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Discussion Starter #1
Working on an 89 automatic 302.

It's been sitting indoors for a year or so.... starts (hard) that is, it has to grind a while before it catches.... but once it starts, it's got a good idle, smooth, good rpm (800 or so) and steady... and then, after a couple of minutes, the idle goes up to 2500, also smooth and steady.

Hitting the throttle doesn't make it slow down.

The check engine light does not come on.

I'm thinking Idle Air Control Valve.

I ran a search but came up with nothing like this.

Help?
 

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IAC and also a new starter are in your near future.

Try unplugging the IAC's electrical connection before you start it. If the idle starts racing again your probably have an intake manifold leak.
 

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Also if the starter is grinding just bump (turn the key to start position and back) the starter to get the solenoid to engage properly.
 

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You can get a can of electrical cleaner and clean the IAC. Mine was doing the same thing. After cleaning the IAC it smoothed out and has been fine ever since. It was gummed up pretty bad inside. Over a year now.
 

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sounds like you need a new starter to fix the hard start problem. i would also invest in a iac, they are about 35.00 from auto zone. i did mine and haven't had a problem since with idle. if this doesnt fix the problem then maybe a small intake leak. intake gasket or the front or rear seal of the intake. good luck
 

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I had this issue on 2 of my broncos in the past.

My 89 had a vacuum leak at the base of the intake plenum that was fixed with a $10 gasket, and recently my 95 had a bad TPS that was diagnosed with a lot of time with a multimeter.

Don't spend any money by throwing parts at it hoping that it'd fix the problem.
 

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I too just replaced my TPS. If it's reading over.95 it's too high. Buy a Motorcraft if you replace it. This was my third one.
 

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Discussion Starter #9
"hard starting" in this instance means it has to turn over quite a bit before it catches. The starter at this point has been fine.

So, the plan is to pull the IAC, and clean it with the electrical cleaner? Any particular brand or type.... or is it just "electrical cleaner?"
 

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If your going to clean it with electrical cleaner you can get it a Wal Mart (aerosol can about $4.00 in auto section is where I get it) It's made to dry extremely fast but make sure its completely dry before you reinstall. Just spray in the holes with the rubber looking plunger inside. You'll see when you take it off. As Seattle said disconnect the neg. battery cable before you start.

I'd say its worth a shot only takes about 15 min. If it doesn't work check codes of course and move on from there. I used the left over elec. cleaner which was most of the can to go through the truck and clean most every electrical plug and connector I could get to and added dielectric grease before reconnecting (just killing time I guess). After 17 yrs there was so much crud in most of them I was surprised they still worked.
 

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Carburator Cleaner, staying away from the solenoid.

Look, you can blindly stab at this or you can pull computer trouble codes as BroncoJoe suggested and find out what is going on. If you choose to clean the IAC, be sure to disconnect the battery for 15 minutes to clear the computer.
Gee.. once again, I agree with Seattle FSB ;)

In my opinion, the order of business would be:

1. look and listen for a vacuum leak
2. pull codes
2a. do whatever troubleshooting is suggested due to fault codes obtained.
3. disconnect battery
4. clean IAC
5. reconnect battery
6. see how she runs.

Note: if you disconnect the battery before pulling codes you will have lost any codes that are stored in Continuous Memory in the computer.
 

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Discussion Starter #13
You guys are awsome.

I've been OBE, so its going to take me a few days. But step one will include pulling the codes and postuing them here.

Thanks!
 

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Discussion Starter #14
Update:

Put a hot battery in it and it started. idled at about 800. I just let it run for around 10 minutes... hit the throttle slightly and it reved up. In short, it acted like it was supposed to... for about 5 more minutes.... then it idled down to about 650 for about 30 seconds... then it just stopped.

Tried to restart it and it wouldn't even fire.

Checked the schrader valve on the fuel rail; dry as a bone. Maybe out of gas? Needle indicated about an 1/8th tank, but it's been sitting awhile.

Went and got 5 gallons, put it in, and it still wouldn't fire.

Schrader valve is still dry.

So... fuel filter?

Checked all the fuses.

I've tried running the codes, but cannot find a seperate sti wire next to the DLC connector.

Will try FP lead test tomorrow.

Any other suggestions?
 
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