1990 GMC Sierra - Page 3 - Answered Questions & Fixed issues

Check for the right location by turning crankshaft till at zero degrees on the pointer scale-the timing scale. Then look at rotor position: should be either pointing to No. 1, or will be pointing directly opposite if you are on the exhaust stroke (TDC) of No. 1. Turn the crank one revolution, and come back to the zero mark. If rotor was pointed opposite before, it should now be directly at the number 1 plug wire tower.

Fluid and filter will not result in loss of just one gear...yes your going to have to take the tranny out and get it overhauled or replaced Btw, I’m available to help over the phone in case u need at https://www.6ya.com/expert/sean_54c3a3dc48a7773c

inside the transmission Btw, I’m available to help over the phone in case u need at https://www.6ya.com/expert/sean_54c3a3dc48a7773c

Try spraying a couple shots of carb spray down the throttle body while a helper cranks it over. If it starts and runs for a couple of seconds check fuel pressure and the resistance of the injectors. I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

Time for a complete rebuild

Blend door malfunction. check for a broken door, or bad door actuator.

I assume this is the HEI coil. If not let me know and I can help further.Instructions

1. • 1 Put your safety first. Engage your emergency or parking brake. Also, disconnect the negative battery cable from the Chevy Corvette's battery.
   • 2 Make the ignition system visible. On older models, you may need to remove the plenum extension for the intake manifold using a screwdriver or wrench. For newer models, remove the cover for the fuel rail.
   • 3 Look for additional parts that you need to remove. For HEI systems, you need to access the distributor through the cap. Other systems use an ignition coil harness connector.
   • 4 Disconnect the secondary wires, or spark plug wires, from the ignition coil. Tag each wire with masking tape, so you know which terminal to reconnect the wire to. If you connect the wrong wires to the terminals, your Chevy Corvette won't start.
   • 5 Detach the ignition coil mounting bolts and remove the ignition coil. The amount and type of bolts vary depending on the part number for the Corvette ignition coil. You may also need to remove the ignition coil arc seal.
   • 6 Clean the distributor cap with a soft cloth. Now is a good time to replace the seal, if needed. Insert your new ignition coil and secure it in place. As you reassemble, use a Torque wrench to tighten the mounting bolts or screws to 13 inch pounds (1.5 Nm) of torque.
   • 7 Reassemble the rest of the parts and reconnect your battery. Start the Chevy Corvette to ensure the repair worked.

Is the check engine light on ? Have you checked the computer for trouble codes ?The O2 sensor could have failed, or the fuel pressure regulator, or a list of other things.

Stop throwing parts at it.Is it a 5.7 eight cylinder ? I'm not aware of a 1990 model with a 4.7 engine.If the check engine light is on you should check the computer for trouble codes next.It could be a faulty injector, or fuel pressure regulator, or any number of things.

could be as simple as thermostat or a pain in the but heater core.

Broken linkage, or the clutch itself has failed.

yes it will be a little less

you mean the condenser in front of the radiator?if the fins are smashed and blocking air then yes it can cause an overheat., the evaporator is in the box behind the dash and will not cause overheat but if defective will stop AC from working.

Check the radiator fan to make sure it is turning at full speed. Could be a bad fan-clutch.

No.The evaporator for the ac would have nothing to do with the engine coolant.

HelloThe Engine and Automatic Transmission (not applicable to manual transmissions) in this vehicles drive train are fully electronically controlled by a computer called the PCM and TCM (Power Train Control Module, Transmission Control Module). When a problem like this or other drive-ability related problems occurs the computer stores a record of the problem (there are of course some exceptions to this, like the fuel pump, engine coolant temperature sensor and MAF sensor for instance) in the form of a fault code in its memory, to read these fault codes you must have the systems memory scanned with a special tool. Once the fault code(s) are read you then must perform the appropriate diagnostic testing to find and resolve the problem(s) DO NOT REPLACE ANY PARTS UNTIL A TRAINED TECHNICAIN HAS DIAGNOSED THE PROBLEM TO AVOID SPENDING YOUR HARD EARNED MONEY ON PARTS THAT MAY NOT CORRECT THE PROBLEM. Also always check fuel pressure for correct spec for your make and engine type.

Torque coverter is bad.

solved by owner

are you sure is the transmission which is giving you the noise or the differential ? check it out first .

To review, you have two temp sensors, one for the gauge on the dash and one for the computer. If you unplug the sensor for the computer the reading will be minus 30 degrees or over 300 which will make it very hard to start. Unplugging the sensor for the gauge would have no effect on the computer.According to the wiring diagram, the wire for the temp gauge is green, and the wires for the temp sensor for the computer are yellow and black.