engine codes and start up trouble

[hatched91]

hello i have a 93 xlt and i'm having problems with it when it starts up cold. tried to get engine codes but no local auto part stores could help. here's the symptoms during a cold start:
will start up, then immediately die.
or
will start up, rev about 2k, then die.
or
will start idal between 400 and 900 then die.

xlt runs fine after it warms up, a little sluggish every now and again, but other than that runs fine, start fine when warm. don't know what's wrong, replaced plugs, pcv valve. planning on a sohc swap in about 3 months, just need to keep it going that long.

i was thinking o2 sensor or Throttle Positioning Sensor. what do you think?

 

[dogfriend]

I'm thinking IAC.

Do you have a MIL (aka Check Engine Light)?

 

[hatched91]

yes i do, but whenever i did my auto to manual swap, i just plugged up the auto trans vaccum line, so the check engine like comes on occasionally, always has, way before this started happening. i got to looking through my book, and i am going to take it to auto zone and have it tested b/c the guy couldn't find the diagnostic connector the first time, and after looking through my book i found it.

 

[dogfriend]

You can actually read EEC-IV codes with a voltmeter. Check out this article:

http://www.corral.net/tech/maintenance/eecivtest.html


If it is your IAC, you probably won't get a code. IAC problems are common on 2nd Gen Explorers, seem to be less common on 1st Gen . Your symptoms might indicate an IAC that is sticking.

 

[BrooklynBay]

It's also a good idea to clean out the MAF, and throttle body. Sometimes the cold start problem could be related to the ECT sensor, and the ACT sensor.

 

[Maniak]

That sounds like IAC isn't working... Its job is the "no-touch" start AND it brings up the idle. When its cold out it should bring up the rpms.. and if it doesn't work it won't idle when cold.



~Mark

 

[hatched91]

well the temp is about 80-90 degrees outside so that's no big deal. i'm giong to go to auto zone today and have them read the engine codes. i'll try and see what's wrong. i was guessing iac valve as well.

 

[drc8404]

Stalling out

Greetings,
My 93 xlt just starting stalling out at stop signs and red lights when I stop for a few minutes. It is doing about 1/4 of the time. I notice if I keep my foot on the gas a wee bit the idle goes up and prevents it from happening. I rather fix the problem than keep going like this. It seems to happen more often with the AC on. Is there anyway I can fix this myself, or do I have a visit to the mechanic in my future? By the way what is a IAC?
Thanks'
drc8404

 

[dogfriend]

Greetings,
I notice if I keep my foot on the gas a wee bit the idle goes up and prevents it from happening.

This is a huge clue that your IAC valve is not working.

I rather fix the problem than keep going like this. It seems to happen more often with the AC on. Is there anyway I can fix this myself, or do I have a visit to the mechanic in my future? By the way what is a IAC?
Thanks'
drc8404

The IAC is the Idle Air Control valve. It regulates bypass air to allow your truck to idle properly when the throttle plate is closed. When you keep your foot on the gas, you are compensating for the non-working IAC.

You can replace the IAC yourself. The part costs between $60 to $80 depending on where you buy. It is held on by two bolts and has one electrical connection. You should replace the gasket for another few dollars at the same time.

If you search on IAC, you will find loads of info - it is a common problem on 2nd Gen Explorers.

 

[BrooklynBay]

Here is a photo of an IAC from Karl Burns's photo gallery:

 

[drc8404]

Thanks so much for the info and pic. I mentioned this at my local pizza parlor and a couple of the guys said I should always turn off my AC before starting my car as a matter of routine as it causes a drain on the starting system. Are they full of it or what? I can't see where starting a car with while the AC turned on will cause problems on down the line however, I've been wrong before.

 

[dogfriend]

. Are they full of it or what?

Yes, they are.

 

[drc8404]

is this the part I am looking for? If yes which one should I get? thanks

Item Price Core Total Add to Cart
TRU-TECH Part # AC23T
{IDLE AIR CONTROL VALVE} $54.79 $0.00 $54.79
STANDARD MOTOR PRODUCTS Part # AC23
{IDLE AIR CONTROL VALVE} More Info
$63.79 $0.00 $63.79

 

[hatched91]

yeah, i need to get a hold of a voltmeter to find the problem. havn't gotten a chance to get to auto zone to have the diagnostic done. i work till 9pm every night :thumbdwn: oh well, i should be able to run there real quick on my lunchbreak today. then i'll let everyone know waht's auto zone says (not that they'll be right.)

 

[Maniak]

The only reason a/c will drain power is by the fan. The compressor is not engaged right away, but the a/c blower could be on..

If you have battery problems, then yes having the a/c blower fan on could cause you to not start, but it isn't the problem, the bad battery is.. If your battery is fine, it doesn't hurt.. it is now drawing that much power.

~Mark

 

[hatched91]

okay went to auto zone, their computer didn't pick up anything, but then again i think the employee didn't know any more than i did other than where the computer was behind the counter. i'm going to get a junkyard IAC valve tomorrow just to see if that fixes it. if that's the problem, i'll go buy a new one, rather than a $5 used one.