Bad Fuel Pump?

[FLIP K1DD]

well im still trying to figure out what is causing my 94 to run rough and while at idle. ive seafoamed her, ive changed spark plug wires (even tho they were only 3 months old), fixed the timing, changed the fuel filter & transmission, and cleaned the throttle body. still running rough and kinda coughing at idle.

So me and my dad got a fuel pressure gauge (or whatever its called) and hooked it up. the cars ratings are supposed to be 38-44psi when the key is turned to ACC mode and 38-44psi at idle. Then +33psi when its shut off for 5 mins straight after. My dads car program thing says that if the readings are above or below it we need to change the fuel pump. If its below we need to check for vacuum leaks.

THe readings we got were 47psi on ACC, 47psi at idle, and like 38psi when shut off. It is off, but not by much.

So...since i have updated everything in this car except for the fuel pump and injectors..is this in fact what is causing my dilemma?

[cj0609]

what happens when you try to take off, Or if you try to pass on the highway.

[ghettosled]

fuel pump sounds fine.

how is the idle air control valve? how are the spark plugs? what about the distributor cap?

[Mike Gerber]

Clean the throttle body again, being sure to spray the cleaner liberally down in to the square or diamond shaped hole in the base of the throttle body. That hole leads to your idle air control valve, where your problem probably exists. Spray the cleaner down there and let it soak for about 10 minutes. Then reassemble everything and take the car for a 10 or 15 minute ride to clear all of the cleaner out of the system. The car will be a bit hard to start and it may die on you once or twice during your ride as the cleaner is being burned up by the engine, but that should stop by the time you come back from your ride. Here's a good thread on cleaning the throttle body that has a good picture of the hole leading to the idle air control valve:

How to: Cleaning Throttle Body -4 Cylinder Engines- With Pictures

Mike

[frenum49]

Have you figured out which cylinder is missing? If it is just one you can narrow it down to a few issues. If it is a random miss across all cylinders its an entirely different story. Start the car and pull 1 plug wire at a time from the cap using well insulated pliers listening for changes in the engines idle. If the engine boggs after pulling a wire, put it back on and goto the next until you pull one that doesn't change the idle. That is the dead cylinder. If you have good spark on the wire then your problem is most likely a crappy injector on that cylinder assuming of course that you don't have any mechanical damage to that cylinder. Before changing the injector do a compression check on all cylinders making sure that the dead cylinder falls at or near the other good ones. Also tap on the cars computer a few times with a screwdriver handle while it is running. If the car stumbles or stalls while doing this replace the computer as this is certainly the cause. I see bad computers monthly where I work that are to blame for mystery misfires.

[Camry LE 94]

Originally Posted by frenum49

Also tap on the cars computer a few times with a screwdriver handle while it is running. If the car stumbles or stalls while doing this replace the computer as this is certainly the cause. I see bad computers monthly where I work that are to blame for mystery misfires.

This isn't my thread but I was just wondering where you'd find the computer...

[frenum49]

Originally Posted by Camry LE 94

This isn't my thread but I was just wondering where you'd find the computer...

Should be behind the glove compartment on that year. There are a few other modules down there as well. You want the big one.

[Camry LE 94]

Originally Posted by frenum49

Should be behind the glove compartment on that year. There are a few other modules down there as well. You want the big one.

oops i forgot to post my vehicle's year. the 94 was my first camry, until the engine went kaput. i now have a 96 LE... would the computer be in the same or a different spot

[frenum49]

Originally Posted by Camry LE 94

oops i forgot to post my vehicle's year. the 94 was my first camry, until the engine went kaput. i now have a 96 LE... would the computer be in the same or a different spot

Probably the same area.

[Camry LE 94]

Originally Posted by frenum49

Probably the same area.

alright thanks