92 will idle won't go

[radrodder]

I was driving my 92 RANGER XLT truck and parked it (my wife said a cloud of white smoke came out from under the hood). The next day It started fine BUT it dies when I try to give it gas. I replaced the fuel filter today no change. I let it sit and idle for 20 minutes (after adding some fuel additive) it Idles fine, unless you cut it off. Then you have to hold the switch on for a minute or 2 without giving it gas then it runs rough for a minute then idles fine. I can put it in drive, I just can't give it any gas because it dies. NOW this maybe totally unrelated but the temp. gauge quit working at the same time???????????????? HELP!

 

[Chris_1]

Check the IAC - idle air control valve it's on the upper intake drivers side, also the air temp sensor (same area but at the back of the intake)dirty ones can cause that. You can clean them with sensor safe spray like MAF cleaner. The MAF could be bad, or just dirty. The other thing is fuel pressure which if it's too low, it will idle but not rev well. I bought a fuel pressure tester for $60 which screws onto the schrader valve on the fuel rail (passenger side between the upper and lower intakes. I know - $60 but it pinpoints or eliminates fuel pressure right away. The IAC and MAF are pretty expensive to buy if what you need is a fuel pump. Mine dropped to 20 lbs and gave me similar symptoms. You should have 35-40 and drop 10 at high vacuum. Good Luck!

 

[adsm08]

Check the IAC - idle air control valve

I cannot believe that you could post this. You include the proper name, and still came up with such a bad suggestion.

It's the IDLE air control valve. IDLE. His truck idles, it dies when he hits the gas. It is fine while he has the computer controlling the amount of air coming in. It dies when he takes over. The computer can't see the throttle opening or the extra air coming in or can't compensate for it.

MAF, MAP, or TPS are the best bets with a dying fuel pump being in the top five.

At this point we pretty much have to know what engine we are working on so that we know what sensors are there. Also, fuel pressure test. Hook up the gauge and rev the engine, see if pressure tries to keep up or if it craps out.

 

[Chris_1]

OUCH!.... a little harsh for a friendly exchange of opinion format don't you think ? You have a point that the IAC is unlikely to cause the problem but a little diplomacy goes a long way. The problem is more likely a fuel delivery problem than a fuel management issue anyway.

 

[RonD]

"Then you have to hold the switch on for a minute or 2 without giving it gas then it runs rough for a minute then idles fine."

What does that mean?

And yes, what engine are we dealing with?
'92 4.0l, 2.3l, ect....

On the upper intake there will be a black box with 3 wires, it is connected to the throttle plate and the gas pedal via a cable.
This is the TPS(throttle position sensor)
It tells the computer where your foot is on the gas pedal, if this isn't working the computer doesn't know you want to go, or go faster, so engine just idles

You can test the TPS with an ohm meter or volt meter.
Also just pull off the connector and make sure contacts are clean and dry.

The MAF sensor tells the computer how much air is coming in, so it knows how much fuel to add.
These can be cleaned, see here:
http://www.therangerstation.com/tech_library/CleanMAF.html

The white smoke isn't good, and now the temp gauge doesn't work.
Have a look for melted wires, it might not be a sensor issue but sensor wiring issue.

 

[Haywire6000]

If it's the mass air flow you can unplug it and try running/driving it. It will set a check engine light but may be able to get you by. It sounds more like the TPS in my opinion though.