The woes of my carb

Emeralddream · Jun 18, 2015

So Recently purchased this beauty and have fixed a few minor issues (replace powersteering pitman arm seal, new steering wheel, 2 inch pitman arm drop, and wheel spindle and bearings replaced. Not sure how the attached pictures will show up but the first one is my truck obviously and the second, third, forth are the carburetor.

I guess I'll start off by saying I am planning on putting a v8 in at some time or another I just have to get the funds. However, I would like to drive the truck on commute and take it hunting in between time.

I have read a lot about the problems of the rangers in the highly extensive tech articles on this site (love those articles keep up good work! It helped me with my from tire wear problem because of the stock pitman arm was still on after a lift was installed). I noticed that a common problem of the v6 2.8 is that it will stutter on take off almost like it is not getting enough fuel. The two solutions were to change accelerator pump (i took the one off of the carb and it looked brand no so not the problem) or the fuel bowl is low. I am not sure how to go about fixing the fuel bowl or even checking to see if it is the problem.

The real issue is it is stumbling on take off :annoyed:

I have not taken the carb off to install the carb kit contents that I purchased on the carb yet but I am wondering if I should just get a new one for 250 since someone has had their hands in this I'm not sure if i should just get a new one or not... I also had a question about the ISC motor... It seems to be spazzing out at times on startup and making it idle very high regardless if the engine is warm or not. Sorry for the essay, but one more question is what in the world the foreign bracket is mounted on the accelerator spring in picture 3. I'm just lost atm and looking for comfort lol... I was also looking a duraspark 2 exchange and tfi conversion but the tfi seems like a lot of work pulling out the engine and all... :dunno:

alwaysFlOoReD · Jun 18, 2015

I'm not real good on carbs but.... A common problem I've seen is the accelerator pump, the leather cup dries out or wears out and then you don't get the volume needed to keep the bogs away. I would try the rebuild kit since you have it anyway.

Richard

RonD · Jun 18, 2015

I would take the carb off first and give it a good look.
Older carbs get air leaks which is the same as "not enough fuel" feeling, because there is not enough fuel when you add extra air

Common leak is the throttle shaft, it gets loose and air gets in thru the shaft holes.

Low float bowl level would tend to present itself at higher speeds not from standing start, but it would seem there was not enough gas available when you stepped on the gas pedal.
A carb works by the engine sucking gas from carb's main jets, when you want to accelerate you open the throttle to get more air and more fuel, but there would be a slight delay in the extra fuel getting sucked out of the main jets.
So an accelerator pump was added, when you push down on the gas pedal the accelerator pump squirts extra fuel into the engine to give instant acceleration.
So if this wasn't working then yes there would be a stumbling or delay.
Look down in the carb(engine off) and open the throttle, you will see fuel squirting out in both barrels of the carb, if there is only 1 barrel getting squirt fuel then you have a clogged passage.

A Holley 350 or Motorcraft 2150 carb(non-feedback) and Duraspark or HEI conversion would be the direction to go in IMO.
If you are not in Calif., they frown on improvements to performance.

HEI conversion requires duraspark distributor
Good read here on that: http://www.fordmuscleforums.com/ignition-articles/492810-tricky-trick-hei-module-inside-duraspark-case.html

You already have the TFI coil, new HEI module is $15-$20, duraspark distributor $65

Not sure what you mean by "pulling out the engine", for this conversion?

Emeralddream · Jun 18, 2015

Thanks for the quick responses alwaysfloored and rond. :beer:

RonD I probably get the carb off tomorrow and have a good look at the carb and really considering the duraspark conversion or the HEI.

Maybe a dumb question but what is the difference in the motorcraft 2150 nonfeedback and feedback? (the 2150 is what I have atm) Is the difference one is controlled by the computer and one doesn't need it ie controlled by idle screw?

Also I mislead you with the wrong acronyms lol... I was reading this http://www.therangerstation.com/tech_library/2_8_FuelInjection.shtml and I guess you have to remove the engine to get the wiring harness totally out... And I figured if it was that much trouble to get rid of a carb might as well put the v8 in while you had it out but dont think Ill go down that road as far as fuel injection conversion. :icon_twisted:

ready to get to messing with the carb though really want to dream some more about the v8 conversion while driving in it with 0% sputter :icon_bounceblue:

martin · Jun 19, 2015

carbs wear as they get older, you might be able to improve the off idle stumble by adjusting the idle mixture jets located on the lower front of the carb. The fast idle cam returns to normal position by gravity, if it is sticky or the base idle is set to high it can cause the fast idle issue. The can on the front left of the carb is a stepping motor that is supposed to be what controls the idle speed, these can also be an issue.The feedback carbs use a mixture control solenoid on the rear of the carb which is controlled by the computer. Feedback carb can be converted to non feedback by making a manual metering block, details should be on the site somewhere.

Emeralddream · Jun 19, 2015

Ok, so after breakfast I'm going to hit the carb and fiddle with the adjustment screws to see if I get any results. I've got a tach and a vacuum pressure tester so should be good there.

I still am wondering about the bracket that someone installed on the carb I have? you can probably see it if i use a picture of a newer carb but the throttle lever end hits the screw after the accelerator is pushed back... it seems like there isn't much more room for acceleration but it has mad the plastic piece worn and a bit loose.

The picture of mine is picture 3 looks a bit different than the one below...

Thanks martin and guys I'll repost later after the rain stops and let everyone know how this is coming along.

RonD · Jun 19, 2015

Yes, feedback carbs were the first attempt at computer controlled fuel system, and they didn't work well new, but could pass emissions testing.
As they got older they became less and less reliable.

You have an EEC-III computer I believe, and I think it only had 4 sensors: temp, O2, BAP(air pressure) and IAT(air temp).
The TFI spark system also gave computer RPM reading, so it could "suggest" spark advance based on the other sensor readings.

These "improvements" were improvements because prior engines had to be tuned(carb and spark timing) and the points set/replaced.
While these required less work it wasn't no work and as they got older it could be more work, lol.
I think there was only a 4 year run(or less) were Ford used feedback carbs, then switched all engine to fuel injection.

So not using the computer to fine tune fuel mix and spark timing will require you to adjust the carb and set spark timing once in a while I think the end results would be better in the long run

enginepaul · Jun 21, 2015

If you have a rebuild kit, use it and get running until you do a swap.
The feedback carb and computer run great IF they are working properly. The big problem now is parts; they are getting hard to find and not all of them are available from part houses. = = SO: do some work and maybe spend some cash on parts to keep it original or get the items needed for a DuraSpark.

wildbill23c · Jun 28, 2015

My 84 Bronco 2 had the same symptoms. After messing with it for a while, I adjusted the 2 screws on the bottom front of the carburetor. I turned them all the way in, then backed them out 3-1/2 turns to start then kept adjusting till the hesitation. I'd try adjusting those 2 screws first before messing around too much.

Emeralddream · Aug 25, 2015

I know it has been a while but between work and some other things havent been able to reply to you all. I messed with the idle fuel mixture screws and even purchased a 20 dollar accelerator motor that automates the idle I believe. anyways... even after doing those things I still had no luck. still haven't went out and taken the carb off completely but may have actually fixed the problem with new plugs, wires, distributor and button. The truck seemed to have woke up and now I can get it up to 70 mph pretty easy without too much hesitation only time will tell and I'm taking it out tomorrow so hopefully the hesitation on acceleration is gone completely and all is well. will reply soon thanks again all!

kimcrwbr1 · Aug 25, 2015

Did you mess with the idle air needles? If so turn them in until lightly seated and then back out 3 1/2 turns each and just leave them there. If your still running the computer disconnect the battery for 1/2 an hour and make sure all the sensers are plugged in before you start it. The computer controls idle speed so messing with the idle air needles is useless unless you disconnect the idle speed motor first then adjust the needles for the best idle. first out for the highest rpm then back in until the idle speed just begins to drop then plug the idle motor back in and the computer should control idle. The idle stop screw next to the throttle cable is called the antidiesel screw just turn it out until it no longer touches the throttle lever, when you give it throttle the idle speed motor should fully retract have someone give it gas and unplug the idle motor fully retracted and adjust the idle speed at around 650rpms. What it does is keeps the throttle buterfly from fully closing when you let off the gas quickly. The last adjustment is the curb idle. Turn the motor off and the throttle motor should fully extend. Unplug the motor and start it up. adjust the position of the motor to control curb idle speed around 1250 rpms then plug the motor back in and the computer should control idle. The most important thing if your running the computer is you have everything plugged in including the air temp senser in the sir filter housing. The computer needs all the sensers to control ignition timing and will quickly go into limp mode if it sees something wrong. Disconnect the battery for 1/2 an hour to reset the computer if you run it with something disconnected.

The woes of my carb

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