Hard Starts on 02

[robsieb]

About 3 weeks ago on a new tank of gas my 02 began experiencing hard starts. Most of the time its after driving at normal operating temperature, shut down for a couple of minutes then on the restart is where the problem begins. However, on occasion it will take several turns of the starter to get it going when its cold. At first I thought I had got a bad tank of gas since on the suspected tank it gave a couple of misses while driving. I ran two tanks through using Heat and one tank with fuel injector cleaner. Now on the 4th tank, I've not had any hessitations since the first tank but still experience the hard starting. As a side note, it starts perfectly if you try immediatley after shutting it off. It only appears to be having difficulty after its sat for a couple of minutes or more after running.

I've replaced the airfilter and bought a fuel filter but have yet to change it. Looks like a quick disconnect on one end and I'm not quite sure if I need a special tool for that. Any advice in this area would be appreciated. I'm not a novice at working on these things but havent had to do much to this truck. My last Blazer, a 92 model, well thats a different story. Lots of hands on experience on that ole beast. lol

[DINO55]

No special tools needed for the quick disconnect end on the fuel filter, Some line wrench's if you got them. Just remember to have a small bucket ready to catch the excess gas once you crack the line open. Be patiant, this job can be a real bear if the filter has never been changed before. I endend up using two small pipe wrenches and it took 40 minutes to remove mine, thats how hard mine were on.
HERES A TIP.. dab some anti seize compound on the threads of the new filter before you install it and your next fuel filter job will take about 5 min to replace.
When was the last time you did a Complete Tune Up to the truck?

Plugs
wires
cap
rotor
PCV valve


A

[muddog321]

Filters are good but check the battery voltage and make sure its at 12.v off and a min of 13.5 running - most common cause if any slow cranking. Never said the mileage but tuneup as above and clean the MAFS also (many posts). Post back on fix or additional help.

[robsieb]

57K miles and haven't done any plug wires, cap, etc as it's not given any problems until now at this point. Battery doesn't seem to be the problem as it turns over great. Just acting like its not getting the right amount of fuel at this point. Didn't know if anyone else had seen this. Will change the fuel filter & pcv valve and see what happens.

[robsieb]

Just an update. Changed fuel filter. No change in hard starts. Seems to be if you let it cool down for 5 minutes or more thats when it gets hard to start.

[BlazerLT]

Originally Posted by robsieb

Just an update. Changed fuel filter. No change in hard starts. Seems to be if you let it cool down for 5 minutes or more thats when it gets hard to start.

Take a voltmeter out and test the voltage when the engine is not running.

Also check fuel pressure. Should be 61-66psi with the key to on, but the engine not started.

Try allowing the pump to prime before starting by turning to the position before start for 2 seconds, you will hear the pump prime. Then start it.

[MT-2500]

Originally Posted by BlazerLT

Take a voltmeter out and test the voltage when the engine is not running.

Also check fuel pressure. Should be 61-66psi with the key to on, but the engine not started.

Try allowing the pump to prime before starting by turning to the position before start for 2 seconds, you will hear the pump prime. Then start it.

As BlazerLT said check that fuel pressure.
Here is some guide lines.

Hard to start cold.
Check cold start fuel pressure.
Check engine running fuel pressure.
Check engine running on the road fuel pressure.
Then shut it off and watch for fast leak down.
Pinch off at rubber part or block off return line and check full pressure.
Later V6 and V8 gm engines should have 60-66 fuel pressure.
Cold start should be 64-65 lbs of pressure.
If you do not have full fuel pressure on a cold start the injectors will not squirt fuel.
Do not leave home without it.
Engine running should be 60-66 lbs pressure depending on engine load.
Full pressure with return pinched off should be 75-85 or more.
And if it has a fast leak down after shut off you have a leak.
Post back fuel pressure readings.