88 Bronco II won't start - Ford Forums

tnrm03 · 02-24-2006, 13:23

I was teaching the Hubby how to drive a standard, and he was hopping the truck and could not get it going. I asked him to get out and let me drive becuase we where in the middle of the road. It would not run, kept cutting out badly.

We pushed it home and parked it for the night because it had started raining. The next day I tried to start it and it would not crank. I figured with all of the hopping it probably needed the inertia switch reset. Once I reset it the truck cranked right up.

After it ran for about 2 or 3 minutes the wire to the inertia switch got hot. I immediately turned the ignition off but it was too late, the switch was fried.

I replaced the switch, the wire from the switch to the fuel relay, and the wire from the switch to the fuel pump. I then tried to crank it and it would not start. I checked the feul pressure and there wasn't any. I also did not hear the pump turn on. I ran a hot wire from the silonoid to both pumps and got feul pressure but it still would not turn over.

I have fire at the plugs, and I have checked the voltage capacitor running from the neg battery cable.

I am at a loss...any suggestions would be greatly appreciated!

miesk5 · 02-28-2006, 10:41

wow, entered following in here yesterday in the new URL, but it did not Xfr to here......

it is weird considering all you describe

ez things 1st;
for the 4th paragraph, since everything else doesn't count now (to me)
check fuel pump fuse(s) - maybe you have 2 fuses, one in interior panel and one underhood along with or in-place of a circuit breaker (for the no fuel pump run/power)
check the fuel pump relay (prob under hood in a plastic box); see if it is fried too; v/current runs from batty to relay to inertia switch to fuel pump; as you prob. know since you did hot wire the thAng!)) - these relays go South a lot; look for another sim. rated relay in there & swap it to see if the FP relay is shot
also, forgot to eneter this yesterday; inertia switch was fried due to a grounded or damaged fuel pump or grounded wiring at connector

check plug(s) for fouling (no run cond.)

also; wiring diagrams:
http://www.autozone.com/servlet/UiB...23d800f9461.jsp

when you can get it running, check for Diagnostic Trouble Codes
http://www.broncoii.org/Tech%20Pages/eeciv/index.htm#Two%20Digit%20Codes:%20(3)

tnrm03 · 03-06-2006, 20:56

I replaced both the eec relay and the fuel relay last week. I now hear a click in the EEC relay when I turn the key on but still know pressure, the pumps do not cut on and it will not start.

We went and bought a code scanner today and I tested the codes and it said:

Code 22: the manafold absolute pressure sensor or barometric pressure sensor signal voltage out of specification

and

code 122: throttle position sensor signal voltage is too low

Tracy

miesk5 · 03-07-2006, 10:03

ok;
22 (orc*): MAP (Manifold Absolute Pressure, for speed-density cars) or BP (Barometric Pressure, for mass-air cars) sensor signal out of range. Suspect MAP or BP sensor and harness.
Sensor Diagnostics Manual & Code Tests (geared to Bronco II, but similar to Broncos) by broncoii.org
Incl MAP; http://www.broncoii.org/Tech%20Pages/eeciv/index.htm#MAP%20Testing:%20(15)

MAP/BP Sensor Testing, Ford & 2 digit EEC codes by minivanmadness.com
http://minivanmadness.com/pdf/files/EEC%20codes.pdf

122? your should have just a 2 digit code; right? ( I could be wrong, but I do believe it's only 2 digits for that yr and model/engine; do the test over for both

http://www.autozone.com/servlet/UiBr...3d800f8e2b.jsp

anyway; here is some TPS info;
http://www.autozone.com/servlet/UiBr...3d800f8dda.jsp
and:
Throttle Position (TP) Sensor
OPERATION
The Throttle Position (TP) sensor is a potentiometer that provides a signal to the PCM that is directly proportional to the throttle plate position. The TP sensor is mounted on the side of the throttle body and is connected to the throttle plate shaft. The TP sensor monitors throttle plate movement and position, and transmits an appropriate electrical signal to the PCM. These signals are used by the PCM to adjust the air/fuel mixture, spark timing and EGR operation according to engine load at idle, part throttle, or full throttle. The TPS is not adjustable.

TESTING
Disconnect the negative battery cable.
Disengage the wiring harness connector from the TP sensor.
Using a Digital Volt-Ohmmeter (DVOM) set on ohmmeter function, probe the terminals, which correspond to the Brown/White and the Gray/White connector wires, on the TP sensor. Do not measure the wiring harness connector terminals, rather the terminals on the sensor itself.
Slowly rotate the throttle shaft and monitor the ohmmeter for a continuous, steady change in resistance. Any sudden jumps, or irregularities (such as jumping back and forth) in resistance indicates a malfunctioning sensor.
Reconnect the negative battery cable.
Turn the DVOM to the voltmeter setting.
WARNING
Ensuring the DVOM is on the voltmeter function is vitally important, because if you measure circuit resistance (ohmmeter function) with the battery cable connected, your DVOM will be destroyed.

Detach the wiring harness connector from the PCM (located behind the lower right-hand kick panel in the passengers' compartment), then install a break-out box between the wiring harness connector and the PCM connector.
Turn the ignition switch ON and using the DVOM on voltmeter function, measure the voltage between terminals 89 and 90 of the breakout box. The specification is 0.9 volts.
If the voltage is outside the standard value or if it does not change smoothly, inspect the circuit wiring and/or replace the TP sensor.