I have a 2001 Blazer 4x4 automatic with a vortec 4.3L engine. Here's my issue, after sitting over night it will only start with starting fluid. Once it running it runs great. I've done a lot of searching on multiple sites about this issue, it seems to be a somewhat common problem. I've tested everything that I could but I'm stumped. Here's what I've either done or tested on my Blazer: new intake seals, plenum seals, fuel line seals, spark plugs, plug wires, cap and rotor. I preformed a fuel system pressure test, when turning the ignition on it seems to be right on spec. 55-60psi and does not bleed off when shutting off the ignition (meaning it stays somewhere between 55-60 for at least 10 minutes). I retimed the engine just in case. I also replaced the ignition module. If I start it with fluid and get it up to operating temp. It will start right back up if I shut it off, but the longer it sits the harder it is to start. But like I said it will not start at all once completely cooled. I've tried letting it turn over for extended periods of time and also cycling the key many times, but still requires fluid. When I had the plenum off I check for any clean areas that might indicate a leak but it all looked the same. Any help with this problem would be extremely appreciated!!!

 

In a 2001 Blazer there is no ignition module and timing is not adjustable. Something not right about your story. Sorry, please explain what you replaced instead of the ignition module and what you mean by retiming the engine. Since you had the plenum off, does your vehicle have the upgraded injectors or not?

 

Correct me if I'm wrong but it does have an ignition control module, it is mounted along side the coil on the coil mount. Search LX381 ignition control module and you will find pictures of it to confirm this. What I meant by retimed the engine was I completely removed the distributer to check the drive gear, which was good. I then put the #1 cylinder on top dead center and reinstalled the distributer making sure that the rotor lined up perfectly with the #6 mark on the distributer housing. My Blazer has the factory CSFI injection system. Like I stated in my original posting, the fuel system holds good pressure and does not bleed off.

 

I really hate it when I'm wrong, but I am wrong about the ignition module. You are correct about it's presence. Just because I never noticed it, does not mean it is not there. I should have known that the PCM would never trigger the coil directly.

OK your checking the timing was really checking the rotor/cam sensor position. Making sure the distributor was installed correctly and the gear not worn. Makes sense.

Now that I have thoroughly destroyed my diagnostic credibility by failing to know about the ignition module, I'll offer my thoughts on your problem.

If you really have the original poppet type injection nozzles (no electrical connector on each nozzle at the end of each spider leg), then fuel pressure requirements become very important. Each nozzle requires a minimum pressure or it will not deliver any fuel. All sources point to the minimum required pressure as being above 60 psi. There is a sticky at the top of the 2nd gen forum that describes extensive testing of the fuel pump pressure. If it was mine I would head there and do the tests. I think it might possibly be that the fuel pressure goes up slightly after the vehicle is started using starting fluid (possibly increased voltage due to alternator charging) and then it stays running.

If the system has been upgraded to MPFI, then the injectors do not require a minimum pressure to deliver fuel. It may run poorly with slightly low fuel pressure, but it will still deliver fuel.

But then again, I may just be full of it (just like about the module).

Good luck and best wishes,

Les