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Discussion Starter #1
My alternator went out this weekend on my 86 302efi so I spent saturday taking care of that. Picked up a working alternator out of a 99 taurus and the wiring harness. perfect fit after swapping out the pulley for the v-belt, no bracket mod, and wired it up. i'm not too familiar with auto electrical so i just spliced it. BKO started up and i'm getting black smoke out of the exhaust (running rich) and all of a sudden I have a water leak. Greenish tinge to the liquid, but no odor so I'm guessing it's water, and it appears to be originating from the water pump. Before replacing the pump I decided to pull codes and see what was up. I pulled the following codes:

21: Engine Cooling Temperature (ECT) sensor out of Self-Test range (engine not warmed up before test)
22: Manifold Absolute Pressure (MAP) sensor out of Self-Test range
24: Air Charge Temperature (ACT) sensor out of Self-Test range
41: HEGO sensor circuit indicates system lean
35: EVP circuit above maximum voltage
77: Operator error during Dynamic Response Test
25: Knock not sensed during Dynamic Response Test (operator error)


Can anybody point me in the direction of the next step? i'm kinda stumped. I'm almost sure that my wiring of the alternator could be causing a few of those problems but where did the water leak spring from? it could just be Murphy's Law which seems to be the case any time I feel accomplished for reviving the bronc...
 

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My experience on the water pump leak: You changed the alternator, then got the jack handle out and tightened the snot out of the V-belt, then the water pump leaked.

It happened to me a couple of times until I figured out that the belt didn't have to be that tight. The pump is probably leaking from the weep hole, which means the bearing/seal is leaking. Too much tension on the pulley.
 

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From the codes I am guessing you did a KOER test on a cold or luke-warm engine. Drive bronco for 30 minutes and shut off. First do KOEO test, then KOER.

Of the codes you have, I would start by replacing the EVP.
 

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From the codes I am guessing you did a KOER test on a cold or luke-warm engine. Drive bronco for 30 minutes and shut off. First do KOEO test, then KOER.

Of the codes you have, I would start by replacing the EVP.
 

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Discussion Starter #6
My experience on the water pump leak: You changed the alternator, then got the jack handle out and tightened the snot out of the V-belt, then the water pump leaked.

It happened to me a couple of times until I figured out that the belt didn't have to be that tight. The pump is probably leaking from the weep hole, which means the bearing/seal is leaking. Too much tension on the pulley.

you were right, i loosened the belt just a tad and completely stopped the leak.


BigWheelz said:
From the codes I am guessing you did a KOER test on a cold or luke-warm engine. Drive bronco for 30 minutes and shut off. First do KOEO test, then KOER.

Of the codes you have, I would start by replacing the EVP.
Today 02:27 PM
You're right, i let it run for 5 minutes before running the test so it probably wasn't hot. Although it isn't running very well, dying at stop signs when RPMs drop too low. I'll keep it running in the morning for a while and retest to see what I come up with.
 

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Although it isn't running very well, dying at stop signs when RPMs drop too low. I'll keep it running in the morning for a while and retest to see what I come up with.
if you step on the throttle and let is go (while in park or neutral) do you notice a low rpm drop (sub 500) or saw while parking and lightly giving it gas to park in an uphill parking spot and notice the truck comes close to dying

I'd say check and clean out your IAC. i think resistance is supposed to be between 7-13 ohms cold?
 

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Discussion Starter #8
if you step on the throttle and let is go (while in park or neutral) do you notice a low rpm drop (sub 500) or saw while parking and lightly giving it gas to park in an uphill parking spot and notice the truck comes close to dying

I'd say check and clean out your IAC. i think resistance is supposed to be between 7-13 ohms cold?
stepping on the throttle in park and letting off drops rpms to the point of the engine sputtering. driving it down the block and rolling to a stop causes the engine to die. Shifting into neutral while rolling also causes the engine to die. I'm guessing that since i threw a 41, telling me the system is lean, rather than rich like I originally thought, i'm not getting fuel, is that right? i replaced the IAC last month but i'll check it just in case.
 

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stepping on the throttle in park and letting off drops rpms to the point of the engine sputtering. driving it down the block and rolling to a stop causes the engine to die. Shifting into neutral while rolling also causes the engine to die. I'm guessing that since i threw a 41, telling me the system is lean, rather than rich like I originally thought, i'm not getting fuel, is that right? i replaced the IAC last month but i'll check it just in case.
Since this all started with replacing the Altenator, I'd go back and make sure your battery is charging properly. Low voltage is going to drive your eec crazy because all the sensors will be reporting bad or readings.
 

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would changing the alternator cause the system to run lean? that's my biggest issue.
No, the alt is likely not the issue.

Retest and post results. Check the vacuum line going from your intake manifold to the MAP sensor
 

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Discussion Starter #12
ran a test this morning after getting the engine to operating temp. Came back with these KOER codes:

12: Cannot control RPM during ER Self-Test high RPM check.
22: MAP/BP sensor out of self test range.
42: No HEGO switching detected always rich (right side).
34: PFE or EVP circuit above the closed limit of 0.67 volts.
77: System failed to recognize brief WOT during Dynamic Response Test (user error).
25: Knock not sensed during dynamic test.

While idling I unplugged the IAC and the engine died so I know that's not faulty. I took it off and cleaned it anyways and no change was detected. When I unplugged the MAP sensor the engine idled smooth at 800-900 rpms, with no black smoke from the exhaust. I just replace that sensor a couple months ago but I've been hearing that the ones from the Zone crap out so I picked another one up and there was no change. I drove around the block a couple times without the MAP hooked up and while the truck didn't die, i had a loss of power in 1st gear, bogging down and sounding like I was out of fuel. I'm resetting the battery right now to clear codes and I'll retest to see what I get.
 

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Discussion Starter #14 (Edited)
Still trying to figure this thing out...I've been going through the sensors that I know of and testing to make sure all are operating correctly. Checked my cap, rotor, wires, and plugs...all were replaced <6months ago but the rotor looks a little crusty. I'm picking up the items for the Sixlitre ignition upgrade because the plugs are shot, carbon covered from running rich.



I've got oil on plugs, guessing it's from leaking valve covers since no oil was found on the firing side.
 

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yo,
DTC 22/126 indicates the Manifold Absolute Pressure (MAP)/Barometric Pressure (BARO) sensor is out of Self-Test range. Correct MAP/BARO range of measurement is typically from 1.4 to 1.6 volts.
Do NOT use an ordinary voltmeter to check a Ford BP/MAP sensor because doing so can damage the electronics inside the sensor. This type of sensor can only be diagnosed with a DVOM that displays frequency, or a scope or scan tool
Also make sure engine manifold vacuum is within specifications at idle. If vacuum is unusually low due to a vacuum leak, retarded ignition timing, an exhaust restriction (clogged converter), or an EGR leak (EGR valve not closing at idle).
A low intake vacuum reading or excessive backpressure in the exhaust system can trick the MAP sensor into indicating there is a load on the engine. This may result in a rich fuel condition.
A restriction in the air intake (such as a plugged air filter), on the other hand, may produce higher than normal vacuum readings. This would result in a load low indication from the MAP sensor and possibly a lean fuel condition.

A good MAP sensor should read barometric air pressure when the key is turned on before the engine starts. This value can be read on a scan tool and should be compared to the actual barometric pressure reading to see if they match. Your local weather channel or website should be able to tell you the current barometric pressure reading.
Check the sensor's vacuum hose for kinks or leaks. Then use a hand-held vacuum pump to check the sensor itself for leaks. The sensor should hold vacuum. Any leakage calls for replacement.
An outright failure of the MAP sensor, loss of the sensor signal due to a wiring problem, or a sensor signal that is outside the normal voltage or frequency range will usually set a diagnostic trouble code (DTC) and turn on the Check Engine light
"...The vacuum gauge should show 18-22 in-Hg @ idle, and maintain a steady needle. Rev it up to ~2500 rpm, hold it steady, and you should see the needle drop, then slowly increase to a level close to the idle reading (though slightly lower is normal)..."
Source: by SigEpBlue (Steve) at FSB

Gauge Diagnosis Source: by Craig U at http://www.classictruckshop.com/clubs/earlyburbs/projects/vac/uum.htm

Possible causes:
circuit open between sensor vehicle harness connector and PCM.
circuit shorted to VREF, SIG RTN, or GND.
Damaged MAP sensor.
Vacuum trapped at MAP/BARO sensor.
Unusually high/low barometric pressure.
Kinked or obstructed vacuum lines (MAP).
Basic engine (valves, vacuum leaks, timing, EGR valve, etc.).
High atmospheric pressure.
Damaged PCM.
VREF circuit open at MAP sensor.
SIG RTN circuit open at MAP sensor.

The pinpoint test directs you to check the voltage to the MAP sensor. With the MAP sensor connected, use paper clips to back probe the MAP connector so you make contact with the terminals inside the connector by inserting the paper clips into the bak of the connector. This allows you to get voltage readings while the connector is plugged in. The other option is to use straight pins to pierce the insulation of the wires. First check the voltage of the outer two wires of the MAP connector by connecting a voltmeter to the clips or pins you have inserted. You should see 5 volts with the key on. This is the power to the sensor.

The BLK/WHTwire provides a ground called Signal Return (SIG RTN on EEC), it will show 0 volts with the black probe on negative battery terminal. The 5 volts VREF (ON EEC) (Reference Voltage) is supplied on the ORG/White wire. The Signal the computer reads is on the middle wire, DK BLUE/-Lt GRN (MAP on EEC). The correct MAP/BARO range of measurement is typically from 1.4 to 1.6 volts on the Signal (middle wire).

If any of the voltages are out of range, there is a wiring problem that needs to be tracked down and repaired. These three wires all go back to the computer. The signal wire (middle) is the only one not shared by other sensors, it goes straight to the computer. The Signal Return and VREF are also provided to other sensors


Wiring Diagram in 87-89 4.9 Bronco & F series (Mitchell) page 2
Source: by equivalent (Beetlejuice) at SuperMotors.net



Vacuum Leak Test; On an idling engine check for vacuum leaks using a mechanic's stethoscope with the probe removed, or a ~3' garden hose section. On COLD ENGINE only, use propane torch w/rubber hose attached, UNLIT or spray carb cleaner, when it gets to the the leak the RPMs will rise. Also check: vacuum hoses; intake manifold gasket & throttle body; Tree Location pic in a 94 5.8 Source: by joelb23 at SuperMotors.net; PCV pic by Bbronco311. Vacuum Reservoirs: EGR Sys Vacuum Tank & 2ndry air (looks like a coffee can in earlier years) Depiction & Location in Parts Break-Out Diagram in a 96 w/Ford part numbers by Ford via miesk5 at http://www.broncolinks.com/gallery_i...6TABTAB5.0.jpg; Thermactor Air Bypass Solenoid (TAB, AIRB, AM1) w/Pink vacuum line & Air Bypass Valve (AIR BPV) & Thermactor Air Diverter Solenoid (TAD, AIRD, AM2) w/Yellow vacuum line & Air Diverter Valve or Air Control Valve (ACV) see my site @ http://www.broncolinks.com/index.php?index=416 & EGR Vacuum Regulator (EVR); also called EGR Vacuum Solenoid & EGR Valve Position (EVP) - MIESK5 NOTE: EVP is used on all years except for 95 5.8L California models & all 96, they use the DPFE Sensor instead of EGR Valve Position Sensor (EVP) etc, see my site @ http://www.broncolinks.com/index.php?index=146. AC, heater, defroster, vent control ckt & vacuum tank (plastic ball, or an irregular box glued to the evaporator cover), under dash & lines to heat/blend/etc. doors; & HVAC vacuum reservoir; Vacuum Tank pic, Ford part number 19A566; on side of evaporator housing by Ford via miesk5 at FSB. Carbon Canister (Charcoal Canister, Vapor Canister, Evaporative Emission (EVAP) Canister for the Evaporative System (see http://fullsizebronco.com/forum/atta...1&d=1315917794. & Line to & the power brake booster, Master Cylinder & Booster Location pic in a 93 by Steve83. ; and line to & Cruise Control sys in 86-91.
 

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yo,
Had to do some work-work
DTC 42 O2 sensor voltage was stuck high for too long. (Rich).; "...Bad O2, or it's connector/wiring bad MAP sensor, Bad fuel pressure regulator, pull vac hose off, any gas in it or gas aroma means it's bad; Leaking injectors,restriction in fuel return line,or exhaust leak or clogged exhaust, lowering vacuum..." read more
Source: by miesk5 at FSB http://fullsizebronco.com/forum/showthread.php?t=184667



DTC 41, 42, 85 OR THREE DIGIT CODES 171, 172, 173, 179, 181, 182, 183 & 565 are received , Check for proper HEGO Ground; in Catalytic Converter Diagnosis TSB 91-12-11 for 86-91 Bronco, F Series, & Econoline
Source: by Ford via Steve83 (Steve, That dirty old truck) at SuperMotors.net
http://www.supermotors.net/registry/media/747751


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DTC 34 - EGR voltage above closed limit - bad EVP sensor, clogged exhaust or convertor, carbon between EGR pintle valve and seat holding the valve off its seat. Remove the EGR valve and clean it with carbon remover. Prior to re-installing see if you can blow air through the flange side of the EGR by mouth. the egr is not closing properly which can cause detonation. remove the egr and clean off any carbon built up on it with carb cleaner and a brush if necessary.
Source: by miesk5

DTC 34 "...in Key On Engine Off (KOEO) or Engine Running (KOER) Self-Test indicates that the EGR valve and/or EGR Valve Position (EVP) sensor may not be fully seated in the closed position. The EVP sensor voltage is greater than the closed limit voltage of 0.67 volt. Because of the preload on the installed EVP sensor, it is very difficult to determine whether the EGR valve is seated or the EVP sensor is in contact with the EGR valve stem..."
Source: by rla2005 (Randy) via miesk5 at Ford Bronco Zone Forums

DTC 34; Next isn't listed by anyone for the 34 Code, but is a good test anyway to rule the EVR out & is a simple multimeter test; The EGR Vacuum Regulator (EVR) controls the opening and closing of the EGR valve. The EVR is an electromagnetic solenoid and should have between 20-70 ohms resistance between the pins. +12volts should be constant on one side from the EEC Relay, the computer controls the ground signal when EGR flow is needed. When the EGR Vacuum Regulator (EVR) is off, both ports vent slowly to atsmophere. To test it mechanically check to see if vacuum is present at the EGR valve with the electrical connector unplugged from the EVR. The top port should not have vacuum! Because that would open the EGR at the wrong times. With everything connected and the engine running ground out the pin 33 side. The EGR vavle should open and the engine RPM should change.
Source: by miesk5

DTC 31, 32. 33. 34. 35. 38 or 84; EGR Valve Position (EVP) Sensor & EGR Vacuum Regulator Solenoid (EVR) Testing
Source: by Dustin S (Dustball, Mellow Yellow, Mr. Laser Boy) at http://ylobronc.users.superford.org/documents/egr/

DTC 33 & 34 "...DTC 33 is triggered when the EVP sensor is not closing.... To prevent the EGR valve from opening when the engine is cold, the vacuum line to the EGR valve may be connected to a parted vacuum switch or a computer-controlled solenoid. Vacuum is not allowed to pass to the valve until the engine is warm. EGR isn't needed when the engine is cold, only when it is warm and under load. Any of these codes could indicate a faulty EGR valve as well. as well as a problem in the ...vacuum solenoids' Miesk5 note; TAB & TAD; so repair those vac lines 1st..." Source: by Larry C
These TAD & TAB are next to Coil;
Location pic; "...the Yellow Vacuum Line goes from the TAD Solenoid (driver's side forward solenoid) to the TAD (Diverter) Valve located at the rear of the Intake Manifold. You have to climb up onto the engine to feel the Diverter Valve or remove the Intake Manifold..The Pink Vacuum Line goes from the TAB Solenoid (driver's side rear solenoid) to the passenger side (adjacent to the Vacuum Reservoir Can) and down to the bottom of the TAB (Bypass) Valve..."

Source: by Seattle FS
Test; Key off. Disconnect both solenoid connectors; measure both solenoid resistances. Is each resistance between 50 and 100 ohms?
If not, replace solenoid
 

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Discussion Starter #17
so now it isn't even starting...turns over but won't fire...i'm chasing sensors now, from everything i've found on here i should be checking the 02 and ECT sensors. What else could possibly be causing the no start condition?
 

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yo; Check MAP sensor code 22 I posted above
&
If your Ford car (pick up, van) is 1994 or older, you see DTC’s 22 or 81 or 72. Your vehicle won’t start or will have a long cranking time before it starts. Black smoke coming out of the tailpipe along with really BAD gas mileage. The engine idles rough when running and has a lack of power when accelerated.
So you’ve tested the MAP Sensor and according to the test results, it’s good...
But the CHECK ENGINE LIGHT keeps coming back on even after you erased the Diagnostic Trouble Code (DTC) from the Computer’s (PCM) memory. Well, here are a couple of suggestions that might inspire your next diagnostic move: The MAP Sensor’s Vacuum Hose or Line is torn or cut or clogged. The Engine has several Cylinders with very low Engine Compression causing it to Idle Rough and thus producing low or erratic vacuum.
For this I suggest a Compression Test. The MAP Sensor is failing intermittently. Which means that it works fine most of the time, but every now and then... it doesn’t: •I have found that the best way to test these intermittents is to slightly tap the MAP Sensor with the handle of a Screw-driver and see if this tapping screws up the Voltage readings as I apply vacuum. The MAP Sensor’s connector is BAD, usually the locking tab is broken and the connector has worked itself loose, causing an intermittent false connection. Your Fuel Pump is starting to go BAD and is not sending enough fuel and/or fuel pressure up to the Fuel Injectors. I suggest a Fuel Pump Test..." See Site for Diagrams
Source: by easyautodiagnostics.com @ http://troubleshootmyvehicle.com/ford_map_4.9L_5.0L_5.8L/ford_map_sensor_1.php

Testing, Symptoms & Overview; "...Surging, Rough idle, rich fuel condition, which may cause spark plug fouling, Detonation due to too much spark advance and a lean fuel ratio, loss of power and/or fuel economy due to retarded timing and an excessively rich fuel ratio; a vacuum leak will reduce intake vacuum and cause the MAP sensor to indicate a higher than normal load on the engine. The computer will try to compensate by richening the fuel mixture and retarding timing, which hurts fuel economy, performance and emissions..."
Source: by aa1car.com


more MAP Testing, Symptoms & Overview LINKS in my site @ http://www.broncolinks.com/index.php?index=138
 
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