Idle Issue?

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Jun 12, 2007 | 11:42 AM

hdwilly

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Idle Issue?

My '89 Bronco w/351fi has an issue with returning to idle. When you rev the motor the engine speed first drops to about 1,200 rpm for a few seconds and then to normal. I already replaced the FPR, and the TPS. I checked the IAC and it ohm'd out according to spec and didn't seem gummed up. It has a fresh tuneup with new plugs, wires, cap & rotor. Also haven't been able to find any vacum leaks anywhere. The idle isn't really erratic it just stops at 1,200 first and then drops.

Anyone have this happen or have any ideas?

Thanks in advance for the help!

Jun 12, 2007 | 11:47 AM

Gacknar

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From: Atlanta Georgia

Is the TB closing all the way as soon as you release the throttle?

Have you checked for any codes?

Jun 12, 2007 | 12:10 PM

hdwilly

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Codes are clear right now. Throttle Body doesn't seem to be sticking and closes all the way from what I can tell. I ran across info in a manual that listed procedures for setting the TPS. I know we didn't do that when we put a new one in as I had no idea it was adjustable. Maybe it's thinking the throttle is at different setting than it really is?

Jun 12, 2007 | 12:23 PM

Gacknar

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From: Atlanta Georgia

Quote:

Originally Posted by hdwilly

Could be, test it and see.
http://fordfuelinjection.com/index.php?p=30

So you get code 11 when you run a self test?

Jun 12, 2007 | 12:32 PM

hdwilly

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The computer isn't actually throwing me any codes right now. It did initially which is the reason I replaced the TPS. It hasn't thrown that code again since so maybe I do have it set right (by dumb luck) and I have other issues?

Jun 12, 2007 | 12:49 PM

Gacknar

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From: Atlanta Georgia

Quote:

Originally Posted by hdwilly

The computer isn't actually throwing me any codes right now.

If it wont give any codes at all during a self test then you either have a wiring problem, a blown check engine light, or a bad computer.

Are you sure you are running the test properly?
http://fordfuelinjection.com/?p=13

Even if everything is fine you will still get code 11

Or are you not actualy running the test becouse you havn't gotten a check engine light?

Only about half of the codes will triger the check engine light.

Jun 12, 2007 | 01:03 PM

hdwilly

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I didn't realize I'd have codes even if everything is "ok" and no check engine light is on. I'll go back to Square 1 and re-test to see what shakes out. Then I think I'll pull the battery cable to re-set the computer, drive it some more and see what happens.

Thanks Gacknar - I'll report back with findings...