Help us help you. By posting the year, make, model and engine near the beginning of your help request, followed by the symptoms (no start, high idle, misfire etc.) Along with any prevalent Diagnostic Trouble Codes, aka DTCs, other forum members will be able to help you get to a solution more quickly and easily!
getting high LTFT on idle 25% both banks. ltft1 and ltft2
changed fuel injectors. no change
did vacuum test. no leaks after changing gasket at plenum
new maf sensor. no changes
did fuel pressure test. key on I am getting 0 pressure reading
engine on I get 50 psi. engine off holds fuel pressure.
car runs fine and has no problem starting or idling.
What could be causing lean condition? Thx!
Vacuum leak
Check hoses, brake booster, intake air tube from filter housing to intake for holes tears, egr assembly, etc. Smoke test it and you should find it. I squirt water on intake plenum while engine running you will hear it get sucked in.
I have the Foxwell nt301 and Techstream which I installed recently on my laptop.
on foxwell it reads 3.28 on b1s1 and same on b2s2 at idle
can you explain what readings you are looking for? I can do tests and post back. Thx
I am only getting code p0171, besides fuel trims car runs perfect
I just replaced the B1S1 to genuine Denso 234-9007
no difference. and seems like ltft jumped to almost 40%
I'll post some graphs soon on both sensors.
Pour x amount of gasoline in milliliters into a graduated cylinder and then add x amount of water to it. These two fluids will not mix and a division line between them will be clearly visible. You may want to mark the level of this line or just record the volume of each fluid. Then agitate/shake the cylinder and then let the fluids settle. If there was alcohol in the gasoline it will merge with the water and the level of both alcohol and water combined will show up above the mark you made before; if you didn't mark the level the combined water and alcohol will have more volume than the water only had.
youtube.com/watch?v=d8pV-x9uLiE
An expert is someone who knows each time more on each time less, until he finally knows absolutely everything about absolutely nothing.
Last edit: 3 years 9 months ago by Noah. Reason: Add hyper link for my homeboy
I checked some videos for checking fuel volume.
for the sienna say for example 30 sec or 1 minute. how much fuel should it use in that time frame?
I have the fuel pressure gauge already hooked up so Ill try to test today.
update:
did fuel volume test with pressure gauge. had duralast fuel filter on.
noticed I had low volume of fuel. only like 1-2 ounces in 30 secs.
put new oem fuel filter and redid volume test thinking fuel filter was issue. seems like little to no change.
here is video.
seraj2000 wrote: update:
did fuel volume test with pressure gauge. had duralast fuel filter on.
noticed I had low volume of fuel. only like 1-2 ounces in 30 secs.
put new oem fuel filter and redid volume test thinking fuel filter was issue. seems like little to no change.
please advise.
That low flow is probably due to restrictions in your gauge. Guessing you're using the vent button on a generic fuel pressure gauge.
Since you say the van drives fine I doubt you've got a fuel volume problem. They usually cause problems under acceleration first.
can someone answer this question. when I have the key to on and the pump makes rrrrr sound should I not have fuel pressure on the gauge then? mine reads 0
why am I only getting fuel pressure only after turning engine on?
The pressure should rise as soon as the pump turns on....and hold after you shut off the switch/the engine. Are you sure the pump starts working with koeo or is it possible that it starts running when the pcm sees an rpm signal? Would you get instant pressure koeo between pump and filter?
Your videos show high LTFT under all conditions so this points to a true fuel delivery problem. The new injectors do have the correct flow rate? Can you measure pump current, voltage under load and pump speed?
An expert is someone who knows each time more on each time less, until he finally knows absolutely everything about absolutely nothing.
when I put key on it does make the rrrrrrrrr sound so is that from the pump?
when I check the fuel pressure gauge it reads 0
now when I turn key on engine on then I get 50 psi pressure on the gauge and it holds at for a while after I turn engine off
another thing I tried is I used techstream to manually turn pump on/off.
this does increase pressure to 50 psi instantly when engine is still off with key on
why is it not giving me pressure with key on? in hanes manual it says I should see pressure.
why only is pressure coming on when engine is on?
even if it does not give pressure when key on but does when engine on why are my fuel trims still high. if pressure is working when engine on should that not make fuel trims normal but it does not.
how do I measure pump current, voltage under load and pump speed?
do I have to do this at the pump itself?
I can do some things but I am still learning. I don't know a lot of this stuff so please post how to do these things.
You're right, you'll have to measure voltage and current directly at the pump. I suppose you do not have an osciloscope which would allow you to calculate pump speed. Don't worry about it but you will need a multimeter....
There is a voltage feed and a ground wire connected to the pump, usually the two thicker wires if there are more than two in the connecter. Put your multimeter - we'll call it DMM (digital multimeter) from now on - to volts DC and connect the positve (red) probe to the feed wire of the pump while the car is running and connect the negative (black) probe to a good chassis ground . With the pump/car running you should read system voltage which would be around 13 to 14.5 volts. If the voltage reading is lower, lets say 10 volts then you have a problem with the power supply to the pump.
Next, still with the pump/engine running, put the positive (red) probe to the ground wire of the pump while the negative (black) probe remains on a good chassis ground. You should get a low reading of a couple of hundreds milivolts. If the reading is significantly higher then you have a high resistance problem on the ground side of the pump, between the ground wire and chassis ground.
Next put your DMM to the DC ampere function in the highest range (typically 10 A or 20A) and connect the probes accordingly to the jacks( do not forget to change them back after this test or you may blow the fuse if you later want to measure something different than current. Then you'll need to connect in series to the fuel pump circuit. You can do so on the feed side or on the ground side, it does not matter. You will have to open the circuit, let's say diconnect the ground wire out of the connector and then connect the red probe to the pin on the pump and the black probe to the ground wire you disconnected from the connector. Then start the engine and you will get a current reading in amps. A general rule of thumb is about 1 ampere per 10 psi, so you know what to expect at 50 psi, more or less. A significant higher amperage/current draw like 8 or 9 amperes would point o a restriction or the pump mechanically binding. A too low of a current draw like 3 amperes or less points to a week pump. A good DMM will allow you to measure peak values that could allow to detect blind/shorted spots on the armature.
If you find a dedicated fuel pump fuse it might be easier to put the probes of your dmm in its place, but then you should use the fuse connected to your probes. DO NOT FORGET to pull the red probe out of the ampere jack after finishing this test!
An expert is someone who knows each time more on each time less, until he finally knows absolutely everything about absolutely nothing.
