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david craig
david craig, Auto Mechanic
Category: Kia
Satisfied Customers: 905
Experience:  owner/mechanic at 3D Automotive
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05 v6 Sedona super lean condition on 1st start up after

Customer Question

05 v6 Sedona super lean condition on 1st start up after sitting overnite. very hard to keep running but once it warms up it runs great. new f pump, t body, cam sensors, mass air, map, it has fuel pres and volume to rail. we r a small shop. its driving us nuts
JA: Are you certain it's the fuel pressure sensor that's in need of attention? What about the fuel rail? Have you checked it yet?
Customer: hard to hook to for a reading. at the 2 bolt flange on drivrs side we have pressure and volum.. it only does this when cold.
JA: Are you fixing your Sedona yourself? What have you tried so far?
Customer: we are a small but well equipped shop. fuel pump, mass air, map, cam sensors t body, fuel relay,
JA: Anything else you want the mechanic to know before I connect you?
Customer: no but its a very strange problem. he have countless hours in this thing both working on it as well as researching the net.
Submitted: 3 months ago.
Category: Kia
Expert:  Cary York replied 3 months ago.

Hi, I’m Cary and I’ll be helping you today.
Please understand that I can't smell, hear, or touch the vehicle, so patience is appreciated. Before leaving the site make sure and leave me a rating. You can still reply to me as many times as needed, even after the rating..

Are there any codes/check engine light?

Expert:  Cary York replied 3 months ago.

Do you have a scan tool that will read sensor values?

Customer: replied 3 months ago.
we have a snap on verus
Expert:  Cary York replied 3 months ago.

What about the coolant temp sensor? Is it reading correctly when the engine is cold and then steadily increases as the engine warms?

Expert:  Cary York replied 3 months ago.

Have you checked the coolant temp sensor?

Remember if you rate me we can still continue the discussion.

Customer: replied 3 months ago.
the coolant temp sensor is now new and is performing properly as well are both o2 sensors. the mass air flow is new and functioning. when cold it will barely start and acts super lean coughing and sputtering back through the intake. if you can keep it running for 5 minuites it will run and idle fine the rest of the day. it has to cool off completely to act up again
Expert:  Cary York replied 3 months ago.

I assume there are no DTC's. Can you tell me the long and short term fuel trims are while it is cold and acting up?

Customer: replied 3 months ago.
it was showing zero trim until we forced it to run for a minuite or 2 then the short term fuel trim was 23-24 after it warmed up the long term trim is 6-8
Expert:  Cary York replied 3 months ago.

I will opt out to see if another expert can help.

Expert:  david craig replied 3 months ago.

Hi Im David, let me pull up some info from my resources, ill get back with you. thanks.

Expert:  david craig replied 3 months ago.

is the coolant temp sensor fails and sends a false signal to the engine management so the fuelling is adjusted to compensate
usually they fail "cold" so the management makes the engine run rich (choke on)
but if they fail "cold" then the mixture is weaker which makes starting and cold running poor but runs fine once warmed up

Customer: replied 3 months ago.
it did the same thing with the original temp sender. we replace it anyway just to cover the bases. the scanner shows it working properly. we originally started wit the fuel pump. I was really surprised when that didn't fix it. we then saw the history of t body problems so we ordered a new one and installed it. same thing. bad thing is you have to let it sit overnite for the problem to come back. once it warms up it runs great the rest of the day. the symptoms seem to change slightly from day to day. but the one main symptom is that it is so lean it will hardly run. very much starting a carbed vehicle with no choke in the winter. yes im old. but I have been doing this for a long time and this thing is whipping my but. we have fuel pressure and volume to the 2 bolt fitting on the fuel rail when cranking. it seems like when you let the switch from start to run the pressure drops off. then when it finally gets warn enough it starts to run pretty good. hate to tell you how long we have been dealing with this thing. the owner is talking about trading it. if you can help me I will show my appreciation.
Expert:  david craig replied 3 months ago.

check the voltage at the fuel pump connector. if its not putting out a full 12vdc, that could be your issue. and check the ground for the pump. take the ground off. clean it, burnish the mount area and reconnect it.

Customer: replied 3 months ago.
will be glad to however in the start position the pump works fine. good pressure and volume at the 2 bolt flange at the fuel rail. I will get a tech to check it now
Expert:  david craig replied 3 months ago.

ok

Customer: replied 3 months ago.
the tech says the problems are in open loop. once it goes into closed loop it starts to run normal
Expert:  david craig replied 3 months ago.

ok gimme a sec

Expert:  david craig replied 3 months ago.

how long does it take for the system to go into closed loop?

Customer: replied 3 months ago.
its very difficult to get it to keep running on cold start. lost of coughing and sputtering and restarting. but it would seem 8 to 10 minuites till it goes to closed loop.
Expert:  david craig replied 3 months ago.

ok then you have either a bad o2 sensor heater circuit or the ecm that sends the signal to heat them

Expert:  david craig replied 3 months ago.

any luck checking the heater circuit for the sensors?

Customer: replied 3 months ago.
we are getting ready to check them now
Expert:  david craig replied 3 months ago.

ok keep me posted

Customer: replied 3 months ago.
ok I had the tech check the o2 sensors again. they seem to work properly. no codes for heater circuit. they are switching properly. we use a snap on verus. the tech said to tell you that he can spray 2plus2 in the intake hose and it perks up indicating a lean condition. we also just unhooked the mass airflow and it started running normal. however we have tried this before and it will still act up when cold.
Expert:  david craig replied 3 months ago.

if its taking 8-10 minutes to go to close loop, thats insane, let me look at something else

Expert:  david craig replied 3 months ago.

what are the readings of the rear o2 sensors?

Customer: replied 3 months ago.
b1 s2 100.81 dc[a] .47 b2 s2 100.66 dc [a] .54
Customer: replied 3 months ago.
of course the engine temp is up to normal at this point
Expert:  david craig replied 3 months ago.

ok. damn. have you down a back pressure test?

Expert:  david craig replied 3 months ago.

also has a vacuum leak test been done... something is letting unmetered air in until it warms up and seals the ares where its coming in.......i would imagine it would have to be done cold though

Customer: replied 3 months ago.
I have a smoke machine. when the guys come back from lunch we will smoke it. for much I would use gas and a match. thanks for taking an interest
Expert:  david craig replied 3 months ago.

sure. hey i have a couple cars here in my shop that could use the gas and match fix...

Customer: replied 3 months ago.
well we did the smoke machine test including the snorkel pipe. we had done the spray test with 2plus2 and had not detected any leaks. im afraid the smoke test did not turn up anything at all. seems like a very tight intake system
Expert:  david craig replied 3 months ago.

geez.....ok. let me figure this out

Expert:  david craig replied 3 months ago.

i think the dam computer isnt responding to the o2 sensors.

Customer: replied 3 months ago.
that had crossed my mind. but its the old thing about always blaming the computer for everything when in fact its very seldom the problem. in this case it may very well be. I have had the van here for 3 months and have over 900 in parts at cost. don't wana even think about the labor I will loose. but I sure hate not being able to fix it.
Expert:  david craig replied 3 months ago.

i hear ya, but if you look at a print, where does the control for the o2 sensor heater come from. plus. everything else is testing normally.

Customer: replied 3 months ago.
I ran the wiring schematic again. it shows the 02 wires heading off to what I would think would be the ecm. they are fused but we have checked them numerous times but we will look again. we have done a lot of back tracking on this deal just to make sure. but we could be overlooking something but im not sure what it would be.
Expert:  david craig replied 3 months ago.

if the vehicle is running lean after sitting all night, and it takes 8-10 minutes to go into closed loop. and the reason the o2 sensor gets heated is to minimize open loop time and that is control by the ecm...???

Customer: replied 3 months ago.
it would appear the ecm does control the 02 heaters
Expert:  david craig replied 3 months ago.

i hate condemning a computer too, but if it walks like a duck.....

Customer: replied 3 months ago.
I checked my supplier. he has no source for the pcm. so its a dealer item and it most likely needs programing. I wonder if going used mite work in this case
Expert:  david craig replied 3 months ago.

as long as it has the exact same part number might be just what the doctor ordered

Expert:  david craig replied 2 months ago.

any update?