Bookmark and Share

 

I have a 1995 Chevy S10 and it usually will not start unless I use starting fluid. Once it even happened when the motor was still warm enough so that I could feel the heat rising off engine as I sprayed into air intake. Once it starts it runs perfectly at all rpm's, under load or not, etc. I can hear fuel pump run when I turn key, I can hear the fuel pump relay click after a few seconds when it "thinks" fuel pressure is right, if I turn key off at this point and turn it back on, the fuel pump doesn't run, indicating to me that the fuel system is holding pressure. My question is: would the motor run perfectly at ALL rpm's, on the highway for as many miles as I care to drive, with low enough fuel pressure as to cause it not to start? Could I be running in part off intake manifold vacuum and in part the weak fuel pressure the pump is still delivering? The check engine light is NOT on but could a sensor or something in computer be failing to let fuel into manifold? I really don't want start replacing things one at a time until I hit the culprit because it's so freaking expensive so please if you get a minute let me know what you think.

Yes it is possible for a car to run well and still not have enough fuel pressure to start! Your Vortec fuel system needs 60 PSI to start! Anything less will cause the exact same problem you are describing. To verify this problem a fuel pressure test must me performed. You may find you have around 50 to 55 psi. This problem is a very common problem on Chevy S-10's. I know I have at least one of these letters in my archives describing this problem. So have your tech VERIFY what I think the problem is. Make sure that you buy the very best fuel pump you can buy. ( if your fuel pump is faulty. Don’t forget to replace the fuel filter.) You still may have an injector unit that may be leaking. The fuel pressure test along with the static pressure test will verify if you have these problems. Go to my web site www.masterautotech.com and click on "technician training" You will see how to test for a faulty fuel pump using the 4 tests I have described. Of course you will need to find a shop to do these test because the test equipment is not cheap :o)

 

  Return to frequently asked questions

 

 

Home :: Show :: Archives :: Links :: Contacts :: Login

Ask The Master Auto Technician © 2009