99 Astro starts great or doesn't start at all?!!!

I've got a 1999 Astro van with about 125K with a split personality. On a good day it fires up immediately and drives perfect all day. On a bad day it turns over but will never fire up. There doesn't seem to be any pattern as to what is causing a good day or bad day (for example does not appear to be consistently affected either way by temp or moisture).

I took it to a garage and they said I might need a new fuel sending unit and that would cost $700 to replace but could not guarantee that would fix it. They asked me if I wanted to spend thousands of dollars in repairs because they said it could be so many different problems.

I changed the fuel sending unit myself and also changed the fuel filter. That provided entertainment in the driveway for a couple weekends - didn't make a difference. I removed the console and engine shield and tested a spark plug and it was sparking when I turned the engine over. I tried removing the wire of the top the coil and reseating it - no difference.

How can the van sometimes be incapable of starting when it sometimes starts up immediately and perfectly???

 

Just curious, but have you checked for codes?

 

tow guy has a very good point on the codes thing but you never said anything about a check engine light....so.....if there is no engine light and as i alway say.you need four things for an engine to run...fuel,spark,compression and air.....so it runs sometimes so you have compression and air....you found you have spark so the controler is not telling it not to run...so it seems to be fuel...so try this...with the miles on your vehicle the fuel pump relay has arced onto it's contacts...(and yes arced)...well who knows how many times.....so give this a shot...swap the fuel pump relay for say the horn relay....or just something you don't use all the time...ie air conditioning....and see if that does it...it's an easy try cost nothing and the neighbors will not point and laugh....good luck

 

Did you replace the fuel pump or the sender? Sometimes a weak battery in combination with a weak fuel pump will cause a no start because the fuel injector needs 53psi (i think) to open the poppet valves. If it happens again try jump starting it, raise the voltage a little to speed the fuel pump up enough for higher pressure.

 

had same prob with 94chev 1/2 ton after countless return trips to garage , replacing fuel filter , pump and coils it turned out to be cdi unit