2.3l Throw rich code and now won't start.

[manny2294]

I need help. I don't know what to do. I bought a 97 2.3l ranger for $400. I swapped the blown motor out for a 91 mustang 2.3l (converted to OBD2). Everything has been great with my little truck, but my check engine light kept throwing a system to rich code. At first my mechanic thought it was an O2 sensor, so we replaced it. Then I thought it was a bad MAF sensor, I replaced it. Then I thought it was a vaccum leak, turned out there where several, including 2 small leaks that some hose repair tape fixed, and another few leaks from a completely dry rotted air intake system. I replaced my air intake with an eBay cold air, and my trucks performance has been significantly better. There was also a lot of oil in the air intake system. I also but on some 16inch wheels and tires.

Today my check engine light was still on so I decided to clean my maf again. I also absent mindedly put a whole tank of 93 in the truck. I've done it before on purpose, but I was in a rush and didn't pay attention to what I was doing and did it by accident. The truck immediately ran not as great as usual. And quieter.

Now it spit out black soot from my exaust, the rear end of the truck looks like it's lifted 2 inches and it's like my engine can't breathe. I can move it a few feet up and back before it craps out on me.

I'm scared to start it up again because I don't want to cause more damage. The back end lifting 2 inches has me completely freaked out, I looked under the car and nothing looks different...

Someone please help.

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[mavereq]

What's wrong with putting 93 in?

 

[tomw]

U-sed:Everything has been great with my little truck, but my check engine light kept throwing a system to rich code. At first my mechanic thought it was an O2 sensor, so we replaced it.

Your mechanic is ignorant. If an O2 sensor dies, it will produce ZERO volts. Low voltage(ZERO!) is a 'lean' condition per the way the O2 sensor works.
If an O2 sensor dies, it will produce ZERO VOLTS, and thus signal LEAN.
IDIOT. Gotchur money though..... AND didn't fix the problem.
I'd be on his/her case, and have them swap in the old part as the new part diagnosed to be THE FIX was incorrect, and was a waste of your money and time.
If only people learned how to think, it would be nice.
You get RICH signal when there are no Oxygen (O2's) molecules 'free' in the exhaust flow. All the O's got burned up consuming the free O's and the HC's in the fuel, producing H2O and other stuff not measured(except CO- monoxide).
If all, absolutely all, O2's are burned, there is LIKELY excess fuel - HC - in the exhaust, and the O2 sensor will bubble back and forth in its produced voltage - flickering less than .9V, and more than .0V. A new O2 will flicker its voltage quicker than an old one.
You fix excess HC by injecting less, or making sure it burns. Check fuel pressure and ignition components before spending your money on a mechanic's guess. A good mechanic would have checked O2 switching. As noted they can get 'slow' but still work, and actually are doing the reporting function(when they work, it's their JOB).
tom

 

[RonD]

I need help. I don't know what to do. I bought a 97 2.3l ranger for $400. I swapped the blown motor out for a 91 mustang 2.3l (converted to OBD2). Everything has been great with my little truck, but my check engine light kept throwing a system to rich code. At first my mechanic thought it was an O2 sensor, so we replaced it. Then I thought it was a bad MAF sensor, I replaced it. Then I thought it was a vaccum leak, turned out there where several, including 2 small leaks that some hose repair tape fixed, and another few leaks from a completely dry rotted air intake system. I replaced my air intake with an eBay cold air, and my trucks performance has been significantly better. There was also a lot of oil in the air intake system. I also but on some 16inch wheels and tires.

Today my check engine light was still on so I decided to clean my maf again. I also absent mindedly put a whole tank of 93 in the truck. I've done it before on purpose, but I was in a rush and didn't pay attention to what I was doing and did it by accident. The truck immediately ran not as great as usual. And quieter.

Now it spit out black soot from my exaust, the rear end of the truck looks like it's lifted 2 inches and it's like my engine can't breathe. I can move it a few feet up and back before it craps out on me.

I'm scared to start it up again because I don't want to cause more damage. The back end lifting 2 inches has me completely freaked out, I looked under the car and nothing looks different...

Someone please help.

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Welcome to TRS

Rich code means computer is cutting down on the Calculated Open Time for the fuel injectors and O2 sensor is still reporting Rich exhaust, too little Oxygen in exhaust.

1997 Rangers still used 35psi fuel pressure, in 1998 and up Rangers it was raised to 65psi.

1997 and earlier used a Fuel Pressure Regulator(FPR) on the intakes Fuel Rail, it has the fuel Return line...AND a Vacuum hose attached.
If FPR's diaphragm should leak then Raw fuel will get sucked in to the intake/engine, causing Rich running.

So check that vacuum hose for fuel

Fuel injectors can leak, and there is also a chance that a shorted fuel injector wire can cause injector to open at the wrong time.
Ford fuel injection system gives all the injectors 12volts when key is on.
The computer has a Ground wire for each injector.
The computer Grounds each injector to open it for a few milliseconds.
If one of these Ground wires had a bare spot, and touched any vehicle metal.............
Then that injector would open when it shouldn't.

You can rent Fuel Pressure tester gauge, there is a test port on the fuel rail, it looks like a tires air valve, because that is what it is, a schrader valve, and it works the same way.
Pressure test with key on might tell you it there is a leak.
Fuel system should hold pressure above 25psi for a few months, not hours, days or weeks.......MONTHS, lol.
So 0psi would mean there is a leak.

You can also use a volt meter to test injector wiring, red wire is 12volt key on, "other color wire" on each injector should NOT be a Ground with key on

 

[scotts90ranger]

I'm with Ron, pull the vacuum line to the regulator and cycle the key and watch for fuel.

Shy of that, could be a sticky injector, I've had that problem before on the Ranger and my Tracker...

 

[manny2294]

Welcome to TRS

Rich code means computer is cutting down on the Calculated Open Time for the fuel injectors and O2 sensor is still reporting Rich exhaust, too little Oxygen in exhaust.

1997 Rangers still used 35psi fuel pressure, in 1998 and up Rangers it was raised to 65psi.

1997 and earlier used a Fuel Pressure Regulator(FPR) on the intakes Fuel Rail, it has the fuel Return line...AND a Vacuum hose attached.
If FPR's diaphragm should leak then Raw fuel will get sucked in to the intake/engine, causing Rich running.

So check that vacuum hose for fuel

Fuel injectors can leak, and there is also a chance that a shorted fuel injector wire can cause injector to open at the wrong time.
Ford fuel injection system gives all the injectors 12volts when key is on.
The computer has a Ground wire for each injector.
The computer Grounds each injector to open it for a few milliseconds.
If one of these Ground wires had a bare spot, and touched any vehicle metal.............
Then that injector would open when it shouldn't.

You can rent Fuel Pressure tester gauge, there is a test port on the fuel rail, it looks like a tires air valve, because that is what it is, a schrader valve, and it works the same way.
Pressure test with key on might tell you it there is a leak.
Fuel system should hold pressure above 25psi for a few months, not hours, days or weeks.......MONTHS, lol.
So 0psi would mean there is a leak.

You can also use a volt meter to test injector wiring, red wire is 12volt key on, "other color wire" on each injector should NOT be a Ground with key on

Thank you! My Ford guy told me he has my regulator set for 95lbs of pressure. I am in no way a mechanic, so I have no clue what that means. But at this time, I have replaced my coolant sensors, and my maf sensor, and have fixed 3 vaccum hoses. After replacing my coolant sensors, my coolant gauge stopped working....

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[RonD]

1997 and earlier Rangers don't have adjustable fuel pressure regulators, so not sure what mechanic was referring to?

They just have a spring inside that holds diaphragm closed until fuel pressure reaches approx. 40-45psi then it is pushed open slightly and extra fuel(pressure) flows back to gas tank in the Return fuel line.
Vacuum also pulls on the spring to pull open valve sooner, at idle vacuum is highest and fuel needed the lowest so pressure is maintained at about 35psi.

All fuel injected engines have TWO coolant temperature readers, well 2005 and up might just have one, lol.

There is the ECT(engine coolant temp) SENSOR, this is ONLY used by the computer(PCM), it will always have 2 wires connected.
ECT sensor is needed so computer can run a cold engine in "choke mode" cold engines still need extra fuel and high idle to run until they warm up, so duplicates what a Choke plate did on a carb engine.

Then you have an ECT SENDER, this is ONLY used by the dash board temp gauge, same type of SENDER that has been used for 80 years, just lets driver know if engine is overheating.
These were 1 wire senders since they were first used, but Ford did start using 2 wire senders in the late 1990's, these are not the same electrically as sensors, so can not be interchanged.
ECT Sensors usually have cone shaped end that goes into the engine
ECT Senders have a cylinder shape on the end

When you go into a parts store they will almost always bring you a SENSOR even though you need a SENDER.
You have to ask for a SENDER then repeat that a few times, lol

Picture of sensor here: https://i.ytimg.com/vi/Podb7WoRE9w/hqdefault.jpg
Picture of sender here: http://i.ebayimg.com/images/g/5vQAAOSw9N1VmRKB/s-l300.jpg

Notice the ends

 

[manny2294]

Thank you for the last post Ron! Went to AutoZone, and bolted it in, it's working again! My check engine light is still on. AutoZone keeps telling me it's my maf, but it can't be at this point, because I've replaced it...

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[RonD]

What is the exact code number?

There are usually about 10-15 codes for each "sensor" that will mention a sensor by name
Like MAF out of range high
or MAF out of range low

This does NOT mean there is a problem with MAF sensor, could be but not for sure.

The computer has several codes it can "set" for any problem, and that exact code number is important, but what is also important is the code numbers the computer does NOT use.

Here are the codes an OBD2 computer can pick from: http://www.therangerstation.com/tech_library/OBD-II_codes.shtml

Easy to see why exact code in very important, and why codes computer didn't use are also important

 

[manny2294]

The exact code was P0712 system to rich.

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[manny2294]

It's the only reason I've had a check engine light since I got the car.

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[RonD]

Well that must be a typo P0712 or any P07xx code is a transmission code, not engine code.

P0172 maybe??

That is a Rich on Bank 1 code and 4cyl engine only has the one "bank" so...........

Not a MAF code per say, basic code which usually means all sensors are working, MAF and O2 but there is a mechanical issue

Check vacuum hose on Fuel Pressure regulator
Then check fuel pressure for leaking injector

 

[manny2294]

Well that must be a typo P0712 or any P07xx code is a transmission code, not engine code.

P0172 maybe??

That is a Rich on Bank 1 code and 4cyl engine only has the one "bank" so...........

Not a MAF code per say, basic code which usually means all sensors are working, MAF and O2 but there is a mechanical issue

Check vacuum hose on Fuel Pressure regulator
Then check fuel pressure for leaking injector

You are correct, I made a typo. Thank you so much for your help. You saved my ass today sir! So you think it's the pressure hose or injectors?

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[RonD]

Vacuum hose, on the Fuel Pressure Regulator(FPR), check it for gasoline inside, the hose isn't the problem gas inside is a sign of the problem..............leaking FPR

 

[tomw]

Ron said:Vacuum hose, on the Fuel Pressure Regulator(FPR), check it for gasoline inside, the hose isn't the problem gas inside is a sign of the problem..............leaking FPR

There is a diaphragm inside the regulator, made with a rubberized fabric(of some kind). If the diaphragm has developed a pinhole leak(or larger) the fuel will be able to squirt through the hole, and get sucked into the intake manifold via the vacuum line. The vacuum line would then smell like fuel. Your fuel pressure would likely be higher than desired as the relief valve would not open to allow excess pressure to bleed off and be sent back to the fuel tank. You would have a 'too rich' condition as the excess pressure would allow the injectors to spritz too much fuel, even as the computer reduced the spritz time to its minimum. Result: glowing SES/CEL light and codes.
If you smell the vacuum line and it has a fuel-like odor, there may be a leak, and the above applies.
Rent or buy a fuel pressure gauge, OR take a sniff of the vacuum line. Latter is free. Former will indicate if the pump works, and the regulator works. You may have a stuck regulator that allows full pump pressure all the time, even with an intact diaphragm.
The regulator on 4.0 EFI systems is Hecho in Germania. They must be REAL proud of that part as it is right around $100(and that was 4-6 years ago!) for a replacement. If it gets stuck, the fuel mileage will drop by 50%, almost right on the money, and there'll be some sooty-looking smoke out the exhaust. The 2.3 regulator costs less, I believe.
tom