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Re: fuel pressure regulator
How do you know that it is the regulator? these 4.3 motors had a lot of trouble from 93 to 98, I know I had 2 of them. What happened to mine was that the intake kept getting very carboned up. After I would clean it, the truck would run fine for about 5 or 6 months, then same thing. Theres actually a class action lawsuit about this that I believe has been settled, you may have recourse if you bought it through a dealer. Good luck.You'll need it.
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its got a 4.3 vortec in it i think got a piece in the intake called a spider that acts like fuel injecors probley not oppening up to let fuel into the motor also has a fuel presure regulator built in it there kinda pricey but that more than likely your problem
The "spider" injector is the problem. You're right that one of the injectors is stuck open, unfortunately it has to be replaced as an assembly. This a common problem on the Vortec V-6's. When you were checking the fuel pressure, the fuel was passing through the open injector, giving you a low reading. After replacing the injector assembly, be sure to change your oil before you start the engine. I'd be willing to be you have a pint or two of gasoline that has gotten into the crankcase. That injector unit will cost you around $350. It's not too hard to put in, just be careful.
Is this the Vortec engine? If so, the fuel injector spider, has a built in pressure regulator and i would say it is spraying way too much fuel into the cylinders. At the same time is is washing your cylinders of lubrication, and that itself is not good.
The most likely 2 causes are leaking fuel pressure regulator on the side of the spider, or leaking fuel LINE going into or out of the spider. Both are reasonably common failures. a replacement spider would come with a new regulator but NOT a new line, so verify which is leaking before you order a spider up.
They do not fail that often anymore, not like 5 or 8 years ago when gasoline still had mtbe in it, the vortec unit is very dependable nowadays.
i would first check the fuel pressure regulator pull off the vacume hose see if fuel comes out ? if so replace regulator if not double check for stuck injectors ? seen bad contaminated fuel cause similar problems ? hope this helps
This fuel pressure regulator is a component part of the SFI (sequential fuel injection) assembly, sometimes referred to as "spider". It resides inside of the air intake plenum and is accessed by removing the upper half of the intake. Good luck and hope this helps. Most of the time when your having problems, it's most likely going to be the whole spider unit. GM has been know to have problems with this type of fuel injection system. Check the vacum line to the fuel pressure regulator at the back of the spider housing by the high pressure fuel line. You can see it just in front of the distributor cap and spider assembly.
A very common failure on these is the CPFI unit , or SPIDER as people like to call it.
There is one single injector which feeds each cylinder via a pipe and poppet. The injector becomes blocked and the engine won't start or run.
Before you go condemning this though, just make sure you have good fuel pressure because the fuel pressure regulator or fuel pump could also have a hand in the problem. Make sure the pump is running, and if not then check the fuse, the relay, and the pump itself.