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Discussion Starter #1
I have been working on some emission codes for some time now. Ran the KOER Test and code 44 came up. The tech manual says to go to pinpoint Test KC1, which is the Air Management System (AM1/AM2)
I followed the following procedures and I am still stuck

KC1: Service Codes 44: Verify Vacuum Lines
Are lines are brand new silicone, so all checked good, EGR new and holds vaccum, Vapor Canister (Coffee Can) new. So Vaccuum is good with all lines leading to and from Air Management System.
If good go to KC4

KC4: Enter Output State Check:
Connect DVOM neg test lead to STO circuit and pos test lead to batt pos
perform KEEO, DVOM will indicate 0 volts when TEST done
Depress and release throttle
Did DVOM change to a high voltage? YES go to KC5

KC5: Check AM1/AM2 solenoid electrical operation
Disconnect Harness at solenoid
Pos test lead to VPWR circuit and neg test lead to AM1 circuit on harness conector
Press and release throttle several times
Repeat for AM1
Does both solenoids cycle On and Off? AM 1 goes from 10.86 to 11.62 and AM2 goes from 10.55 to 11.56 So I would say this is a YES. Go to KC6

K6 Check AM1/AM2 for vacuum cycling
Install Vacuum pump on AM 1 supply port and vacuum gauge to output port
Cycle outputs On and Off by depressing and releasing throttle
Note: Maintain Vacuum
Repeat for AM2
Do both vacuum outputs cycle on and off? Both cycled with decrease in pressure each time throttle was depressed at supply port and increased at output. I think it jumped about 10-15ish PSI did not write it down. So I said YES, Go to KC7

KC7 Check manifold vacuum lines for blockage or leaks
Vacuum lines disconnected at AM1/AM2
Start engine
Check for vacuum ( I am guessing the output side?)
Is vacuum present? Had Vacuum from output on AM1, none on AM2, if NO service vacuum source blockage.

But all the lines are fine and I was able to cycle vacuum through AM 2 from test K6.
So what am I missing?

Just to double check a few things voltage to AM1 and AM 2 is greater than 10.5V so its getting power.
I measured solenoid resistance for both (77 ohms) spec just needs 51-100 ohms so Good.
Vacuum lines good and it holds a vacuum and cycles.

So again what am I missing here?
 

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Hi @First89Bronco
i've used some silicone lines in the past for vacuum only to later find that the walls are not strong enough to hold pressure (I guess negative pressure) and they collapse on themselves.
i know it's a pain but it might be work putting a gauge on each line to ensure the lines are holding pressure.
 

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Discussion Starter #3
92Broncoboy,

Did that already they are holding a vacuum. I got the lines from silicone intake, walls are pretty thick, designed not to collapse.
 

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if all of the vacuum and thermactor lines are good, your only option is electro-mechanical - so either the solenoids are not responding to signals to open/close or they're not receiving those signals.
 

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Discussion Starter #5
What other tests can I run besides what I already did to see if its something not sending the signal to the AM1 or AM2?
 

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What other tests can I run besides what I already did to see if its something not sending the signal to the AM1 or AM2?
Yo First89Bronco,

RE,
KC7 Check manifold vacuum lines for blockage or leaks
Vacuum lines disconnected at AM1/AM2
Start engine
Check for vacuum ( I am guessing the output side?)
I believe it means checking vacuum lines from Vacuum tree to and through vacuum cannister to TAD & TAB Solenoids,
Is vacuum present? Had Vacuum from output on AM1, none on AM2, if NO service vacuum source blockage.

I assume you checked vacuum with engine cold through normal operating temperature.
What is the vacuum reading?

I just replaced TAD Solenoid in our 96, bought new, Last year I replaced TAB Solenoid. Both were original.
 

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Discussion Starter #7
Miesk5,
I will get you the vacuum numbers here in a few. Trouble shooting AC/Heat blower switch right now. Found this when I pulled apart the pigtail from the switch.
20200322_164001.jpg


Looks like the the ground wire is the one that shorted. Tested continuity/ resistance through all wires all good.
Have to find the ground G701 that is somewhere in behind the console. Checking the resistor for continuity now, will test blower then will do drop test on blower switch (using jumper wire) to blower. Any idea what the resistance specs are for the resistor?
155679
155680
155681
 

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Yo,
That could have started fire!
G701 also serves heater control bulbs, ashtray lamp,instrument cluster, tailgate window motor, etc. So if others components list are ok...
 

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Discussion Starter #9
Miesk5,

O I know. If you want me to start a new thread for the blower motor switch let me know.

So back to ENG Code 44 then follow up with Blower Motor.
ENG Code 44: Vacuum 18 psi from Vacuum Tree to EVR. Vacuum from EVR to EGR did not register on gauge, starts at 5 psi. When I goosed the throttle vacuum gauge flicked. Pulled Vacuum at EGR and started to sputter, released vacuum went back to normal idle (replaced EGR a month ago). So with the trouble shooting from first post and double checking vacuum whats next? I hate swapping parts for the sake of swapping parts.

Break, Break, Break
Blower Motor Issue:
Trouble shooting done so far:
Resistor has continuity across all connectors that are used for the blower switch
Good power from fuse box to Resistor: Engine running 14.80 - 14.76 (jumping around a bite)
By passed the resistor by jumping the harness terminal, while jumping the wires for the blower switch. Blower worked as advertised.
So while still by jumping the resistor terminal and jumping the blower switch I did a voltage drop test on the blower. Ran the voltmeter from the power side of terminal to power side of blower motor. Ran a jumper wire from ground side of terminal to ground side of blower motor. I could never get the blower to turn on.

Outputs from each test of different blower motor speeds:
Low - 14.8-14.78 Volts / 1.10 amps
M1 - 14.9 -14.7 / 0.4-0.3 amps
M2 - 14.9 -14.7 / 0.4-0.3 amps
High - 14.84 / 0.9 - 0.6 amps

Again Blower never turned on.
So I went back to have terminal connected to blower motor and by passing resistor, never got the motor to turn even though it worked in the first test???

Since the blower motor switch terminal was melted I believe to be the ground wire (see picture from previous post) and it just suddenly stopped working I am thinking a ground wire issue.
Picture of ground wire for blower motor switch

155684



Blower motor terminal: The power side seems a little worse for ware, not sure how that helps identify the blower motor switch problem. Also because it has some scaring on it do I need to replace the blower motor?
155685
 

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Discussion Starter #10
If anyone has any input let me know. I am almost done with pulling my entire dash looking for the ground C701 (behind center console). I have to just disconnect some wireharness on the back side. I found a ground but it was about a 22g red/white wire?

Any pictures or suggestions for ENG Code 44 or the dang short I am trying to find with my blower switch/resistor/blower motor.
 

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Yo First,
Bill once wrote, "The ground wire is grounded at G701 and is located behind the I/P at the center. It is not grounded to the frame as the frame may or may not be a ground. It is grounded to the body." That's all I have found over many years.

G701 Ground wire is shown as black in attached 89 wiring diagrams;
155815

155816

155817

I don't have resistor ohms, lost them in another forum when they "upgraded" recently. Will try to find info.

ANY LEAVES found in resistor area etc?
●□●

DTC 44 (KOER); AIR system inoperative – Air Injection; "...I had a similar issue that turned out to be the vacuum line to the Thermactor Air Bypass Valve. No CEL, just a code; 1. First check that the two vacuum lines are connected to the Vacuum Reservoir (coffee can) and the resevoir is in good repair with no leaks on the bottom. Frequently the can leaks or the vacuum lines are accidentally knocked off. Check the vacuum hose to the bottom of the TAB (Bypass) Valve. Check the vacuum hose to the TAD ( Diverter) Valve. Check the vacuum hoses to the TAB/TAD Solenoids. Then check your TAB/TAD Solenoids.
Then check your TAB/TAD Solenoids. These are common easy to miss problems. Once these are ruled out all that is left is: Thermactor Air Supply Hoses. One-way Check Valves. Main TAB/TAD Valves..."*
I

Source: by SeattleFSB

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. I'd rather climb up using plans, ala a scaffolding type set-up; maybe remove hood depending on circumstances such as me now, w/ backache..."

&
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. Note that my Pink Vacuum line appears Yellowish in this pic and is not yet connected to the base of the TAB Valve as I was working up a solution at the time.

&
Test; Key off. Disconnect both TAB/TAD Solenoid connectors and measure both solenoid resistances. each resistance should be between 50 and 100 ohms.

Source: by SeattleFSB

Pump Test; "...
1.Check and, if necessary, adjust the belt tension. Press at the mid-point of the belt's longest straight run. You should be able to depress the belt about 1/2 in. (13mm) at most.
2.Run the engine to normal operating temperature and let it idle.*
miesk5 note, beware of fan blades, belts, pulleys, hot engine, etc.
3.Disconnect the air supply hose from the bypass control valve. If the pump is operating properly, airflow should be felt at the pump outlet. The flow should increase as you increase the engine speed. The pump is not serviceable and should be replaced if it is not functioning properly..." by Ford


Try my vac leak test @ https://www.fullsizebronco.com/forum/21-noobie-bronco-tech-questions-flame-free-zone/206824-help-dtc-codes-idle.html?highlight=Vacuum+Leak+Test;+idling
post #11

One tip in it is, 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.
 

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Discussion Starter #12
Miesk5,

Well I got the dash off and I am tracing the black ground a see where it goes.
155819


I did not find anything behind the center if the Instrument Panel. This is the only thing I have found:

Right next to the fuse box. I think its G502
155820



Then this wire on the left hand side of the radio (as you are looking at it) its red/wht not sure where it goes.
155821


Pulling apart the wire harness to see where the ground for the blower switch goes and that Red/White.

CODE 44 will have to wait for a bit.
 

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Discussion Starter #13
Quick update, the red is the ground G119 for the radio, electric schematic even shows red, I just missed it.

I did a quick continuity test on the blower switch ground to the one I found next to the fuse box G502, it read 0.3 ohms.

I still cannot find the original culprit G701 or G209 Center DASH, G703 Steering column, G710 LG side of Dash
 

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Yo First89Bronco,
All I have found that has a mouse hair's more than what you have is:
G209 forward of RH side of dash panel.

Will try internet searches later, need to work on our 96... squirrels again!
 

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Discussion Starter #15 (Edited)
Miesk5,

So when the tech manual says G701 is center of the IP, I intuitively thought it was a black wire with an eye terminal that is crewed into some metal, the same with the other grounds. But after starting at the ground wire which I am calling G710 (LH side of dash panel), that is right by the fuse box see pervious picture. I started following it to where ever it may lead and this is what I found.
In the main wire harness directly behind the Instrument Panel.
155915


That goes the grounds for the items in the instrument cluster (tachometer, fuel guage etc..) then it goes for the accessories below it. (check engine light, high beams etc) also for the back window switch, wipers etc.. And some other items like the door chime, IMS, ABS

But I didn't stop their, I kept going then right above the a/c, heater controls and radio, again bundled in the main wire harness. I found this.

155916


This goes to everything else that is on G701, per the wire diagram. So long story short all the grounds in the front of my cabin lead back to this one eye terminal.
155917


I hope this keeps someone else from trying to find the infamous G701 in the future.

Once I get my steering column put together I will to voltage drops on the parts to see if I have a stray voltage somewhere, not that I know where all the grounds lead to. Then since I have my dash off, I will test the vaccum motors and lines I have a problem with the doors closing properly.

Does anyone have any other things to look for since the dash is off?

On that note does anyone know of any good youtube videos on how to correctly re-wrap a wire harness and brand of tape to re-wrap everthing? I hear electrical tape is NOT the way to go .

I have seen a few posts on people looking for grounds in the cabin, so I will re-post this as G701 hunt, so it does not get buried in ENG Code 44 search.
 

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Yo,
Good hunting! Your determination and findings will nomdoubt help many others!!!

A good you tube is @

See some Wiring Harness Repair Tips in a 79 by Kevin M (Project Double Agent) @ Project Code Name "Double Agent"
Kevin shows and refers to "...the method to protect the harnesses was in the form of a mesh tube made from some sort of cotton like material. It was porous and did not protect the wires all that good ... Then I wrapped the entire harness with a special non-adhesive harness tape. This tape is specifically made for wiring harnesses and when stretched, it will stick to itself and hold tight."

Consider WRAP TAPE, WIRE HARNESS, 1 1/4 INCH, NON-ADHESIVE, ORIGINAL TAPE USED TO WRAP WIRING HARNESSES, TERMINATE WITH 913-4 @ WRAP TAPE WIRE HARNESS 1 1/4 INCH NON-ADHESIVE - #913-2 - National Parts Depot

913-4 is @ Product Search - National Parts Depot

automotive spiral cable wrap and instructions @ How Should Spiral Wrap Be Applied?

More harness items @ Products - Zippertubing Co.
 
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