SO i have a 2005 Sonata 2.7L V6 GLS and I am having problems with the engine running lean on both banks. all the o2 sensors are reading normal but the fuel trim on both banks creeps up to 14.8. Someone said it would be my fuel pump or fuel filter. That's fine and dandy but I don't have 300 bucks to replace all that. I've checked for vacuum leaks and even bought a new MAF as the old one did show odd readings. The IAT *which seems like a odd spot to put it* reads around 170-187 degrees when the engine is at operating temps. the maf always reads 0.40 to 0.60 when idle and the TPS reads 4.6-5.5 when idle and will go to 86 when fully depressing the gas pedal. Car runs great for the most part considering it was bought for 500 out of a field and rebuilt top end.
05 sonata 2.7l V6 lean issues
1 - 20 of 24 Posts
Joined
·
1,342 Posts
Being as it sat for so long you could have injector issues.
You could have a perfectly fine fuel pump and fuel filter but if the injectors are partially clogged you're not going to get the fuel the engine wants to deliver.
Obviously the ECU is not able to richen the mixture enough to compensate for the lean condition.
How does it run on the freeway or when you really put it under a load?
You could have a perfectly fine fuel pump and fuel filter but if the injectors are partially clogged you're not going to get the fuel the engine wants to deliver.
Obviously the ECU is not able to richen the mixture enough to compensate for the lean condition.
How does it run on the freeway or when you really put it under a load?
It picks up fine. That's why I am so confused. I can go on the highway with no lag issues or hesitation and if I use the shiftronic to lock into lower gears it takes off like a bat out of ****. has no problems under load as I have pulled a stalled car with it before and it had no issues doing that. It does however have a issue when starting it from cold sometimes where the RPM's will fluctuate sporadically like it wants to stall but never does then it settles out. Right now I have no cel as I had to fix a small electrical issue and disconnected the battery. but I have went 80 something miles since then and still no CEL but my fuel trims have crept up from 0 to 12.6 on bank 2 and 7.8 on bank one. bank 2 always throws the error first then after it hits 14.8 bank one will max out at 14.8. the stft on both banks vary between -8 to +8 during idle and under load *while on the highway for example* they go up to 28 on both banks until it goes to lean mode then they will be all over the place. Maybe non related to the issue but I have a phone mount on my dash and I can see the phone shake slightly and it seems like its constant then like a big jump then back to constant while idle but I don't feel it in the car it's self and no odd vibrations from the pedals either.
I'd expect clogged injectors to cause misfire trouble codes, unless they are all clogged to the same degree (highly unlikely).
Your STFT do suggests a fuel delivery issue though, so I'd advise a fuel pressure test. Or just spend the $300 for the new pump and hope for the best.
If you decided the new pump assembly no need to spend 300 on OE hyundai one. I ordered an Auto 7 402-0010 and it was the OE hyundai pump in oe box with an auto 7 label over it. It normally goes for about 150 on amazon. If you watch the price it does does dip once in a while. I picked mine up for 48 bucks. At such a low price I figured it was good to have one on hand and beats paying way more.
Ok hold on Ill go get them. BTW no vacuum leaks no maf issue it's brand new still have the old one they both read the exact same (check the wiring too) Could possibly fuel related in some form or fashion but I've dumped plenty of B12 Chemtool in the tank (more than I should have) multiple times and while it did help slightly on idle it still is acting like poo with these lean codes
as stated by my scan tool P0174 System too lean (Bank 2) P0171 System too lean (Bank 1)
During idle from cold battery voltage at 13.6 V
(Need a new alternator as the voltage drops to 12.3 under load (Lights on blower motor on stereo going))
STFT B1 0.8% -anywhere between -7.6 to +8.0 LTFT B1 14.8%
STFT B2 -anywhere between -13.3 to +6.7 LTFT B2 14.8%
ECT 129F IAT 118F
MAF 0.39-4.4 (lb/min) -Same as the old one but it reads slightly lower at 0.36-0.40 (lb/min)
TPS 4.9-5.1% it will bounce sometimes do to the weather but generally stays at 5.1%
O2S B1S1 0.760 to 0.115(V) fluctuates as normal STFT B1S1 same as other reading O2S B1S2 0.410(V) ((Engine Cold) STFT B1S2 99.2%
O2S B2S1 0.800 to 0.075(V) fluctuates as normal STFT B2S1 same as other reading O2S B2S2 0.410(V) ((Engine Cold) STFT B2S2 99.2%
During idle from cold battery voltage at 13.6 V
(Need a new alternator as the voltage drops to 12.3 under load (Lights on blower motor on stereo going))
STFT B1 0.8% -anywhere between -7.6 to +8.0 LTFT B1 14.8%
STFT B2 -anywhere between -13.3 to +6.7 LTFT B2 14.8%
ECT 129F IAT 118F
MAF 0.39-4.4 (lb/min) -Same as the old one but it reads slightly lower at 0.36-0.40 (lb/min)
TPS 4.9-5.1% it will bounce sometimes do to the weather but generally stays at 5.1%
O2S B1S1 0.760 to 0.115(V) fluctuates as normal STFT B1S1 same as other reading O2S B1S2 0.410(V) ((Engine Cold) STFT B1S2 99.2%
O2S B2S1 0.800 to 0.075(V) fluctuates as normal STFT B2S1 same as other reading O2S B2S2 0.410(V) ((Engine Cold) STFT B2S2 99.2%
That sound more like voltage drop in the wiring than an alternator issue. You might want to carry out a few simple voltage drop tests on the circuit before replacing the alternator.
Actually already did. It is the alternator. can be proven turning my amp and and blasting tones through the sub. I have ran a 8 gauge wire from the alternator to the battery positive post and that's how I managed to get 13.6 volts before I did that it was way lower at 13.4 so not much voltage drop. And the alternator has nothing to do with my lean issues. the car had no problems for several months till it got cold last November. since then it has been this issue with running lean. I replaced the MAF sensor as everyone was saying that would more than likely fix it. wasted 130 bucks because problem was not solved.
Who suggested it did?
Unfortunately, that's what happens when you replace parts based on what "everyone" is guessing could be the problem rather than having the problem properly diagnosed.xeratais said:
Joined
·
4 Posts
What did it end up being?
I have an 06 Tucson, same engine, same symptoms. Can't find a vac leak, cleaned my maf (reads 5.0) fuel trim is at 14.7. And like you mine sar, for almost a year after my dad passed to when i was able to put it on the road.
I have an 06 Tucson, same engine, same symptoms. Can't find a vac leak, cleaned my maf (reads 5.0) fuel trim is at 14.7. And like you mine sar, for almost a year after my dad passed to when i was able to put it on the road.
Are there any codes set? Any performance issues? Is the lean condition present more-so at idle or high rpm under load?
Joined
·
4 Posts
P0420 P0170 P0173
Since my last post I've replacey the throttle body(smoke test revealed a leak via worn bushings) which came with a new IAC and TPS. Ive changed b1s1 and am going to change b2s2 and plugs while the manifold is alreafy off. Begining to think my cat is toast
Joined
·
30 Posts
u
Nice diagnosis on the leaky throttle body. Is it still running lean/setting p0170/173 since you fixed that? I would make sure the fuel mixture is good and engine controls are all in working order before replacing the cat.
Joined
·
4 Posts
Replaced all 4 o2 sensors. Seems to be down to just the lean codes now, tu3me will tell. While I had the manifold off to get the one sensor i replaced plugs and wires. Plugs look good, no signs of running lean. From that I took the engine would be lean without the 30% fuel trim. Now just why
So far, everthing I've done even not related to my check light
New TPS
Had garage replace exhaust manifold on bank 2 and replace master brake cylinder
New MAF
New throttle body with new TPS & IAC
New plugs, wires, valve cover gaskets, manifold gasket and all 4 o2 sensors
Joined
·
4 Posts
New sensors seem to have fixes the p0420, so thats progress. Still eunning lean on both banks
1 - 20 of 24 Posts
Join the discussion
