In this page we will illustrate how to replace the fuel pump in a 1992 Chevrolet S-10 Blazer, these steps will be similar for 1989-1995 S-10 Blazers.
This particular Blazer is equipped with a 4.3 L CPI engine, the fuel pump in this Blazer even though it was still working, it was not able to deliver the correct fuel pressure for the CPI Injection, throttle body injected S-10 Blazers only required 13 psi of fuel pressure, a CPI Injection requires 52 psi of fuel pressure.
NOTE: If your Blazer has low fuel pressure and you don't know if the problem is the pump or the fuel pressure regulator, visit our page " fuel pressure regulator " .
The fuel pressure test port in a 4.3 L CPI engine is located behind the intake plenum near the distributor, once you are sure that your problem is caused by a bad fuel pump follow the steps described in this page for its replacement.
Before you start this job, raise the Blazer with a floor jack and secure it with jackstands under the rear axle and the front control arms, next remove the negative battery cable followed by relieving the fuel pressure by depressing the valve in the fuel test port.
As shown in this picture, remove the screws that secure the fuel inlet assembly to the body.
Next, undo the hose clamps on both fuel inlet hoses and slide the hoses off.
NOTE: Make sure that the fuel tank has less than half of its capacity, otherwise fuel will spill out.
If you want to make this job easier, now that the fuel inlet hose has been detached from the tank, you can insert a small hose to siphon the remaining fuel in to an approved container.
Remove the bolt that attaches the fuel pump ground wire to the frame.
Place a floor jack with a wooden block under the fuel tank to hold it in place as you remove the bolts that attached the fuel tank straps to the fuel tank, remove the fuel tank straps and set them aside.
Carefully, tilt the fuel tank slowly, once you can insert your hand between the fuel tank and the frame unplug the fuel pump electrical connector as shown in the picture.
Here is the hard part: You need to tilt the fuel tank enough to access the fuel line connections without damaging the fuel lines, the space is quite limited but with a little atience it can be done, first remove the hose clamps and the rubber hoses, next, as shown in the picture; using two wrenches, one to hold the fitting from turning and the other one to loosen the fuel line, separate both fuel line fittings from the fuel pump module.
Once the fuel lines have been separated from the fuel pump module, lower the fuel tank all the way down and slide it out from under the Blazer, using a wide chissel and a hammer, remove the fuel pump module retaining ring, next pull the entire assembly all the way out.
It is recommended to cover the opening while you remove the fuel pump from the module, to keep dirt from entering the fuel tank.
Set the fuel pump module on a work bench, start by removing the old fuel pump strainer as shown in the picture.
Next, unplug the fuel pump electrical connector.
Loosen the fuel pump hose clamps and separate the fuel pump from the bracket.
Remove the old rubber insert, install the new one provided with the new fuel pump.
Slide the new fuel pump hose provided with the pump slightly further than its normal position to allow enough clearance to install the fuel pump, slide the new hose clamps in.
Slide the new sleve over the new fuel pump, install the fuel pump on the bracket.
Make sure that the pump is facing in the right direction, tighten the hose clamps and plug the fuel pump connector to the new fuel pump.
Install the new fuel pump strainer.
Inspect the fuel line seals, lubricate them with petroleum jelly for easy installation.
Install the new fuel tank/fuel pump module mounting gasket, install the module back on the fuel tank, install the retaining ring back on making sure that it is turned all the way.
The installation of the remaining items is reverse of removal, make sure that you tighten all bolts, fuel lines and hose clamps as you install them back on on their original locations.
Once you are done installing all the components back on, connect the negative battery cable and turn the key on without starting the engine, listen for the fuel pump, it should come on for a couple seconds, look for fuel leaks, if you don't see any, proceed to start the engine.
Allow the engine to run for a few minutes, turn it off, look for fuel leaks again, double check that all components are properly installed and properly tightened, if they are, lower the Blazer to the ground and take it for a test drive, it should run as good as new.