O/T: Pesky GM 4.3 V-6 Vortec

Posted by Maine Fordson on April 28, 2005 at 15:21:17 from (172.129.159.80):

I'm about at my wits' end with this situation, and I'm hoping that I may find an answer in this forum, given the wide range of expertise to be found here.

I have a GM Vortec V-6 (4.3-liter) on a '93 Blazer that does not like to start after setting for more than a day or two. The engine (a GM "Goodwrench" rebuilt) has about 25K miles on it, and if it is used every day, starts and runs absolutely fine -- not a hint of trouble.

But, if I don't use it for a couple of days, the trouble begins.

When I turn the key to the "on" position, I hear the fuel pump pressurize the fuel system and then shut off, like it's supposed to (about 3-4 seconds, usually). When I crank the engine over, though, it doesn't even offer to start. It'll crank and crank, usually not even hitting on any cylinders at first, and then I can hear the fuel pump running for at least 20 seconds or so. When I turn the key back to the "on" position, the fuel pump will run for 3-4 seconds and then shut off, and I try to start the engine. Same thing happens, and fuel pump runs its 20+ seconds and then shuts off. Strange.

Oddly enough, though, there have been times when I've said to heck with it and left it alone until the next day. When I go out to try it again (at least 12-18 hours), it'll sometimes start right up on the first try.

This first started happening in the winter -- I thought it was cold-related. Tried Dri-Gas (and other fuel water-removal additives). I'd take the heat gun out and warm the top of the plenum, and usually could coax it into starting. But temps here today are in the mid-40s, and I've been hassling with this thing for the past couple hours again.

Fuel pump is nearly new, central-port injector is nearly new, distributor was replaced last summer, fuel filter is only a couple months old... I can't really think of a part that could be faulty.

I'm out of ideas here, guys. What am I overlooking?

-- Maine Fordson

Follow Ups:

• Re: O/T: Pesky GM 4.3 V-6 Vortec Maark 15:12:56 04/29/05 (0)
• Re: O/T: Pesky GM 4.3 V-6 Vortec Bryan in Iowa 13:58:57 04/29/05 (0)
• CPI pressure problems difficult to diagnose jdemaris 05:07:26 04/29/05 (3)
  • One more thing . . . jdemaris 05:10:34 04/29/05 (2)
    • Re: One more thing . . . JHT 07:00:37 04/29/05 (1)
      • Re: One more thing . . . jdemaris 07:19:14 04/29/05 (0)
• Re: O/T: Pesky GM 4.3 V-6 Vortec MarkB_MI 19:08:34 04/28/05 (0)
• Re: O/T: Pesky GM 4.3 V-6 Vortec cdmn 18:40:30 04/28/05 (0)
• Re: O/T: Pesky GM 4.3 V-6 Vortec Bob 15:42:05 04/28/05 (4)
  • Re: O/T: Pesky GM 4.3 V-6 Vortec Maine Fordson 15:56:28 04/28/05 (3)
    • Re: O/T: Pesky GM 4.3 V-6 Vortec AV 18:27:37 04/28/05 (0)
    • Re: O/T: Pesky GM 4.3 V-6 Vortec Bob 18:25:54 04/28/05 (0)
    • Re: O/T: Pesky GM 4.3 V-6 Vortec buickanddeere 17:40:41 04/28/05 (0)

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