Took the falcon cruising today - rough idle?

[Bradbutlernc]

Well, i took the falcon out today to cruise around to get togethers and whatnot, and it runs great, starts great, etc. But one thing that bothers me still is it has a bit of a rough idle while in drive. Its like it will idle then puff a bit from the exhaust, and keep idling fine then puff a little again, kinda low and shaky idle while in drive only. I assume this would just be the pilot/idle fuel adjustment screw needs to be adjusted out some? Also i plan on checking the timing, what should i look for when i use a regular timing light? Sounds maybe like a vac leak too but i cant find one.

 

[rbohm]

8) sounds like you set the idle speed with the trans in park rather than in drive as is required. set the idle mixture and idle speed in drive and see is that clears things up. as for ignition timing, set that to where you get the highest vacuum reading at idle. you might have th back the timing off a couple of degrees if you run into detonation.

 

[Bradbutlernc]

Alright, i will do that tommorow when i get some light, let it warm up and set the idle and mixture while in drive with the e-brake on i assume?. Not sure what you mean by detonation, care to elaborate on that? Im no expert on timing but have a basic timing light and want to learn about it.

 

[ludwig]

Detonation is also called 'knock' or 'ping' or 'can of bolts' like a rattle. It comes when you are accelerating. If your engine rattles (pings) under load, back the timing off a touch. That means back it a degree or two clockwise. Don't go too far or you de-tune it again.

First however, you need to get your optimum idle. BLOCK THE WHEELS, set the e-brake, then put the car in D and let it idle. You want to set the warm idle to about 750 rpm.

Before you use the timing light, you might want to check the idle with a vacuum gauge. Connect it to the intake manifold and adjust the idle fuel mix by screwing it in until the engine just starts to stumble. Then back it out until you get max vacuum - at least 18". Then back it off one quarter turn more. There would be your optimum idle mix. Check the idle once more and set it at 750 rpm.

NOW you are ready to start playing with the timing light.

Vacuum gauge is cheap, like $25 or so.

 

[Bradbutlernc]

Thanks ludwig, i have a friend bringing over a timing light and vac gauge today so i can mess around with it. Another thing that concerns me is when i set the idle in gear so it idles good, when i actually put it in gear it jolts really bad, like into drive or reverse or something for example. Is this normal? My other daily driver doesnt jolt that bad, but maybe its normal for the old fords? Almost feel like somethings going to break everytime i put it in gear.

 

[ludwig]

It shouldn't do that. If you get the idle at the right spot it won't.