Need a PRO's Help.Timing advances by itself

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Nov 29, 2004 | 10:11 PM

cfhurdle

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Need a PRO's Help.Timing advances by itself

I have an 85 with a 4.9L. We were having a lot of trouble with the engine running smoothly. We replaced the Exhaust and intake gaskets and all the carb gaskets. We unplugged the electric automatic advance on the distributor and (static)timed the truck. It now idles at 650 RPM and runs very smoothly. However, when we plugged the advance back in, the timing automatically advances the truck (at idle) and it idles at 400 RPM and runs terrible. We thought it was the PCM on the distributor... So we changed it out tonight and it didn't make any difference. The distributor, spark plugs and wires are all new. The spark gaps are correct. We can't figure this out. Please help.

Nov 29, 2004 | 10:27 PM

Chas1234

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From: Quaker Hill ,CT U.S.A.

do you have a in line spout connector - it looks like an oversize blade fuse .
When you time the engine make sure you unplug the spout connector , it should be close to the dizzy and will look like the one in this pic. .http://homepage.mac.com/pkrwud/.Pict...0Two/F150.jpeg

Last edited by Chas1234; Nov 29, 2004 at 10:31 PM.

Nov 29, 2004 | 11:15 PM

cfhurdle

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Control module/timing advance problem

Thank you. we unplugged the spout connector (thats what it is called) The problem occurs after we plug it back in and the engine advances the timing and runs terrible. Wehn it is unplugged and properly timed it runs great.

Nov 30, 2004 | 06:27 AM

jwtaylor

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If the computer were advancing the timing it would increase in rpm not decrease. Something is causing the timing to retard, other than that, I haven't a clue. Good luck

Dec 1, 2004 | 08:55 PM

74F250

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yea it is suppose to increase after you plug it in. Check for bad wires going to the TFI module or from the spout connector. Have you tried setting the idle via fact specs. Disconnect the ECT, then rev the engine 3 times (i usually drive ten mins or so), adjust idle then plug ECT back in.