trouble starting my 3.0

[adam17]

I have a 93 3.0 ranger. its having trouble starting only when its cold....... It starts up then falls on its face and almost dies(sometimes it does die) then picks back up again and does this several times until it clears up, then runs fine the rest of the day. I have also noticed when it does this the battery meter also falls when the rpms fall. put it on a computer and it isnt throwing any kind of codes at all. anyone know what this could be???

 

[creepinjeepster]

Straight from the tech library........

Engine hard to start when cold
1. Battery discharged or low
2. Fault in the fuel or electrical systems

It could be several things within either of those two listed above. Best to start with one or the other and see what you find out.

 

[oachs83]

First check your volts of the battery when it is cold not running and when it is running. You should be in the 11's for not running and in the 14's for voltage when it is running with your lights off. If your battery checks out try priming the fuel system. Before you start it turn the key all the way forward without starting it and then wait about 3-5 seconds then repeat. Do that 3 times and see if it fires up much better. Also it is possible your temp sensor is going out. Telling your engine it is running warmer than it really is so it does not add the extra fuel needed when cold like a choke does.

 

[TomB1269]

IDLE AIR CONTROL valve, sounds like it to me. Get a hold of a chilton or like manual and find the resistance values for the ambient tempature and measure the IACs resistance. This sound clearly indicate any issue with IAC.

 

[Earl43P]

Loss of fuel pressure.

Turn the key to Run, do not crank the starter, wait 2 seconds hearing fuel pump run and stop, turn key to Off. Repeat 2 more times, THEN crank the starter.

 

[Bob Ayers]

IDLE AIR CONTROL valve, sounds like it to me. Get a hold of a chilton or like manual and find the resistance values for the ambient tempature and measure the IACs resistance. This sound clearly indicate any issue with IAC.

I agree it's the IAC (Idle Air Control) valve, but the resistance check you are describing would apply to the ECT (engine coolant temp) sensor or IAT (Incoming Air Temp) sensor.

 

[adam17]

is it possible to clean my IAC?

 

[lorenambrose]

Sounds more like a MAF sensor to me. What you describe is happening in only in cold engine situations, true? If that is the case then the IAC would not be my first guess. Sounds like the engine is running lean due to a faulty or dirty MAF sensor. The PCM is in a cold loop until the engine reaches a certain temp as referenced by the ECT sensor. This is a classic symptom of a dirty MAF sensor.

As far as the electrical sys goes, it sounds like it is operating exactly as it should. As the engine falls below about 500 RPM's the volt meter will drop. Remember this guage actually reads 6-8 volts on the low end to 16-18 on the high end accurately. It is not designed to read low voltage of 2-4 volts.

If the IAC were bad you would have idle issues all the time, although they would be more exagerated when cold. One way to tell if IAC is working is to turn on the A/C. The vehicle should bump it up a notch and maintain RPM's or even a little higher. RPM's of the engine cold should be around 1000 with a properly working and CLEAN IAC.

Neither the MAF or the IAC will set fault codes as a general rule. After awhile you may get lean codes, but those will be set by the O2 sensors.

 

[adam17]

how do i clean my MAF? i pulled it out and cleaned it with a rag, but i dont know if that would make a difference. and sometimes when i let off the gas to come to a stop my rpm's stay at about 1,300-1,500 rpm, and when i put it in neutral it goes back to normal. but that only happens some of the time.

 

[adam17]

oh and i dont have the pleasure of a/c, it didnt come factory on my truck. although my heater works great! lol

 

[oachs83]

If you look closely inside the intake tube where your MAF is mounted you will see a very thin wire. Looks as thin as dental floss. Take a cutip with some cleaning solution on it and clean the wire. Be careful not to damage it. Also the IAC is cleanable in some cases it depends on the type used. For some reason there was two types of IAC one is servicable and the other not. The most common one is the type you can clean.

 

[adam17]

ya i know what your talking about, it looks like a light bulb filament. what kind of cleaning solution should i use for the MAF? Is MAF cleaner good to use? how and what do i use to clean the IAC?

 

[lorenambrose]

Clean the MAF with a can of MAF cleaner. Clean the IAC with carb spray or throttle body cleaner, but the carb spray is cheaper.

 

[adam17]

thanks alot for all the info and help guys! just cleaned the MAF sensor and the IAC valve. The IAC valve was extremely dirty and the bolts were finger loose. truck runs fantastic now! (knock on wood)

 

[lorenambrose]

Glad to hear it.