DTC P0174 after putting in 3 new coils

[eL eS]

Well I got my last 3 coils today for my V6 and rigth after the swap the CEL came on, yes i cursed and swore the car will be the death of me, any way the code is P0174.

There was a thread we discussed this in recently and I am aware of what can cause it. Just curios why it the car woud throw that code right after a coil change. I did have a misfire problem and it is gone now. I have since cleared the code and have driven the car like it was stolen. Turned the car off back on and drove it like it was mine then like it was stolen, becasue it felt good to do it, and no recurrence of the code.

Do you think it threw the code becasue it was some how making up for the misfire by correcting the AF mix?

 

[l-m tech]

po174 is a lean code ,poss. vacume leak,contaminated maf.if you had carbon trailed plugs it would throw a rich code.early v6 and v8 had a poorly designed pcv system,there hoses are junk .

 

[eL eS]

po174 is a lean code ,poss. vacume leak,contaminated maf.if you had carbon trailed plugs it would throw a rich code.early v6 and v8 had a poorly designed pcv system,there hoses are junk .

Yeah I suspect it might be the K&N that I use since it has the oil in the filter. The plugs are 2 weeks old. I have a new pcv valve but I could not locate the location of the one on my LS. I will check the sho manual and alldata.com again this weekend.

I did have to push some hoses around to get to the coils so it is even possible that I might have unseated one slightly. But I cleared the code and it has not return YET. But I do not know how long itwould take the pcm to ID that problem again after clearing it since many of the DTC metrics are flushed during reset.

I guess I will continue to observe the car tomorrow and if it returns take my own advice and clean the MAF with electrical contact cleaner.

Thanks for taking the time to address this issue.

 

[eL eS]

well it keeps coming back and this is what I have

P0171 AND P0174
CALC LOAD 21%
cOOLANT TEMP 214
B1 SHORT TERM FUEL TRIM 10.92%
B1 LONG TERM FUEL TRIM 24.96%
B2 SHORT TERM FUEL TRIM 13.26%
B2 LONG TERM FUEL TRIM 24.96%
ENGINE RPM 905

I recently replaced all my coils and plugs becasue of a misfire condition. Shortly afterwards the aforementioned code were thrown. I cleaned my MAF and checked the integrity of the seal on my air tube. I strictly run 93 octane fuel and since the misfire condition has been corrected there are no other drivability concerns.

any help would be appreciated.

 

[Quik LS]

well it keeps coming back and this is what I have

P0171 AND P0174
CALC LOAD 21%
cOOLANT TEMP 214
B1 SHORT TERM FUEL TRIM 10.92%
B1 LONG TERM FUEL TRIM 24.96%
B2 SHORT TERM FUEL TRIM 13.26%
B2 LONG TERM FUEL TRIM 24.96%
ENGINE RPM 905

I recently replaced all my coils and plugs becasue of a misfire condition. Shortly afterwards the aforementioned code were thrown. I cleaned my MAF and checked the integrity of the seal on my air tube. I strictly run 93 octane fuel and since the misfire condition has been corrected there are no other drivability concerns.

any help would be appreciated.

P0171Fuel Trim System Lean Bank 1
P0174Fuel Trim System Lean Bank 2


B1 SHORT TERM FUEL TRIM 10.92% <- doesn't look right.

Could the electrical connectors on some of the injectors be loose?

Did you have to pull the injector connectors off when replacing the coils?

If I recall, they had a crappy design with squeeze tabs that break off eaisly and therefore do not lock on anymore.

 

[eL eS]

P0171Fuel Trim System Lean Bank 1
P0174Fuel Trim System Lean Bank 2


B1 SHORT TERM FUEL TRIM 10.92% <- doesn't look right.

Could the electrical connectors on some of the injectors be loose?

Did you have to pull the injector connectors off when replacing the coils?

If I recall, they had a crappy design with squeeze tabs that break off eaisly and therefore do not lock on anymore.

Did not have to touch the FIs at all. My neighbor that owns andoperates his own shop just rolled up. I found an area wehre there was a hissing sound on the LH side of the engine. A few vaccum hoses come togther. He helped narrow down the sound to a pin hole in a hose.

Like the fella above said crappy hoses. I found a few little vaccum lines that are made of hard plasitc that have gotten brittle as hell. One was patched together with a small section of rubber hose. Obviously a crappy patch job but the dealer. MFers.

Thanks for checking in. I will post back later after I replace the hose.

 

[eL eS]

well that didnt get it. In fact after further inspection of the hoses they all have little holes in them that only go skin deep and they are spaced apart along the hose about every 4 inches. Looks like they were fabricated with them.

The codes keep coming back and I am stumped. I add hose clamps on hoses that the dealer negelected to put back on hoping that would help.

I sure could use some ideas if you have them. TIA

 

[eL eS]

this is what I am looking having to sort through.


1. HO2S sensors are not likely to be the cause of adaptive DTCs P0171, P0172, P0174, P0175: Most warranty-returned HO2S sensors (replaced for these DTCs) are found to function normally. Additional related DTCs will normally be present if there is a concern with the HO2S sensors. Do not replace an HO2S sensor unless verified through pinpoint diagnostic tests found in the PC/ED Service Manual.

2. DTCs P0171, P0172, P0174, and P0175 are not related to downstream H028 sensors: When diagnosing a vehicle with a MIL On and DTC(s) P0171, P0172, P0174, and/or P0175 in continuous memory, do not replace the downstream HO2S sensors. These DTCs have no connection to the downstream HO2S sensor function nor its diagnosis for faults. Always verify the vehicle concern, then perform the pinpoint diagnostics from the appropriate PC/ED Service Manual.

3. Diagnosing lean conditions and lean DTCs P0171, P0174: Freeze Frame Data can often help to identify the type of lean condition, even if the fault is intermittent, by indicating how the vehicle was being driven when the fault occurred. Diagnosis of lean conditions and lean adaptive DTCs can be difficult, especially if the concern is intermittent. Verifying the concern is extremely important. There are different types of lean conditions. The ability to identify the type of lean condition causing the concern can be crucial to a correct diagnosis. When DTCs P0171 and P0174 are both present, there is a strong likelihood of another concern being present:

a. Vacuum leaks/unmetered air: In this type of condition, the engine may actually run lean of stoichiometry (14.7:1 air/fuel ratio) if the PCM is not able to compensate enough to correct for the condition. This condition is typically caused by air entering the engine through an abnormal source (opening), or due to a MAF malfunction. In this situation, the volume of air entering the engine is actually greater than what the MAF is indicating to the PCM. Vacuum leaks will normally be most apparent when high manifold vacuum is present, during idle or light throttle. If Freeze Frame Data indicates that the fault occurred at idle, a check for vacuum leaks/unmetered air when the engine is cold might be the best starting point.



Examples: Loose, leaking or disconnected vacuum lines, intake manifold gaskets or 0-rings, throttle body gaskets, brake booster, air inlet tube, stuck/frozen/aftermarket PCV valve, unseated engine oil dipstick, MAF reading lower than normal, etc


All I did yesterday is remove and replace the 3 LH coils. Now is it possible that this condition existed prior to the coils being replaced?

 

[thamarkman]

I'm sorry this has nothing to do with your problem, but doesn't this ever make you wish you could go back to having a car with a carberator?

 

[eL eS]

you know horse and buggy would be great about right now.

Honestly with all the money I have spent in the last few months it has vaporized my bank account. sadly I cant even afford to take this thing into the dealer to handle. the feeling of defeat is horrible. I am certain things can get worse but right now is an all time low.

 

[lsbit]

I'm sorry this has nothing to do with your problem, but doesn't this ever make you wish you could go back to having a car with a carberator?

A distributor with ONE coil would be really nice, at least.

I am sorry to hear of the problems you are having Noah. The rule I use is, if it wasn't broke before I worked on it, then I must have done something. It has worked for me in the past, but things seem to break quicker on an LS. I have seen lean codes come back to me in my Mustang after changing the tune around and forgetting to clear the KAM. I was hoping your problem would be solved when you cleared the PCM to clear the adaptive. You checked vaccum..how about wires. Anything crimped by mistake?

 

[eL eS]

yeah I have combed over the vacuum lines a hundred times. Do you think I should clear the pcm by removing the batt terminals?

does anyone know if clearing the pcm with the scan too has the same result as removing the batt terminals?

 

[Quik LS]

yeah I have combed over the vacuum lines a hundred times. Do you think I should clear the pcm by removing the batt terminals?

does anyone know if clearing the pcm with the scan too has the same result as removing the batt terminals?

it does, but cutting the power offers the added benefit of resetting all the 'learned' behavior as well.

 

[eL eS]

Thank Lou. I am going to pick my car back up from the lincoln dealer. They have had my car since 1030am today. They are just as stumped as I am. Don't know if I should feel good about that or not.

The car has no drivability issues at all. The only malady is when at a stop or idle the rpms roll up and back down rhythmically. So I will drive it till Wednesday and drop it back off for them to continue to troubleshoot. When I get it home I will remove the battery completely.

 

[eL eS]

well they definitely aree of the opinion that it is not a vacuum leak in any of the hoses. Their next best guess is it is inside the intake.

So I am going back in to install that part I didnt have time to do 4 weeks ago. The PCV Valve.

Supposedly it is in the lower intake. So i will have to remove the fuel rail with the lower intake as one piece. Any one have any tips on how to handle disconnecting the fuel lines when i get there?

 

[Quik LS]

Supposedly it is in the lower intake. So i will have to remove the fuel rail with the lower intake as one piece. Any one have any tips on how to handle disconnecting the fuel lines when i get there?

glad the V8 don't have a PCV.

to disconnect the fuel line - you'll need a special 'spring lock valve' tool - you can get it at autozone for a couple of bucks.

the manual will say to depressurize the fuel line - I never do, just have a rag underneath the valve when you pop it apart, a little bit of fuelcomes out.

you'll be tempted to NOT drain the rad, but DO, as when you pull the intake off, the heater lines running in/out of the trottle body are full of coolant, so the last thing you want to have happen is some coolant leak into an open intake....

 

[eL eS]

yeah when i look back upon my purchasing decision I can see where I made all sorts of mistakes not getting the V8, doh I should of had a V8, being one.

Thanks for the tech tip.

I am waiting for my parts runner, my lovely wife, to return froma fun day at the parks.

 

[eL eS]

any one know how to disconnect the fuel line electrical connector man that thing wont budge

 

[eL eS]

well the elbow to the pcv is collapsed!

 

[l-m tech]

well the elbow to the pcv is collapsed!

see this often try makeing a liveing at it.

 

[eL eS]

see this often try makeing a liveing at it.

GOD BLESS Ya' and the rest that do the same thing day in and day out.

When I say my prayers tonight I am going to thank the lord for the IT Industry and ask the lord to bless the automotive techs that have to untangle all the BS that comes out of the Wixom plant.

 

[eL eS]

I found some elbow tubing at auto zone that is just about as perfect fit as one could ask for during a crisis. I am hose clamping to make up for any play in the tube.

 

[eL eS]

well hell. I just discovered that cap to the tube that feeds back to the air intake tube on the RH valve cover has two busted tabs. One guess where the tabs must be resting.

I thought I would have had this thing done tomorrow but looks like I will have to remove the RH valve cover to remove some broken platic teeth.

Man I can buy a break today.

I doubt that the cap will even fit back snuggly enough to prevent another vacuum leak.

 

[Chris_n_FL]

The little elbow that sits on the head near the knock sensor under the lower intake manifold gaskets?? Yup, had to replace mine last week aswell. Mine looked like it was melting from the inside out, which caused a hole which lead to a vac leak. I cant remeber how many times I had to install and remove the intake mani!! I know now that I can do it again in less than 10 minutes!!

 

[eL eS]

The little elbow that sits on the head near the knock sensor under the lower intake manifold gaskets?? Yup, had to replace mine last week aswell. Mine looked like it was melting from the inside out, which caused a hole which lead to a vac leak. I cant remeber how many times I had to install and remove the intake mani!! I know now that I can do it again in less than 10 minutes!!

Yep that is the one. I am closing up the project right now. It is much easier to work in if you remove the sway bar. I sure wish you could have checked in yesterday morning or friday. Man you would have had yourself a nice steak dinner.

You ought to come out to the mustangs and mustangs event with us. I posted the link in the other thread but here it is again.


http://www.lincolnvscadillac.com/showthread.php?t=6171