helusay

Hey guys,
I am having some problems and I hope some of you can help me out. OK, prior to this event, I have noticed smell of gas in the morning when the truck is cold, and that my idle isn't the greatest. It hovers around 900-1000 in Park and from 500-600 when it is in gear (it's automatic).

The other morning I noticed my truck was leaking something when I backed out of my parking spot, so I put my truck in park, hopped out and walked over to the leak to investigate. Apparently, I had sprouted a gas leak, so I turned and looked at my truck, and noticed that it was still leaking (at a pretty good rate too).

So, I pulled my truck back in and the leak appears to be coming from the right side of the engine compartment, actually there were two one towards the front is the worst and the one towards the back drips about half the rate of the one in front. I was REALLY ticked off because I was dressed for work and not prepared to get under the truck. So, I popped the hood and could see no evidence from the engine bay of a leak from up top. I got really frustrated and turned off the truck and was going to go inside and call in sick to work, and I remembered it's payday, I have to get my check. I got REALLY frustrated thinking of everything I had to do, and I looked back under the truck, and the leak had stopped.

I figured screw it, I HAVE to go to work, and fired the truck back up, and looked for a leak, still nothing. I drove 15 miles in to work eyeballing the gas gauge the entire trip. I got to work and looked under my truck, still no leak. The truck has been parked for an hour, still no sign. Granted, I parked the truck in the part of our lot that is dirt so that any gas would be absorbed, but no sign of discoloration that there would be if something was dripping. Weird.

I recently switched some vacuum hoses that go from the intake plenum to some regulator on the right fender because I thought I had them backwards, and I cleaned my throttle body, but that is about it.

I have always noticed a gas smell that came from the truck when it was cold in the morning and I took off while the engine was still @ a high idle, but I never had a leak before the other day.

During my lunch hour, I started the truck, no leak, no smell, nothing. Drove to the bank to cash my check and noticed the truck (while still in high idle) was sputtering when I took off from the light. Parked at the bank, looked under the truck, no leaks.

On the way home I noticed that everything was running ok, no sputtering, but I was under a quarter tank, so I stopped and put $10 worth in figuring, if I am going to lose gas, I better keep it cheap.

When I got home, I had to run errands, so I did with no problems or leaks at all. I have had a crappy idle, but I figured it was either the fuel filter, or I needed a tune up. I changed out the fuel filter yesterday, and I switched the two vacuum hoses back to the way they were before (just to be safe). No problems or leaks so far. I figure, I may be in the clear.

I went and ran all my errands yesterday after all the work was done, still no leaks or gas smell, but I noticed that after errands and having my mechanic change my fuel filter, I was back down to a little less than a 1/4 tank again. No biggie, I would get gas in the morning.

I got in the truck this morning, and got a good smell of gas, looked under the truck, nothing.

Drove the truck down the street, parked it, looked under the truck, fuel leak.
I crawled under the truck, and noticed that the leak was coming from somewhere in the engine compartment, and leaking down the motor on to the trans, and dripping from the off the trans, again at a pretty good rate like the other morning. I hopped in the truck, drove back down the street and noticed that the sputter was back and that I needed gas. I drove to the gas station put $10 in the tank. Looked under the truck, no leak, but since the truck wasn't running, I figured it would when I started it. By the way, all of the driving this morning was about 2 miles, 3 tops. Parked the truck, left it running, looked, no leak. Apparently, the leak stopped after truck warmed up. I went to my mechanic this morning, and he told me he can't find where the leak is coming from either because it had stopped and that it is really hard to find it, unless it is leaking so he can track it down.

I am beyond frustrated with this and I don't know what to do.

So, here are my common symptoms with my leak so far:

Only leaks in the morning when the truck is cold, and I am under 1/4 tank of fuel.

Also when I am low on fuel is when it appears to run worse/sputter under load.

Please someone help.

The reason I wrote "what a shock" is because I have read many posts on the 3VZE having gas leaks, but I haven't read any resolutions. I even read one post that was practically identical to my problem, and the guy got a lot of great suggestions, but he never posted which one worked. I will make sure that I will post a reply to what ever works for me.

Thanks

thook

Look at and around the fuel pressure regulator. See if any fuel is puddling on the manifold in that area. And see if the regulator still good by pulling the vacuum line from it and checking for fuel there.

4JOGGER

Anybody has fuel system diagram?

mt_goat

This would lead me to think about the cold start injector. Try disconnecting the wiring (plug) going to it and see if the leaking stops. But first before you start your truck again start carrying a big fire extinguisher with you.



Or it could be that when the engine is hot the evaporation is so fast the gas never makes it to the ground. Also check the connections where the high pressure fuel line goes from a hard line near the passinger side frame rail to a flexable hose. should look something like this:

mt_goat

http://personal.utulsa.edu/~nathan-b...fsm/index.html

http://personal.utulsa.edu/~nathan-b...81descript.pdf

helusay

Hey guys,
Thanks for all of the suggestions so far, I will look at the ones I can, but I might have to wait until tomorrow morning to see the leak again and if my changes are effective. I will post results and if I fix it, I will post the fix for the next guy.

Do you guys think this will do the trick for safety? I am strapped for cash right now, and I am hoping it will.

-Thanks

P.S. keep posting suggestions if you have any, and wish me luck with the 2 lottery tickets I buy. Maybe I can win enough to restore this old truck.

justinking060310

im with goat on this one - sounds like the CS injector is a culprit

thook

Good point, Dale. But, it could also leak from the fuel press. reg. at that point, too. Not to mention, fuel is less likely to run onto the transmission from the CSI, rather from the FPR down the manifold towards the back (or front) of the motor, onto the tranmission, and also (as you suggested) evaporate up there.

But, so I'm clear.....which "right side" of the motor did you mean, helusay? The pass. or driver's side?

helusay

Sorry thook,
It is definitely the passenger side (american, just in case we have friends from down under or across the pond). The leak isn't visible from up top, and I think (not sure) the pressure regulator is up top, towards the front of the motor, under the intake plenum, I could be wrong though. Maybe the goat could post a pic, if he has one.

Justin,
I would buy the whole 1990 4Runner off of you, if I could afford it. I sure could have used it when that pulley bracket (fake water pump) died, can you say EXPENSIVE?

thook

Nope, it's not under the plenum, but it's also definitely not on the pass. side. CSI then. Right...could be evaporating on the exhaust.

One other thing I thought of, though. On one end of the fuel rail (which end and which rail I'm not sure of....I can't look at my 3.0 right now) there's a metal gadget...kinda mushroom/dome shaped....with plastic on it. I forget what it's called, but it's obvious when you look for it...you only have so many rail ends. Anyway, it's a possible source.

helusay

OK, no leak this morning. I don't get it. I am thinking it might be pressure related. I had less than 1/4 tank both times it has leaked, and over 1/4 tank when it did not leak, but then again, I don't know. Does this make sense to anyone? I did notice that the truck does a high idle every time I start it with the CSI connected. I checked the fuel pressure regulator, and there was fuel that came out of the lower/bigger hose, but I figure that has to be a fuel line. Then I checked the upper/skinnier hose on the top, nothing came out of it, but it was cracked, so I replaced it.

Anyone have any ideas?

Thanks

helusay

OK, I was leaking this morning. So now I know this has nothing to do with how much fuel I have. I forgot to disconnect the CSI, but I could see no visible leak coming from it. I think it might be the fuel pressure damper. It seems to happen every other day. This is getting to be a goose chase. My local mechanic will fix it, if he can see it, but he doesn't have any ODBI equipment. I am frustrated. Help anyone please.

-Thanks

thook

The fuel damper is where I'd suggested looking before....the part I couldn't remember the name of on the fuel rail. I know it can be frustrating, but you'll just have to track it down. There's only so many places where fuel could be leaking from. And unfortunately, this is a problem the ODBI equipment will not be able to help with.

Trace down the entire fuel delivery route and mark around every connection with some chalk or even a crayola crayon. Some spray on foot powder would be even easier. Wherever it leaks, it will become obvious. That ought to alleviate some your bewilderment.

helusay

Alas, I have given up the search and taken the truck to my local Toyota dealer. I might have to leave it overnight, but at least I will know the exact location of the leak and if they want too much to fix it, I can take a day off (because if it is the fuel damper, I have to remove the whole intake plenum) and fix it myself. I just don't want to play this guessing game anymore. Anyway, as soon as I get my diagnosis, I will post it.

-Thanks guys

P.S. While I have it @ Toyota, I will be having my recall work on the front end done too. I wonder if they will do the alignment when they fix it.

helusay

Ok, the truck has been @ the Toyota dealer overnight and they still see no sign of a leak. I will keep you posted as more news comes in.

Gonzo4Runner

Get the Factory Service Manual, if you don't already have it. It has trouble shooting procedures and will instruct you on how to turn on the fuel pump without starting the engine (this is very helpful for this type of problem).

My V6 4runner developed this problem (a fuel leak on the passenger side) a year ago. It was this fuel pressure damper.

If this happens to be your problem and you have to remove the plenum to fix it, you might as well do some other work while you have it off, such as:

replace PVC valve
check valve clearances
check/replace fuel injector gaskets

If you have a known fuel leak, you do not want to start your vehicle. Also, have a fire extinguisher handy.

helusay

Thanks Gonzo,
I will be looking for that service manual next paycheck. I am sure that it is the fuel pressure damper, but I didn't want to do any guessing. So I took it to my local Toyota dealer, I might have to pay more, but if leaks after they "fix" it, I can always take it back and tell them to try again on their dime. I hope. The truck has been with them since yesterday, I am hoping they find it soon. I have had the intake plenum off before and I ended up replacing practically every hose connected to it, not fun. Since I am not an experienced mechanic, I would rather not handle something a serious as locating some mystery fuel leak, I can let a pro handle it, just like my valve adjustment that I plan on getting done next.

Alex 400

I had a similar problem except mine would spray little bits of gas on the firewall. and exhaust. Had to take the whole upper plennum off to get a wrench on it. but yeah i had that problem. Hard starting and seemed like low fuel pressure, like a blown regulator, but it turned out to be the fuel damper on the passenger side (american) fuel rail. You can feel it with your hand if you stick your hand down behind the intake manifold and feel for the fuel rail or i used a mirror to find it first. good luck to you

thook

Oh man, don't spend all that money on the FSM when you can download it free from the internet.
http://personal.utulsa.edu/~nathan-buchanan/93fsm/

helusay

Hey Guys,
Just thought I would update everyone. Today marks the third day that my truck has been at Toyota without a diagnosis. They said this morning that they still haven't found a leak and that now they have involved the shop foreman. Apparently, he knows how to run some "tests" that the other guy did not know how to do. Supposedly, I will have my answer by 1:30 today. I am kinda getting pretty angry with them @ this point. but, all I am being charged for is one hour of labor. That is all I signed for on Monday morning anyway. Oh well, I will keep you all posted as promised.