theBrit Posted January 8, 2003 Share Posted January 8, 2003 I decided on an MSD pump after I read some suggestions on another thread, but now I am wondering does the ECU expect the fuel to be at a particular pressure or does it expect to be able to vary it ? Mike Quote Link to comment Share on other sites More sharing options...
Owen Posted January 8, 2003 Share Posted January 8, 2003 The ECU doesn't depend on fuel pressure directly. A lot of the tuning is based on testing at the factory and what pressure they found to be the best. I think I read 43 psi was best but lower than factory spec? The values programmed into your ECU at the factory are based on this factory spec, say 45psi, and then the air per manifold pressure (MAP) or air flow (MAF) values are plugged in. So I guess maybe the answer IS yes, the ECU expects a certain pressure - check the specs. Owen Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted January 8, 2003 Share Posted January 8, 2003 ECU, does not read fuel pressure. Which MSD fuel pump did you get? If it is suitable for fuel injection applications, it will supply enough fuel pressure for the LT-1. You should have the factory fuel pressure regulator on the fuel rail that came with the engine. That will give you the correct fuel pressure. If you don't have the fuel rail then try to find one or you will need and adjustable regulator and a fuel pressure gauge. That might not be a bad idea anyway if you are going to run a non stock motor. My lt-1 likes 43psi. It will run on as low as 30 and as high as 55 but it is had to start at the higher pressures and it doesn't run well at the lower pressures. Hope this helps. Mark Quote Link to comment Share on other sites More sharing options...
theBrit Posted January 9, 2003 Author Share Posted January 9, 2003 There is something connected to the fuel rail and it has a wire comming off it in addtion to the fuel line. Is that a cut off valve or pressure sender ? Mike Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted January 9, 2003 Share Posted January 9, 2003 My 93 had no such beast. Sorry I can't help you there. Do you have the factory service manual for the 95 F body?? If not, it would be worth the 100 or so to get one. Mark Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted January 22, 2003 Share Posted January 22, 2003 My 94 Caprice and 96 buick engines are both LT-1's and they have the fuel Press. regulator at the back of the LH fuel rail. Sort of crossways, above the EGR valve. HTH Cheers Carroll Quote Link to comment Share on other sites More sharing options...
Danno74Z Posted January 22, 2003 Share Posted January 22, 2003 Here is what the fuel pressure regulator looks like on the LT1 engine. To my knowledge all years look like this. The item at the top of the picture that looks like a vacuum advance on a distributor is the fuel pressure regulator. Danno74Z LT1 Conversion Quote Link to comment Share on other sites More sharing options...
Mudge Posted January 22, 2003 Share Posted January 22, 2003 IIRC on the 93 the shraeder valve is offset elsewhere, but I dont recall, basically thats where it is, on the back of the rail. LT1 injectors are rated at 43psi, so shoot for 43-45 psi or thereabouts. LS1s I think are 60-65 PSI but I forget, Ford SVO stuff is rated at 39. Using a different pressure on a 94+ car, will screw with the BLMs and that will hurt overall operation, you do not really want to use a regulator as a tuning device on these cars (it wont work), speed density is OK but not the MAF LT1s. Quote Link to comment Share on other sites More sharing options...
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