GMC Repair: 88 GMC random no start when cold, oil pressure switch, fuel pressure regulator

Question
I have an 88 GMC K 1500. Rebuilt crate motor with 11,000 miles. My problem is when the vehicle sits for a while, mainly overnight, it will not start. It trys to turn over but will not. I've checked fuel pressure from the inline fuel filter to the motor and it's fine. Fuel pump, fuel filter, gas tank, fuel pressure regulator, electronic spark control module, ignition module, computer, new tune up (cap wires rotor and plugs), map sensor, have all been replaced. The last thing I just did was replace the ignition module and it started fine for 2 days. Now nothing. I tried for 2 days. Then the next afternoon, I tried and it started right up. I'm thinking the coil or pickup coil could be bad. Now I've heard that the coolant temp sensor will play a factor when the temp is cold. Also heard the same about the oil pressure switch. I'm running out of options and also things to replace. It all started when the first thing I did was replace the cap, wires and rotor to do a tune up.  Please help.

Answer
First off, I do not mean to be rude and or disrespectful, But obviously GUESSING has not solved your problem from the amount of parts that you have already installed.

I need to know if you have an ignition problem or a fuel problem. When the vehicle fails to start next time, See if your getting any ignition from the coil.

If you get no ignition from the coil, Pull the distributor cap off and remove the rotor. loacte the 2 wire connector at the ignition module which goes to the pickup coil within the distributor. using an OHM meter check each wire to be sure that it not reading as if it were grounded, Do the same for the other wire. If neither show any type of grounding, Use your ohm meter across both terminals and tell me how many ohms of resistance that you are reading.

Make sure that when you are doing the above said tests that you manipulate each wire with the meter attached. GM is famous for faulty intermittent pickup coils as they either have an intermittent fault within the pickup coil and or one of the 2 wires is rubbed thru on the bottom side of the wire(s) causing an intermittent short to ground.


Perform the above tests and let me know.

If the coolant temp was faulty you would in most cases have a CHECK ENGINE light illumination on the dash panel and or the spark plugs would be soaked with fuel. I also need some past history of any type of repairs of any kind what-so-ever that have been performed on this vehicle.

As afr as a faulty oil pressure switch, This is possible but very unlikely.

Are you positive that you assembled the distributor cap components correctly such as the ground strap, the metal ground bracket that you have to swap into the new cap as well as making sure that you installed the rubber insulator rubber for the carbon button in the center of the cap ?.


Take another look at your newly installed components.

One thing to always remember about new parts, Just because they are new does not mean that they can be defective.

If you have the ability to e-mail pictures of the cap showing the components so that I can see if you may have possibly forgot to install one of the components incorrectly, E-mail them to me at:

meperganfortis@msn.com


and I just may see something that you are overlooking.



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