Idle Problem

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Nov 14, 2004 | 06:49 AM

ggnmb

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Idle Problem

Have full size 87 Bronco 302 (5.0) - when you first start it surges - after warm it idles at 1400 rpm - how do I correct? Thanks for any help

Nov 14, 2004 | 09:44 AM

XLTBronco90

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Try disconnecting the vaccuum line from the EGR and see if the problem still persists. I had a similar problem which seemed to fix itself once the vaccuum line was disconnected. I plugged the line and will replace the EGR when I get the chance.

Nov 14, 2004 | 07:07 PM

Trublufords

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Joined: Apr 2004

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From: Central Va.

XLT- sounds like your EGR is ok- look at EGR vac solnoid on drivers side of upper intake-green vac. and red vac. hose going to it and elec. two wire plug.Does not have vac. going to EGR all the time.Ggnb- try cleaning throttle body first, although pulling vac. hose at egr is simple- who knows - MIGHT work!!!!!Sounds like hunting for idle to me.

Nov 14, 2004 | 07:17 PM

pfogle

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From: Oak Harbor, OH

It sounds like a bad throttle position sensor to me. There are 3 wires, red, green, and black. The red one should have 5v+ with the key on, black is ground, and the green is the signal wire that feeds the computer. IT should be .9 volts at idle and ~5v at WOT.

Nov 14, 2004 | 07:43 PM

Trublufords

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From: Central Va.

Bad tp is poss. I thought reference voltage was raised to 7 volts sometime around 81. Three wires- reference voltage, signal and signal return- I would like to hook up my NGS (new generation star) tester to read pids- but you know working on these on a daily basis - cleaning throttle body cures an awful lot of idle concerns (esp. cold weather) Who knows- hope all this might help Ggnmb- spelled it right this time!!!sorry

Nov 15, 2004 | 08:28 PM

JBronco

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From: Loveland, CO.

IAC valve, perhaps.

Nov 15, 2004 | 08:48 PM

Joboo

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/\/\ What JBronco said.

I would certainly start by looking at the iac for a carbon fouling condition or even a bad valve or controll circuit problem before randomly guessing at a tps or egr. Not sure if you have a way to scan this but if you do have a vaccum leak where as the iac is out of range and cant bring the idle back in range you would be able to see this with obviously low iac counts. If you cant scan it definitly look for a vaccum leak but it sounds like one hell of a vaccum leak if your running at 1400rpm's. You would think ud hear it or see it fairly easy.

If you dont or hear an obvious vaccum leak id really steer towards the iac/isc first.

Hope it helps.