97 Blazer Cold Start Problems

[cybermoser]

I have a 1997 S-10 Blazer with a 4.3L (W), lately have have been having problems starting it when it is cold.

I performed some diagnostics last evening and here is what I came up with. Looking in the Chilton's manual for the 97 S-10 Blazer under Fuel Testing page 5-10, item 7. "Monitor the fuel pressure with the pump running. The pressure should be 60-66 psi (415-455 kPa)." I monitored the pressure and it never reached 60 psi. The highest reading I monitored was 50 psi. From this reading alone I think I should be able to say my problem is either a bad/faulty Fuel Pressure Regulator or a bad/faulty Electronic Fuel Pump in the gas tank. After seeing the 50 psi. reading I then let the pressure gauge attached and checked it after setting for 1 hour, the resulting reading was then 40 psi. I then left the engine set over night for 7 hours and when checking the reading then found the reading to be 0 psi. I am not sure what the timed readings should be. I replaced my fuel filter 5 days ago thinking that was the problem, so my filter should not be causing the under pressure readings. Can 10-16 psi. cause a cold starting problem? My next question is how do I narrow the problem down further? Is there a way to check to see if my Fuel Pressure Regulator is working properly or not?

With finding that the Fuel Pressure is only 50 psi., can I safely say that I do not have a problem with my poppets?

What sensors might be schewed? I am not getting a check engine light. It has been starting kinda hard for the last 3-4 months, I just thought it had water in the tank so I have been running Heat through it I also ran a bottle of GumOut Fuel Injector Cleaner through it this week, thinking it maybe dirty injectors. However just the last 2 weeks is where it has really been acting up. When I go to start it after it has been setting for a while the engine just cranks and cranks. I found that if I turn it over briefly then shut it off, wait 5-10 sec, then turn over again and repeat this procedure 5-10 times the engine then starts, and it kinda seems that the engine is then loaded up with fuel, not sure but the engine kinda studdars for the first 2-5 secs of running.

Anyone have any thoughts on this?

[tom3]

Very common problem and you've nailed it. When the pressure falls below 60 they just won't fire right. Replace the pump assy. and you're in business. Kind of a tough job on the Blazer though. The fuel lines have to be unhooked right on top of the tank, takes lots of patience. Have to buy complete pump assy. I think, gets expensive.