20 Most Recent 1988 GMC C1500 - Page 7 Questions & Answers

should be in the discharge line near the evaporator or out near the condenser

There should be a pigtail connector for trucks with or without rear bumpers. Did you look in the harness for a brown wire ?Same as the marker lights.

You'll have to figure out if it is a water pump, thermostat, or fan clutch problem.Could be other things too.One important question is how long does it take to boil over ?

The vacuum signal for the advance needs to come from a ported vacuum source on the carburetor, and not from manifold vacuum. Ported vacuum means little or no vacuum at idle, because the throttle plates at idle shut off the ported vacuum hole. Look for a vacuum tube coming from near the base of the carburetor. I have no resource to find a diagram. You may need to check a repair manual that your local library might have. Or purchase a Haynes or Chilton manual for around $25. Or join a forum for older Chevy/GMC trucks; somebody there could help you, I'm sure. Good luck.

The common reason for this is no charge inthe system due to a leak.

Hello! Just because you changed an engine does not mean that something unrelated hasn't occurred... In the fuse box is the 10A fuse in the far left row...Third fuse down?....If it is that is the ECM ignition Fuse...Tracing from the ignition switch it is a Pink wire that goes to a 3A in-line fuse and changes color to Purple/White then on to the ECM...When the fuse blows is there battery on the Pink wire?...If not...Pull the blown fuse...Disconnect the main Battery terminal...Set multimeter to the X 10 scale...Place one lead on each side of the pulled fuse socket and the other lead to bare metal ground...Does either side read resistance to ground?...If it does turn the ignition key from off...To ACC,.. to start and finally hold on run...Does the ground go away in any of those positions? if it does I would suspect one of the ignition switch wires is touching ground...Hard to find...But if you alligator clip the meter in place and wiggle the ignition wires you may see it come and go...Indicating where you are moving the harness the bare wire is pinched to ground...However...If the movement of the key does not produce a change...Remove the fuse box...Flip it over... identify the wire on the fuse that blows and trace it with meter in-place wiggling as you move through the harness until you find the bare spot touching ground...An easier softer way is to identify the color of the wire that connects to the ECM IGN FUSE...It will be Red, or Purple/White and go to the ignition switch...Cut it on both ends and run a wire of the same gauge from point to point...Guru...Saailer I’m happy to help further over the phone at https://www.6ya.com/expert/david_6df67de3b14de867

I just fixed one.There is a small pin that you can push out to remove the coupling that pushes into slave cyclider. Then you have to heat up silver soder or brazing that holds tube into square fitting that goes into slave. After removing do the opposite to braze in new tube. If you know were the line is bad cut it about 3 inches further away to make sure you have a good strong tube to splice from. You will need 2 compression fittings one to splice the one your adding and one for the original line. The fun part comes trying to bleed out air after its back together Takes at least 30 pumps between each opening of bleeder that's located on back of slave unit. And make sure that you never leave the resevour run low or dry on fluid while bleeding or your going to have to start over.You will need to keep adding fluid throughout bleeding process. Regular brake fluid is what is used for clutch. Good luck

firing order is 18436572 drivers bank 1 3 5 7, passenger 2 4 6 8