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2.9 running issues


pimtool

OTOTM Winner
OTOTM Winner
Joined
Aug 6, 2007
Messages
484
City
prosperity,SC
Vehicle Year
1994
Transmission
Automatic
89 bronco 2, auto trans, manual t case

I just got an 89 b2 thats obviously been neglected.

New fuel pump, filter, plugs, wires, cap, rotor, set timing.

It starts and runs ok, bit of a miss at idle. If i slowly press the gas it revs fine.

If i open throttle quickly it boggs and coughs, If I power brake it will miss pretty bad. it does seem to run a little better warm than cold.

I cant seem to locate a map sensor, tps voltage seems to move smoothly as throttle is opened.

I just put a another fuel filter on it, the one I took off that was a week old was full of rusty gas.

I pulled the injectors and sprayed them out with carb cleaner, that seemed to help for a few minutes.

So, I guess what I am asking is should I go after the fuel system and replace all of the fuel lines front to back and clean fuel rail and injectors or is there some other engine management sensors that need to be checked first. possibly O2 sensor?

Thanks
 
A side effect of bad o2 sensors is bogging down during acceleration...but its hard to say with a system that far neglected what it could be. Did you check the air filter? Or any part of the air intake/hoses that might have a hidden mouse nest? Another to look at is a malfunctioning IAC sensor, which was the reason for my Bronco's rough idling and "bogging down."
 
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Intake is clean, had it off several times.

If I unplug the IAC the engine will almost stall out until it catches its breath.

If I unplug the coolant sensor idle changes, so that is at least doing something. (not sure if its right or wrong though)

I only checked a couple plugs. I think I have an o2 sensor laying around that might fit.

So I will try the rest of the plugs and the o2 and go from there.

Thanks
 
have you check the in-tank fuel pump. if its been sitting for a long time the rubber hose in the tank may be rotted and not producing enough fuel to the rail pump. also the map sensor is located on the top of the firewall left of the back of the intake manifold.

if i were you i would change the ects. and the ats. btw way there are two ects's cool thing is there are right next to each other.

but the only thing i can think of why your having the bogging down issue is because of fuel delivery.

check the in-tank pump first. poor little thing only puts out 6psi. redundant if i say so myself. but check it. lol
 
have you check the in-tank fuel pump. if its been sitting for a long time the rubber hose in the tank may be rotted and not producing enough fuel to the rail pump. also the map sensor is located on the top of the firewall left of the back of the intake manifold.

if i were you i would change the ects. and the ats. btw way there are two ects's cool thing is there are right next to each other.

but the only thing i can think of why your having the bogging down issue is because of fuel delivery.

check the in-tank pump first. poor little thing only puts out 6psi. redundant if i say so myself. but check it. lol

I was thinking it was a fuel problem also. The in-tank pump is the one I changed, I didnt realize there was another pump. Where is the second pump? its not between the tank and filter.

Also, someone has messed around with it before, the lines were the filter is are hacked up.

Thanks
 
the second pump is on the drivers side frame rail. behind a golden colored plate, like you said if someone he messed with it, it might be gone. it is very important to get that pump working. 6ish psi is not enough to get it to stay running.

but the pump should be about 2 feet behind the filter.
 

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