Hi guys!
Great forum, lots of good threads. Spent hours here last night and now i think i'm suffering from too much information. not sure if i should pull the motor or change the air in the tires to nitrogen... Anyway, i have a few problems that i am chasing down on my sons blazer. he left it at his mothers house last april and moved to texas, now i'm trying to sort out why it won't fire up. first, dead battery- charged. now it cranks ok. won't fire. right before he moved, he had it in a shop and threw hundreds at fuel problems. replaced some fuel lines and pump. ran great then... I double checked this weekend and couldn't find any new lines...but saw a shiny hose clamp on the top of the tank. tested the fuel pressure and get 42 at key-on then drops instantly to 10 and holds when the pump stops. now questioning the new fuel pump... so i give it a shot of starting fluid down its throat and it fires right up and idles great. Its alive!!! ...but, any throttle at all and it starves for fuel and dies. Won't start again without ether. I suspect that all of you are going to tell me that the pressure is low and the pump is faulty but what about the drop in pressure, is that also a pump thing or am i looking for a pressure regulator too? are they integrated in to the "spider" or is that a separate thing? maybe the fuel line that they replaced is the spider? looks like a new intake gasket on the plenum and the insides are evenly sooted no difinitive signs of fuel spraying in there. I'll probably start with the fuel pump tomorrow and check back in to follow up.

Thanks for all of the leads in the other threads!

Dan

 

I take it it's a Code W engine? If so your pump isn't putting out enough pressure. Should be 55 - 61 psi. I've had the guy at the auto parts store give me the wrong pump (for a Code Z) and it just won't run on that low of pressure. Yes, question whether it's the right pump.

 

There is a check valve in the pump assembly that goes bad and can cause the bad leakdown in pressure. If the pressure hits 42, it's not a TBI pump (9-14 PSI).

If the plenum gasket looks new, I'd say they probably replaced the fuel pressure and return lines under the plenum, called the Nut Kit by GM. You can look at them and tell - old ones will be yellowish or red and really dirty. New ones will be rather white and probably not covered by much sooty goop at all.

The other suspect item with leakdown is the fuel pressure regulator, but you're not getting the proper pressure in the first place. The fuel pressure regulator is a separately-replaceable part, made by Dorman/HELP! and available for about $40. It comes with the Torx security bit needed to replace it (and yes, it's under the plenum).

I'd suspect the pump. And guess they didn't put in an AC Delco/Delphi pump, which means it easily could be bad off the shelf.

 

yes, it's a code (w), not tbi. i'm thinking he may have shopped around and found the least expensive pump available.(shoe-string budget) I asked him about the repairs and he said he and a buddy changed the pump before it went in the shop. so,... i need to have the " you get what you pay for" talk with him again... went to my favorite NAPA and got the Delphi pump kit today. figure i can't go wrong with the oem pump that ran great for 19 years. now there's a new obstacle, I hop on my creeper and shoot under the blazer and go face first in to a billion spider webs that are so fine i couldnt see them. the entire under side is blanketed in black widow egg sacks that just hatched. Just fogged the garage and showered his truck with raid. Think i'll give it a day or so and wait for the smoke to clear before i go back in. Thanks for the heads up on the regulator and torx bit. I'm anxious to see if the new pump helps to hold the pressure. hope it's that simple!

I'll check back in when i clear the cobwebs and run the new pump.

Thanks,
Dan

 

Wow, I would hate to be under that Blazer! me and spiders don't get along good at all.

 

Me, either! Especially not ones that can make you very, very sick

 

Ok, so two more days of spraying for spiders and i finally stopped seeing them come out from undr the blazer. dropped the tank enough to reach in on the passenger side. got the assembly out and it was a Carter pump that got put in last april. didn't last very long... The new one is delphi. should last another few decades, right? hooked up the fuel pressure tester. test fired at 67psi and holds at 58. turn the key one more click and fires up instantly!!! woo hoo its alive!! i suppose the pressure bled back through the faulty pump, and the regulators and injector system are ok. likely that's what was replaced last year. everything is running like it's suposed to. Kinda like this truck and would probably keep it if i didn't have something a little newer right now.

Thanks for all of the support from the forum.

now to find out if he wants to ship it to texas or let it go here... anyone want to buy a blazer?

Dan