P0172

This is the place to ask questions about your engine components like cams, valves, pistons… just anything that is generally "engine" specific. This also includes questions about exhaust systems such as exhaust manifolds, piping size, mufflers, ect...
Post Reply
User avatar
Gnuserup
2GN Member
Posts: 661
Joined: Sun Jun 28, 2009 3:06 pm
Location: Germany

P0172

Post by Gnuserup » Mon Apr 21, 2014 1:00 pm

On the RT I get a P0172 from time to time.

I have to confess that I actually only let the engine run a while at idle sometimes as I am actually not allowed to drive on the road (you probably remember I got the RT recently and it is a RHD).

Dan said he got the RT with that code and drove it a while that way.

Now the RT has about 86000 miles on the clock.

What I read so far it often might be an issue of the O2-Sensor.
So I swapped the first sensor to a used but until now working one.
It is the first sensor in line (so on regular 2.0 this sits in the exhaust manifold.
Before I installed it I "cleaned" with just a little compressed air.

After three or four times letting the engine run until it gets warm, the code came back.

I found the intakemanifoldmotor (the butterflything) stuck and swapped it as well.
Again the code has been away for three/ four times.

Today it came back again.

The sparks were looking good, the airfilter pretty new.

Now I swapped the IAC at the throttlebody a cleared the code.

I hope to get some "temporaryplates" soon to be able to do a testdrive.

Any suggestions ??

Maybe the other O2-sensor ??
a neon - what else ?

User avatar
Gnuserup
2GN Member
Posts: 661
Joined: Sun Jun 28, 2009 3:06 pm
Location: Germany

Post by Gnuserup » Sat May 03, 2014 4:57 pm

No idea - anyone?

:-(

I suspected the 2nd sensor at least after I compared the Voltage-values between the RT and the LE.

https://m.youtube.com/watch?feature=you ... PjqnZ_NmJc

My LE and a friends shows a lot less then 0.765 V
when idling with warm engine.

https://m.youtube.com/watch?feature=you ... ivLAtGPZwY

I tried a spare today which shows mostly 0.725V, sometimes a lot less but most time around that.

How should a working RT behave?

Sensor or Cat dead?
a neon - what else ?

ragek23
2GN Member
Posts: 2476
Joined: Wed Sep 27, 2006 9:22 am
Location: Torrington, CT

Post by ragek23 » Sat May 03, 2014 5:18 pm

P0172(M) 1/1 Fuel System Rich A rich air/fuel mixture has been indicated by an abnormally lean correction factor.

This means that your not burning fuel correctly. Either too much fuel is being sent to the engine or its not being burned. Its either lack of spark or too much fuel.

Your upstream O2 sensor seems to be functioning correctly. That's what mine looks like. I am wondering if you may have a stuck injector or possibly a bad injector driver in the PCM. Check to make sure your spark plugs and wires are OK.

2002 Neon SXT Sold
2006 EVO MR Weekend Warrior
2003 SRT 4 DD
-Kevin

Image

User avatar
Gnuserup
2GN Member
Posts: 661
Joined: Sun Jun 28, 2009 3:06 pm
Location: Germany

Post by Gnuserup » Sat May 03, 2014 5:41 pm

Sparks and plugs where looking fine.

I measured the resistance of the injectors recently and found all four about 13.4 when cold and 14.9 when warm.
But I haven't been taking them out to see if one leaks or something.
a neon - what else ?

occasional demons
Junior Admin
Posts: 19908
Joined: Thu May 03, 2007 12:14 pm
Location: Ashland Ohio

Post by occasional demons » Sat May 03, 2014 10:20 pm

The downstream o2 is 1/2, so it has nothing to do with the short term fuel mixtures. It mainly acts to check the performance of the catalytic converter.

Once the 1/2 sensor readings are close to the 1/1 sensor readings, the PCM knows the catalyst has lost it's efficiency. You would get a P0420 code when that happens. Rich or lean codes will only come from the 1/1 sensor.
Bill
Probably shouldn't listen to anything your penis says, that guy's a dick.
Patience, of course, is a very powerful weapon, but sometimes I start to regret that it is not a firearm.
Too much time spent here is a sign of a bad case of Ownaneonvirus.

2000 Neon MTX swap with '02 R/T PCM
1999 neon coupe 2.4 swap

User avatar
Gnuserup
2GN Member
Posts: 661
Joined: Sun Jun 28, 2009 3:06 pm
Location: Germany

Post by Gnuserup » Sun May 04, 2014 2:52 am

So I have to expect a P0420 soon maybe?

Then I probably should check the injectors for a leaking next -
how do you suggest to do that?
Just pull them all out and connect them to the fuelrail outside the intake to ser if one is leaking,
or might there be an easier way to try keeping them installed?
a neon - what else ?

occasional demons
Junior Admin
Posts: 19908
Joined: Thu May 03, 2007 12:14 pm
Location: Ashland Ohio

Post by occasional demons » Sun May 04, 2014 7:07 am

Shouldn't, as long as the converter is good. I was just making the point that your o2 after the converter is not giving you that P0172 code.
Bill
Probably shouldn't listen to anything your penis says, that guy's a dick.
Patience, of course, is a very powerful weapon, but sometimes I start to regret that it is not a firearm.
Too much time spent here is a sign of a bad case of Ownaneonvirus.

2000 Neon MTX swap with '02 R/T PCM
1999 neon coupe 2.4 swap

User avatar
Gnuserup
2GN Member
Posts: 661
Joined: Sun Jun 28, 2009 3:06 pm
Location: Germany

Post by Gnuserup » Sun May 04, 2014 9:10 am

Strange thing at all.

Today I let the engine run a while and with swapped O2-sensor I got the same values.

https://www.youtube.com/watch?v=kK_yfBf ... e=youtu.be

After about 10 Minutes I tried again and they are pretty different

https://www.youtube.com/watch?v=wYczFVh ... e=youtu.be

I made a "sound" test with the injectors after I read elsewhere that they should sound like hard clicking noise. If smooth they might be dirty they said.
I guess the sound might be hard enough...

https://www.youtube.com/watch?v=znQIiP4 ... e=youtu.be

When I startet this thread I had installed a different IAC and a different air-temperature sensor (the thing at the snorkel to the airfilterbox).

Actually the P0172 hasn´t shown up again, but I don´t trust it for the moment. Last time the code came back sporadically, too. Can only hope it is fixed now, though I would not know what it had fixed finally if so.

I already sprayed brakecleaner a few times around the intake manifold but I believe there was no effect.

If it comes back, what should I look for then ?
a neon - what else ?

User avatar
Gnuserup
2GN Member
Posts: 661
Joined: Sun Jun 28, 2009 3:06 pm
Location: Germany

Post by Gnuserup » Mon May 05, 2014 4:32 pm

Today I luckily was able to testdrive the R/T.
Happy I had no issues.
Hope and will see how it goes tomorrow.

Btw. RHD feels way strange, esp. as I am used to shift with the right hand and switch the turnlights with the left.
Here you have to do both with the left :tardbang:

But nice - highly recommended.
a neon - what else ?

Post Reply

Return to “Engine”