Hey Guys/Gals!
Was hoping you could give me guidance once again?
2000 Blazer 4.3 V6 Vortex has sluggish starts and sometimes sounds like gears grinding. When that happens it wont start at all. Waiting 30min-hour it will start no problem. Recently we've been noticing a strong gas smell when it starts. Also when it rains it wont start. And its back to very slow acceleration.... Most times it will not go above 45-50mph. I'm thinking I have a couple separate issues here.
So far I've cleaned the MAF, changed the air filter, changed the oil pressure sensor, and changed the distributor cap. Spark plugs and wires changed. Distributor cap changed thinking possibly a crack and it letting moisture in?

Anyway none of this has helped and everything we do seems to make the problem worse or does nothing at all!
This morning it had a very sluggish start... Turned over... Sputtered and died. This happened several times until I gave up called it bad names and rode with my husband to work! We desperately need 2 cars but cant afford to keep throwing money at this thing and can not take on another car payment...

 

forgot to mention after changing the oil pressure sensor the truck ran great for about 4-5 days and then went back to its old song and dance but bring the starting problems with it...

 

try turning the key to the one position accesories position for about 5min then turn it back off then try starting it. see if that does anything

 

aka prime the fuel pump.

 

Think your going to have to work on checking your fuel pressure. The thing is most likely IMO priming for the two seconds then when you crank it the the prime is not sufficant to start. As the moter turns the oil pressure builds in turn turning the fuel pump back on letting it start.
Also when you turn the key on and prime it will need key off for five seconds for the pcm to send the signal to prime it again.
What Imean to say is there is a five second key off that it needs before you go to key on again.

 

I think Spittybays is on the right track, check fuel pressure and leakdown. Key ON, engine OFF, fuel pump running, (pump prime): Pressure must be 60psi to 66psi and must remain above 55psi for at least 10 minutes after the pump shuts off.

Replacing the oil pressure sending unit does not affect fuel pump operation on your 2000: strictly coincidental that it ran any differently. Some of the older 4.3's had a circuit from the oil sender directly to the fuel pump. The purpose of the circuit was to allow more amperage flow to the fuel pump while the engine was running, that's all. If the circuit from the fuel pump relay to the fuel pump failed while the engine was running, the oil pressure sender circuit would keep the pump running, provided the engine had sufficient oil pressure. That was inherent with the design of the circuit, and not a safety feature to shut the fuel pump off if oil pressure dropped too low. Also on your 2000: when you initially turn the ignition to the RUN position, the fuel pump relay is activated for ~2 seconds. If the PCM does not receive a signal from the crankshaft position sensor during that time, (pump prime) it deactivates the fuel pump relay. The PCM activates the fuel pump relay continuously when cranking, and when the engine is running. Cycling the ignition on and off will also activate the relay, and each time you turn it to the off position, the relay activates for ~2 seconds.

Anyway, check your fuel pressure and leakdown, and post the results.

 

I'm thinking the gear grinding sound and sluggish starts would indicate an issue with the starter motor? Just my .02

 

That's a good possibility!

 

So I caved and took it back to the shop. They said it showing 14 codes. They said they start with the first and go from there. First one to show was the MAF sensor and the second was the timing being off. I just had the timing reset and now they are saying its off again. They said they needed to pull the distributor and realign it. I can change the MAF myself...easy.

For the timing... I don't know why the timing would slip?? But I do know I don't want to pay them $220 for them to reset it!

 

Annie, without the DTC's that they pulled, we're only guessing. What exactly did they do to it before? You're right about the timing, it doesn't just change unless something was left loose. Sounds like they're feeding you a line.