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f150 running badly - diesels

I have the inline 6 that tries to die at idle, diesels at shutoff after warmed up and does not want to pull when cold. soem suggested that it is too lean and there might be a vacuum leak. well i looked and thinki found the leak.

I aint no mechanic.

there is a valve on the rear of the valve cover that rattles and sucks air (egr valve?) through the two vacuum hoses attached to it. could this be causing it? maybe it is supposed to hold the ball down by spring tenstion and the spring died

also, who was the genius that put the hi and low idle speed screw so that you cant get at them without the air cleaner off? chiltons says they have to be set with the air cleaner on.

also where is the fuel mixture screw? cant tell if the dingus i am turning is changing anything cause the electronic throttle stop (or 8something*) keeps adjusting the idle.

no, chiltons dont show where the idle mix screw is. dont show the carberator. or the vacuum system.

Reply to
tater schuld
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On Tue, 16 Sep 2003 18:46:38 -0500, tater schuld rearranged some electrons to form:

I think I guessed that already. What year?

PCV valve. It is supposed to rattle.

Uh, you probably want to stop turning screws if you don't know what they are for.

Chilton's manuals are not very good. Do an inspection of your hoses, make sure there aren't any rotten ones.

Reply to
David M

86 F150 inline 6. actually i was paid to work as a mechanic for 6 months, then i went to school

ok. others mentioned vacuum leak and this sucker was sucking in air

I got a strong hunch that what i was turning was the mix screw. also made mental note incase something went wrong that i knew where it should be back again. Idle speed screws were easy to figure out.

they all feel rotten, but no leaks, I pull one hose and symptoms grow more pronounced.

Anyway, putzed with it as much as i dared. drove today and it *seemed* to run a lil better. still not sure, maybe didn't run it enough for it to diesel. almost temped to adjust a lil more, but how many turns are ther supposed to be on the idel mix screw? already turned it out a full turn (easy to remember) don't want to turn it to far, as i did that once tuning a bad lawnmower carb till the screw fell out.

Reply to
tater schuld

The idle mixture screw is located at the bottom of the carb on the 'tire-side' of the carb. Preliminary adjustment is one full turn out from fully-seated position. To adjust the idle mixture with the engine running, first: the engine must be at the correct idle RPM(650rpm on my '6'). You need to use a tach in order to set the correct idle RPM. If the engine is out of the idle RPM range, the mixture screw will have no noticeable effect. Once you have the idle-speed adjustment correct, you turn the mixture screw (just a little bit at a time) to obtain the higher RPM and smoothest idle you can.

DS

Reply to
putt

On Wed, 17 Sep 2003 17:13:01 -0500, tater schuld rearranged some electrons to form:

It's supposed to suck air, too. That ain't the problem.

To look for vacuum leaks, get a can of carb cleaner or WD-40.

With the engine running at idle, spray around some leak-prone places ... carb. base, intake manifold, suspect vacuum hoses, etc. The engine will speed up when the leak sucks the carb cleaner into the manifold.

But there are many other possible reasons for it not running well. Like the other poster said, the mixture adjustment will have no effect once you go beyond idle speed.

Reply to
David M

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