trouble code assistance.. please

[dreamr]

We were headed to Mt Baker for some camping, and after about a 120 miles I had a CEL come on though there were no noticeable runability issues.

A bit of history. The Vehicle is a 99 4.0 OHV. Current engine add-ons include a K&N open air intake, BBK 66mm T-Body, after market wires, and the most recent, in fact the day before I left, An Apten performance program.

Anyway, we didn't head in too deep to the mountains, and the first thing I did after getting home was check the trouble codes.

P1131 - Lack of HO2S11 Switch- Sensor indicates lean
P1151 - Lack of HO2S21 Switch- Sensor indicates lean

Admittedly I have absolutely no clue what that means, but after a short stint with the search feature it seems that O2 sensors may be a culprit as may a dirty MAF.

I suppose I should flash it back to stock and see what happens. I'll post back if it makes a difference....... after a shower that is. I smell like wood smoke and sweat.

I should also mention that there has got to be a vacuum leak somewhere, that is causing a very mild and random "stumble" in the idle. I can hear a faint whistle, but can't seem to find it.

If anyone could give a bit of input on what is the likely problem, it would be appreciated. Also if it is something I can do myself please let me know, as I really hate pulling off my toys to visit the dealer for warranty work.

Thanks for any help!!

 

[mrboyle]

A vacuum leak will allow unmetered air into the engine, this will lean the air/fuel ratio and will cause the codes you have.

 

[aldive]

Sorry about your problems, however, I can only say wonderful things about my Apten Flasher.

Good luck resolving the situation.....

 

[dreamr]

Mrboyle- Thanks, a question though. I have been trying to hunt down this vacuum leak for over a month. Would it have taken this long to show a CEL?
Would the tuning have just exagerated the exhisting condition?

Aldive- I actually really like the Apten program, and have no doubt that they are a good group of people. I just happened to be the guy at the end of a series of mistakes, and am getting over it. Hopefully Gene will live up to the quality of customer care I have been led to believe they were in possesion of and alleviate me of my concerns.

Hmmm where to start. What is there an easy test for a faulty O2 sensor, or MAF.....actually there is that snap-on e-mail that probably has instructions for the MAF test.

 

[dreamr]

Al righty then, time to update this thread and see if anyone can offer a bit of advice.

I reset the CEL right after my last post to this thread, and drove around town for a few days. It never came back on, but the truck is still idling very unevenly, and I believe there is still a vacuum leak.

Since My last post I have checked everywhere I can think of with an unlit propane torch for air leaks. I found none. I went ahead and pulled the throttle body and IAC as they were both recently installed. The gasket on the T-Body showed that the seal was great. The IAC however was not seating as well as it could and was slightly leaking.

I replaced the IAC gasket with a better material as well as the t-body gasket.
No change.

I pulled the IAC and gave it a good cleaning even though it is relatively new, and also cleaned the MAF. The idle is a bit smoother, but I still hear a whistle.

The CEL has not returned and their are no codes when I checked. I guess my question is why has the CEL not returned even before I started messing with things. And furthermore what do I try next.

Ford recommended swapping back to motorcraft wires (currently running new accel superstocks) I kind of ignored them, but possibly I should look into that as my next attempt at curing this prob.

My last question. Would a random misfire throw codes for a lean condition?

 

[dreamr]

To bump the thread and keep begging for guidance.

That pesky little check engine light returned today while driving down to Olympia. Apparently it needs to be on the freeway for a while to trigger the light. Interesting since I actually put more miles on it in town than on the freeway.

I have used every method I can think of to find a vacuum leak, and it all seems to be sealed well.

Two things I should still do is swap back to the factory wire set I suppose.

The second is flash it back to stock, but I just can't seem to be able to give up my better shifting.

Any more input anybody??

 

[Glacier991]

Well it doesn't come thru pretty (AT ALL!), but here i a list of possible causes:

P1130 - Lack of HO2S ³ The HEGO Sensor is ³ Electrical: ³ A fuel control HO2S-11Switch, Fuel Trim ³ monitored for ³ ù Short to VPWR in ³ PID switching across ³
³ at Limit ³ switching. The test ³ harness or HO2S ³ 0.45 volt from 0.2 to ³
³ ³ fails when the HO2S ³ ù Water in harness ³ 0.9 volt indicates a ³
³ ³ fails to switch due to ³ connector ³ normal switching HO2S. ³
³ ³ circuit or fuel at or ³ ù Open/Shorted HO2S ³ ³
³ ³ exceeding a calibrated ³ circuit ³ ³
³ ³ limit. ³ ù Corrosion or poor ³ ³
³ ³ ³ mating terminals ³ ³
³ ³ ³ and wiring ³ ³
³ ³ ³ ù Damaged HO2S ³ ³
³ ³ ³ ù Damaged PCM ³ ³
³ ³ ³ Fuel System: ³ ³
³ ³ ³ ù Excessive fuel ³ ³
³ ³ ³ pressure ³ ³
³ ³ ³ ù Leaking ³ ³
³ ³ ³ /contaminated ³ ³
³ ³ ³ fuel injectors ³ ³
³ ³ ³ ù Leaking fuel ³ ³
³ ³ ³ pressure ³ ³
³ ³ ³ regulator ³ ³
³ ³ ³ ù Low fuel pressure ³ ³
³ ³ ³ or running out of ³ ³
³ ³ ³ fuel ³ ³
³ ³ ³ ù Vapor recovery ³ ³
³ ³ ³ system ³ ³
³ ³ ³ Induction System: ³ ³
³ ³ ³ ù Air leaks after ³ ³
³ ³ ³ the MAF ³ ³
³ ³ ³ ù Vacuum Leaks ³ ³
³ ³ ³ ù PCV system ³ ³
³ ³ ³ ù Improperly seated ³ ³
³ ³ ³ engine oil ³ ³
³ ³ ³ dipstick ³ ³
³ ³ ³ EGR System: ³ ³
³ ³ ³ ù Leaking gasket ³ ³
³ ³ ³ ù Stuck EGR valve ³ ³
³ ³ ³ ù Leaking diaphragm ³ ³
³ ³ ³ or EVR ³ ³
³ ³ ³ Base Engine: ³ ³
³ ³ ³ ù Oil overfill ³ ³
³ ³ ³ ù Cam timing ³ ³
³ ³ ³ ù Cylinder ³ ³
³ ³ ³ compression ³ ³
³ ³ ³ ù Exhaust leaks ³ ³
³ ³ ³ before or near ³ ³
³ ³ ³ the HO2S(s) ³ ³
ÃÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÅÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÅÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÅÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ´
³ P1131 - Lack of HO2S ³ A HEGO sensor ³ See Possible Causes ³ ³
³ -11 Switch, Sensor ³ indicating lean at the ³ for DTC P1130 ³ ³
³ Indicates Lean ³ end of a test is ³ ³ ³
³ ³ trying to correct for ³ ³ ³
³ ³ an over-rich ³ ³ ³
³ ³ condition. The test ³ ³ ³
³ ³ fails when the fuel ³ ³ ³
³ ³ control system no ³ ³ ³
³ ³ longer detects ³ ³ ³
³ ³ switching for a ³ ³ ³
³ ³ calibrated amount of ³ ³ ³
³ ³ time. ³ ³ ³


Put another way thre are 2 lean codes. One means a lean mixture, one means lean at the end of test cycle, indicating an over rich mixture is attempting to be compensated - you are the latter. On both codes. FPR comes to mind. Intake obstruction? other things could also contribute. Think OVER RICH! Here is where a scanner showing fuel trim (and other real time data) would be invaluable. I bet your fuel trim numbers are 20%

 

[ga_sport4X4]

Check the point at which the exhaust manifolds meet the tail pipes on both sides of the truck. This union is next to the o2 sensors on both sides of the engine. If there is black soot around or near this union, you have and exhaust leak directly in front of the 02 sensors. Which will cause the lean reading. The whistle, in my case, was the upper and lower intake manifold gaskets. Replacing these gaskets and torquing them to spec. cleared my lean codes and helped tremendously in overall performance.

This previous post mine may help as well:

So here is a list of repairs I have done to fix the lean problem, eratic idle and poor gas mileage:

1. Change fuel filter and air filter

2. Cleaned MAF sensor with denatured alcohol ($7)

3. Cleaned Throttle Body with denatured alcohol

4. Check for damaged 02 wires, correct connections, and if possible, for correct power signals and grounds to each of them.

5. Check plugs and wires. I changed them since they were out of the engine and they looked horrible from running lean for 3 months. The gaps in the Motorcraft +4s were not near there pre gapped spec. They ranged from .026 to .044, and most of which were in the .032-.038 range. So, make sure they are gapped to spec.

6. Check for exhaust leaks at the manifolds and especially around the O2 sensors. Easy to detect if you have been running lean for some time. There was black soot at the point at which the exchaust manifold joins the exhaust pipe. This is directly in front of the O2 sensors. A leak here causes excessive air to enter the system. At this point, your truck makes up for the high air reading by using excessive gas to try to balance the air to fuel ratio. If you useSEAFOAM, the white smoke will reveal where there are leaks are located.

7. Check fuel pressure - my fuel pressure was up to spec, so not my fuel pressure regulator or clogged fuel line. I priced a fuel pressure regulator at Ford dealership over the phone, and they wanted $415.00. This was for the FPR and some of the metal fuel lines. I laughed and so did the parts guy. He said try somewhere else and that it should run between $60 and $115.

8. Tighten the lower and upper intake manifold bolts and change the gaskets since you are in there. This is a major pain in butt if you have never done this work. It was in my case. I wanted to do everything correctly and didn't want to break anything, primarily my plastic intake. Thanks to the good write up i finished it. This took care of the eratic idle.

9. Seafoam in the brake booster line and the gas tank.

My truck runs as if it were new. The gas mileage went from 10.5 mpg to 16mpg, the response is great, normal rpms through shifting points, no eratic idle at startups or once the engine has warmed up, and no hesitation. Goodluck.

 

[dreamr]

Thank You for all the info!

As soon as I get my painting projects out of the garage I will get back in there and see what I can find. It may be getting time to pay someone else to point out the obvious thing I missed while getting overly involved with the issue.

Here'a an interesting tid bit I would love an explanation to.

Yesterday I put about 70 freeway miles on my truck and the CEL was triggered after having been cleared.

Ok same codes. I leave the light alone, and did not clear the codes. As I am driving around town today about 35 total miles the CEL suddenly turns off.
There was no noticeable difference in the runability, just no more light.
WHY?

 

[barnieman]

AFAIK: The CEL lights up only after the lean mixture was detected during two run-cycles (you have to drive a few minutes 30 mph, then a few minutes 70 mph, to complete one run-cycle). It turns off after two run-cycles without the problem. My Explorer has the same problem, but reports only the P1151 code.
As long as the Explorer can adjust the mixture to compensate for the lean mixture, the error will not occur, even though you have the problem. The CEL only lights up when the Explorer can not compensate no more.

 

[Arnie897]

Bump....

Dreamr, did you ever resove this problem?

I have the same two codes. The only thing is when they turn themselves off they sometimes come back as p1132 and p1152....the rich reading instead of the lean.

I also have the hiss under the hood, poor milage, and the rough idle.

 

[dreamr]

I should remember to come back to threads like this and post my results huh. Oops, well thanks for reminding me to do so!

To answer your question I went through everything I could think of trying to solve the vacuum leak. I to this day have not found where the sound is coming from. However the trouble codes were being caused by my flasher that had been programmed by Apten. Seems they not only made it a nightmare to aquire, shipped the wrong tuner order to me, but in the end also leaned my air/fuel ratio out entirely too much. Luckily for me I contacted Doug of BamaChips and he kindly offered to reprogram the tuner the way it should have been from Apten for the price of shipping. Good Guy we have there to sponsor the site!!!!!!

The light has not been seen since.

 

[Arnie897]

Interesting

I have an Apten chip in my truck too. Maybe that's the problem. I can't switch mine back to stock though or take it out for that matter. How do you think I could verify that is the problem?

 

[dreamr]

I would suggest contacting Doug904 on the board and seeing if he has any input for you. Other than that it would be good if you could look up the optimal A/F ration then test yours to see where you sit.

In many cases though the O2 sensors can be the cause of this code. If you have been running fine with the chip for a good amount of time and then the code popped up I doubt the chip has anything to do with it.