BAD FUEL PRESSURE

1991 Toyota Camry

Tiny

thomasthomas1

November, 28, 2009 AT 11:58 AM

Engine Performance problem
1991 Toyota Camry 6 cyl Front Wheel Drive Automatic 202000 miles

I have rebuilt a dozen engines in my life and am a fair shade tree mechanic. My car occasionally sounds and feels like it is running out of gas. It sputters and once in a while stalls but starts again like nothing has happened. Sometimes when I stop at a stoplight and start to go it stumbles for a second or 2 and then moves right a long or just quits but restarts immidiately and off we go. In the mornings it is hard to start - sounds like it is trying to pump the gas and eventually starts and runs fine till it starts it's occasional sputter problem. I replaced the fuel pump, filter, and fuel regulator but no difference in the problem. Yesterday when I pulled off the fuel rail regulator there was no pressure. I talked to a couple of mechanics at the local Toyota dealer and they had no answer but Toyota dealer wants $90+ to diagnose my problems. I'm stumped. Any ideas?

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12 Answers

Tiny

mhpautos

November, 28, 2009 AT 5:21 PM

Hi there,

Thank you for the donation, the first thing to do is hook up a fuel pressure gauge and run the engine, check the pressure readings with the Toyota specs, let me know what you get.

Mark (mhpautos)

Tiny

thomasthomas1

November, 30, 2009 AT 7:59 PM

There is no place to attach a fuel flow meter. I will have to cut a hose and splice in the gauge. Lets assume I have intermittent low fuel pressure. I've replaced everything from the gas tiank to the fuel rail. What else can it be?

Tiny

mhpautos

November, 30, 2009 AT 8:04 PM

The fuel pressure regulator will give this problem. And a leaking injector will drop static fuel pressure as well.

Mark

Tiny

thomasthomas1

November, 30, 2009 AT 9:06 PM

Thanks. I'll hook up a fuel pressure gauge tomorrow and ducktape it to my windshield and see what happens when the engine stumbles. It's late - take the rest of the day off!

Tiny

mhpautos

November, 30, 2009 AT 9:15 PM

O let me know how you get on, it's only 2 in the afternoon here, lots more to be done yet,

mark

Tiny

thomasthomas1

December, 3, 2009 AT 11:47 AM

I assume I am replying to your last reply - can't tell from this screen. I spliced a fuel pressure gauge between the fuel line from the tank and the fuel filter and drove the car. The gauge read 7 inches of something and remained steady even after the car warmed up and occasionally started to act like it was running out of gas. Apparently it isn't a fuel problem. I don't think it's a spark plug because it has stalled once or twice and one spark plug can't do that. I suspect the distruibutor cap and rotor. What do you think?

Tiny

thomasthomas1

December, 3, 2009 AT 12:24 PM

Attached is a photo of the cheap Chinese vacuum/fuel gauge with numbers all over the place and no instruction in the pamphlet in 6 languages. the needle initially sat at 0 until I used the gauge and now it sits on 2 with no adjustments. When the gauge is hooked up to the car and running the needle runs counterclockwise to the just south of ther big number 6 on the left hand side of the gauge. I assume that is showing 22 on the inside gauge. I don't know what that means. My Toyota manual says "with the vacuum sensing hose attached . . . 33-37 psi. Does that mean I have low pressure? What would cause that? I have replaced everything in thee fuel line.


http://www.2carpros.com/forum/automotive_pictures/440856_File0009_1.jpg

Tiny

thomasthomas1

December, 7, 2009 AT 3:57 PM

I finally got a fuel pressure gauge that works and set it up so I could read it while driving thee car. It read 40-50lbs depending on acceleration and did not drop when the car sounded like it was running out of gas. Since it has completely stopped a couple of times in the past I am ruling out a bad sparkplug and guessing I should change the distributor cap and rotor. I have never seen the check engine light come on. Whadaya think?

Tiny

mhpautos

December, 7, 2009 AT 7:27 PM

Well it looks as if the fuel system is ok, I think that we are having ignition problems, coil may be breaking down under load, this will not throw a code either.

Mark (mhpautos)

Tiny

thomasthomas1

December, 7, 2009 AT 7:34 PM

Someone else mentioned the coil. I think I'll cruise over to PullAPart and get one of everything. This ranks high among all the mysteries I've had as a shadetree mechanic since I was 14 years old. Make me an offer and the car is yours.

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