fuel issue? piston issue? electrical issue?

Ask technical questions about your Ford Bronco II here. Technical write-ups on your axle swaps, engine swaps, chop tops, etc. are encouraged.
annoyedeasy
Posts: 1
Joined: Sat Jun 15, 2013 11:22 am
Location: NC

fuel issue? piston issue? electrical issue?

Postby annoyedeasy » Sat Jun 15, 2013 11:25 am

1990 Bronco 2 2.9L V6
OK, Here is the symptoms my truck starts right up and idle's at 1200 RPM and idle's just fine with no fluctuation. While it is still in Park I press the gas pedal and it rev's just fine I am able to hit 4k+ RPM.
It is the same way in neutral runs good sounds strong.

BUT when I put it in either Reverse or Drive/OverDrive, I press the gas and it acts like it wants to stall out. But it doesn't stall out, it just stops accelerating just rumbles really low. Then soon as I let go of the gas it goes back to idling fine. I can drive the truck around the neighborhood while just barely giving it gas not to exceed 2k RPM and 25 MPH it seems.

I was told to try replace/repair a few things so I did.
all things are put on correctly :))

Fuel Pump
Fuel Filter
Fuel Pressure Regulator
Spark Plugs
Ignition Coil
Throttle Air Bypass Valve
O2 Sensor
Catalytic Converter
Muffler
Distributor Cap
Cap Ignition Rotor

kirkland2887
Posts: 86
Joined: Sun Jan 29, 2012 6:00 pm
Location: Albion, Idaho

Re: fuel issue? piston issue? electrical issue?

Postby kirkland2887 » Sun Jun 16, 2013 4:41 pm

it should not idle that high. sounds like something is out of calibration. im not sure if it has an idle air control valve. could be an egr valve. and you should check the reference voltage on your throttle possition sensor. at closed throttle should not be above 1v. at full throttle should be no more than 5v. in reality .8v-4.8v or 4.9v

kirkland2887
Posts: 86
Joined: Sun Jan 29, 2012 6:00 pm
Location: Albion, Idaho

Re: fuel issue? piston issue? electrical issue?

Postby kirkland2887 » Sun Jun 16, 2013 4:44 pm

just thought of this to. check your timing. my 88 when i first got it had exact same symptom. only mine is standard. turned out the rotor wheel in distributor was rusted and messing with timing. i found the problem on accident replacing the rotor.


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