2000 Blazer, turns over but won't start. Let it sit a day or two and it starts right up like there was never a problem. Runs great for days or weeks and then does it all over again. I've had it towed twice now. By the time my mechanic has time to look at it, it starts right up and there's nothing to diagnose. It's not throwing any codes.

Anyone ever run into this?

 

You have to travel with the ability to measure fuel pressure and check for spark so that when it happens again you can at least cut your possibilities In half.

fuel pressure gauge, multimeter and spark tester.


George

 

it has spark and doesn't sound like it's skipping. Is it possible the fuel pump could be failing by degrees? If so, would the pressure be lower than normal when it's running?
I've decided I'm having the distributor cap (although I don't think this is the issue as it turns fine but there's no fire at all) and fuel filter replaced regardless. Bought this vehicle 3 months ago, only paid $500 and it's in really good shape. Worth putting a bit of money into, certainly worth replacing maintenance parts even if it's been done recently.
From what I'm finding online (with my Duckduckgo and YouTube degree, lol), I've sort of narrowed it down to fuel (filter and/or pump) or ignition switch. It's the testing to get a definitive answer and wondering if I might be missing any other possibilities.

 

Yes the ignition switch can fail but you would then most likely have no spark or other functions might quit. Yes the fuel pump can fail intermittently. It may or may not show marginal fuel pressure while its running. Do the test in the sticky, you might find it there. Just getting fuel to squirt out of the fuel line schrader is not good enough with this system.

George

 

Excellent article for fuel pressure test. Any way to test the ignition switch?

 

Power leaves the ignition switch in run and/or start on a pink wire so you can check in the harness under the column. That power routes to 4 fuses: ECM1 Fuse, 15a in the underhood fuse box. That one runs the injectors, coil and ign module. The other 3 are in the I/P fuse block and dont involve starting the truck. Here is a good video where the same problem was the ign switch. I dont think this is your problem if you have spark, but here goes:

https://blazerforum.com/forum/2nd-ge...cement-103464/


George

 

That (the diagnostic video) is exactly what my Blazer is doing. And this answers my question on a way to test it to either confirm or eliminate it as the issue.
You've been extremely helpful and it's much appreciated! If you can think of anything else that would cause a vehicle to sound just like that Jimmy (but "fix" itself a day or two later), let me know. Aside from maintenance items (like the fuel filter), I prefer to test before ripping things apart.

 

OK well then you don't have spark. See if you have power to the ecm 1 fuse in start and run and if so see if you have power on the pink wires for the ignition module and the coil. If not probe the pink wire under the dash.

George

 

Ok guys, finally made it back to Florida. Brought my spark tester. Definitely have spark. Got wife to crank while I did the ether thing. Not even trying to start.
I have the option of purchasing or not purchasing vehicle. The idea behind buying it is to have a low cost auto to leave here in Florida. So I am not interested in spending a lot of money to repair.
Any suggestions or thoughts? Thanks in advance!
Short version of what I have done. Flushed gas tank and drained and poured in fresh gas. Replaced fuel filter. Verified that fuel pump is pumping. Verified that I have spark to spark plugs.
The only time engine has tried to start was the first time I used ether. This was after cleaning tank and changing fuel filter. I manually opened throttle at throttle body. Squirted one squirt of ether. Walked around and cranked engine. Momentarily started. (Very briefly) . Has not tried to start since.

 

Are Chuck750SS and Nitehawke the same people with the same truck or is this post for a different truck than the 2000 Blazer in post 1 of this thread? This doubly confusing because the next post for both users would be #5.

George