I have a 95 xlt, 5.8L, auto, 149,000 miles, 4inch lift with 33's. I have owned this bronco for less than a year and have had the same problems come and go. I have put over $7000 into it, complete accell tune up, throttle body spacer with cold air intake, complete bassani exhuast with headers, new front bearings and brakes, tps sensor, iac valve, egr valve, pcv valve, starter, new motorcraft battery cable harnass, o2 sensor, ignition mod. and tumbler, igntion solenoid, crossover tube with thermactor, new silicone vacuum lines, seafoam in tank, crankcase and I did an upper intake clean, engine restorer in crankcase, everything I could think of. when it's running right the idle is so smooth you don't know it's running and it has great acceleration. when it's running bad it has a very rough idle, like it has a big cam or something. you can see the hood shaking. it won't accelerate smoothly, and it's not as loud. the worst thing is when go over 30mph you feel this vibration, mostly in the steering wheel, when you let off the gas it goes away. when you hammer on the gas you don't feel the vibration, just when your cruising normally. it fires right up no problem in either running mode, after about 45 sec it idles down to around 650rpm. this has been going on since I have had it, it runs good for weeks then it will run like crap. a couple of times I would hammer the gas to pass someone and then it would run fine as if I just blew something out. when I replace something I would unhook the battery and then when done hook it back up and it would take a couple of days to reset everything and it would run good. when I checked for codes koeo I was told I had no codes a 111 111 is what I was told. I have no engine lights and yes it works. my last major upgrade was the pcv, egr valve and the battery cable harnass. it ran good for about 2 weeks. yesterday I replaced all my vacuum lines with silcone tubing, hooked the battery back up, started it and no change, except now I have a battery light on for the first time. I'm running out of options and things to replace, everytime I think I fixed the problem, it comes right back. can't be a u-joint cuz it only does in rough idle mode. I'm ready to get rid of this problem soon if I can't figure it out. I'm hoping someone here has had the same problems.........
rough idle and vibration
- Thread starter brownbear
- Start date
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yo BB,
WELCOME!
Try a Self Test anway for Diagnostic Trouble Codes (DTC)s by my pal, BroncoJoe19
http://broncozone.com/topic/14269-code-reader/page__pid__74587__mode__threaded
Do this only if batty has not been disconnected for at least a few drives. Was batty disco'ed before shop tested for Codes and found none?
Do not disconnect battery to clear Continuous Memory. This will erase the Keep Alive Memory (KAM) information
The engine temperature must be greater than 50° F for the Key On Engine Off (KOEO) Self-Test and greater than 180° F for the Key On Engine Running (KOER) Self-Test.
Run it around to heat the engine up and shift thru all gears incl Reverse. Then turn off all accessories/lights, etc.
Make sure A/C is off and transmission is in Park (automatic) or in Neutral for a Manual & release clutch.
Do Key On Engine Off (KOEO) portion first.
Look Codes up in my broncolinks.com site using the new Search function.
And Post em here according to:
KOEO
&
KOER
Joe also has a vacuum leak test in therer; do the HVAC ck vacuum lines and compoents as well under dash and at HVAC vac tank and check valve
Ford often recommends a "Wiggle Test" of harnesses, connectors and wire strands for non-Code intermittents
Ford states; "By definition "intermittent" is a randomly occurring drive symptom for which no hard DTCs (KOEO, KOER) are revealed by Quick Test. Often the Quick Test results in "Pass DTCs" while the drive symptom still exists. Other results, such as Continuous Memory DTCs, will also apply to the scope of this section.
Before proceeding with the following procedure, be sure that:
Customary mechanical system tests and inspections reveal nothing. (Remember, mechanical component problems can make a good EEC system react abnormally.)
This is from the 94 Bronco (almost 99.9999% = to your year) PCED OBDI-A SECTION 7A: EEC-IV Intermittent Fault Diagnosis by Ford;
Symptom Charts Chart 4
As you can see these are possible causes for your intermittent rough idle.
UNIQUE IDLE CONCERNS System Possible Causes Visual/Mechanical:
Air/Vacuum Check vacuum lines for leaks or wear.
Check air filter.
Check air intake system.
EEC (hopefully a Code will pop up for these sensors)
IAC solenoid
MAP/BARO sensor
MAF sensor
TP sensor
IAT sensor
Fuel Check for correct fuel pressure.
Check for fuel contamination/quality.
Check fuel filter.
EEC:
HO2S(s)
Fuel Pump System:
FP circuit
FPM signal
FP relay
FPRC solenoid
Fuel Injection:
INJ 1, 2 (MFI)
INJ 1, 2 .. (SFI)
CANP solenoid
Ignition Check for correct base timing.
Check distributor cap, adapter, and rotor.
Inspect spark plugs and plug wires.
Inspect ICM for damage.
Ignition System: circuit
Power and Grounds Check for low battery voltage.
Inspect electrical connections, wires, and harnesses.
EEC Power:
VREF
EEC Grounds:
SIG RTN
Other:
Check engine coolant level.
Check thermostat for proper operation.
Check EGR valve sticking.
Check PCV valve for correct operation.
Check for restricted exhaust.
Check for worn camshaft lobes.
Check camshaft timing and cylinder compression.
ECT sensor
EGR Systems:
EGRT, EVP, DPFE sensor
EGR solenoid(s)
A/C Systems:
ACC, ACCS, WAC, ACD or ACON
BLR circuit
DEF circuit
HDL circuit
PNP switch
PNP signal
Air/Vacuum Check vacuum lines for leaks or wear.
Check air intake system.
TP sensor
MAP sensor
MAF sensor
ISC solenoid
Fuel Check for correct fuel pressure.
Check fuel lines for water contamination or restrictions.
Fuel Injection:
INJ 1, 2 ..
FPRC solenoid
HO2S
Ignition Check for correct base timing.
Inspect ICM for damage.
Ignition System:
PIP circuit
SPOUT circuit (ck SPOUT Connector for looseness)
Other Check EGR valve sticking.
Check PCV valve for correct operation.
Check for restricted exhaust.
Inspect electrical connections, wires, and harnesses.
Check for low A/C refrigerant charge.
EGR Systems:
EGR, EVP, DPFE
EGR solenoid(s)
TCC solenoid
A/C systems:
ACC, ACCS, ACD, ACON or WAC
MLP sensor
BOO circuit
WELCOME!
Try a Self Test anway for Diagnostic Trouble Codes (DTC)s by my pal, BroncoJoe19
http://broncozone.com/topic/14269-code-reader/page__pid__74587__mode__threaded
Do this only if batty has not been disconnected for at least a few drives. Was batty disco'ed before shop tested for Codes and found none?
Do not disconnect battery to clear Continuous Memory. This will erase the Keep Alive Memory (KAM) information
The engine temperature must be greater than 50° F for the Key On Engine Off (KOEO) Self-Test and greater than 180° F for the Key On Engine Running (KOER) Self-Test.
Run it around to heat the engine up and shift thru all gears incl Reverse. Then turn off all accessories/lights, etc.
Make sure A/C is off and transmission is in Park (automatic) or in Neutral for a Manual & release clutch.
Do Key On Engine Off (KOEO) portion first.
Look Codes up in my broncolinks.com site using the new Search function.
And Post em here according to:
KOEO
&
KOER
Joe also has a vacuum leak test in therer; do the HVAC ck vacuum lines and compoents as well under dash and at HVAC vac tank and check valve
Ford often recommends a "Wiggle Test" of harnesses, connectors and wire strands for non-Code intermittents
Ford states; "By definition "intermittent" is a randomly occurring drive symptom for which no hard DTCs (KOEO, KOER) are revealed by Quick Test. Often the Quick Test results in "Pass DTCs" while the drive symptom still exists. Other results, such as Continuous Memory DTCs, will also apply to the scope of this section.
Before proceeding with the following procedure, be sure that:
Customary mechanical system tests and inspections reveal nothing. (Remember, mechanical component problems can make a good EEC system react abnormally.)
This is from the 94 Bronco (almost 99.9999% = to your year) PCED OBDI-A SECTION 7A: EEC-IV Intermittent Fault Diagnosis by Ford;
Symptom Charts Chart 4
As you can see these are possible causes for your intermittent rough idle.
UNIQUE IDLE CONCERNS System Possible Causes Visual/Mechanical:
Air/Vacuum Check vacuum lines for leaks or wear.
Check air filter.
Check air intake system.
EEC (hopefully a Code will pop up for these sensors)
IAC solenoid
MAP/BARO sensor
MAF sensor
TP sensor
IAT sensor
Fuel Check for correct fuel pressure.
Check for fuel contamination/quality.
Check fuel filter.
EEC:
HO2S(s)
Fuel Pump System:
FP circuit
FPM signal
FP relay
FPRC solenoid
Fuel Injection:
INJ 1, 2 (MFI)
INJ 1, 2 .. (SFI)
CANP solenoid
Ignition Check for correct base timing.
Check distributor cap, adapter, and rotor.
Inspect spark plugs and plug wires.
Inspect ICM for damage.
Ignition System: circuit
Power and Grounds Check for low battery voltage.
Inspect electrical connections, wires, and harnesses.
EEC Power:
VREF
EEC Grounds:
SIG RTN
Other:
Check engine coolant level.
Check thermostat for proper operation.
Check EGR valve sticking.
Check PCV valve for correct operation.
Check for restricted exhaust.
Check for worn camshaft lobes.
Check camshaft timing and cylinder compression.
ECT sensor
EGR Systems:
EGRT, EVP, DPFE sensor
EGR solenoid(s)
A/C Systems:
ACC, ACCS, WAC, ACD or ACON
BLR circuit
DEF circuit
HDL circuit
PNP switch
PNP signal
Air/Vacuum Check vacuum lines for leaks or wear.
Check air intake system.
TP sensor
MAP sensor
MAF sensor
ISC solenoid
Fuel Check for correct fuel pressure.
Check fuel lines for water contamination or restrictions.
Fuel Injection:
INJ 1, 2 ..
FPRC solenoid
HO2S
Ignition Check for correct base timing.
Inspect ICM for damage.
Ignition System:
PIP circuit
SPOUT circuit (ck SPOUT Connector for looseness)
Other Check EGR valve sticking.
Check PCV valve for correct operation.
Check for restricted exhaust.
Inspect electrical connections, wires, and harnesses.
Check for low A/C refrigerant charge.
EGR Systems:
EGR, EVP, DPFE
EGR solenoid(s)
TCC solenoid
A/C systems:
ACC, ACCS, ACD, ACON or WAC
MLP sensor
BOO circuit
I started with the evr test, I let it run at 2500rpms for 2 mins. I checked the red wire and it had 12v, I got nothing when I checked the ground wire (brown and pink) for continuity. when I pulled the hose off the egr there was not vacuum. when I grounded out the pin 33 the bronco stalled out. what does all this mean? is the evr bad, is it the ground wire or computer needs replaced? I'm looking for more ways to test the egr system. not sure where to go from here.
yo BB,
Red is 12 volts
EVR Testing:
vacuum should vent from the green line (supply port) on a good valve NOT energized. When energized, vacuum should hold from the black (source port) to the green.
Resistance across the terminals should be 30-70 ohms
Wiring Diagram in a 95
Source: by SeattleFSB (Seattle FSB)
Testing; "...Follow this procedure to rule out the EGR/EVP/EVR and then look elsewhere. As a side note, on one truck I had an EVP that tested good, but after replacement it cured my problem. The EVP is a potentiometer that can mechanically wear and the EVR solenoid can become stuck. On another truck, I eliminated the EGR Code 334 with a TPS replacement and adjustment. The EGR should only operate during cruising, never during Idle and WOT. Start by deleting the code and see if it returns. Then, perform a DTC Test and observe the EGR. When the PCM is in test mode, at some point during the test the diaphram should move and the engine rpms drop. We now know if the EEC is in control of the EGR. If the DTC returns, continue on. If no or inadequate change is seen, test the Manifold Red Vacuum line between the Manifold Vacuum Tree and VRESER (MAN port), then the VRESER Check Valve (AMP port) and then Black Vacuum Lines between the VRESER and lower ports on the TAB/TAD/EVR Solenoids. We have now ruled out an Emissions Manifold Vacuum Leak. With the engine off, locate the green vacuum line at the EVR (EGR Vacuum Regulator) located in front of the TAD and TAB Solenoids next to the coil. Attach a vacuum tester to the upper vacuum line and see if applied vacuum can operate and hold the EGR Diaphram. Disconnect the other end of the green vacuum line at the EGR. I you want, plug the end of the line with your finger and test again just to be sure. We have now ruled out the EGR vacuum line and EGR diaphram. If the line is good and the EGR is not holding vacuum, reattach the EGR vacuum line and remove the EVP (EGR Valve Postion Sensor) located on top of the EGR. The three attachment screws should not be loose causing an air leak. When removed, check the bottom of the EVP for an O-ring and if the position sensor pole can be moved up and down. Next, manually block the now open hole on top of the EGR with your hand and vacuum test again. We have now ruled out the mechanical portion of the EVP. Next, reinstall the EVP. With KOEO, check the unplugged harness connector with a DVOM for 5v reference voltage at pins VREF and SIG RTN. Then test the unplugged EVP Sensor for approximately 5000 ohms resistance at sensor pins VREF and EVP. Now apply 10 in. Hg. vacuum to the EGR. You should see a gradual decrease in resistance to approximately 100 ohms. If the vacuum, EGR and EVP test good, reconnect everything, except for the vacuum tester at the EGR and continue on. We have now ruled out the electrical portion of the EVP. Disconnect the harness connector to the IAC (Idle Air Controller) located on the side of the Throttle Body and start the engine. Start the engine and note that the idle should be lower than normal as the IAC is no longer in control. Apply vacuum to the EGR and watch for the engine idle to drop. Release the vacuum and the engine idle should return. If all is good, turn off the engine and reconnect the IAC and the green vacuum line to the EVR. Relocate the vacuum tester to the EGR end of the green line and connect using a "tee" between the vacuum line and the EGR. Start the engine and idle to warm. Idle vacuum from the EVR should be below 1 in. Hg. Now have someone raise the engine speed to 3500 rpm and observe the vacuum gauge for increase and the EGR Diaphram for movement. We have now ruled out the mechanical portion of the EVR. If the vacuum lines are good, next start KOER DTC Test with the Vacuum Hand Pump once again located at a "tee" at the EGR. While watching the vacuum gauge, observe for a change in vacuum and EGR Diaphram movement when the PCM activates the EGR during the test. If the test once again fails, either the EVR Solenoid is stuck or the there is a short to the EVR. Electrically test the EVR. The EVR has two connector pins. One to 12v battery power and the other to PCM Pin #33. Test the 12v to ground and the Signal wire to the PCM for continuity. Then you can mechanically test the EVR. The bottom port should hold vacuum and the upper port will not unless 12v are applied to the connector pins. Apply 12v, plug the lower port with your finger or cap and see if you can apply vacuum to the upper port. We have now ruled out the electrical portion of the EVR. If all is good at this point, start at the top of the page and look at the TPS link..." see EVP pin-out diagram & pics Source: by Seattle FSB (SeattleFSB)
Red is 12 volts
EVR Testing:
vacuum should vent from the green line (supply port) on a good valve NOT energized. When energized, vacuum should hold from the black (source port) to the green.
Resistance across the terminals should be 30-70 ohms
Wiring Diagram in a 95
Source: by SeattleFSB (Seattle FSB)
Testing; "...Follow this procedure to rule out the EGR/EVP/EVR and then look elsewhere. As a side note, on one truck I had an EVP that tested good, but after replacement it cured my problem. The EVP is a potentiometer that can mechanically wear and the EVR solenoid can become stuck. On another truck, I eliminated the EGR Code 334 with a TPS replacement and adjustment. The EGR should only operate during cruising, never during Idle and WOT. Start by deleting the code and see if it returns. Then, perform a DTC Test and observe the EGR. When the PCM is in test mode, at some point during the test the diaphram should move and the engine rpms drop. We now know if the EEC is in control of the EGR. If the DTC returns, continue on. If no or inadequate change is seen, test the Manifold Red Vacuum line between the Manifold Vacuum Tree and VRESER (MAN port), then the VRESER Check Valve (AMP port) and then Black Vacuum Lines between the VRESER and lower ports on the TAB/TAD/EVR Solenoids. We have now ruled out an Emissions Manifold Vacuum Leak. With the engine off, locate the green vacuum line at the EVR (EGR Vacuum Regulator) located in front of the TAD and TAB Solenoids next to the coil. Attach a vacuum tester to the upper vacuum line and see if applied vacuum can operate and hold the EGR Diaphram. Disconnect the other end of the green vacuum line at the EGR. I you want, plug the end of the line with your finger and test again just to be sure. We have now ruled out the EGR vacuum line and EGR diaphram. If the line is good and the EGR is not holding vacuum, reattach the EGR vacuum line and remove the EVP (EGR Valve Postion Sensor) located on top of the EGR. The three attachment screws should not be loose causing an air leak. When removed, check the bottom of the EVP for an O-ring and if the position sensor pole can be moved up and down. Next, manually block the now open hole on top of the EGR with your hand and vacuum test again. We have now ruled out the mechanical portion of the EVP. Next, reinstall the EVP. With KOEO, check the unplugged harness connector with a DVOM for 5v reference voltage at pins VREF and SIG RTN. Then test the unplugged EVP Sensor for approximately 5000 ohms resistance at sensor pins VREF and EVP. Now apply 10 in. Hg. vacuum to the EGR. You should see a gradual decrease in resistance to approximately 100 ohms. If the vacuum, EGR and EVP test good, reconnect everything, except for the vacuum tester at the EGR and continue on. We have now ruled out the electrical portion of the EVP. Disconnect the harness connector to the IAC (Idle Air Controller) located on the side of the Throttle Body and start the engine. Start the engine and note that the idle should be lower than normal as the IAC is no longer in control. Apply vacuum to the EGR and watch for the engine idle to drop. Release the vacuum and the engine idle should return. If all is good, turn off the engine and reconnect the IAC and the green vacuum line to the EVR. Relocate the vacuum tester to the EGR end of the green line and connect using a "tee" between the vacuum line and the EGR. Start the engine and idle to warm. Idle vacuum from the EVR should be below 1 in. Hg. Now have someone raise the engine speed to 3500 rpm and observe the vacuum gauge for increase and the EGR Diaphram for movement. We have now ruled out the mechanical portion of the EVR. If the vacuum lines are good, next start KOER DTC Test with the Vacuum Hand Pump once again located at a "tee" at the EGR. While watching the vacuum gauge, observe for a change in vacuum and EGR Diaphram movement when the PCM activates the EGR during the test. If the test once again fails, either the EVR Solenoid is stuck or the there is a short to the EVR. Electrically test the EVR. The EVR has two connector pins. One to 12v battery power and the other to PCM Pin #33. Test the 12v to ground and the Signal wire to the PCM for continuity. Then you can mechanically test the EVR. The bottom port should hold vacuum and the upper port will not unless 12v are applied to the connector pins. Apply 12v, plug the lower port with your finger or cap and see if you can apply vacuum to the upper port. We have now ruled out the electrical portion of the EVR. If all is good at this point, start at the top of the page and look at the TPS link..." see EVP pin-out diagram & pics Source: by Seattle FSB (SeattleFSB)
I have been reading all these posts now for about 3 hrs. now and I'm still lost. ohms is 32 on evr, when I popped the top off it was pretty corroded, definitely oringinal from canada. can you tell me why it stalled out when I grounded the pin 33,is it a bad ground wire going to the connector. egr valve is a month old, I thought the first test was the evr and I don't read continuity when I test the ground wire. from what I have read that means there is a short in that wire, how can I trace the wire, where is it going? don't really understand the diagram. A real pic. of where the wire runs to would help. everything is so taped up it will take hrs. to unwrap everything. plenty of vacuum from the black hose but nothing from the top hose at 2500rpm. with no signal wire the evr is not working right, correct? first ford I have ever owned and I am lost, your help and patience is greatly appreciated.
unplugged iac valve and rpms dropped low, applied vac to the egr truck stalled. checked evp, it looked good, 4.9v when tested and 3300 ohms when tested, not sure if thats bad because of how far away from 5000 it is should it be replaced? applied vac to evp and the numbers went down.
BroncoJoe19
Active member
Does an accell tuneup include the use of motorcraft or Autolight sparkplugs?
Many ford engines puke if other plugs are used.
Did you change your plug wires?
Are they routed properly? Check miesk5 's site for more specifics.
Does a '95 have a MAF or MAP the MAF can be affected by an overly oiled
yo Pin 33 is EVR
The EEC outputs a duty cycle to the EVR that regulates vacuum level to the EGR Valve
With everything connected and the engine running ground out the pin 33 side. The EGR vavle should open and the engine RPM should change
The EEC outputs a duty cycle to the EVR that regulates vacuum level to the EGR Valve
With everything connected and the engine running ground out the pin 33 side. The EGR vavle should open and the engine RPM should change
the kit came with accel shorty plugs and yes the wires cap rotor and coil was replaced 9 months ago. as for the map or maf, I'm not seeing one, if it's attached to the air intake, i didn't remove one when I replaced it. Is that where it is located?.........miesk5 I thought I explained it twice when I mentioned I grounded out pin 33 and the truck stalled out. what I'm asking to see is where does the other end of that brown and pink wire go? an actual picture is what I'm looking for. does it go straight to the pcm, if so where is the pcm? from what I read it was supposed to be behind the driver front kick panel, but I don't see anything there.........
yo, my Comcast hiucupped again and I lost most of my edit reply
I enter some relevant info first and then click Reply in case Comcast drops conn; then I do an edit to add the rest of the info
this time, I took too long and lost the additional info for your Qs
EGR valve
Vacuum is not allowed to pass to the EGR valve until the engine is warm. "...The PCM will not operate the EGR valve unless it sees: 1. The engine warmed up to normal operating temperature. 2. TPS at partial throttle. 3. TPS not at Wide Open Throttle (WOT). 4. MAP/MAF must be indicating light or moderate load. 5. A certain amount of computer clock time has to be elapsed. If you can borrow or buy a relatively inexpensive Vacuum Gauge, it helps a lot and is one of best DIY repair tools and also a helpful way to improve MPG while driving if you get the so-called MPG type that has colored bands on the gauge that show by accelerating in a way that keeps the gauge pressure as high & as steady as possible.
Source: by miesk5 at Ford Bronco Zone Forums
Pin 33;
Red wire is constant 12 volts+ (batty voltage) to Splice 149 in Fuel charge harness, near Take/Out to air charge temperature (ACT) solenoid
BR/PK wire to EEC
Overview, Test & Pin-Out Depiction; "...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 valve should open and the engine RPM should change. Ford EGR valves will open 50% at 4 inHg of vacuum, and 100% at 8 inHg of vacuum. Possible causes: Damaged EVR regulator; Corroded or dirty connector; Damaged EGR valve; Faulty Vacuum system; Broken wire in harness; Grounded harness; Damaged Computer..." Read More
Source: by Ryan M (Fireguy50) at http://oldfuelinjection.com/index.php?p=43
disconnect the vacuum line going to the top of the EGR valve. There should be no vacuum there at this time. If there is then check for proper EVR (EGR vacuum regulator) operation and vacuum line routing. Repair and continue testing. Hook up your hand vacuum pump to the EGR valve and slowly apply a vacuum. If the EGR valve is functioning then the engine should begin to run poorly and stumble. If you apply full vacuum and notice no RPM change or can’t pull a vacuum at all, then check for a faulty diaphragm in the valve or a restriction of the EGR tube, exhaust or intake manifold EGR ports. I have run across many concerns where the EGR passages in the intake manifolds become plugged with carbon and prevent EGR flow, so try to keep this in mind during testing
When you did the Pin 33 ground test; the engine should begin to run poorly and stumble; and shut down
I enter some relevant info first and then click Reply in case Comcast drops conn; then I do an edit to add the rest of the info
this time, I took too long and lost the additional info for your Qs
EGR valve
Vacuum is not allowed to pass to the EGR valve until the engine is warm. "...The PCM will not operate the EGR valve unless it sees: 1. The engine warmed up to normal operating temperature. 2. TPS at partial throttle. 3. TPS not at Wide Open Throttle (WOT). 4. MAP/MAF must be indicating light or moderate load. 5. A certain amount of computer clock time has to be elapsed. If you can borrow or buy a relatively inexpensive Vacuum Gauge, it helps a lot and is one of best DIY repair tools and also a helpful way to improve MPG while driving if you get the so-called MPG type that has colored bands on the gauge that show by accelerating in a way that keeps the gauge pressure as high & as steady as possible.
Source: by miesk5 at Ford Bronco Zone Forums
Pin 33;
Red wire is constant 12 volts+ (batty voltage) to Splice 149 in Fuel charge harness, near Take/Out to air charge temperature (ACT) solenoid
BR/PK wire to EEC
Overview, Test & Pin-Out Depiction; "...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 valve should open and the engine RPM should change. Ford EGR valves will open 50% at 4 inHg of vacuum, and 100% at 8 inHg of vacuum. Possible causes: Damaged EVR regulator; Corroded or dirty connector; Damaged EGR valve; Faulty Vacuum system; Broken wire in harness; Grounded harness; Damaged Computer..." Read More
Source: by Ryan M (Fireguy50) at http://oldfuelinjection.com/index.php?p=43
disconnect the vacuum line going to the top of the EGR valve. There should be no vacuum there at this time. If there is then check for proper EVR (EGR vacuum regulator) operation and vacuum line routing. Repair and continue testing. Hook up your hand vacuum pump to the EGR valve and slowly apply a vacuum. If the EGR valve is functioning then the engine should begin to run poorly and stumble. If you apply full vacuum and notice no RPM change or can’t pull a vacuum at all, then check for a faulty diaphragm in the valve or a restriction of the EGR tube, exhaust or intake manifold EGR ports. I have run across many concerns where the EGR passages in the intake manifolds become plugged with carbon and prevent EGR flow, so try to keep this in mind during testing
When you did the Pin 33 ground test; the engine should begin to run poorly and stumble; and shut down
yo'
PCM = EEC or "computer"
It is located inside driver's kick panel, but connector is inside engine bay, Driver's Side on firewall below power brake booster
here is a pic of the connector attached to PCM
http://ylobronc.users.superford.org/projectbenjaminf-250/f250tiretofirewallclearance.jpg
another pic
PCM Removed
PCM = EEC or "computer"
It is located inside driver's kick panel, but connector is inside engine bay, Driver's Side on firewall below power brake booster
here is a pic of the connector attached to PCM
http://ylobronc.users.superford.org/projectbenjaminf-250/f250tiretofirewallclearance.jpg
another pic
PCM Removed
BR/PK to PCM via Connector C101
C101 Location in Engine Bay Diagram in a 94
Source: by Kenny B (Ken B, Kenny's 94)
C101 Location in Engine Bay Diagram in a 94
Source: by Kenny B (Ken B, Kenny's 94)
traced pink and brown wire all the way to the pcm plug and I had continuity, so that tells me it's the pcm! I have no problem replacing it unless someone else has anymore ideas. the pcm is not grounding that wire (pin 33) on the evr. there has to be more than that wrong to cause me the rough idle and vibration in the steering wheel, so maybe a new pcm will fix all of that? I'm tired of testing things, I just want it fixed. I tried to test the act sensor and when I pulled it out of the manifold and tested for ohms I had none, and it looked pretty bad. really dirty and this center pin looking thing was loose and bent. looking to put in an order to rockauto for most of the parts, any suggestions where to pick up the pcm. I can get a refurbinshed one for 160$, is there any place cheaper?
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