1988/302/C6/4x4 Pulled it out of storage last week since the weather warmed up. Filled it with gas and been driving it to work every day with no problems. Friday morning, started it up, drove it to the bank, went in cashed my check, came back out started it up drove it to my grandma's house. Left there an hour later started it up drove it to work. Came out on break to go to the store, hit the key and it would sit there and crank but not fire. Sprayed carb clean in the intake, still couldn't get it to fire. Smelled like it was getting fuel anyways. Checked for spark getting spark. Nothing appeared to be wrong with the truck but I stayed out there till about midnight with no luck before I called it a night. Went back saturday morning, hit the key and she fired up. Drove to the gas station, shut it down, filled her up, started it and drove it home. Went to go to my buddy's house about an hour later, got in it, hit the key, and it would sit there and crank, but not fire. Same symptoms. What the hell?

 

It threw an EGR code, I've never replaced the EGR so I went ahead and put one on, didn't expect it to correct the problem but I did it anyway. Test drove the hell out of it yesterday, I would start it, drive it around, bring it home, park it, repeat. I did that intermittently all day, started it probably 10-15 times between noon and midnight. Put 25 miles on it doing so. Ran great, started every time. Come out this morning to take it to work, got in, hit the key, and she fired up. Sat there for about 30 seconds and she just died. Hit the key and she started again, but was running rough. Gave it throttle and blew black smoke out of the tailpipes...when I let off the gas she just died again. I decided screw it and drove Ol Reliable to work instead but what the **** man. I drove that truck all around yesterday and it ran great.

 

You have a good one there.
If you list all the possible causes and go down the list you may find it without too much trouble. The problem is you are getting spark, but possibly not hot enough to ignite the mixture. Until you can pin it down through different tests how about we make a list of the possibles.
Ign switch
coil
pick-up in the dist
loose ground wire in dist
rotor
ign module
distributor worn
wiring and connections from ign switch to coil or to dist to ign module
ECA (computer) or Connections at plug that connects to computer
Coolant temp sensor and wiring to sensor( sometimes coolant gets past sensor and into wires)
That is only some of the possibles.
Something to give thought to , the black smoke usually a result of an overfueling condition which could be from continued cranking and injecting, but no fire. If the injectors are working that would eliminate the dist pulse to the computer.
I'm sure some people will be able to add to that list. THE CRAZY PART IS IT COULD BE NONE OF THE ABOVE.

 

Ignition Switch, Coil, Distributor, Cap, Rotor, Plugs, Wires, ECA, and Coolant Temp Sensor all new <5k miles. ECA brand new <200 miles.
You're not the first person to say distributor module. I heard that the auto parts store will test them so I'm going to pull mine off and have it tested.

 

It is important to know if you had the exact same problem before replacing all those parts. You are not providing all the info until a suggested possibility is offered. Please disclose all steps taken and all parts changed so time can be saved and a possible worthwhile suggestion could be offered.
Your module could test good and have poor or loose connections at it's plug.
I really do not feel that there is a defective part as much as a poor connection in the system.

Sometimes a poor ground cable or connection can rob the system of the required power to operate because all the available power is being used trying to start the engine.

 

Well, before the problem that I had was not this same issue. I could get the truck started with starter fluid, after that it would stay running. I replaced coil, cap, rotor, plugs, wires, fuel pump, oil pressure switch, fuel filter, ignition module, ignition switch, distributor, relays, fuel injectors, coolant temp sensor, MAP sensor, idle air control valve, took out smog pump, and put a brand new computer in it. The ECM was the culprit of my last issue, after i replaced it I did not have the same problem, this is a new problem. this time i can't get it to fire even with the starter fluid. Sometimes it does crank kind of slow when I know I should have plenty of battery. is there a good way to find and locate bad connections/grounds?

 

Just because a part is "new" , doesn't mean it can't be defective especially if the parts came from chow mien land. Whenever possible I try to stick with OEM parts to keep the problems to a minimum.
The best way to check for poor connections is to first do a good visual inspection. Some things like a broken wire inside the insulation may look good , but can be partially separated inside. That's when voltage drop testing helps find those. And even then, if it's making a good connection at the time of testing , vibration, engine movement , bumps can cause things to move enough to separate the connection .
This is what I would try,
At the time it will not fire/start, that is when you need to start from the beginning of how the spark is generated and trace from there.
There is also the possibility of a poor ground from the battery to the engine. That is one of the basic checks that should be done. Just looking at the connection does nothing to confirm it's quality. It needs to be removed, cleaned and replaced .
Since it would start and run after using a "little" starting fluid brings the fuel pump system into the picture. The pump could be getting ready for retirement and is letting you know before it goes on vacation. A fuel pressure check at the time it refuses to start would be a good move to consider. You have replaced a lot of parts and are assuming all the "new" ones are good. That is the problem with replacing parts with the shotgun approach.
If you carefully unplug and look at the connections to make sure they are clean is as good a place to start as any.

 

Before I replaced the ECM was when it would start with starting fluid. Now when it won't start it won't start even with starting fluid; so I will do a fuel pressure check but I'm not confident that I have a fuel issue. I've never experienced a problem like this and I'm not sure whether I'm more confused or frustrated.

 

Don't feel bad !
There are experienced techs that after doing all the right tests and correcting what appeared to be the problem and still could not get what they wanted to happen me included. Anybody that says they were right and on the money all the time just hasn't had their time in the barrel yet .
MANY times it was something so simple we never even gave it a thought, but nevertheless it threw us for a loop. You , IMHO , are doing the right thing by asking for assistance and if you think you are alone go on to the IATN site. Some of the best heads in the trade are on there to help and we still can get stumped . Hang in there this is one of those situations where persistence pays.

Please be careful when using starting fluid, too much can and will take the tops off pistons among other things.

 

When it wouldn't start this last time, I had a spark checker with me, and I appear to be getting spark everywhere, but like i said, would not fire even with a shot of starting fluid.