hartergm

Guys,
Twice now in the last 30 days, my car throws a fuel rich code. It happens at slow speed, engine shutters, gas penal disengages, and engine light comes on. A simple switch off resets everything and the car runs fine. We have replaced the spark plugs, cold flow intake sensor and cleaned the throttle body. We also just ordered a new Bama Tune hoping that will help. Modifications installed 5 years ago: 1. Cold flow intake from Airaid 2. BBK 62 mm throttle body

Someone suggested replacing all the ignition coils, hard to imagine that is the issue.

Marshall

Bert

I think that code is triggered by the front O2 sensors, so that might be a good place to start . . . not sure if they might need to be replaced but it is possible on a car that is 14 years old.

If you haven't already, get the actual diagnostic code number and Google it; you will find more specifics about what could be causing it.

I know aftermarket throttle bodies can be troublesome but I don't think the throttle body would cause a rich condition.

If you haven't done it lately, I'd clean the air filter, but I doubt that is the cause. Be careful not to over-oil it.

Bama tune could also be the problem, but I would not expect it to change or "go bad" intermittently. For a good remote tune, you can contact "Lito" (Manuel Pazo) at support@tudyno.com ; he is widely recognized as one of the best tuners for these cars. He will have you do a datalog and provide the log to him, so he can see what is going on and then correct the tune if needed. I think he charges about $100-150 for a tune, including a few revisions based on datalogs.

houtex

Gonna need the specific code(s) that are being thrown. Might need to grab it from history if you have it. As Bert says, the tune, or all sorts of things could be the problem. I mean the overall thing is relatively simple: (siphon with a large amount of negative pressure), squeeze, bang, blow, and that requires air in, fuel in, spark happens, and shoving of all that exhaust out. So a rich situation is too much fuel (duh, houtex), and then one must solve the equation for why that is a thing. To that end, it's either fuel delivery issues (too much) or loss of air issue (not enough oxygen).

Also, remember the car's not actually measuring the fuel amount itself, it's measuring the oxygen in the exhaust, trimming the fuel dynamically to reduce the oxygen from quite a bit of oxygen (relatively speaking) to some small number above zero. If there's less than the desired amount of low oxygen in the exhaust, it'll remove fuel until it hits that number it wants. It's an oxygen sensor in the exhaust, not a fuel sensor. If it can't lean the thing down enough to get the oxygen down to whatever low level it's looking for, then there's too much fuel in the system, period. If it always has oxygen and too much, it's too lean, and it'll throw that code instead.

So. With all that, what's the problem? Quite a few things: Assuming first that it's something like the P0172 (too rich, bank 1, side with the number one cylinder, right/passenger side of the engine) and not P0170 or something, then the potential problems are as below, ostensibly:

Fuel injector(s) spurtin' in too much fuel because staying open too long. Related, but not the same, fuel injector(s) not closing, leaking fuel into the cylinder. In either event, gotta test and/or flow check and/or clean and/or replace the injector(s) in question.

Loss of oxygen/air somehow on that side, which would be... odd. Except that it's possible the exhaust on that side is blocked, which would cause a loss of intake air charge, which MIGHT cause a rich condition because the computer's not able to compensate for the lesser air amount to the extent it needs to... but that's a real outlier. Still... that would likely mean cats, or possibly exhaust header or gasket in some weird way (as the pressures of air flow in the exhaust are needed to be semi-decent to correctly scavenge the cylinders of exhaust gases, so any weirdness of exhaust could cause that to break down... again, outlier, but I mention it anyway.)

Bad oxygen sensor(s) on that side.

Wiring issue in general.

Bad spark plugs (Carbon tracks/broken ceramic)/wrong spark plugs (temperature/type)/other spark issue. I recommend going back to the two piece if you've replaced them with something else to avoid the two piece issue. Just put a little nickel anti-seize on the shrouds above the strap of the plug and they'll never be an issue.

Bad coil on pack. Cracked boot causing carbon tracks, rust in the spring... dielectric grease is nice, but it does have its issues... Please note that unless you're extremely hotrodding, the Motorcraft OEM COPs are about the best you can ask for on these motors, and you shouldn't 'upgrade' to anything else, even with a tune.

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Now, all that's to address one side of the engine. If the entire engine is rich, that's a whole other code, and that's where the intake, throttle body, intake snorkle, MAF, IAT, even the air filter could be all involved at that point, along with the above. Along with the potential of the computer's malfunctioned and causing too much fuel to be demanded. Or maybe the fuel pressure regulator's gone stupid and you're overpressuring the system, which would cause all the injectors to overspray fuel, and the computer can't compensate... Or there's a problem with the return and the pressure's up that way... I don't know if there's a code for that one... Bad grounds possibly...

And then you've also got all those mods going on and... well, that could be throwing wrenches used by simian life forms into things, as they do... Although probably not as likely as some of the above.

Dunno if any of that's the answer, as it's entirely possible it's something else I missed/don't know, but I do hope it helps you figure it out. Good luck! And welcome to the forums!

hartergm

Well, finally threw a code, appears it was a bad throttle body sensor. Ford dealer found it and darn that was expensive using them.