I have a 89 ford ranger with the dual spark plugs. The motor is blowing out a blue flame out of the muffler. Pluse the same codes are comen up. they are:21,31,41. The sensors are new and I put a new computer in the truck. What could cause this?

 

????? Flames out of the muffler? Ouch.

My first thoughts would be a seriously over rich mix, or maybe the exhaust valves are opening too early. Like if the cam gear is out of position it will be opening the exhaust valves while the fuel is still trying to burn in the cyl. How does it run otherwise?

The first code is about the ECT (?), not sure what that is, and the second is for the EGR system. I get the same code too, and I have replaced the valve & position sensor, so the only thing left is the solenoid for me. The last one I don't really understand with out looking it up.

Welcome to FTE

 

The code 21 is the engine temperature sensor and I have replaced it. The last code was the O2 sensor is lean.It was missing and I found a bear wire and fixed it. I think that the motor is running to cold because I can let it run for an hour and it will not heat up. thanks for the hlep.

 

It runs ok

 

Ok, temp sensor, got it. As far as the engine temp sensor goes, I think I have seen where sometimes the sensors have been plugged into the wrong place because they are so close to each other, or they are not properly grounded. I am trying to remember which one is which when I put my engine back together. Is that ECT = Engine Coolant Temp sensor? I think mine was in the lower intake manifold on top near the injectors. When you replaced it, did it look like fresh coolant was getting to it? When you say "cold" does your temp gauge go up at all?

It is possible 2, or more of your codes are related. You said you think it is running "cold" (which in turn will make the computer to run the engine rich), and there is a temp sensor problem to boot. Well if it never gets up to proper temp, or even "thinks" it isn't up to the proper temp the computer will try to compensate. I have to imagine it is getting terrible fuel economy running like this. So when you say it is running "cold", can you blow HOT air out of the heater vents and the 2 radiator hoses are HOT to the touch? Or does it take forever to get the heat going?

If your engine is "physically" getting up to temp (IE - heater blows HOT air and coolant is flowing properly), then you have a sensor/wiring issue.
If your engine is not getting up to temp, you have a blockage or malfunction somewhere in the cooling system. Could be a thermostat stuck open, water pump not working properly, radiator blockage, coolant passage blocked, etc...

 

The truck can run for hours and not heat up. It will not blow hot air out when it is sitting. The only way it will blow hot air is when i drive it for a mile or two. Now, It was raning today the truck shut off. It would start up after something dryed out. It acted like it was starving for gas. I think it has a fuel pump wireing prolbem. Thanks for your help.