm and barley. The air cleaner was broken in the accident and im wondering if the vaccume lines to the fuel pressure regulator could have been effected. I plugged the vaccume lines to the aircleaner so it shouldnt have vaccume leaks to the engine but the vaccume system of the truck is disconected. Also the gas is about a year old and im thinking that could be the cause. Looking for suggestions please help ?

norcal707

check the timing and all hoses for leaks......do you have a v6 or 4 cylinder engine

sweden

Sorry I have a v6 4wd automatic 141 k miles, Just pulled of the vaccume line to the fuel pressure regulator and a little fuel poured out. There are 2 large vaccume lines that plugg to the air cleaner that are not connected. They are fed into hard lines that go under the intake manifold and from there its hard to tell where they go. Looking at all the lines they appear pretty good from what I can see. I will work on finding the timing but when i can get it "running" it seems to be a fuel issue to me.

thook

"Fuel poured out of the regulator"......that's a bad regulator. The internal diaphragm has failed. Time for a new one.

sweden

Word I need quite a few things untill i can really figure it out , FPR , and aircleaner are the priority for now. I thought it was just the gas being old but now leaning towards regulator. Anyone else have a regulator fial this way with similare results ?

thook

Um.....well, gas being that old is going to affect things considerably. Put some Seafoam in there to help stabilize the fuel and remove moisture. That should help......maybe a lot.

The FPR is pretty important. It may be the entirety of your problem, but that's assuming. Replace it, fix the vacuum hoses or block them off for the time being, then see where you're at.

Read this. It'll explain a lot.
http://www.wisegeek.com/what-is-a-fu...-regulator.htm

sweden

Thanks for the help. Poor seafoam in the gas tank ? am I reading that right ?

thook

Indeed you are....

sweden

Ok replaced the fuel pressure regulator as well as the aircleaner. Still no results. It runs a little bit better, basically if i pump the gas pedal quickly I can get it to somewhat stay running. As soon as i try to let the truck take over she dies quickly. I chased down the vaccume line the gas was leeking into from the FPR and didnt really find anything wrong. The wierd thing is no check engine light ? Also i foun that if I disconect the Mass airflo sensor it doesnt change a thing. Thinking now I need to replace the gas and try fresh fuel. Any other ideas Im welcom to them.

sweden

Intake pipes are good. Air cleaner replaced and good. It seems to start and then when its time to run, thats where it doesnt want to cooperate.

thook

It should make a dramatic difference disconnecting the airflow meter. I'd test that.

http://personal.utulsa.edu/~nathan-b...33volumeai.pdf

Also, make sure you're getting vacuum at the fuel regulator line. It may "look" fine, just make sure it's getting vacuum.

sweden

Looking over the airbox i found a hidden crack on the back of the large hose going into the throttle body. I will try that next for sure. Now its got me thinking that could finally be it. After that I will make sure the FPR is getting vaccume.

thanks for everyones help.

sweden

Thanks for the link to the VAF sensor, really good link.

thook

You're welcome. Here's some more.....

http://personal.utulsa.edu/~nathan-buchanan/93fsm/
http://www.autoshop101.com/

There are more links to manuals on the front page of this forum. See "sticky", fourth thread down from top.