1983 S-10 Blazer trouble starting hot
 

Hello,

I have a 1983 S-10 Blazer that starts OK in the morning (Arizona, so it's never freezing).

If I drive it for 20 minutes and let it sit for an hour it can be hard to start. Starter cranks but I have to floor gas pedal and wait until it fires up. When it starts there is a heavy fuel smell and lately I swear I hear a "wheezing" sound coming from the back (gas tank?)

It appears to be less of an issue with a full tank of gas - but that means totally full, like if I fill it on my way to my destination it seems to start OK after sitting an hour.

When I bought it (six months ago) it needed carb work done in order to pass emissions (TPS was bad). At the time the mechanic said the gas was really nasty and it would take some time to work out.

Even when it has trouble starting, it seems to drive fine once it's running.

I am thinking it it the temperature sensor that feeds the ECM, but I am new to all of this.

Thanks for any thoughts and ideas!

Could be a clogged fuel filter, or maybe the "wheezing" sound is a bad/going bad fuel pump. That's just my opinion though.

If you have to floor it to get it started that is know as "Clear Flood" mode, when you push the pedal all way down it cuts fuel injection pulse and allows the fuel to clear out while cranking and once the cylinders get some fresh air and the right mixture to burn it will start, as soon as let off once it fires the injector starts sending fuel again. There are of course a few possibilties, given that there was crappy fuel in it you may have an injector thats got someting sticking it open, run the engine and take off the air cleaner so you can see the fuel injector, get a notecard or peice of paper and shut the engine off and immediately put the card or paper under the injector and watch for drips, there shouldnt be anything, if you dont get anything in a few minutes then the injector should be ok, open the throttle plate and look down into the intake with a flashlight, it should be dry if the engine is somewhat warm, if there is a puddle of you can see dripping you may have a leaking fuel pressure regulator, you need to unbolt the throttle body and lift it up an inch or so just so you can see or slip a piece of paper under it and then cycle the ignition switch on for 3 seconds off for 10 on 3 off for 10 on 3...do that a few times, this will cause the fuel pump to prime, now check your paper or card for evidence of fuel, if you have fuel here this would mean the regulator diaphragm is ruptured allowing fuel pressure to bleed off into the intake.

I went this route because your description sounds like you are having a flood condition, one other thing to check is for a fuel tank vent hose plugged or kinked, crude test would be to leave the gas cap cracked loose so the system cant build pressure and see if the problems continue. Also these tests are made to be pretty simple so you dont need any special equipment.

Also your temp sensor idea is probable too, often when they fail they will tell the ecm that the coolant temp is -40 degrees below zero which will also give you same symptoms but shouldn't run real well though...

Sorry long post but this should get you some where with daignosis or at least eliminating some simple things.

Thanks for the responses. I just got back it did the same thing. It tried to start hot without flooring, but it didn't hold. Once it starts it seems to run fine. I will try your suggestions.

I talked to a mechanic buddy who suggested taking it on my daily run with the gas cap off. I still hear the "wheezing" sound, but it started hot without going though the constant-crank-while-floored routine. Could be clogged gas tank vent?

thats possible. i built a few fullsize trucks that were diesels but put a gas motor in it, first trip to the gas station it lets off a huge suction as soon as you open up the gas cap. also had a lawnmower that did the same thing... i checked everything but didnt even think of the gas cap.

easy thing to try, you dont have to leave it totally off just leave it pretty loose

+1^ I agree, gas caps are like maintenance anymore... could be that the vent on the cap itself is stuck too, not only tank. Sometimes when there's too much pressure in the tank, fuel will run up to the charcoal canister vacuum line. If you unplug vapor line at canister to tank and there's wetness, it's also a sign of this. -not always. Is yours still mechanical pump driven, btw?