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

[Former Member]

My last thread got hijacked kind of...plus i want this to be seen cuz i really need input.

Shop said my car threw a left bank lean code. Anyone get this code befor?

They are saying that the fuel pump is bad, im not sure if i beleive them. and they cant really tell me and answer when i say "if you replace this, and it doesnt fix it, what are you going to do?" and they cant answer me.

Does this sound like its a fuel pump issue? heres typically how ive been starting the car...

turn key....cranks no start....turn key again cranks and starts (sometimes) and idles rough as hell. after awhile it will smooth out and idle fairly smooth. you give it gas and it will sometimes rev in neutral. sometimes it just goes to choppy again. put it in drive...pull out and misfires all over the place when you give it any gas over say 5%.

Should i let them do the fuel pump? or what?

 

[Right on the Mark]

You know you just pull up the rear seat cushion and pull the fuel pump out thru the little window in the floor right? Seems real easy and maybe a 1 hour job. I would not pay the price they want. You can get pump on ebay from 38 to 150 dollars.

 

[Former Member]

your positive? 2000 lincoln LS v8....window in rear seat....gets to fuel pump...

 

[Quik LS]

if they did their diagnosis correctly - it's fairly simply to prove that it is the fuel pump. Silly for us to second guess them...

and yes - under the rear seat is the pump and 'jet' on the other side. Their are a few thread on swapping them.

 

[Former Member]

ill tell them to shove there 665$ then...i dont think its the fuel pump anyways. something happened when i had my drivers side valve cover off. i dont know what...but when i put it all back together, it didnt want to run. I had the fuel line apart....could this cause anything bad to happen? Also all the oil drained into the cylinders that was in the plug wells then burned out. Do you guys really think its my pump?

Im tempted to replace the EGR and the Fuel filter first befor spending the money on the pump. its just weird that the pump is "not working" yet the car idles fine sometimes.

 

[Quik LS]

fuel pressure gauge on the scharder valve - will test for the correct pressure.

if you had the vc off - check the PCV hoses - often they are tough to re-align and fit properly.

 

[Former Member]

they said they found zero vacuum leaks....

I guess its possible that the fuel pump is just "weak"?

its not throwing the EGR code anymore they said...which is weird.

Would you replace the fuel pump?

 

[Right on the Mark]

Its to simple to test fuel pressure why don't you rent or buy a FP gauge for 50 bucks and see for yourself and end this wondering. Roughly 40 psi when running. The gauge screws right on the shrader valve on the fuel rail. It looks like a tire valve stem. Also I hope you didn't dump alot of oil into a cly when it was on compresion stroke because it doesn't take a lot to hydro lock a motor. You take a rag and shove down around the plugs to soak up large amounts of oil BEFORE pulling plugs.

 

[Quik LS]

remember - that's 40psi at the nozzle - meaning rail pressure - vacuum (which is roughly 18-22hg or ~10psi) so a gauge should read roughly 30psi at the rail at idle.

 

[Right on the Mark]

Yep thats correct don't need full pressure at idle. Best thing to do is tape gauge to windshield take for a spin and make sure the gauge swings thru its range 30psi idle and 40 psi when on throttle.

 

[Former Member]

alright well it wont "drive" per-say lol.

So say this....gauge says 30 while idling...you hit the gas and it drops instead of going up.

Fuel pump..orrr?

thats kind of where im at right now. I just need an asnwer that says "YES CHANGE THE FUEL PUMP!" lol. Would the pressure dropping instead of rising say the fuel pump is bad?

 

[LS4me]

If you got oil in the cylinders check the plugs. They may be fouled and the car won't run very well, if at all.

 

[joegr]

alright well it wont "drive" per-say lol.

So say this....gauge says 30 while idling...you hit the gas and it drops instead of going up.

Fuel pump..orrr?

thats kind of where im at right now. I just need an asnwer that says "YES CHANGE THE FUEL PUMP!" lol. Would the pressure dropping instead of rising say the fuel pump is bad?

There's no simple test that will 100% guarantee that it is the fuel pump. The suggested pressure test is the best compromise. However, before doing it you need to replace the fuel filter. If it is clogged you will get a low pressure reading. Also note that certain failures of the REM or of the fuel pressure sensor could cause low fuel pressure. (Fuel pressure on the LS is electronically regulated.) Is your check engine light on while the engine is running? I would think that low fuel pressure would turn it on. The LS computer does monitor fuel pressure directly.

 

[luxuryrules]

Silly question, but has the shop thought to test the output of the O2 sensors? Should be a simple test of output voltage, and the LS shop manual should tell you what range you need. If the left bank is leaned out I wonder if a severely clogged O2 sensor would tell the computer to deliver less fuel on that one bank?

 

[Former Member]

Well i got the car back, its at work right now. fuel pump is comming and im going to do it friday.

The shop report said that when the car is started gauge reads 7psi. it slowly builds up, then when you snap the throttle it drops waaay down again.

Says that the o2 sensor is reporting a "lean condition".

They say there are no vacuum leaks at all.

They said shop reccomends replacing fuel pump. they wanted 665$ to do it. i said i would do it myself.

Thats what they told me for 175$

If the fuel pump doesnt fix it...then what? o2 sensor? i think its possible that the o2 sensor is baked with oil and :q:q:q:q from when the oil drained from the plug wells into the cylinders when my valve cover gaskets went out. Why its only on the left bank...who knows.

 

[ILLS]

If you are only getting one bank lean then that would seem like an O2 sensor problem more than anything else. However, some issues come in combinations at times. If your fuel pressure is dropping really low as well then you may end up needing to swap your fuel pump too.

BTW, I think I heard you talking of performance for your car before too. If you ever had any plans for nitrous, supercharger, or turbo in the future now is the time to swap to a GT fuel pump if you are already planning to swap to another fuel pump. Save you time and money in the end.

 

[Former Member]

:LOL: knowing my luck...

all in one week...VCG's...ignition coils...spark plugs...fuel pump....and 02 sensor.

That should keep it running no issues for another 100k lol.

as far as performance goes...i bought a bike..so this thing really just needs to keep running. id like to keep it for atleast another 2-3 years, more if i can. id rather put montly payments into bike then the car.

 

[Former Member]

put the fuel pump in. Car is still :q:q:q:qed....

:q:q:q:q this :q:q:q:qing :q:q:q:qer.


:q:q:q:q

 

[Right on the Mark]

Did you check the fuel pressure after pump in? Also are you sure you changed the fuel pump and not the jet pump. I need to see a fuel pressure reading from you.

 

[Former Member]

i changed the pump on the passenger side of the car. as far as i know thats the primary fuel pump.

Havent checked fuel pressure after pump install. was pretty much doing the same thing.

Starts after a few trys. then when i rev it the rpms just drop. i did notice today if i held the throttle all the way open it didnt die. rpms just went way down...bounced from prolly 300-800 back and forth like crazy.

Maybe ill get a video of it for you guys :lol:

 

[ILLS]

Did you check the fuel pressure after pump in? Also are you sure you changed the fuel pump and not the jet pump. I need to see a fuel pressure reading from you.

The jet pump is not a real pump. It is just a siphon jet pump (drivers side of fuel tank) that operates off of venturi affect from fuel cycled from the real fuel pump (passenger side of fuel tank). It looks NOTHING at all like an actual fuel pump and would be next to impossible for anyone to somehow pull it out and swap a real fuel pump in its place. Though it would be pretty hilarious if someone somehow did it.

 

[ILLS]

My thoughts are this. Check your "front" set of O2 sensors and replace. Check your IAC (Idle Air Control) Valve to see that it is operating and doesn't stick. This is the valve that essentially controls where and how your car idles when your foot is not on the gas. Then after that I would move onto the MAFS and check it out. I bet that you will find the root cause of your issues before ever getting to the MAFS though. OF course what I have suggested is assuming that you have THOROUGHLY checked your PCV system and vacuum hoses to ensure there are no leaks. Smoke test of carb cleaner spray test will help reveal that.

 

[Right on the Mark]

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.

 

[Right on the Mark]

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 open 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.

 

[smdandb2]

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.

+1

o2's wont cause starting issues. A bad MAF will, and they dont always pull codes either. I know when I had my WRX when a charge pipe exploded it wouldnt run. I had to limp it home, so I unplugged the maf and it ran.... albeit with a big ass leak. It defaulted to a map that based the fuel on the TPS vs RPM table.

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.

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.