Fuel Pump Pressure Test

Loosen clip on fuel line between pressure regulator and fuel distributor pipe. Cover fuel line fitting with shop towel and loosen fitting slowly to relieve pressure.
Install a fuel pressure gauge between fuel pressure regulator and fuel distributor pipe. See Figure.
Start engine. If engine will not start, go to step 6. Bleed air from fuel line to pressure gauge. Measure fuel pressure at idle. Disconnect fuel pressure regulator vacuum hose. Note fuel pressure at idle with vacuum hose disconnected. See FUEL PUMP PERFORMANCE table.
If fuel pump pressure is low, check for fuel leaks, restrictions in intake side of fuel pump, leaking injectors, faulty fuel pressure regulator or faulty fuel pump. If fuel pressure is too high, check for restrictions in return line to tank or faulty fuel pressure reguator. If fuel pressure did not change when fuel pressure regulator was disconnected, replace pressure regulator.
Disconnect and plug vacuum hose from fuel pressure regulator. Stop engine. Fuel pressure should only drop slighty after engine stops. If pressure drops drastically, check for leaking injectors, fuel pressure regulator or bad check valve in fuel pump. I-Mark has an in-tank fuel pump.
If engine does not start on, by-pass fuel pump relay to check for fuel pressure. Connect battery voltage directly to Red/Blue (1.5L Turbo) or Red/Green wire (1.6L) at fuel pump relay.
On 1.5L Turbo, fuel pump relay is in right rear corner of engine compartment. On 1.6L, fuel pump relay is 4-pin relay in center of firewall (6-pin relay in center of firewall is A/C relay).
On both models, check for fuel pump operating sound and fuel pressure. If fuel pump does not operate, check fuel pump and circuit.

NOTE: If engine will not start, fuel pump relay can be by-passed. Also see ENGINE CRANKS BUT WILL NOT RUN in this article.