Do you have to release the fuel pressure on 79 Seville prior to changing the fuel filter if so will removing fuse and starting work?

Because of the age of the car, I'm not exactly sure where the filter is - for most Cadillacs it is on the fuel line under the car near the front on the inside side of the frame. However, that usually won't cause your problem - the fuel pump is probably ceased.

Did you follow these procedures?

1. Release the fuel pressure from the fuel line as follows:
   
   1. Remove the fuel pump fuse at the fuse box.
      
   2. Start the engine.
      
   3. After the engine stalls, crank the engine two or three times to make sure that the fuel pressure is released.
      
   4. Turn the ignition switch OFF and reinstall the fuel pump fuse.
      
2. Loosen the hose clamps at the fuel inlet and outlet lines. Wrap a shop towel or absorbent rag around the filter, then slide each line off the filter nipples.
   
3. Remove the fuel filter and old hose clamps.
   

To install:

1. Place new hose clamps on the fuel inlet and outlet lines.
   
2. Connect the fuel filter, being careful to observe the correct direction of flow, then tighten the hose clamps.
   
3. Start the engine and check for fuel leaks.
   

Always use a high pressure-type fuel filter assembly. Do not use a synthetic resinous fuel filter

Hi,

IMPORTANT: Do not skip the fuel system pressure release step. Injury and other damage can result!
Safety Step! Relieving Fuel System Pressure
· allow engine to cool
· relieve fuel system pressure
· put on your eye protection
Before you begin the job of replacing your fuel filter, you must relieve the pressure in your fuel system. A fuel injection system operates under very high pressure. If you don't release this pressure before you start unscrewing fuel lines the result can be explosive. Do this before you attempt to change the fuel filter.
To release the pressure in your fuel lines (and fuel filter) you'll need to locate the fuel pump fuse in the fuse box. If you don't have a fuel pump fuse, find the relay that operates the fuel pump. Once you've found the fuel pump fuse or relay, start the car. With the engine running, pull the fuse or relay out. If you pulled the right one, the engine will quickly die. Since it's using all of the pressurized fuel in the system, the fuel lines won't be pressurized when you crack the fittings on your fuel filter.
Now that you've relieved the fuel pressure you can remove the old fuel filter.
If you didn't do this yet, you must go to the previous step and do it. Very dangerous!

Best regards.

Fuel Filter REMOVAL & INSTALLATION CAUTION
NEVER SMOKE WHEN WORKING AROUND OR NEAR GASOLINE! MAKE SURE THAT THERE IS NO ACTIVE IGNITION SOURCE NEAR YOUR WORK AREA! 1970-83 Carbureted Engines The fuel filter is located on the right inner fender in the engine compartment. It is a disposable cartridge type.

1. Using a pair of pliers, expand the hose clamp on one side of the filter, and slide the clamp further down the hose, past the point to which the filter pipe extends. Remove the other clamp in the same manner.
2. Grasp the hoses near the ends and twist them gently to pull them free from the filter pipes.
3. Pull the filter from the clip and discard.
4. Install the new filter into the clip. Push the hoses onto the filter pipes, and slide the clamps back into position. Start the engine and check for leaks. Fig. 1: Fuel filter - 1970-79
   Fig. 2: Fuel filter - 1980-83
   

1984-86 Carbureted Engines The fuel filter is located on the inside of the frame above the left rear spring front shackle. Changing the filter is VERY awkward. Since it is in-line and below tank level, fuel will pour from the fuel lines when they are disconnected from the filter. The only way of preventing this, is to siphon all of the gasoline from the tank before replacing the filter. Another possible method is to clamp and plug the fuel line, but this is not recommended because of the danger of leaking fuel or damage which could occur to the fuel line when clamped. It would, therefore, be a good idea to run the tank almost dry before changing the filter. Once the tank is dry, disconnect the fuel lines at the filter, unbolt the old filter and install a new one. Reconnect the fuel lines, fill the tank, start the engine and check for leaks. Fig. 3: Fuel filter - 1984-86
Fig. 4: Remove the shield mounting bolts
Fig. 5: Remove the shield, if necessary for fuel filter removal
Fig. 6: Removing fuel filter - always replace fuel line clamps
Fuel Injected Engines WARNING
Never attempt to remove the fuel filter without first relieving the fuel system pressure!

1. Release the fuel pressure from the fuel line as follows:
   1. Remove the fuel pump fuse at the fuse box.
   2. Start the engine.
   3. After the engine stalls, crank the engine two or three times to make sure that the fuel pressure is released.
   4. Turn the ignition switch OFF and reinstall the fuel pump fuse.
2. Loosen the hose clamps at the fuel inlet and outlet lines then slide each line off the filter nipples.
3. Remove the fuel filter.
4. Replace the fuel filter. Always be sure to use new hose clamps. Fig. 7: Fuel filter - 1986-88 VG30i
   Fig. 8: Fuel filter - 1986-88 Z24i
   

this is not a problem follow the steps below.Some might say it's a pretty straight forward job. The filter is under the rear of the car, just above your rear axle-it is secured by a single fastener, and has 3 "quick release" connections to the nylon fuel lines.
To Release Fuel Pressure:


Turn the ignition OFF.
Disconnect the battery negative cable in order to avoid possible fuel discharge if an accidental attempt is made to start the engine. Refer to Battery Negative Cable Disconnect/Connect Procedure in Engine Electrical.
Loosen the fuel filler cap to relieve the fuel tank vapor pressure.
Remove the cap from the fuel pressure service port.
Remove the engine identification cover nuts and cover.
Connect the SA9127E , or the J 34730-1A to the fuel pressure service port connection. Wrap a shop towel around the port while connecting the gage in order to avoid spillage. Refer to Fuel Pressure Gage Installation and Removal .
Caution: Do not drain the fuel into an open container. Never store the fuel in an open container due to the possibility of a fire or an explosion.
Install the bleed hose of the SA9127E , or the J 34730-1A into an approved fuel container.
Open the bleed valve on the SA9127E , or the J 34730-1A in order to bleed the fuel system pressure. The fuel connections are now safe for servicing.
Place a shop towel under the fuel pressure service port to catch any remaining fuel spillage.
Disconnect the SA9127E , or the J 34730-1A from the fuel pressure service port connection. Refer to Fuel Pressure Gage Installation and Removal .
Drain any fuel remaining in the gage into an approved fuel container.
Install the cap to the fuel pressure service port.

AND/OR PRIOR TO THAT...
a common "cheater" practise is to remove the fuel pump fuse and run the engine until it stalls, then crank it (wont start) for 10-20 seconds (1-2 automatic crank cycles) to minimize pressure in the lines.
ALWAYS WEAR SAFETY GLASSES AND DONT USE AN INCANDECENT (BULB TYPE) TROUBLE LAMP - FLOURESCENT ONLY!! (they've started more undercar fuel fires than almost any other source). So please be carful as this is a fuel job and do not start a fire.
If you need further assistance or have any questions. Please feel free to follow up with a comment. If this solution helped you in your problem please feel free to rate the solution. Thanks, Midwest-tek

FUEL INJECTED ENGINES The fuel filter on fuel injected vehicles may be located in one of two locations. On all 1976–79 vehicles except the Seville, the filter is mounted in the engine compartment near the fuel pump. On the 1976–79 Seville, and all 1980–85 vehicles, the fuel filter is located on the left side of the chassis just ahead of the rear axle. On 1986–89 vehicles, the filter can be found near the frame, in back of the left front wheel. There are two types of fuel filters used on the gasoline fuel injected vehicles, the one-piece disposable inline filter, used on all 1982–86 250 and 1988–89 273 V8 engines, and the replaceable element type filter used on all the other engines. CAUTION
Fuel is under high pressure: if the steps below are not followed, the fuel could spray out and result in a fire hazard and possible injury.

1. Disconnect the negative battery terminal.
2. Release the pressure from the fuel system:
   • Without pressure fitting: Cars without a pressure fitting in the fuel line, cover the fitting to be removed with a shop towel while loosening so that fuel will be absorbed. Dispose of gasoline properly.
   • With pressure fitting: Locate the pressure fitting in the fuel line and remove the protective cap. Loosely install a special valve depressor (G.M. tool no. J-5420) on the fitting. Wrap a towel around the fitting to block any spray and slowly tighten the tool until the pressure has been relieved.
3. Replace the filter as follows:
   1. On the replaceable element type filter; the fuel filter element is replaced by unscrewing the bottom cover and removing the filter element. Replace the element and gasket with an AC type GF 157 or equivalent. Hand tighten the bottom cover.
   2. On the in-line disposable type filter; the fuel filter canister is replaced by loosening the fitting on the end of the filter, then use a pair of pliers to expand the clamp on the other end and slide it down past the point where the hose extends over the inlet of the filter. Gently twist and remove the hose, unscrew and remove the fitting. Remove and discard the old filter. Install the new filter into the hose and replace the clamp. Reinstall the fitting, and check for leaks with the engine idling. NOTE: A dry fuel system on cars equipped with EFI/DFI may require a substantial cranking period before starting. Be sure to crank the engine in short bursts, allowing time for the starter motor to cool between each burst. Fig. 1: Fuel filter location, disposable type — 1986–87 8-250 and 1988–89 8-273 engines
      Fig. 2: Fuel filter location, sealed type — 8-250 and 8-273 engines
      Fig. 3: Common fuel filter location — lower right corner Fig. 4: Removing the fuel filter hose clamp Fig. 5: Removing fuel filter lines — always use a back-up wrench Fig. 6: Removing fuel filter mounting

Start the vehicle, and remove the fuse or relay for the fuel pump. Then check for any pressure remaining at test fitting on the fuel rail.

Fuel filter for SRDE20B15 engines (00-01) are in the tank mounted on top of the fuel pump inside the fuel assembly. Release fuel pressure by starting car and removing the fuel pump fuse, open fuel filler cap, remove rear seat, open fuel assembly cover by turning the screws clockwise, remove harness, remove fuel line quick connector carefully (if pressure was not relieved, gas will leak, make sure to release pressure completely), take out fuel assembly (watch out for fuel level sensor and temp sensor thingies). Pop top off the fuel assembly and pop fuel level sensor unit with screwdriver. Remove fuel pump harness connector, quick connectors. Pop top off completely, pop fuel filter+pump assembly out, remove fuel pump bracket on the bottom of it. Push fuel pump down from the top harness connector, Take out the rubber grommet (very important - car won't start) between fuel filter and fuel pump, put it into new fuel filter, and reverse all the steps to close it up.

1) jack-up left front of car (drivers-side)and remove wheel.
2) Remove plastic inner fender .
The maintenance schedule is every 12-thousand miles.

Caution prior to removing fuel filter-
Pull the fuel pump relay or fuse while engine is running, this will disable the electric fuel pump and release fuel pressure in line.

You can guess all day, best to do a fuel pressure test then you will know. Its simple and cheap to do, you can rent the guage at auto zone, and they also can tell you what the pressure should be.