running rich at idle??

the98stang · Aug 16, 2007

My car is running super rich at idle (between 10 and 13 AFR). At first I thought maybe I had a vacuum leak, causing the PCM to dump fuel into my car, but my vac reads 16-18 at idle. Then I thought about my spark plugs. My intercooler piping blew off about 3 times within the past week, causing my AFR to hit 10:1, most likely fouling my plugs. So if my plugs are bad, could they cause this rich condition at idle? Maybe the spark plugs are not firing completely, leaving some gas behind. Any thoughts on this?

RandyStinchcomb · Aug 16, 2007

could be sparkplugs or it could be O2's aswell, is your vaccum gauge doing anything else? as a vac gauge is a very good tuning tool and can tell you alot of whats going on inside your engine

the98stang · Aug 16, 2007

RandyStinchcomb said:
could be sparkplugs or it could be O2's aswell, is your vaccum gauge doing anything else? as a vac gauge is a very good tuning tool and can tell you alot of whats going on inside your engine

The vac guage seems pretty steady at idle. I don't think I have a vac leak. 1 of my o2 sensors IS the original though. Bank 2 front o2, I believe. I'm going to change the spark plugs soon and see if that fixes the problem. If not, I'll try something else.

RandyStinchcomb · Aug 16, 2007

O2's dont last forever, if you have more than 75/80k on them, replace them wth new OEM Ford/Motorcraft O2's.

Mike97gt · Aug 16, 2007

RandyStinchcomb said:
O2's dont last forever, if you have more than 75/80k on them, replace them wth new OEM Ford/Motorcraft O2's.

Agreed...

the98stang said:
The vac guage seems pretty steady at idle. I don't think I have a vac leak. 1 of my o2 sensors IS the original though. Bank 2 front o2, I believe. I'm going to change the spark plugs soon and see if that fixes the problem. If not, I'll try something else.

you could still have a vac leak. or even a bad FRPS..

What you need to do is check your live data and see what your long and short term fuel trims are at idle. post back with what you find.. also maf voltage at idle and baro pressure will help. Hell even a air flow restriction could cause this

the98stang · Aug 17, 2007

Well, I pulled the plugs and found some more crap wrong with my car . They looked black (obviously from the rich coniditions), but they also had oil on the threads . The oil was at the top of the threads, farthest from the electrode. All of the plugs on the drivers side had oil. The plugs on the passenger side were fine. This leads me to believe I have a bad valve cover gasket. Or, do you think I have oil blow by? I have a oil separator, and it does catch oil, so I know I have some oil in my intake system. Any thoughts or opinions are appreciated.

Mike97gt · Aug 18, 2007

the98stang said:
Well, I pulled the plugs and found some more crap wrong with my car . They looked black (obviously from the rich coniditions), but they also had oil on the threads . The oil was at the top of the threads, farthest from the electrode. All of the plugs on the drivers side had oil. The plugs on the passenger side were fine. This leads me to believe I have a bad valve cover gasket. Or, do you think I have oil blow by? I have a oil separator, and it does catch oil, so I know I have some oil in my intake system. Any thoughts or opinions are appreciated.

All intakes will have some oil in them, and any forced induction car will have more blowby than a N/A car..

I would clean or replace the fouled plugs then make sure your cam cover gaskets are good then try to figure out why it's rich

the98stang · Aug 18, 2007

svttech76 said:
All intakes will have some oil in them, and any forced induction car will have more blowby than a N/A car..

I would clean or replace the fouled plugs then make sure your cam cover gaskets are good then try to figure out why it's rich

Yea I have new plugs installed. I'll pull the valve cover tomorrow and check out the gasket. I'll also log some data and see if I can find anything wrong. If there is a "bulge" in my intake sleeve (going to the TB), do you think that could cause a problem?

RandyStinchcomb · Aug 18, 2007

who's plugs are you using, what heat range and what gap
also the IAC, O2's, IAT and other sensitive electronics should be for what- everyear PCM you are using and like I preach, STAY-A-WAY from aftermarket electrionic componets!!

the98stang · Aug 18, 2007

The plugs are NGK BR7EF's gapped at .033

I use nothing but motorcraft/Ford replacement parts, especially for electronics

the98stang · Aug 18, 2007

Ok I did a compression test and got good results. All cylinders are within 10 percent of eachother, and range from 155-170. This leads me to believe that I don't have blow by. And IF the rings are allowing oil to go by, they aren't completely worn yet. So I guess the next step is to replace the valve cover gasket. Although it doesn't LOOK like it's leaking .

Also, my spark plugs don't look to good. The 2nd electrode (part that hangs over the 1st electrode) is white. Really white. What does this mean? I'll post pictures soon.

the98stang · Aug 19, 2007

OK I ordered some new valve cover gaskets. I figure if I'm going to replace one side I might as well replace the other. So, I'll see if that will fix the problem.

Unfortunately, I got a CEL the other night. It was p0190 (fuel rail pressure sensor error). So, I just bought a new one. Apparently they upgraded them in 2001, so maybe mine was just a POS. More updates to come....

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