Average Idling RPM?

[Dugan]

I just recently purchased a 89 2.9 5spd 4x4, and ive been tinkering with it and I was told that idling at 1400rpm is not normal. It was at 2k but then I replaced the IAC and it dropped to 1300-1400. What is a normal RPM for these motors? And if that is high, whats somethings that could be an issue? Thanks

 

[clvanhorn]

not sure what you can do to bring it down cuz i'm not all that familiar with fi, but my 88 2.9 idles around 8 or 900

 

[freedom5]

I just recently purchased a 89 2.9 5spd 4x4, and ive been tinkering with it and I was told that idling at 1400rpm is not normal. It was at 2k but then I replaced the IAC and it dropped to 1300-1400. What is a normal RPM for these motors? And if that is high, whats somethings that could be an issue? Thanks

Disconnect the IAC with the engine running and see if the engine dies. If it doesn't, back off the positive idle stop (it's where the throttle cable is connected) until it dies. Then turn the stop screw in about 1/2 turn. Reconnect the IAC and restart the engine. It will probably race for a few seconds then idle down. This should reset the IAC. You may have to disconnect the neg battery cable for 30 minutes then re connect it to reset the ECC.

freedom5

 

[Dugan]

The idle screw is completely backed out all the way and its still idling the same, the truck sat with no battery for years. I mean i went from 2k to 1.4k with a newer IAC but im still a little lost maybe its a vaccum leak

 

[fastpakr]

maybe its a vaccum leak

That's where I'd be looking.

 

[Psychopete]

^^^ Yes, you have a massive vacuum leak if the throttle plate is all the way closed.

 

[Dugan]

Right after i posted this, the idle went down to 900 ran fine, the last two days its back up to 1200 and runs funny once started cold. It will start idle fine for about 5 seconds then die. Restart it and its fine. If you jump on the gas it sounds like its trying to suck air through a straw, but after a second or two on the throttle itll jump. I think the fuel system is clogged up. This truck sat for 2 years with a bad FP. Also when running it is dripping water out the exhaust. The heads arent cracked, no water in oil, and the antifreeze isnt dropping. And when feeling the water its not oily like antifreeze. Could the ethanol in the bad gas have pulled in a lot of moisture and held it and im just now getting it out and its making the motor wacky? I put some new in today but maybe a 1/4 a gallon and its still doing this.

 

[freedom5]

I had some similar problems that I fought for several months. After changing all of the sensors including the engine coolant sensor and the 02 sensor I started adding fuel injector cleaner every fill up for awhile. Once it started running better I now add injector cleaner every third fill up. These engines weren't designed to run on ethanol which is made (here in the US) mostly from corn which is a celulose base. My 2.9 now runs smooth, good acceleration and idles at about 950. Also my milage has increased.

freedom5

 

[Dugan]

I had some similar problems that I fought for several months. After changing all of the sensors including the engine coolant sensor and the 02 sensor I started adding fuel injector cleaner every fill up for awhile. Once it started running better I now add injector cleaner every third fill up. These engines weren't designed to run on ethanol which is made (here in the US) mostly from corn which is a celulose base. My 2.9 now runs smooth, good acceleration and idles at about 950. Also my milage has increased.

freedom5

Yea ethanol is only good for moonshine... haha. Which did you use? I usually buy the 10$ lucas full system cleaner, but I know they have the cheaper ones also. And a lot of people rant and rave over techron

 

[freedom5]

I use B-12 Chemtool. You can buy it at most parts stores. I buy mine at Walmart which is $3 something a can.