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HELP BRONCO ll DOWN

4K views 14 replies 3 participants last post by  ctg2 
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#1 ·
Hi I have a 86 bronco ll 2.9 v-6 automatic that won't run. Every time I start it up it runs about 5 sec. and sounds like it's running on three cylinders. The computer says all codes are clear. We swaped out every sensor still nothing. different distributor and module Put different fuel injectors new fuel pump and fuel filter and last a different computer . Is there something I missed??? Any help will really be appreciated Thanks
 
#2 ·
i am thinking there might be an idle air control valve
on the engine and it sounds like that isnt working.
those arent seen by the puter so if its bad no codes tell you it is bad.
but if it is bad the engine will not idle but will run fine as long as you hold your foot on the pedal to keep the idle up.
 
#4 ·
This may sound kind of obvious, but have you double checked your firing order? Ford numbers their cylinders from front to back with number 1 on the passenger side. Cylinders 1-2-3 are the right bank and 4-5-6 is the left bank.

You didn't say if it ran fine when giving it gas. If it does, I agree with the others on the IAC.
 
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#5 ·
Hi I put a new idle air control valve on still does'nt run right also checked the plug wires .It runs for about 5 seconds and dies evenwhen I give it the gas. after about four or five times the plugs foul out.
 
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#7 ·
I didn't reset it but I did now and it runs somewhat better but it still spits and sputters and idles goes from 400 rpm to 700 rpm has no power and the dies.I have clean the plugs a couple of times . I'm going to put some new ones in and see if that helps.
 
#8 ·
well obviously these type problems involve several components and you still didnt find the bad one but i am gunna say the O2 sensor will cause a rich condition with a loss of power and suity smoke but i never seen it cause a flood.
the other thing could be are they the right lb/hr injectors for your motor that would cause a flood if you bought them from an autozone and they were the wrong size.
 
#9 ·
Just one more thought.....

A plugged return line to the fuel tank will cause the fuel pressure to be too high which would result in a very rich mixture. The fuel pressure regulator can't work if the return line is not open.

Regardless of whether or not the return line is plugged up, the increase in fuel pressure to the injectors should not be enough to flood the engine out and foul the plugs after such a short time. Even running a much larger injector wouldn't be enough to stall the engine. The excess raw fuel would just get blown out the exhaust and eventually clog up your cat.

Turn the engine over until number 1 reaches TDC on compression. Pull the distributor cap and be sure the rotor is pointing in the general direction of number one. Then double check your wires are following the firing order in the direction of rotor rotation. The problem your describing wreaks of a distributor installed incorrectly(ignition timing) or incorrect cam timing (timing chain installed incorrectly).
 
#10 ·
yes it seems that the problem could be any of a number of things so if you arent goin to take this to a garage and you want to fix it yourself start by pulling one plug wire at a time and use a timing light to check the spark on each cylinder.
actually i recommend getting an inductive light because then you dont have to pull off a wire to check it.
but first make sure it is firing and it has a good spark then you can use the light also to see if the static timing is correct. or use 92's method using the rotor cap.

if you find an erratic spark then you should replace the magnetic pick up assy in the dist, they do go bad occasionally.
 
#12 ·
yes we are curious to see what the problem really is and maybe the garage was a wise choice at this point.
it is very difficult to diagnose a problem when you cannot actually be there and see and hear what is happening.
sorry we havent been able to help you more !!!
 
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#15 ·
Hi,Well they replaced the fuel pump had it running about 15 minutes and it died again !! I found out the frame was rotted and I was going to use it for a plow truck So I junked it and bought snow blower Thanks for the help If I get another truck I'll keep this site in mind if I have any trouble with it. Thanks again
 
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