20 Most Recent 1988 GMC S-15 - Page 4 Questions & Answers

You dont state which engine
4 cyl 1-3-4-2
6 cyl (2.8l) 1-2-3-4-5-6 No 1 passenger(RH) side front
6 cyl (4.3l) 1-6-5-4-3-2 No 1 driver side(LH) front
Distributor rotation for all is clockwise (except 1.9l 4 cyl which is anti-clockwise)

On what size motor?

You'll need a bench vice for this. A few sockets help as well. Once you get the shaft off the truck, put a smaller diameter socket on one side and a much larger diameter socket on the other and sandwich in a vice. Compress vice to drive the U-Joint through shaft (smaller socket will drive the one side through the other with the much larger socket). Installation is the reverse of removal.

black wires are normally ground wires.....if nothing has gone bad..then nothing is really wrong...but just to be safe get it checked by a local mechanic

GM S10/S15/Sonoma Pick-Ups 1982-1993 Repair Manual Electric Fuel Pump - REMOVAL & INSTALLATION

1. Properly relieve the fuel system pressure.
2. Connect the negative battery cable.
   

Be sure to keep a Class B (dry chemical) fire extinguisher nearby.

CAUTION Due to the possibility of fire or explosion, never drain or store gasoline in an open container.

1. Drain the fuel tank, then remove it from the vehicle. refer to the procedure found later in this section for details.
2. Using the GM fuel gauge sending unit retaining cam tool No. J-24187, J-36608 (or equivalent) or a brass drift and a hammer, remove the cam locking ring (fuel sending unit) by twisting counterclockwise. With the locking ring released, carefully lift the sending unit from the fuel tank.
3. Remove the fuel pump from the fuel sending unit, by performing the following procedures:
   1. Pull the fuel pump up into the mounting tube, while pulling outward (away) from the bottom support.
      

When removing the fuel pump from the sending unit, be careful not to damage the rubber insulator and the strainer.

1. When the pump assembly is clear of the bottom support, pull it out of the rubber connector.
   

To install:

1. Inspect the fuel pump hose and bottom sound insulator for signs of deterioration, then replace, as necessary.
2. Push the fuel pump onto the sending tube.
3. Using a new sending unit-to-fuel tank O-ring, carefully lower the sending unit/fuel pump assembly into the fuel tank.
   

When installing the sending unit, be careful not to fold or twist the fuel strainer or it may restrict the fuel flow.

1. Secure the sending unit by turning or driving the lockring clockwise and into position under the tabs.
2. Install the fuel tank assembly to the vehicle.
3. Connect the negative battery cable and check for proper pump operation.

Good luck (remember rated this).

on the 88 gmc the fuel pump is located in the gas tank

Under the left side of the dash. Left of the steering column near the parking brake.

hi, the firing order is 1,6,5,4,3,2 clockwise rotation on the distributor. number one cylinder on the cap should point at the ignition coil tower.

check the bulbs

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start checking fuel pressure easier then changing pump re check that all is plugged in by air cleaner

Start at your spark plugs follow them "the wires" (all of them) they should all be located at one central place. This is your cap sometimes they are black or brown or hope this helps

Follow any ignition wire back from the spark plugs; this will bring you to the distributor cap and once this is removed (clips or two screws), the rotor will be underneath and this just pulls straight up and off.

The firing order is almost always cast in the intake manifold in front of the throttle body.But here it is 1-6-5-4-3-2....Rotation is clockwise. The cosest front terminal on the cap is #1.

massair frow sensor

if i has started knocking you probably have shards throughout the engine, best bet is to buy a reconditioned short block , they even come with a guarantee if you have it professionally installed

you will need a gear puller

fault code 23.Inlet air temperature sensor signal showed an air temperature below -22� F after the engine has been running for 5 minutes,,,,,code 23: MAT low temp indication, sets if the manifold air temperature sensor connections or wires are open for 3 seconds

that being said I'd start by unplugging the wires and make sure the connections are not corroded if so clean them and plug em back in if that does not work try the air charge sensor (the problem when mine had this code) with it acting normal after being shut off and restarted I would lean more toward a corroded or loose connection.

THE ONLY REASON IT MOVES WHEN COLD IS THE FLUID IS THICKER AND THAT GIVES THE CLUTCHES A LITTLE MORE GRIP IN THE CLUTCH DRUM OF THE TRANSMISSION, THE OTHER POSSIBILITY IS THAT THE TRANS HAS A INTERNAL HYDRAULIC PRESSURE LEAK THAT SEALS COLD, HAVE BEEN A DEALER TECH FOR 40 YEARS AND I KNOW YOU WILL HAVE TO TEAR THIS TRANS DOWN AND REBUILD IT FOR EITHER PROBLEM, THERE IS NO QUICK FIX FOR THIS ISSUE