Related fuel / cranking problems?
 

Been a member of this forum for about 8 months - this being my first post. I have always been able to find the answer to my issues in earlier posts until now.

We have a 2001 Blazer, Vortec 4.3L engine - 155,000 miles, bought used about a year ago. It is a great car (other than gas mileage, and perfect for what we were looking for). Took it out for a short errand yesterday morning everything was fine. hour later, turn the key on, all the dash lights light up (brake, seat belt, check engine, etc), but the engine will not crank. After a few minutes of trying to start, it cranks and starts right up. We run a few more errands, including getting gas and it everything is fine. My wife drives it for 15 miles after getting gas and it does the same thing when she turns the ignition key on (dash light on, but does not crank). After a few trying it, it cranks and starts right up, but runs really rough - won't idle, and definitely not able to drive it and had it towed home. (Check engine light came on when it was running). Going to get a scanner this morning to scan codes.

I've long suspected the fuel pump would be a problem, as you can continue to hear it pump long after the engine starts. (Fuel guage also jumps around a lot, with the low fuel light coming on when there is about 4.5 - 5 gallons left). You can still hear the pump with the ignition on. I've not yet tested the pressure on the fuel line yet.

Wondering if there is any connection between the car not cranking and what I think is a fuel pump issue. Is there a sensor that won't allow the car to start because of fuel pressure issues? Or is this just two or more unrelated problems.

Thanks for any direction you can provide.

Nope. You have two distinct problems.

You do understand that the fuel pump runs all the time the engine is running. Noisy is another thing. So save the fuel pump and gauge stuff till later.

You say it wont crank sometimes.. do you hear anything at all?
A loud 'click'?
When that happens do the lights dim at all?

Only thing that could affect both is charging system health. Where does your alt needle sit first thing in morning? When the engine is running. Ever go below 12v running?

thanks for the reply. Yes I understand the fuel pump run all the time, but shouldn't be able to hear it.

When trying to start the car, you don't hear any thing at all, no loud clicks.

I think the light do dim slightly, when when turning the ignition to the start position.

Just went out this morning and tried to start it. Same issue with not cranking, everything does dim. After 4 or 5 tries it did turn over and the engine started, but running rough. Alt meter is sitting above 14 when it did start up this morning.

Now... what does it read when you first turn key on.. and then when you turn to start and it wont crank.

When the key is turned to the on position it reads about 11, and the same when you crank it and it won't start. Do you think (I say hopefully) this a battery issue? If I hold the key on the start position, everything dims.

Should read twelve. take battery to parts store and have it it checked. Suspect you also have another problem, though.
If it didnt dim, I'd suspect the park/neut position sw. And tell you to jiggle shift lever

https://blazerforum.com/forum/attach...kt_strtr_r-jpg

Thanks a bunch for your help. I'll let you know how it turns out.

Battery checked out okay, with 82% charge. Might be the cable - positive side showed some corrosion which I cleaned up with a wire brush as best I could - no change in outcome. Jiggling the switch lever doesn't seem to make a difference. I'll research the park neutral position switch. Thanks again for all your help.

Okay.. I dont think that's it, like I said if it was P/N switch there wouldnt be any effect on light.
Just for drill pull the starter relay and check the pins closely for any discolor/signs of overheat. Or swap it with a like relay.. think rear defog is same one.

Tough test coming. NExt thing is when it does it, get under car pass side and rap on the starter solenoid once. a sharp tap is all. If it then cranks, you need to replace the solenoid. Which involves pulling the starter, since it's mounted atop it.

Sorry for the delay in the follow up. I wasn't able to mess with this over the past week. Rapping on the solenoid does shake up enough for the engine to turn over - I am curious why this happens. So it looks like, from your earlier comment, I need to replace the solenoid.

I am more concerned with the engine running rough and the P0300 code. In reading up on this, it looks like there are many options. I'll probably start with replacing distributor cap, rotor and plugs unless you have any other suggestions? thanks again for any help.