no power under throttle

[meekial]

Hey everyone, I am having more trouble with my car...... again . When I start it up it will either idle normally or run like it has a "miss". Then if it runs normally it will only last for a minute or two then die because of a "miss". It also blows black exhaust. It is clean when it idles normally.

I have my timing set at 5 degrees advance.
My fuel pressure regulator is at 42-43 psi at idle with my walboro 255.
My o2 senser IS plugged in.
My tps IS plugged in.
My battery was unplugged from my car for two days, could this have erased my tune on my ecu?



Could my FC 750's injectors be bad?

 

[GRAVEDIGGER]

Plugs and wires good and or new/replaced recently? Kind of sounds like the coolant temp sensor on the bottom of the thermostat housing. If it's bad it can cause the car to run unusually rich and even miss or stall too. The resistance across the two terminals should be around 2500 ohms at room temperature (60-70*) Maybe check your wires where they attach to the sensor too as they like to become brittle and break.

 

[Gavin24]

I agree...check coolant temp sensor...I ripped out a motor because of this and found out the wires were ripped out..

 

[robtheturbopric]

If it were a stock ecu unplugging the battery would simply delete all adaptive memory but should not erase a tune because its programed in not just adaptive. to recover adaptive memory the engine has to idle for at least 10 minutes to allow the computer to relearn the engine. The coolant temp sensor may be at fault but that would also cause an erratic idle and not allow the engine to start in cold weather(below 50).

 

[Talipse96]

Do you have a CEL? I was driving my car and it started to run very very rich, ran the codes and it said engine coolant sensor circuit. I replaced the coolant sensors and it still did it. Pulled the ECU... YUP leaking compacitors. This may not be your problem but if its not the sensor its self, check the ECU.

Hey Gavin24, you might want to check the avatar rules.

 

[GRAVEDIGGER]

The coolant temp sensor may be at fault but that would also cause an erratic idle and not allow the engine to start in cold weather(below 50).

I think you might have your facts mixed up a little on this one robtheturbopric. Actually when a coolant temp sensor goes bad the sensor gives a false reading to the ecu of like -40*. This tells the ecu to add lots of extra fuel, because of the cold reading it is getting from the sensor. Now this is usually not a problem in a cold start situation, because the ecu likes to add more fuel when the engine is cold.(it's a normal funtion) But as the engine gets up to temperature and this sensor is still giving a false reading it begins to dump too much fuel for the hot(up to normal operating temperature) engine and it begins to stumble/miss/stall like meekial is experiencing.

So to condense what I'm saying a bad coolant temp sensor will run ok when the motor is cold AND it is cold outside, but once the engine warms up it will start to run poorly. When the motor is cold, but it is WARM or summer it will run poorly pretty quickly, because of all the extra fuel and no cold air outside to help the cause. And of course a warm engine on a warm day with a bad sensor won't hardly run at all. Make sense?

 

[robtheturbopric]

I think you might have your facts mixed up a little on this one robtheturbopric. Actually when a coolant temp sensor goes bad the sensor gives a false reading to the ecu of like -40*. This tells the ecu to add lots of extra fuel, because of the cold reading it is getting from the sensor. Now this is usually not a problem in a cold start situation, because the ecu likes to add more fuel when the engine is cold.(it's a normal funtion) But as the engine gets up to temperature and this sensor is still giving a false reading it begins to dump too much fuel for the hot(up to normal operating temperature) engine and it begins to stumble/miss/stall like meekial is experiencing.

So to condense what I'm saying a bad coolant temp sensor will run ok when the motor is cold AND it is cold outside, but once the engine warms up it will start to run poorly. When the motor is cold, but it is WARM or summer it will run poorly pretty quickly, because of all the extra fuel and no cold air outside to help the cause. And of course a warm engine on a warm day with a bad sensor won't hardly run at all. Make sense?

I see what your saying. but when my sensor failed the computer was reading 70* causing the ECU to give less fuel than required to start on a cold chicago day. i could get it to start with starting fluid or enough attempts at cranking it,but the idle would then surge. replaced the sensor and all was back to normal. no problem starting and no idle problems at all.
I suppose both types of failure are possible, and am not ruling out the temp sensor in this situation.

also my name is a typo the signature should explain.

 

[ty92dsm]

Are both of the sensors on the thermostat considered coolant temp sensor? I know the one with two terminals is the actual coolant temp sensor and the other one is the temp gauge but what is it called?...sorry for the random question

 

[robtheturbopric]

the upper sensor is for the a/c it's called the coolant temp switch and the lower is actually the temp sensor

 

[GRAVEDIGGER]

I see what your saying. but when my sensor failed the computer was reading 70* causing the ECU to give less fuel than required to start on a cold chicago day. i could get it to start with starting fluid or enough attempts at cranking it,but the idle would then surge. replaced the sensor and all was back to normal. no problem starting and no idle problems at all.
I suppose both types of failure are possible, and am not ruling out the temp sensor in this situation.
also my name is a typo the signature should explain.

You're absolutely right. It is possible that the sensor could read anything, but they usually default to the coldest reading.

Are both of the sensors on the thermostat considered coolant temp sensor? I know the one with two terminals is the actual coolant temp sensor and the other one is the temp gauge but what is it called?...sorry for the random question

I've attached the best picture with description that I know of for you to reference.


P.S. What did you make out with this meekial?