# Service Engine Soon



## Bigplanz (Apr 10, 2009)

SES popped up yesterday on my 2000 Navigator. I loaded my OBD Link scanner software and pulled the diagnostic report. Code P0171 and P0174, fuel trim too lean.

Attached is a screen shot from the report, with out of range values highlighted.

This morning, I ran Forscan while driving and monitored the MAF sensor and O2 sensors, both banks. All values were normal. The MAF status sensor read No Fault, and the O2 sensors (both banks) reported normal values. 

This morning I am heading out to my son's school, which is about 15 miles of interstate driving. I will run real-time short and long term fuel trim monitoring to see what's going on. Not sure how Long Term Fuel trim could be over 20 on both banks without some obvious problem. The Navigator is running perfectly, no surges, no hesitation, nothing. Any ideas on what else to look for would be appreciated.


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## Bigplanz (Apr 10, 2009)

A video...


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## chandler48 (Jun 5, 2017)

SES light just tells you that it is due for service. Normally it doesn't indicate anything wrong with the car. A CEL light illumination will indicate that you check for malfunctioning parts. What are the parameters of the long term trims? What do you have to compare it to? Don't compare it to short term trim.


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## Brainbucket (Mar 30, 2015)

Ok. You have a vacuum leak. Check the PCV hose as the boots/tees fail. Check all vac lines. But I believe your intake plenum and/or intake is leaking. If it does it more with a cold engine that hot, plenum gaskets and or intake. The only safe way to check that is with a smoke machine. But if you have checked all vac line and still haven't found it, plenum gasket/intake. When you see a 20.31 long term means it's adding fuel cause it's lean. When you see a -20.31 it's taking fuel away cause it's too rich.:vs_cool:


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## de-nagorg (Feb 23, 2014)

Dirty air filter?


ED


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## Bigplanz (Apr 10, 2009)

chandler48 said:


> SES light just tells you that it is due for service. Normally it doesn't indicate anything wrong with the car. A CEL light illumination will indicate that you check for malfunctioning parts. What are the parameters of the long term trims? What do you have to compare it to? Don't compare it to short term trim.


An SES light in Ford world is the same as a CEL. They both mean that a fault condition has been detected. My scanner showed two codes P0171 and P0174, fuel trim too lean.

Diagaostic software confirmed this. Long term fuel trim pegged at 25, at idle and went down to about 10 under load. That's a bigly vacuum leak.


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## Bigplanz (Apr 10, 2009)

I replaced a vacuum hose yesterday, due to dry rot. There was no evident leak at this hose connection, but I replaced it anyway, since it was deteriorated.

Drove to work this AM and the LT trim level is still 25. Oh well, didn't expect to work, but the hose needed to be replaced anyway.

A video shot this morning.


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## jdimari4 (Nov 2, 2017)

There is a TSB from Ford for those codes. What you describe matches the TSB for a vacuum leak. They advise first plugging/pinching off different portions of the intake system while observing your short term fuel trim. If the fuel trim goes down after stopping off a branch of the intake system, then that's where your vacuum leak is coming from.

If this method does not show any changes, then the problem is mostly likely intake gaskets. To be sure, spray carb clean in different areas around the engine bay, the vacuum leak will suck up the carb clean thus adding fuel to the system and making your engine rev. this should help pinpoint the area of concern.


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## Bigplanz (Apr 10, 2009)

jdimari4 said:


> There is a TSB from Ford for those codes. What you describe matches the TSB for a vacuum leak. They advise first plugging/pinching off different portions of the intake system while observing your short term fuel trim. If the fuel trim goes down after stopping off a branch of the intake system, then that's where your vacuum leak is coming from.
> 
> If this method does not show any changes, then the problem is mostly likely intake gaskets. To be sure, spray carb clean in different areas around the engine bay, the vacuum leak will suck up the carb clean thus adding fuel to the system and making your engine rev. this should help pinpoint the area of concern.


The carb cleaner on the intake manifold is my next step. It is a big leak; I can hear it.


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## Brainbucket (Mar 30, 2015)

Can you say *FIRE!:vs_no_no_no: *Carb cleaner burnt a truck down in a shop where I use to work. If you can hear it, get a mechanics stethoscope and remove the sound inducing part and stick the hose end toward the leak. You'll be able to pin point it. :vs_cool:


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## Bigplanz (Apr 10, 2009)

Brainbucket said:


> Can you say *FIRE!:vs_no_no_no: *Carb cleaner burnt a truck down in a shop where I use to work. If you can hear it, get a mechanics stethoscope and remove the sound inducing part and stick the hose end toward the leak. You'll be able to pin point it. :vs_cool:


I looked up "using carb cleaner to find a vacuum leak" and found the advice you list above. Basically, DON'T do this on a hot engine. If you do it on a cold engine, have a fire extinguisher. I am a pretty conservative guy, and fire adverse, so I will go with the "don't do it at all" option. Gives me an excuse to buy a stethoscope too. 

I can hear the hiss, even above the engine noise. It sounds like it is on the driver's side of the engine. I have some questions about what I am looking at in the engine bay. See attached pictures. One thing (number 1 in the photo) I have no idea what it is. Number 2 is, I think, the PCV valve. Not sure though, since three hoses run off it. Every PCV valve I have ever seen has only one hose on it, so I am not sure. Someone, please ID these for me? Oh, and how do you get them off?!?!? I replaced the PCV valve on my Olds but that was just pull straight out, push straight in. Thanks.


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## ron45 (Feb 25, 2014)

Have you found the reason for the high idle speed.


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## Bigplanz (Apr 10, 2009)

ron45 said:


> Have you found the reason for the high idle speed.


I assumed it had something to do with the vacuum leak. Maybe not, though. The car is starting to stumble a bit at idle so the leak needs to be found and repaired sooner rather than later. Oh well. If I got mad about having to eff around with old cars, I would stay mad. Learned that one a long time ago.


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## Bigplanz (Apr 10, 2009)

Ghetto smoke machine! I love the internet!

https://www.ebay.com/itm/EVAP-Smoke...acuum-Leak-Detection-Tester-NEW-/282339070632


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## Windows on Wash (Aug 30, 2011)

Wouldn't both with that. 

Just use a Wizard stick or incense near those areas. 

https://www.amazon.com/Zero-Toys-Wizard-Stick/dp/B000FIN0V8


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## jdimari4 (Nov 2, 2017)

Bigplanz said:


> I looked up "using carb cleaner to find a vacuum leak" and found the advice you list above. Basically, DON'T do this on a hot engine. If you do it on a cold engine, have a fire extinguisher. I am a pretty conservative guy, and fire adverse, so I will go with the "don't do it at all" option. Gives me an excuse to buy a stethoscope too.
> 
> I can hear the hiss, even above the engine noise. It sounds like it is on the driver's side of the engine. I have some questions about what I am looking at in the engine bay. See attached pictures. One thing (number 1 in the photo) I have no idea what it is. Number 2 is, I think, the PCV valve. Not sure though, since three hoses run off it. Every PCV valve I have ever seen has only one hose on it, so I am not sure. Someone, please ID these for me? Oh, and how do you get them off?!?!? I replaced the PCV valve on my Olds but that was just pull straight out, push straight in. Thanks.


 
#2 is indeed your PCV valve (I think there's one on the other side too?? maybe not) as long as the hose isn't dry rotted, you're probably good there, but I would remove and inspect just in case, some time it will rot on the "inside" of the elbow joint. #1 is just a T to direct airflow to different parts of the intake system, just look for cracks in the plastic.

I have used carb clean many times with no issues :vs_worry:, but I guess I can't officially recommend it.

If you believe it's coming from the driver side, make sure to check your brake booster. Best case, the hose isn't seated all the way in the booster or intake. Worst case, your booster has a leak. If it's an audible sound, that's a pretty serious leak.


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## jdimari4 (Nov 2, 2017)

Another recommended way to find the leak: Instead of using carb clean, use propane.


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## Bigplanz (Apr 10, 2009)

jdimari4 said:


> Another recommended way to find the leak: Instead of using carb clean, use propane.


I read that too. Read it was safer than carb cleaner. I will try the non-flamable, not burning up the car tests first, although my Navigator burning up parked in front of the house would make for an awesome video.


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## de-nagorg (Feb 23, 2014)

Bigplanz said:


> I read that too. Read it was safer than carb cleaner. I will try the non-flamable, not burning up the car tests first, although my Navigator burning up parked in front of the house would make for an awesome video.


And an expensive replacement price.

Insurance companies balk at paying for obvious negligent acts.

And you have been warned enough about using any flammable tests , that it will look deliberate if not negligent.


I apologize if this offends you, I do not mean to, just pointing out a fact.


ED


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## Brainbucket (Mar 30, 2015)

The PCV on that engine is water cooled so be careful on which hose you yank on. It is a PCV hose assembly which plugs into 2 or 3 places. I can't remember but generally you have to get it from the dealer. When you find the leak, you might be able to put a 3/8 PCV hose there from the parts house but the other 2 or 3 tees and elbows are right behind it as in age and wear. You see 3 hoses going to the PCV? 2 of those is coolant plunged into a circular pipe around the PCV valve. Those are always fun to work with. Do this on a cold engine or hot coolant will spray everywhere.:vs_cool:


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## Bigplanz (Apr 10, 2009)

de-nagorg said:


> And an expensive replacement price.
> 
> Insurance companies balk at paying for obvious negligent acts.
> 
> ...


I was just kidding.


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## Bigplanz (Apr 10, 2009)

Now I have stumbling idle, multiple error codes re: 02 sensors and trim levels. This is related to the "soon" part of the "Service Engine Soon" light. "Service Engine NOW" is next. No light for that; the car just stops running.


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## Bigplanz (Apr 10, 2009)

Took the SUV out at lunch, ran live data. Short and Long term trim, on both banks said "0." O2 sensors, bank one and two, sensor one and two, both read "0."

Error code said Open Loop. 

I assume that this means the vehicle is in "limp mode" and will not run right until I fix my leak.

Attached are updated diagnostic data. If I am wrong, please let me know. Thanks.


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## ron45 (Feb 25, 2014)

Do a full and complete tune up.


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## Brainbucket (Mar 30, 2015)

Until you fix that major vacuum leak, the PCM, Powertrain Control Module, will go crazy. O2s will go crazy. Mass Air flow can't measure all the air going into the engine as it has another source. Codes will pop up. It won't run right... see where I'm going? You cut and artery and bleeding profusely. Then blood pressure goes down and heart rate goes up. Your getting light headed and then pass out. If you stop the bleeding, you cure all the other ailments that go along with it.:vs_cool:


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## Bigplanz (Apr 10, 2009)

Brainbucket said:


> Until you fix that major vacuum leak, the PCM, Powertrain Control Module, will go crazy. O2s will go crazy. Mass Air flow can't measure all the air going into the engine as it has another source. Codes will pop up. It won't run right... see where I'm going? You cut and artery and bleeding profusely. Then blood pressure goes down and heart rate goes up. Your getting light headed and then pass out. If you stop the bleeding, you cure all the other ailments that go along with it.:vs_cool:


Yeah, it is cascading. Each drive cycle brings more fault codes. O2 codes took 2 days to show up. My assumption is that the Navigator is staying in open loop and will stay there until I fix the leak. It doesn't stall...yet. But still... not something you let go. At least I don't. I have friends who have had a CEL for over a year and they just keep driving it. Me, I don't like that little light.

If the leak isn't a hose, I guess I will have somebody fix it for me. Not that i want to, but, well 35 degrees, nowhere other than the street in front of the house to work on it, plus, well, taking the intake manifold off to replace the gasket DIY requires either desperation or high confidence in the likelihood of success. I am not desperate, but I am not confident either. Damn.


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## Brainbucket (Mar 30, 2015)

If you can hear it, it's proly a hose. Buy more tools...(cough cough mechanics stethoscope....cough cough). LOL:vs_cool:


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## 47_47 (Sep 11, 2007)

I'd quit driving it and find the leak. Keep dumping the raw fuel in it and sooner or later you'll take out the cats.


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## Bigplanz (Apr 10, 2009)

Brainbucket said:


> If you can hear it, it's proly a hose. Buy more tools...(cough cough mechanics stethoscope....cough cough). LOL:vs_cool:


I went looking for one yesterday, but the one they had a HF didn't see quite what I needed. Since it is only $4, maybe I'll pick it up anyway.

That's a bad cough you got there, BB. Might want to have it checked out by a doctor. :smile:


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## Bigplanz (Apr 10, 2009)

47_47 said:


> I'd quit driving it and find the leak. Keep dumping the raw fuel in it and sooner or later you'll take out the cats.


That is an interesting point, that I had thought of too. Here is a question for all:

I know over rich conditions lead to other problems, but I "thought" that when a car is in open loop, it ignores the O2 sensor readings, defaults to generic fuel trim levels in the ECM's lookup table and protects the system that way. Limp home mode, I have heard it called.

My 02 sensor and fuel trim live data now reads "zero," which I assume means the car is ignoring them. 

Is this correct?

I will be getting it fixed one way or the other soon.


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## 47_47 (Sep 11, 2007)

Bigplanz said:


> That is an interesting point, that I had thought of too. Here is a question for all:
> 
> I know over rich conditions lead to other problems, but I "thought" that when a car is in open loop, it ignores the O2 sensor readings, defaults to generic fuel trim levels in the ECM's lookup table and protects the system that way. Limp home mode, I have heard it called.
> 
> ...


You are correct ECU does default to set values.

Maybe take out a cat wasn't the best choice of words. How about running so lean that you melt a piston. Just don't want to see you cause needless additional damage.


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## Bigplanz (Apr 10, 2009)

47_47 said:


> You are correct ECU does default to set values.
> 
> Maybe take out a cat wasn't the best choice of words. How about running so lean that you melt a piston. Just don't want to see you cause needless additional damage.


I really appreciate anybody who is trying to help me! Thanks!

My Alldata subscription has actually been useful on this. If it is an upper intake manifold leak, it actually looks like something I could do, if I take my time and move in deliberate steps, following the detailed instructions I found. Maybe I will DIY (if that's the problem). Old School, on the street in front of the house, in mid-November. Represent!


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## ron45 (Feb 25, 2014)

Just my opinion.
If you haven't tuned it up ( complete tune up ) within one year, tune it up.
Erase all codes.
Disconnect the battery for about 20 minutes ( factory set) and start over.


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## Bigplanz (Apr 10, 2009)

ron45 said:


> Just my opinion.
> If you haven't tuned it up ( complete tune up ) within one year, tune it up.
> Erase all codes.
> Disconnect the battery for about 20 minutes ( factory set) and start over.


As I understand it, the term "tune up" is something of a misnomer for modern cars. There is nothing to actually "tune up." On my particular car, a tune up would consist of replacing the plugs, COPs (coil on plugs) and, possibly, the PCV valve. Also, perhaps, cleaning the throttle body, possibly replacing a few vacuum lines or general maintenance inspections.

Mostly (in terms of cost) a tune up is replacing plugs and coils.

Question, since I am unclear on this: how does this tune up address or correct my fuel trim issue/vacuum leak?

I am certain a tune up would improve performance on a functioning engine, but how would it address my underlying fault conditions?


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## de-nagorg (Feb 23, 2014)

In my area there are "rent a shops" where a person can take their vehicle into, and do the work.

They provide all the tools necessary a warm shop, and even have a "Master Mechanic on duty to help anyone that needs it.

If you could afford the cost of something similar around there, it might be a good idea.

They have all the special tools ( stethoscope) available to use to pinpoint your leak, and advice on it's repair.

In my book a tune-up also includes a new air filter, plug wires, pcv and a thorough cleaning of the throttle valve.


ED


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## ron45 (Feb 25, 2014)

de-nagorg said:


> In my area there are "rent a shops" where a person can take their vehicle into, and do the work.
> 
> They provide all the tools necessary a warm shop, and even have a "Master Mechanic on duty to help anyone that needs it.
> 
> ...


And a fuel filter.

Why would a car being driven spit out 3 or more sensor codes.?


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## de-nagorg (Feb 23, 2014)

If it's like my Explorer, the fuel filter is under the car, behind a plate, and framework, a real PIA to get to.


ED


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## Bigplanz (Apr 10, 2009)

ron45 said:


> And a fuel filter.
> 
> Why would a car being driven spit out 3 or more sensor codes.?


And a serpentine belt. 

First two codes were lean codes, the others followed a day later. The ones that followed are related to O2 sensors not reading voltage. I assume these are related to the first two and when I find the root cause and fix it, they should all be resolved.


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## Bigplanz (Apr 10, 2009)

Success! Took the engine cover off and the rubber elbow on the manifold felt like taffy. KNote to self, check stuff like that right of way.

I went to NAPA, bought an elbow, cleared the codes and the Navigator runs fine.


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## de-nagorg (Feb 23, 2014)

:thumbup::thumbup::clap::clap::clap: YAY, a simple fix.

ED


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## Brainbucket (Mar 30, 2015)

I love a cheap fix.:vs_karate:


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## Bigplanz (Apr 10, 2009)

A few pictures. Replacement elbow was $10.


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## ron45 (Feb 25, 2014)

You still need to do the rest of the tune-up.
Or.........................................


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## Bigplanz (Apr 10, 2009)

ron45 said:


> You still need to do the rest of the tune-up.
> Or.........................................


A tune up, on a 17-year old SUV with 80K mileage, is a sound recommendation.

When I changed the elbow, I hooked up my live data diagnostic program and headed out on the interstate. The Navigator ran like a scalded dog, quickly snapping up to 75 from the bottom of the ramp and into traffic (I made sure I had clearance), then smoothly went back down to 60. Long Fuel trim numbers were better than they have been since I got the SUV, in the 4-8 range, under load and 0 to 3 at idle. O2 sensor data was also normal. Driving it around, performance was excellent, on the interstate, stop and go in traffic, etc. I am calling it good.


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## Brainbucket (Mar 30, 2015)

Bigplanz said:


> A tune up, on a 17-year old SUV with 80K mileage, is a sound recommendation.
> 
> When I changed the elbow, I hooked up my live data diagnostic program and headed out on the interstate. The Navigator ran like a scalded dog, quickly snapping up to 75 from the bottom of the ramp and into traffic (I made sure I had clearance), then smoothly went back down to 60. Long Fuel trim numbers were better than they have been since I got the SUV, in the 4-8 range, under load and 0 to 3 at idle. O2 sensor data was also normal. Driving it around, performance was excellent, on the interstate, stop and go in traffic, etc. I am calling it good.


Your learning. Good for you!:vs_karate:


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## ron45 (Feb 25, 2014)

Hey, I don't have a dog in this fight.


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## Bigplanz (Apr 10, 2009)

ron45 said:


> Hey, I don't have a dog in this fight.


There is no fight.


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## Bigplanz (Apr 10, 2009)

Forgot to post the picture of the final repair. Oops! New PCV elbow circled in blue.


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