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2004 Dodge neon sxt 2.0l with p0171 and hesitation


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10mm
Novice

Aug 24, 2023, 1:25 PM

Post #1 of 17 (2616 views)
2004 Dodge neon sxt 2.0l with p0171 and hesitation Sign In

Journey starts with customer asking to replace fuel pump and do a transmission flush. Both performed and been chasing p0171 since.

IAC valve also new

Spark is strong, noid test passed, fuel pressure at 58psi, plugs look good(not white or black), carb clean showed no leak or surging, pressurized intake with a shop vac and found no bubbles, compression 125-135psi, throttle is reading accurate, fuel volume is good, pcv working correctly, booster holds vacuum, and cruise holds steady(vacuum operated), fuel additive was in the tank I dropped, that gas has all been used up. No visual or auditory intake/exhaust leak, and the cat seems to be doing it's job right

P0304 and p0344 both came up once during testing, replaced and cleaned cam and crank sensors, never seen again. Also at this time LTFT went from 99% to 32%, STFT bounce between -10 and +10.

Replaced both o2 because the front one dropped voltage once, put in new MAP at this time as well for assurance. O2s now slightly high but fluctuating as desired(rear .8 volts). I hard reset the computer at this point, LTFT went from 0% back to 32 in about 8 minutes of driving.

MAP reading 9.5inHg in neutral, 10.5-11 in gear, still get p01710 and hesitation to accelerate has gotten worse, but have plenty of power after hesitation. Checking timing now


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Aug 24, 2023, 1:57 PM

Post #2 of 17 (2590 views)
Re: 2004 Dodge neon sxt 2.0l with p0171 and hesitation Sign In


Quote
carb clean showed no leak or surging, pressurized intake with a shop vac and found no bubbles,


Huh? Cars haven't had carbs for 40 years. I don't know what you are trying to do with the shop vac but you certainly aren't testing anything.

You need to locate any vacuum leaks and the only accurate way to do that is with a smoke tester.

If you LTFT is only 32, that will not set a code so you may not have the issue any more.

You also need to look at the IAT and ECT sensor data with a scan tool on a cold engine before starting it. They should match each other.



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



10mm
Novice

Aug 24, 2023, 2:14 PM

Post #3 of 17 (2585 views)
Re: 2004 Dodge neon sxt 2.0l with p0171 and hesitation Sign In

Don't have a smoke tester, so was using what's available. I've found intake leaks this way before. Carb clean used to make sure seams and gaskets weren't pulling unmetered air, vehicle would surge or sputter with the extra "fuel"

Vehicle sets code no matter if I plug all vacuum sources or not with that FT

Definitely acts like an intake leak, with no intake leak. Shop vac blows air into intake through the accordion tube, spray entire intake and vacuum system with soapy water, should bubble at leak, just like smoke would show you the leaky point.

Etc and iat sensors both accurate, thermostat works as well, so does all the EVAP valves even though like I said I've plugged all vacuum sources and still get the code and hesitation with acceleration


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Aug 24, 2023, 2:19 PM

Post #4 of 17 (2581 views)
Re: 2004 Dodge neon sxt 2.0l with p0171 and hesitation Sign In

Those "old school" tricks don't work on todays cars.

If you don't have access to a smoke tester, then you re going to have to pay a shop to do it for you. There are far too many secluded areas that can leak.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



10mm
Novice

Aug 24, 2023, 2:31 PM

Post #5 of 17 (2577 views)
Re: 2004 Dodge neon sxt 2.0l with p0171 and hesitation Sign In

Good enough method to blow off a weak vacuum hose after a minute, definitely would show an intake leak, or any other pinhole.

And if a person plugs off those secluded areas and still has the same issue, then what?


10mm
Novice

Aug 24, 2023, 5:59 PM

Post #6 of 17 (2517 views)
Re: 2004 Dodge neon sxt 2.0l with p0171 and hesitation Sign In

Smoke test showed no leaks, including the EVAP system working correctly when actuated. The timing marks line up as well. I've also put an actual vacuum gauge on it to make sure the MAP is correct, which it is.

I'm at a loss but will update any further findings or fix


Sidom
Veteran / Moderator
Sidom profile image

Aug 27, 2023, 7:58 PM

Post #7 of 17 (2349 views)
Re: 2004 Dodge neon sxt 2.0l with p0171 and hesitation Sign In

Can you post the freeze frame data for when the p0171 set?


10mm
Novice

Sep 1, 2023, 11:37 PM

Post #8 of 17 (2135 views)
Re: 2004 Dodge neon sxt 2.0l with p0171 and hesitation Sign In

DTC = p0171
Fuel system 1 status = CL
Calculated load = 45.9%
ECT = 195°f
STFT =17.2%
LTFT =32.8 %
MAP = 12.3 inHg
RPM = 727
Speed= 0mph
#1 timing advance =11°
Intake air temp =132°f
Absolute throttle position = 9.8%

In addition this freeze frame data is from after I put a smoke machine on before the throttle body and plugging the hose coming from the back of the valve cover. The spring for the throttle plate had a decent amount of smoke coming from it so I repaired it. No further leaks afterwards(including exhaust).

Rear o2 also around .65v and then fluctuates rapidly on accel/decel. Possible cat issue??


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Sep 2, 2023, 5:07 AM

Post #9 of 17 (2118 views)
Re: 2004 Dodge neon sxt 2.0l with p0171 and hesitation Sign In

It doesn't help to post data from before repairs were made. We need current data to diagnose a current problem..



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



10mm
Novice

Sep 2, 2023, 7:25 AM

Post #10 of 17 (2110 views)
Re: 2004 Dodge neon sxt 2.0l with p0171 and hesitation Sign In

That is current bud


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Sep 2, 2023, 7:36 AM

Post #11 of 17 (2104 views)
Re: 2004 Dodge neon sxt 2.0l with p0171 and hesitation Sign In


Quote
In addition this freeze frame data is from after I put a smoke machine on before the throttle body and plugging the hose coming from the back of the valve cover. The spring for the throttle plate had a decent amount of smoke coming from it so I repaired it. No further leaks afterwards(including exhaust).


This response is a bit confusing. It sure sounds like you meant before the repairs.

The long term fuel trim is still seeing a lean mixture and is nearly maxed out with adding more fuel.

Since this problem originated with a fuel pump change I would be very suspicious of that. Have you monitored the fuel pressure while driving the vehicle?



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



10mm
Novice

Sep 2, 2023, 9:28 AM

Post #12 of 17 (2095 views)
Re: 2004 Dodge neon sxt 2.0l with p0171 and hesitation Sign In

Sorry for the confusion, I tested from the throttle back, found a leak in the throttle spring, repaired, tested again and no leak anywhere. The fuel pressure remains good while driving and the volume from injectors is the same across the board.

I have also rechecked all my work and pulled the tank back down and all connections are good.


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Sep 2, 2023, 9:34 AM

Post #13 of 17 (2092 views)
Re: 2004 Dodge neon sxt 2.0l with p0171 and hesitation Sign In

I don't know. We are missing something here. There aren't that many things that can cause severe lean condition. It's basically excess air or insufficient fuel. You missed something somewhere.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Sidom
Veteran / Moderator
Sidom profile image

Sep 5, 2023, 10:33 AM

Post #14 of 17 (1959 views)
Re: 2004 Dodge neon sxt 2.0l with p0171 and hesitation Sign In

I don't know if you got a handle on this on yet but those trims are way high at idle. Do the trims come down to normal at @ 2000 - 2500 rpms?
Did you block off the PCV valve or put a vacuum gauge on the oil dip stick to eliminate it?
You mentioned the B1S1 O2 voltage is high which is odd with a 171, you would think it would be on the lower end?

Was the P0171 the original problem and why your cust wanted a fuel pump or did this pop up after the work?


10mm
Novice

Sep 6, 2023, 8:49 AM

Post #15 of 17 (1908 views)
Re: 2004 Dodge neon sxt 2.0l with p0171 and hesitation Sign In

Definitely something odd or that I'm missing...

Fuel pump done for initial hesitation, code was part of that.

Long term Trims stay high, will come down a little but bounce back up.

No intake or exhaust leaks either with smoke test(haven't back-pressured)

LTFT and the rear o2 bouncing around, and continued hesitation are the only indicators to me at this point that it still has an issue. I have swapped o2's and watched the data stay in that higher range.

I'm certain it's not fuel, spark, compression, timing components, cam/crank sensors and correlation, map, temp sensors, pcv, IAC, EVAP system, vacuum lines, throttle body, or injectors.

All I can think of is catalytic, computer controlling, and adaptives. Mainly sluggish to accelerate above 3k rpm after fixing the throttle body leak


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Sep 6, 2023, 10:32 AM

Post #16 of 17 (1900 views)
Re: 2004 Dodge neon sxt 2.0l with p0171 and hesitation Sign In


Quote
I'm certain it's not fuel, spark, compression, timing components, cam/crank sensors and correlation, map, temp sensors, pcv, IAC, EVAP system, vacuum lines, throttle body, or injectors.


If you're so sure about all those items then it only leaks vacuum leak. Like I said either not enough fuel or too much air for whatever reason are the only way you get a lean condition.

You're also wasting your time blaming the Cat.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



(This post was edited by Hammer Time on Sep 6, 2023, 10:36 AM)


Sidom
Veteran / Moderator
Sidom profile image

Sep 6, 2023, 11:21 AM

Post #17 of 17 (1887 views)
Re: 2004 Dodge neon sxt 2.0l with p0171 and hesitation Sign In

When you say the trims stay high, what is the percentage and at what rpm/speed?
I;m sure you know when the trims are high at low speed/rpm it's usually to much air related and when they are high at high speed it's a lack of fuel problem

Usually when the trims are high all the time it's a bad MAF but this is a speed density motor that uses a MAP.
I dunno, I haven't heard of a bad MAP causing this problem but if it was me I would be tempted to disconnect it to see what type of a change it made to the trim issue & hesitation problem.
My database is a bit out of date. I looked thru the TSBs and didn't see anything that was related. Just a bunch of flash issue TSBs. But considering the problem, the lastest flash update might not be a bad idea?






 
 
 






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