Can you test the ignition control module? i have a 1988 chevy g20 van w/5.7 motor it sat for a long time . it ran good and then one day it would start i put in a new fuel pump,fuel filter,coil,plugs,dist cap,rotor,sparkplug wires,one fuel injector, cleaned fuel tank and put fresh fuel in tank, also took apart to make sure timeing chain didnt jump a tooth it was ok still wont start it has spark wha tcould it be

check egr valve for carbon and proper function --also check cat converter possible clogging

make sure of connection of fuel pump ,and check by ignition if it works or not.

not sure your set up on it but most are under the pass seat

Check the plug wires with a spark tester, to see if they all spark good. That will verify all of the parts you replaced. If they look good, do a compression test on cylinder five.

There are three relays all grouped together on the firewall on the passengers side. All three are related to your situated. We can eliminate one of them because you stated that the fuel pump is operating fine. Now that leaves the relay for the ECM(engine control module) this tells the injectors, cold start and run, when and how much fuel to supply and also controls ignition timing and spark advance. The third controls the AC compressor. Now I've got to remind you that I started working on fuel injection systems the day they started failing here in the US around 1972.These were such vehicles as Mercedes, Saab and Volvo. I've worked on every configuration, TBI, MPI, diesel etc.etc. I may on occasion cross one fact with another or mispronounce certain aspect of a system however, These three injectors are where you want to concentrate your efforts. With some finnesse you can swap the harnesses from one to another. If your car runs fine and your AC suddenly does not, then you know that that relay is faulty. Do this until you get your answer. Best of luck my friend, Dana

you may have a split hose inside the tank
had the same problem on a 94

sounds like ignition module inside of distributor cap under distributor rotor button.these do go bad and can easily be replaced.strong suspicion from your details that this is the culprit.

I just had the same problem. If it is a regular van try under the driver seat in a plastic box. If it is a conversion van try in a pannel just behind driver seat on side of van wall behind a pannel that looks like a vent.

Normally on chevy ignition modules when they go bad, they will quit when they get hot & after cooling down will work again, so when you have them tested they have cooled down. I would try changing it & see if it wont fix it.

Check for spark and fuel. If you have spark make sure your fuel pump is working. If pump is working and no spark, check for spark off coil wire. If nothing there either, remove ignition module and take it to Napa and have them check it. Have them test it several times.