Page updated on 04-22-2018

Fuel leak

09-28-2009, 12:34 AM
I have a 1995 Toyota extended cab pick up truck and I am smelling fuel only after I have been on the High way and get out of the truck I smell it towrds the rear of the truck around the gas cap the truck has 250,000 miles on it is there any known common problems with the fuel lines by the tank?

09-28-2009, 08:51 PM
Not normally but your truck does have a lot of miles on it. Some of the fuel lines are rubber lines but most of them are matal lines.

If there is a leak in the lines, your truck should take a little time before it fires up. Another thing is if the leak is big enough, you should be able to crawl under the truck and visually see the leak. This is due to the lack of fuel pressure while the truck sat over night. Otherwise you truck should just start right up.

Another thing to check is to see if your gas tank is leaking. If i'm not mistaken, your truck has a metal tank which are notorious for corrosion. Plus there is a drain plug on the bottom of the tank with a stupid little gasket. Either way you should visually notice the leak.

Some older fuel injected vehicles often get a aftermarket inline fuel pump installed since it is a pain in the *ss to remove the in tank fuel pump. Sometimes those pumps give you problems since they are made of plastic or just leak after a few thousand miles.

Either way, the best way to diag this concern is to use a creaper and your nose and follow the lines from the tank to the engine until it's found. - Happy Hunting :)

09-28-2009, 08:53 PM
Oh one more thing... Gas caps do go bad over time. If you can't find the leak, try replacing the gas cap and see if this resolves the issue. - Good Luck :)

10-11-2009, 06:37 PM
I have an '89 PU SR5 V6. I've had fuel odor (leaks) 4 times in 20 years.

The first was 2001, the Fuel Pressure Dampner. It's screwed onto the end of the fuel rail, passenger side, rear of the engine, under the air plenum. It's a little plastic disk. You can't see it. You have to feel for it. (I had a hard time finding it until I viewed a parts diagram like this one. ( See the cap threaded onto the end of the fuel rail, near the fuel filter.).

The next was 2004, the Fuel Pressure Regulator, like a silver space saucer, driver side front top corner of engine. Screws into fuel rail and has one or two hose bibs on the side (I forget how many).

The next was 2005, the Cold Start Injector, bolted onto passenger side of air plenum.

Today, the Fuel Pressure Regulator again(!)

In all cases, I had to crank the engine about 10 times before it would start (to represurize the gas lines after they bled off).

In the case of the Pressure Regulator and Dampner, there was an odor while driving, and after I stopped (very strong).

In the case of the Cold Start Injector, it would smoke when it started (burning off all the gas that bled into the air plenum?). There was an odor of gas after I stopped. I suspect it traveled through open valves and through the exhaust system?

You can check the Regulator and Dampner by jumping +B & FP in the check connector (a grey rectangle plastic box mounted on the top of the passenger fender, under the hood, top snaps open and should have a decal under the top indicating which pin positions are which). Turn ignition on, but do not start. This will cause the fuel pump to pressurize the system. Hold your hand behind rear passenger-side of air plenum, pretty far toward the center and feel the Dampner for a gas leak. (Smell your hand.). Examine the Regulator for a leak. Look around the exterior, and smell the vacum line attached to it.

I'm not entirely sure how to test the Cold Start Injector. If your vehicle smokes when you start it (after many cranks), then that's a likely suspect. The fact that you say you smell the odor in the rear sounds like you might be smelling it coming from the exhaust pipe, pointing to the CS Injector. You could remove it and pressurize the system as mentioned above to see if it leaks.

My first Pressure Regulator leak was internal to the Regulator and fuel was sucked into the EGR pressure valve (a saucer-shaped disk on the passenger top front corner of engine), and into the EGR itself.

The leak I have now is around the body of the Regulator, leaking externally. It seems to be coming out of the crimp around the underside of the cap. The cap seems to be crimped to the body which threads into the fuel rail. It's leaking around that crimp.

That's everything I know about fuel odors (gas leaks). I'm about to order a Regulator from They're a lot less expensive than the locak Checker.

Also, whenever I had these leaks I noticed my mileage drop. I'm probably losing 1-2 gallons for every 15 gallon fill up.

Add your comment to this topic!