Blazer not starting....how much fuel needed to start?

[iluvmy72]

OK I have a 1993 Blazer with the Vortec engine. I can't get the engine to start unless I put starting fluid in it first and then it runs fine. I put a fuel pump tester on it and it read to be around 40. Is that enough? I have replaced the fuel filter and the engine does have 130,000 miles but I don't think its injectors since it runs once it starts. Could it be electrical? Or do I do the tank drop and swap out the stupid pump? I'm going to kill the person who thought a fuel pump in the tank was a good idea!!!!

[ChevyTech]

Is this a full size Blazer with a V8, or is it an S-10 size with a 4.3 liter W engine?

[iluvmy72]

its a s10

[ChevyTech]

1993 CMFI – 4.3 W engine - 55-61 PSI running and should approach 61PSI when throttle is cracked, dropping the engine vacuum.

Your pressure is low, and my first guess would be a bad pump, but it all depends on how you did the testing and when you got the 40 PSI reading.

The fuel pressure regulator can also fail.

Another problem that happens on the CMFI system is, the plastic fuel supply and return lines that connect to the spider assembly under the upper plenum can crack. When this happens the leaking fuel flows into the intake causing the system to loose control of the mixture.

This is all out of site because this is all under the upper plenum.


There is some testing you can do:
Install a fuel pressure tester to the test port.
Turn the key on without cranking the engine and watch the fuel pressure.
1993 Blazer W engine (vortec) 55-61 PSI running per fuel & emissions manual
The pump will only run about 2 seconds.
When the pump stops the pressure should not immediately start to fall.
If the pressure does start to fall within a minute there is a problem.


I suggest only using OEM (Original equipment manufacturer) fuel pumps.
I have seen so many aftermarket fuel pumps fail during their warranty, or just after the warranty expires, that I strongly suggest you stay away from aftermarket pumps.