Explain the Vortec engine as opposed to a regular engine on a'94 GMC JIMMY? I'm trying to make sure I fix the problem I'm having with my fuel pump putting out 11psi instead of the 55psi minimum.
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.
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Here is my original post : I have a 94 GMC Jimmy 4.3 Vortec and when I crank it it runs for about 5 seconds then turns shuts off. I've changed the fuel filter, the fuel pump , spark plugs and coil. The problem was that it would'nt turn over as if it was out of gas at first. Once I changed the fuel pump it would turn over but would not start. Did the plugs and it started but died after about 5 seconds. But when I changed the plugs I noticed one was soaked with gas so I cranked it with the plugs out and all the injectors were spraying except for one. ONE WAS JUST POURING OUT GAS INSTEAD OF SPRAYING. I'm thinking it's the regulator because it should at least run with 5 injectors. Solutions) I went ahead and changed the fuel pressure regulator and I still have the same problem (start then die). I had the Jimmy checked out by someone using an electronic device and the test results were that my "NEW" fuel pump was only putting out 11 psi instead of the 54 to 62 psi. So I exchanged it again and the sending unit as well, along with the fuel pump relay. Same results. So I opened up the manifold to check to see if the fuel pressure regulator was installed right and I noticed 2 puddles of gas sitting by the regulator and injectors. Is that supposed to be there giving that I've been constantly trying to crank it? Please Help!! I'm going crazy!!***** So Roniecon suggested that I changed that injector or it will never have the psi I need to start it. I was about to, when someone else said that since I have a vortec engine with some special kind of suction, the injector may not be the problem. That's why I wanted to know what is a vortec engine. Please Help! Thanks.
Here is my original post : I have a 94 GMC Jimmy 4.3 Vortec and when I crank it it runs for about 5 seconds then turns shuts off. I've changed the fuel filter, the fuel pump , spark plugs and coil. The problem was that it would'nt turn over as if it was out of gas at first. Once I changed the fuel pump it would turn over but would not start. Did the plugs and it started but died after about 5 seconds. But when I changed the plugs I noticed one was soaked with gas so I cranked it with the plugs out and all the injectors were spraying except for one. ONE WAS JUST POURING OUT GAS INSTEAD OF SPRAYING. I'm thinking it's the regulator because it should at least run with 5 injectors. Solutions) I went ahead and changed the fuel pressure regulator and I still have the same problem (start then die). I had the Jimmy checked out by someone using an electronic device and the test results were that my "NEW" fuel pump was only putting out 11 psi instead of the 54 to 62 psi. So I exchanged it again and the sending unit as well, along with the fuel pump relay. Same results. So I opened up the manifold to check to see if the fuel pressure regulator was installed right and I noticed 2 puddles of gas sitting by the regulator and injectors. Is that supposed to be there giving that I've been constantly trying to crank it? Please Help!! I'm going crazy!!***** So Roniecon suggested that I changed that injector or it will never have the psi I need to start it. I was about to, when someone else said that since I have a vortec engine with some special kind of suction, the injector may not be the problem. That's why I wanted to know what is a vortec engine. Please Help! Thanks.
The Vortec engine has a completely different injection system. There is an injector module inside the plastic intake manifold that has 6 nozzles, each one pointing to an intake port for each cylinder. Hence the term "spider injector". This is not quite multiport injection, where there is a different injector for each cylinder, but it is better than the old throttle body injection. The heads were also redesigned to boost compression a bit. These motor run noticeably better than the previous throttle body ones while actually getting better gas mileage. If you have throttle body injection, 11 psi is on the low side, should be 13. The throttle body injection motor as an aluminum intake, not plastic (it is painted black, so you will ahve to scrape some paint to see).
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