"Left bank lean" --anyone get this befor?

[ILLS]

I know the Jet pump is not a real pump but its called a pump.Ford lists it as a Jet pump transfer module. I never stated that someone could pull out a jet pump and try to stuff in the actual fuel pump in its place. I just wanted to make sure he took out the right side unit. On many sites they list the jet pump as left side FUEL pump. So some peep out there might get that mixed up. If you don't think so you should see some f-ups I've seen peeps do.

I understand what the literature says but once you take a look at the one inside the LS tanks then you will see what I meant by it being damn near impossible for someone to somehow manage to swap a real fuel pump into the area where the siphon jet pump is.

 

[ILLS]

I'm gonna go out on a limb here and say the O2's will not cause his car to run the way he is stating. When first started the 02's need about 60 to 90 seconds to light off, untill then they are not switching so computer is in closed loop and will run fine. Just like all cars do when they first start. As for the IAC thats only for idle so how would that effect reving the motor or in his case lack of reving. IAC is just a little metered channel around the throtte plate. Now the MAF could cause the problems he is stating but should pop a CEL for that. As for vacuum leak engine will run rough at idle but still rev with a 1/4 inch or 3/8 hose open. I've had many a peeps come in and they didn't even know they had a good sized vacuum leak till i showed them. Please check your fuel pressure again. If that is still at like 8psi thats your problem. If you see 30-40 psi we can move on from psi issue.

When the computer is in closed loop it is pulling information from the front O2's and trimming the fuel accordingly. Closed loop= O2's. Open loop= MAFS. Admittedly I did not go through the OP's posts with a fine toothed comb but I believe he did state that this problem happened at more than just initial start, and intermittently at that correct? Also if he was having idle surge issues then that can indeed be a IAC problem. I believe he stated something to that affect as well. A large vacuum leak can indeed cause enough issue where a car will not want to rev and want to die. This is even more the case when dealing with cars that have electronic returnless fuel systems which rely upon the FRPT to sense the pressure difference between rail fuel pressure and manifold vac/pressure. If there is a leak close enough to that then quite a few running and revving issues can arise.

 

[ILLS]

I don't know if the LS will run with the MAF unplugged. But try it. Maybe it is sending bogus signals to the ECU but its not enough to trigger an MIL.

These cars will not stay running with the MAFS unplugged.

And like ROTM said, check the fuel pressure again. If it is dipping at tip in, you have other issues. I would check the voltage at the pump and see what it is doing. Then replace the fuel filter if you havent already. Hell, I don't know where the FPR is on the LS but that could cause pressure issues too.

The FRPT is located on the fuel rail, I believe that the Gen1 have them in the same location as the Gen2's which is on the front passenger side mounted on the fuel rail.

 

[Right on the Mark]

If there was a big enough vacuum leak it would only tell the fuel regulator to add fuel pressure not reduce. O vacuum means more fuel pressure just like your foot is down on throttle. Also i was writing so fast yes open loop no 02's. In his post he states that when he opens throttle it will lower revs then bounce around 300 to 800 rpm its not at idle because he says throttle wide open. Or did I read that wrong in his post?

 

[ILLS]

If there was a big enough vacuum leak it would only tell the fuel regulator to add fuel pressure not reduce. O vacuum means more fuel pressure just like your foot is down on throttle. Also i was writing so fast yes open loop no 02's. In his post he states that when he opens throttle it will lower revs then bounce around 300 to 800 rpm its not at idle because he says throttle wide open. Or did I read that wrong in his post?

When I referenced the vacuum system in reference to the FRPT my purpose was to illustrate the point that with a large enough vacuum leak that these cars will not want to stay running. Sometimes problems don't occur in just one form and so it is nice to know what symptoms may arise from a given condition. If he is still having fuel pressure problems then something else is indeed likely to be the culprit but it is always easier to start out simpler and cheaper in the troubleshooting process then go big right away. Rechecking the vac lines is not a huge ordeal and is something that should be a prereq when diagnosing why an engine isn't running well. Checking the fuel pressure is another important item that can be accomplished inexpensively too, and can tell an important story too.

I don't know maybe I read it wrong. I thought he was having issues with it wanting to idle too.

 

[Former Member]

its at lincoln now. dropped it off yesterday. couldnt give it more then 5% gas or it would fall on its face.