1995 Chevy Astro starting problem

The other day I went out to start my van and it wouldn't start. It’s ran wonderful since I rebuilt the motor back in November. After many turnovers it finally started then bogged down and stalled then it fired up and ran fine. It’s been doing the same thing for the last few days and it’s driving me nuts. Fuel pressure is fine 63psi during relay engagement and 56psi when motor is running. I have great spark to all cylinders. I checked all my grounds and their fine. No codes are stored after any episode. I also took off my top manifold to check the spider injector assembly and it’s working fine. I really don’t know where else to look. I’ve tried many ideas from this message group but to no avail. Like I said, once it starts it will run all day without an issue but let it sit for about ½ hour and the problems begin. Please help if you can, thank you

95 Astro AWD Vin W

Your fuel pressure, key on, engine off, of 63psi is good. Spec is 58psi to 64psi for your engine. GM does not publish any "engine running" fuel pressure specs, there are far too many variables involved. Have you checked leakdown? Key on for the 2 second prime, after the pump shuts off, the pressure must remain above 53psi for 3 to 5 minutes.

Your fuel pressure, key on, engine off, of 63psi is good. Spec is 58psi to 64psi for your engine. GM does not publish any "engine running" fuel pressure specs, there are far too many variables involved. Have you checked leakdown? Key on for the 2 second prime, after the pump shuts off, the pressure must remain above 53psi for 3 to 5 minutes.

Leakdown time remains at 55psi. I let it go over 6 minutes and it stayed there. I'm stumped. Thanks

Just a hunch but..... behind the underhood fuse panel there are several connections... over time they can corrode and cause intermittent problems. Eventually it can cause a no-start condition. Unbolt the fuse panel and check all of the wires for green fuzz growing on the connections.

Well, I am still stumped. I cannot figure this out for the life of me. I have great fuel pressure, great spark, great compression and when it starts in runs like a champ. It will start up every time when it sits for about 3 hours. It will run all day without an issue when it starts but let it sit for about 1/2 an hour that's where the problems begin. I have a question, are the poppets supposed to spray gas when the key is turned on to prime? because they didn't when I had the upper manifold off when I changed the injector components. Thanks again

You need to find out if its losing fuel pressure or spark when it acts up. Connect the fuel pressure tester and tape it to the mirror or windshield, then watch it when the engine acts up. Depending on the results, you'll know what to start checking.

You need to find out if its losing fuel pressure or spark when it acts up. Connect the fuel pressure tester and tape it to the mirror or windshield, then watch it when the engine acts up. Depending on the results, you'll know what to start checking.

That's one of the first things I did when it acted up. When it doesn't start, my fuel pressure is fine and so is the spark and that's one of the reasons why I'm so puzzled. Thanks

Did you check the wiring connector at the injector? (The plenum must be removed to check it.) Make sure the connection is clean, tight, and not damaged.

Did you check the wiring connector at the injector? (The plenum must be removed to check it.) Make sure the connection is clean, tight, and not damaged.

That's one of the first things I did when I took the plenum off. This is a very specific problem. When the motor warms up to operating temperature and then cools down for 1/2 hour to 3 hours it will not start. After around 3 hours it will fire up normally. It's very consistent in its behavior

It must be losing either spark or fuel for it not to start. You mentioned it has spark and fuel when it will not start.... is the injector pulsing? The injector should have battery voltage to it when the ignition is in the RUN and START positions. The ECM supplies a pulsing ground when cranking and running.

Had the same problem. Just fixed it today. Ended up being the Engine Coolant Temp. Sensor. $20 part just below the thermostat housing.

Had the same problem. Just fixed it today. Ended up being the Engine Coolant Temp. Sensor. $20 part just below the thermostat housing.

I thought about that but haven't changed it out yet. Was your sensor working? As in, it registered on your gauge correctly? Or what brought you to that conclusion?

Threw a code a few months ago along with many other codes. Changed everything but that. Check engine never reappeared so I just forgot about it. Apparently it won't always throw a check engine light. Your temp guage on your dash will read normal too! My starting issues started about a month ago. After changing every component except for injectors, I talked with a Lincon Tech teacher who told me that the engine coolant temp sensor can cause that problem too. I then remembered the code it threw a couple months ago and realized that must be it. Sure enough it was. Starts everytime now with no problems. Good luck.

Kevin

Well, after a few months of grinding and ripping my hair out I finally found the culprit that threw me in a tailspin. For almost 3 months now my poor Astro has taken a mean beating in the process. Strange thing is that I thought about this in my initial assessment of what could be the problem, but I let it go because it was new. It turned out to be the fuel pressure regulator. I dismissed it because it ran so good that I could not conceive it would shut down itself in a certain environmental situation but that’s exactly what it did, just like clockwork. I should know better than to buy cheap crap Chinese parts in looking for the easy and cheapest way out. Thank you all again for your contribution and I hope this will help somebody also