I have a 90 Bronco that dies when in gear, trying to take off at a stoplight. It idles fine, but as soon as i touch the gas, it dies. It runs great once you get going. I can rev it up in neutral. It has a new pcv valve and 2 open element air filters at the end of stock intake tubes. Thanks

 

pull the codes. we can guess all day long, but your trucks computer will give us more insight. Ford Fuel Injection

 

The codes I got were 2 blinks, pause, 1 blink, long pause, 2 blinks, pause, 4 blinks, repeated again, then 1 blink, long pause, 1 blink, pause, 1 blink, long pause, 1 blink, pause, 1 blink.I think that means code 21 and code 24 and code 11? am i right?

 

Thats the way I would read those codes, now look them up. run a search on here "reading codes"

 

jake, was the truck at it's normal operating temp when you pulled the codes? I ask, because these are codes that we normally see when the codes are pulled when the truck is cold. By the way, after looking at your first post, have you check the fluid level/quality in your tranny?

Let us know what you find...we will try to help. We don't mean to seem short, but if you review most any post, you will see that anyone's advice includes pulling codes. You need to list them as Key On, Engine Off (KOEO), and Key On, Engine Running at normal temperature (KOER).

Hope this helps.

 

KOEO-31-PFE or EVP circuit below .24v 63-TPS below .6v 87-fuel pump circuitKOER-98-Hard Fault present 63-TPS below .6vtruck was warm when codes were pulled.Someone help me translate to basic english please? I need a TPS and a fuel pump?

 

Ok, short run down as the what the computer is actually telling you.

The ECM (main computer) in Ford vehicles sends out a 5 volt reference signal to all of the on-board sensors and such. What happens to that voltage once it hits the sensor and comes BACK to the ECM is what the computer is reading. The Code 31 is telling you that the voltage coming back from the EVP (Egr Valve Position) sensor is BELOW what the computer expects to be seeing from it. This could be caused by a couple of things. First, dirty or corroded connections where the sensor plugs into the wiring harness can cause excessive resistance causing the low voltage reading. The sensor itself could have failed or be filthy (which still amounts to replacement in most cases). The same can be said for the TPS (Throttle Position Sensor). With both of these sensors the lowest expected voltage is 0.24 volts for the EVP and 0.6 volts for the TPS. The computer is getting voltage LOWER than that from the circuits that handle those sensors. Frayed wires, corrosion, and bad sensors can all be the culprits here.

Worry about the EVP and the TPS first because with faults at each of these, the computer has no idea how much fuel to send to the engine so it won't properly control the fuel pump circuit either as a result of the other two issues. Its a fail-safe situation. If the computer can't tell how much fuel to send, it just won't send... better that than sending fuel into a potentially dangerous engine environment. Since the truck will run under the certain conditions, its unlikely that your fuel pump has failed anyway.

Notes:

EVP location - on top of the EGR valve. Mounted with three screws and connected with a short pigtail to the main engine bay wiring harness.
TPS location - bottom of the throttle body. Mounted with two screws and connected with a short pigtail to the main engine bay wiring harness.
(This one sometimes is easier to remove with the throttle body separated from the intake but as I recall is not a necessity with the right tools).

 

Thanks for your response. I will go pull the TPS and EVP off my parts truck and see if they cure the Fuel pump code, if not, i will let you guys know.

 

Is there any way i could just delete the egr? or would that cause it to still run badly? I know my mustang doesnt have egr anymore and it runs great.

 

Don't even bother... the EGR is something the computer relies on for exhaust and emissions control information. Earlier vehicles could be stripped of these components and if things were plugged properly you could get away with it. The ECM relies too heavily on the information from the EGR sensors to effectively remove them in these trucks. Since the EGR system is in constant fluctuation while the truck is running there is no way to "fool" the ECM into thinking the system is still functioning properly.

 

Where does the EGR tap into? Where the cat is? if so, i removed the cat and have no tube going into the exhaust. Or is that for the air pump?

 

on the 5.0 engine, the tube that runs from the underside of the egr runs to the middle of the lower intake manifold.

 

The fresh air injection pump feeds both the EGR and the cat but the air flow is directed throughout engine operation by the TAB (Thermactor Air Bypass) and TAD (Thermactor Air Diverter) solenoids (mounted behind the ignition coil on the driver's side of the engine). These two, taking commands from the ECM, control vacuum through the diverter valve (behind the passenger side valve cover) which in turn redirects air from the air injection pump to either the cat (which obviously has no air injection supply if you say its been removed or if it does the metal tube that ran from the diverter valve to the cat is just dangling there randomly blowing air from the air injection pump into nothing) or the EGR system via the crossover tube between the cylinder heads at the rear of the engine.

The probem with removing the EGR and the air injection system is that all of these components are upstream of the O2 sensor(s). The O2 sensor(s) have the "final say" in fuel/air delivery and anything that disrupts the readings they produce will affect engine performance. This includes the removal of smog equipment upstream of the sensors.

 

my o2 sensor was before the cat.

 

Yes, but its downstream of the EGR and the rest of the system so the effect will still be detrimental to the system functionality.