2002 ZR2 Blazer

7/15/2012

My Blazer use to start with the first turn of the switch. Until some recent events came about 2 weeks ago, this starting issue has arisen. Ok, say it sits over night or a day or two without being started, it hesitates to start. Engine turns over, sputters some and cuts off. Try again, same thing. On the third or fourth try it starts as usual. I do hear the fuel pump start, pump up and turn off after I turn the key on. I was curious if it kept running before I tried to crank it. What happened two weeks ago was the storm that came through knocking out power and there were only a few gas stations with power. I got slightly jammed up with the fuel light coming on and sweatingly close to running out. I waited my turn in line to get gas at a Wilso/Hess station. I would pull up, cut it off and restart to advance. The pump at the station was R-E-A-L slow, about 20 minutes to fill it up. After that was when my problem started. I thought about water and trash. Added Seafoam to that tank, drove it out and filled up again at my regular local station where I've had no issues from. Now once it has started and run, it starts like normal. Some mornings it's ok and some not. More not than normal. No engine lights. Runs and drives fine once started. Before I get too involved with it, what you guys think? Keep driving and see if it goes away or? Thanks.

Update below 7/16/2012 9:00pm

OK, did a filter change. Readings were done with a fuel pressure test kit fron O'Reilley Auto Parts loaner tool.

Before filter:
54 koke 4 times 10 minutes later 38 with key off.
52 running

After filter change:
56 koke 4 times 10 minutes later 44 with key off.
52 running

Blazer does run ok after once started. There were no problems until see above.

 

Key ON, engine OFF, fuel pump running, pressure must be 60psi to 66psi and must remain above 55psi for at least 10 minutes. Your fuel pressure is too low. Next step is check maximum pump output pressure at the fuel filter. It will require modifying the tester so fuel flows ends at the tester. Pressure must be 73psi to 108psi and must remain above 55psi for at least 10 minutes. Post your results.

 

Clarify and bare with me here. Do you want me to deadend into the tester gauge at the fuel filter area or fabricate a T fitting into the filter?

I understand to get the pressure readings but what sets me off course is that it runs fine after it starts. Like this morning, koke a couple of times, cranked right up. Same today when leaving work. Would this be the beginning signs of the pump going bad or possibly something else? I don't mind fixing the problem, I just want to replace he faulty part the first time.

Thanks.

Also, if a new pump is needed, I'll change it. My question is, instead of dropping the tank, has anyone made an access door? If so, is there a thread on it to read to get the measurements?

 

I understand what you're saying, diagnosis is key here.
Installing a T fitting would be no different than measuring regulated fuel pressure at the service port by the plenum, and we already know it's low. You need to check the maximum output pressure of the pump itself. This is done by, as you say, "dead end" the fuel flow at the tester. The pump has a relief valve and it will bleed pressure to around 60psi when the pump shuts off, (it must remain above 55psi).

 

Ok, that might take a couple of days to getto it but I'll do it and post results. Thanks for your input.

 

Not to hijack...but I'm having EXACTLY the same problem. Didja fix it???

 

had same problem. changed pump twice. tap into fuel pump wiring and use another batt. or 12v source on grey (pos) black (neg) if pressures go up to proper. run a new ground from plug to frame. look at my post in fuel pump starting in 95' blazer fo more in depth info. the thing drove us crazy.

 

Right now the problem is almost nonexistent. This leads me to think possible trash. Haven't checked pressures again but not filling tank to full either just in case. I'm kinda still riding it to see what happens.

 

Final update

Problem(s) came back but was getting progressively worse. Replaced fuel pump with oem and symptoms went away. This was a semi pain in the rear. Almost as bad as the LIMG. But anyway, done.