Getting the 86 4.9 back on the road.

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Mitch925

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Hi guys,
I am trying to get my 86 bronco Custom with the Feed Back 4.9ltr to pass smog here in California. It doesn’t have A/C and it has a manual 4 speed granny low. My issue right now, lol, is the EGR solenoid is always open when the key is on. What I mean by that is with the key off the solenoid is not applying vacuum to the EGR. Once I turn on the key. The red wire to the solenoid gets 12.5 volts and the green wire to the solenoid gets .72 volts. How I am testing this, is by taking the volt meter to the negative on the battery and then taking it across the engine to the solenoid plugs. What should the voltage be on each of those wires at cold temps and also at operating temps? I am starting to suspect the computer is bad. On my solenoid pack, there is just three solenoids. The other two solenoids are getting 12.5 volts on all the wires. Thanks again in advance.

-Mitchell
 

miesk5

96 Bronco 5.0
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Yo Mitch,
Welcome to our site!

For now here is some EGR System testing until I can return bere as soon as high winds ease down and my internet cable stays on.

EVR Testing, Ford; "....check the filter on the solenoid (Fig. 4, EVR filter shown). If this is clogged it will inhibit the venting of the solenoid; "...EVR Solenoids should be 20 to 70 ohms (100 to 135 ohms for 7.5L engines). A functional test can be performed on most applications by using a Scan Tool. Enter the Output State check and cycle the accelerator pedal. This will turn all the solenoids on and off. Using a DVOM monitor the voltage at the EGR solenoid(s). They should toggle from a high voltage to a low voltage. Typically this is stated in the manuals and scan tools as above 10.5 volts to below 2 volts. If the voltage does not toggle make sure that you have system voltage on the power side of the connector. If system voltage is present and the voltage does not cycle to the low side check the connector and wiring to the PCM. If the wiring and connector are okay the problem may be in the pin at the PCM or the driver in the computer itself..." READ MUCH MORE by Tomco.

See my vacuum leak test in post #11
Excerpts;
When vacuum leaks are indicated, search out and correct the condition. Excess air leaking into the system will upset the fuel mixture and cause conditions such as rough idle, missing on acceleration, or burned valves. If the leak exists in an accessory unit, such as the power brake, the unit will not function correctly. Or Air Conditioning when in MAX mode may switch to Defrost.

FYI, here is some 86 info;
1986 Ford Bronco Sales Brochure

GcSBFc78Z6Fx03RCIWqniHzSdnNgWYR3Wc9FRVWD0_1N_prO&s.jpg


1986 EVTM - Gary's Garagemahal (the Bullnose bible) by Ford via Gary

1985-1986 Fuel System Adjustments by Ford via Gary

1986 Bronco Operating Guide by Ford via Gary @ 1983 Ford Bronco Manuals & Pamphlets (Scanned) picture | SuperMotors.net

1986 Owner Guide by Ford via Gary

1986 Exterior Colors by Ford via Gary

1986 Bronco Accessories Catalog by Ford via Gary. @ 1986 Ford Light Truck Accessories Brochure

1980-86 Pickup Fasteners by Ford via Gary, but mostly for front clip

1986 Bronco Rapid Specs Guide by Ford via Gary @ 1986 Ford Light Truck Accessories Brochure

1986 Color & Trim Selection Options by Ford via Gary

Haynes Red Manual for 80-95 Bronco & F Series @ Hanes guide 80-96 bko f series.pdf via
BroncMom

See my mostly recovered site by member schwim @ Ford Bronco And F-150 Links - FORD BRONCO
It contains boo-koo component repairs, installation & parts sources

See this Index of /Bronco/Projects in an 86 by my friend Chris B @ http://chrisb.users.superford.org/Bronco/Projects/
Al
 
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Mitch925

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Location
Brentwood, CA
Yo Mitch,
Welcome to our site!

For now here is some EGR System testing until I can return bere as soon as high winds ease down and my internet cable stays on.

EVR Testing, Ford; "....check the filter on the solenoid (Fig. 4, EVR filter shown). If this is clogged it will inhibit the venting of the solenoid; "...EVR Solenoids should be 20 to 70 ohms (100 to 135 ohms for 7.5L engines). A functional test can be performed on most applications by using a Scan Tool. Enter the Output State check and cycle the accelerator pedal. This will turn all the solenoids on and off. Using a DVOM monitor the voltage at the EGR solenoid(s). They should toggle from a high voltage to a low voltage. Typically this is stated in the manuals and scan tools as above 10.5 volts to below 2 volts. If the voltage does not toggle make sure that you have system voltage on the power side of the connector. If system voltage is present and the voltage does not cycle to the low side check the connector and wiring to the PCM. If the wiring and connector are okay the problem may be in the pin at the PCM or the driver in the computer itself..." READ MUCH MORE by Tomco.

See my vacuum leak test in post #11
Excerpts;
When vacuum leaks are indicated, search out and correct the condition. Excess air leaking into the system will upset the fuel mixture and cause conditions such as rough idle, missing on acceleration, or burned valves. If the leak exists in an accessory unit, such as the power brake, the unit will not function correctly. Or Air Conditioning when in MAX mode may switch to Defrost.

FYI, here is some 86 info;
1986 Ford Bronco Sales Brochure

View attachment 31056


1986 EVTM - Gary's Garagemahal (the Bullnose bible) by Ford via Gary

1985-1986 Fuel System Adjustments by Ford via Gary

1986 Bronco Operating Guide by Ford via Gary @ 1983 Ford Bronco Manuals & Pamphlets (Scanned) picture | SuperMotors.net

1986 Owner Guide by Ford via Gary

1986 Exterior Colors by Ford via Gary

1986 Bronco Accessories Catalog by Ford via Gary. @ 1986 Ford Light Truck Accessories Brochure

1980-86 Pickup Fasteners by Ford via Gary, but mostly for front clip

1986 Bronco Rapid Specs Guide by Ford via Gary @ 1986 Ford Light Truck Accessories Brochure

1986 Color & Trim Selection Options by Ford via Gary

Haynes Red Manual for 80-95 Bronco & F Series @ Hanes guide 80-96 bko f series.pdf via
BroncMom

See my mostly recovered site by member schwim @ Ford Bronco And F-150 Links - FORD BRONCO
It contains boo-koo component repairs, installation & parts sources

See this Index of /Bronco/Projects in an 86 by my friend Chris B @ http://chrisb.users.superford.org/Bronco/Projects/
Al

Thank you for the information.
 

miesk5

96 Bronco 5.0
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L\Bronco

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Hey Mitch, welcome to the zone!
Your EGR solenoid should have batt voltage on both pins when it is off and it should be off with the key on and engine off.
The test miesk5 is referring to is called the output state test. It is done by initiating a key on engine off self test and waiting till the last memory code is done flashing on the check engine\emissions lamp. you will have a few seconds to start the output state test by cycling the throttle from closed to WOT and back. once initiated, everytime you cycle the throttle, the outputs (all of them) will change from off to on or the other way around depending on where you start. Just measure the voltage on the solenoid wires before and after cycling the throttle.
When the solenoid is off you should see 12v on both wires and when its on you should see 12 on one and very low to zero on the other.
If you always see 12 on one and low on the other. turn off the key, wait 30 seconds, disconnect the PCM. Turn the key back on, and retest voltage.
If you see 12 and 12, the PCM is faulty, if you still see 12 and low, the control wire is shorted to ground.
Hope that helps
Cheers
 
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Mitch925

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Hey Mitch, welcome to the zone!
Your EGR solenoid should have batt voltage on both pins when it is off and it should be off with the key on and engine off.
The test miesk5 is referring to is called the output state test. It is done by initiating a key on engine off self test and waiting till the last memory code is done flashing on the check engine\emissions lamp. you will have a few seconds to start the output state test by cycling the throttle from closed to WOT and back. once initiated, everytime you cycle the throttle, the outputs (all of them) will change from off to on or the other way around depending on where you start. Just measure the voltage on the solenoid wires before and after cycling the throttle.
When the solenoid is off you should see 12v on both wires and when its on you should see 12 on one and very low to zero on the other.
If you always see 12 on one and low on the other. turn off the key, wait 30 seconds, disconnect the PCM. Turn the key back on, and retest voltage.
If you see 12 and 12, the PCM is faulty, if you still see 12 and low, the control wire is shorted to ground.
Hope that helps
Cheers

This is very helpful. I will try this, this weekend.
 
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Mitch925

New member
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Feb 22, 2023
Messages
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Location
Brentwood, CA
Hey Mitch, welcome to the zone!
Your EGR solenoid should have batt voltage on both pins when it is off and it should be off with the key on and engine off.
The test miesk5 is referring to is called the output state test. It is done by initiating a key on engine off self test and waiting till the last memory code is done flashing on the check engine\emissions lamp. you will have a few seconds to start the output state test by cycling the throttle from closed to WOT and back. once initiated, everytime you cycle the throttle, the outputs (all of them) will change from off to on or the other way around depending on where you start. Just measure the voltage on the solenoid wires before and after cycling the throttle.
When the solenoid is off you should see 12v on both wires and when its on you should see 12 on one and very low to zero on the other.
If you always see 12 on one and low on the other. turn off the key, wait 30 seconds, disconnect the PCM. Turn the key back on, and retest voltage.
If you see 12 and 12, the PCM is faulty, if you still see 12 and low, the control wire is shorted to ground.
Hope that helps
Cheers

I have been pretty busy on this thing. Did a lot of trouble shooting. My truck is running super lean until I unplug the egr. I disabled the egr and installed a vacuum gauge and drop around. At idle I am not getting any vacuum. Once under load the vacuum starts to climb and leaks at about 15in of vacuum. Then falls off when I shift or apply the clutch. I am wondering if I have the wrong orifice in the egr which is allowing too much air in and is causing my lean problem. Would you happen to know what size orifice I need? My specific truck is a 1986 custom manual trans, no AC, California emissions.
Thanks again for any response.
 

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