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89 5.0L engine wiring diagram

51K views 61 replies 4 participants last post by  wrenchhead427 
#1 ·
Working on a friend of mines 89 5.0L and I have been searching the forums and can't find a schematic for the coolant sensor wire color and the oil sending unit wire color. I am sure steve83 has it on has site but I cant figure out how to get around to it, can someone direct me here a little bit, Thanks guys.
 
#2 ·
You can't figure out how to get TO my pictures, or you can't figure out how to find the relevant ones? Click my black Bronco in my signature & scroll through the album list to find the MOST-applicable one. If you don't find what you need there, try another album.

Almost everything related to gauges is in this album:



But Ford always uses R/W for temperature & W/R for oil pressure. Tell your friend to buy a red-cover Haynes:

 
#3 ·
Thank you

Thank you Steve! I couldn't find a link to take me to the info you have in all those folders listed as when It did after I clicked on the black bronco in your sig. That is what I was looking for, I was unsure of the navigatrion means to reach the info, thank you. I tried so many searches but didn't ever see something that I recognized.
 
#5 ·


Here is a diagram I found in Steve83's registry, hopefully it will help you with your TPS issues. I think code 77 is a goose test code correct?

As for my wiring problems, I have searched for the oil pressure sending unit wire, temp sensor (single wire) wire and the Tachometer wire going into the coil and no luck, I'm stuck. I need some help. I have a Yellow/Red stub sticking out of my loom close to the #5 Injector and a White/ "dotted or dashed" Red wire coming out of the loom above the drivers frame rail in the Oil Pressure sending unit area. There is also a veru small stub of a red wire in the same area. I took a pic also of the four main harnesses that I was hoping to see the R/W and W/R wires I'm looking for in but they are not in the bundles. As for the Tach wire, I see no DG/Y wires which from what I have found on the site is what I'm looking for.... Still working on the Vacuum lines and a couple funky grounds that just don't look right. I have provided some pictures of my dealings with the said items, Thanks!
 

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#7 ·
Are you reading what you're typing?
...I have searched for the oil pressure sending unit wire, temp sensor (single wire) wire and the Tachometer wire going into the coil and no luck... I have ...a White/ "dotted or dashed" Red wire coming out of the loom above the drivers frame rail in the Oil Pressure sending unit area. There is also a veru small stub of a red wire in the same area.
You say you can't find the R/W or W/R wires, and the next thing you say is that you have a W/R wire and a R wire. :shrug Did you peel back the harness wrap to see if there's a W stripe on that R wire?
I see no DG/Y wires...
That's odd - I see one at least 4x in 3 of your pics. :wowcb: Behind the LHR compressor bolt right next to that stub of a R wire, and again going into the Br connector.

But based on the colors of the burned, frayed, exposed wires going to that coil & RFI capacitor, I don't think the DG/Y is gonna be your tach feed.
i am new to the site...
Start by reading this caption, filling in your profile, and creating a signature with your truck's details:



You already know how to find my diagrams album, so look through it. If you still can't find what you need, search for old threads similar to your issue, and read them. If that doesn't solve it, start your own thread.
 
#8 ·
I apologize, I do not mean to be confusing. I am looking for a Red wire with a white tracer - R/W , or a White wire with a red tracer - W/R for the oil pressure sending unit wire. The White wire i am speaking of does not have a solid red tracer, it has a broken red tracer (hope that makes sense). I have examined the red wire stub and it is a red wire, no white tracer.

Again i am sorry for not being clear, I meant to say that I am not seeing a DG/Y wire any where in the neighborhood of the coil. I am looking for a DG/Y based on this diagram I found on the site, first picture below. The diagram I found in your pictures also implied that it would be a DG/Y wire.

This bronco has a replacement Vin tag in the door jamb and no factory sticker. The replacement tag VIN matches the dash VIN so I am assuming it is indeed an 89, however the front clip is rounded, unlike my semi square 90 Bronco. Maybe it is a newer truck, I will go back and look in your pictures for a diagram covering the newer vehicles. thanks
 

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#9 ·
okay I made some progress this morning with a fresh mind and daylight. The loom with the gray terminal end 8 pin that goes to the dizzy and coil I believe to be from a different vehicle possibly. I think this would account for the different color wiring going to the coil. On my 90 the O/P and W/T are also in this loom so I am starting to see why I can't find R/W and W/R. Anyone have an idea of what ford vehicle had R/G going to the coil along with a T/Y as in my above pics?
 
#10 ·
It doesn't matter. Find the wires at your instrument cluster going to those gauges, and note their colors. Find them at the big round firewall connector, and note their positions. Find them on the other side (in the engine bay), and note their colors. Find them at the engine connectors and note any change in color. Follow them thru the harness to the engine or cut ends.

And it doesn't matter if the tracer is broken, solid, dotted, or anything else - W/R is W/R is W/R.
 
#11 ·
Alright, so I have hooked up my oil pressure wire to the gauge, coolant temp sensor to the stock gauge and Tach wire. Coolant is good to go, aftermarket gauge installed also and the two are reading the same. Now my first new problem, my oil pressure is pegged out on HIGH. I disconnected the sender wire from the sender and took a voltage reading with key on, 5.5-6v . I shut the key off and checked for continuity between wire terminal end and ground and I'm around 41k ohms. Trying to find refrences for help. Should I have continuity or should it be open? I was thinking open but what do I know.


The second new problem is the Tachometer is jumpy, reads fairly correct at idle but jumps at the first small rpm increase to 3-4K and is all over the place.

Took it for a test drive and no speedometer...... lots a problems, crawled underneath and speedo cable is hanging by frame rail, next to the transfercase plug.....which is disconnected:rockon Hey if your gonna start ripping crap apart go for it I guess!!! So my saga continues, oh yeah I almost forgot, the brand new tranny wont shift out of first!!!! LOVIN IT:doh0715:
 
#13 ·
Steve's the man, had to say it. I read what you told me and clicked farther into the sub pictures this time to find the additional info I missed the first time I went through that section, sorry again I don't mean to be a pain or waste your time. So now that I have a basic working knowledge of the Oil Pressure gauge, I have a hypothetical question because I don't truley understand the mechanical functioning of the magnetic's and all. If you installed a jumper wire across the resistor, wherever that may be, while you still had the original sender in the block, what would the gauge do when you started the motor?
 
#14 ·
Found this

On the other hand, installing the open/closed switch on a vehicle that incorporates the conventional oil pressure gauge circuit will result in a pegged gauge needle after starting the engine. Sometimes you can tell that you need a switch instead of the variable resistive sending unit by the presence of the in-line resistor a few inches from the switch connector. This is not a good rule of thumb though, since many vehicles have the fixed resistor on the back of the cluster, and some of the digital dashes have that circuit built into the cluster. To determine what style circuit you have, simply ground the sending unit wire with the key on. If the gauge reads exactly half-scale, you can be fairly sure you need a switch-style sender. If you ground the sender wire and the gauge pegs, a variable resistor-style sender is needed..."
,

This makes sense to me, My gauge is pegged when I ground it out or hook it up. I believe the resistor must have been in the factory loom that someone removed and replaced with the loom that is lacking the R/W and W/R, hence the confusion. Sweet! Hope the quote comes out okay, not really sure how to do it but I tried.
 
#17 ·
Resistor on my gauges



Yes I see those pictures, but mine doesn't have one on it, the bronco I'm working on is an 89, in your commentaries on the pictures you wrote:

"Afterward, a wire must be installed across the oil pressure resistor. I'm not sure where the '87-91 resistor is, so it may be necessary to overlay a wire onto the harness from the switch connector at the engine all the way to the instrument cluster. On '92-96, the resistor is on the instrument cluster film circuit. I normally make the jumper wire long enough to hang down below the cluster so it can be cut if a future owner chooses to convert back to the original switch & have an idiot-gauge again.."

After reading miesk5"s information about the gauges, I believe that the resistor for an 89 is in the wiring loom in the engine compartment. Since the loom has been replaced on this truck with the incorrect loom from another vehicle that does not have a resistor, it seems to be mimicking what would occur with the installation of the jumper wire. I am going to go down to Home Depot today and get the plumbing to install the old school O/P sender and hook it up. If my gauge reads properly then I'll be done with this portion of the repairs, if not I will try and figure out what is wrong from that point, I am not really sure what else to do.

This is my gauge:
 

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#16 ·
yo,
I have some 89 wiring diagram Links in my site @ http://www.broncolinks.com/index.php?index=143
go there for hot Links to;
Ignition Wiring Diagrams in an 89 from Ford EVTM
Source: by Seabronc (Rosie, Fred W) at Ford Bronco Zone Forums

Ignition, Emission, EFI, Sensors, Fuel Level Sender & Pump, etc. in Electrical and Vacuum Troubleshooting Manual (EVTM) Partial, Wiring Diagrams in an 89 by SeattleFSB (Seattle FSB) at SuperMotors.net

Oxygen (O2) Sensor Wiring Diagram in an 89 5.0, 5.8 & 7.5. Diagram #2
Source: by Seabronc (Rosie, Fred W) at Ford Bronco Zone Forums

EEC Ground Location pic in an 89 by Will H (kf4amu, The Beast) at SuperMotors.net

EEC Power Relay Wiring Diagram in an 89
Source: by SeattleFSB (Seattle FSB) at SuperMotors.net

EEC Power Relay Wiring Diagram in an 89 5.0, 5.8 & 7.5
Source: by Seabronc (Rosie, Fred W) at Ford Bronco Zone Forums

EGR Vacuum Regulator (EVR), Thermactor Air Bypass (TAB) Solenoid (AIRB) & Thermactor Air Diverter (TAD) Solenoid (AIRD) Wiring Diagram in an 89 5.0, 5.8 & 7.5. Diagram #2
Source: by Seabronc (Rosie, Fred W) at Ford Bronco Zone Forums

Fuel Pump Relay Wiring Diagram in an 89
Source: by SeattleFSB (Seattle FSB) at SuperMotors.net

Fuel Pump Relay Wiring Diagram in an 89 5.0, 5.8 & 7.5
Source: by Seabronc (Rosie, Fred W) at Ford Bronco Zone Forums


Fusible Link: A-Brown 18ga to Rear Window Defroster; W-Blue 20g to Fuel Pump Relay; N-Blue 20g to EEC Power Relay; F-Blue 20ga to Trailer; Y-Blue 20ga to N.C.; L-Brown 18ga to ?; M-Brown 18ga to ?;G-Blue 20g to Exterior Lamps, Trailer; P-Blue 20ga to ?; & J-Green 14ga to Alternator as shown in Wiring Diagram in an 89
Source: by Seabronc (Rosie, Fred W) at Ford Bronco Zone Forums
 
#18 ·
Have you tested the terminals on the back of the cluster that supply power & ground to the oil gauge with the key in RUN? If they're good but a new old sender still doesn't make it work, overlay a new wire from the sender to the gauge. If it still doesn't work, the gauge is bad.
 
#19 · (Edited)
Progress....

Hey Steve! thanks for the suggestion! I didn't see it till I did a bunch more to the truck. I just got back from running around today and picking up parts for the bronco. I installed a new VSS, and installed the 1/4" X 4" galvy pipe and coupler, was bummed out that they didn't have a 45 degree fitting to help angle the sender upward and help clear the P/S pump outlet and oil filter but what do you do:shrug. It fits but is slightly touching the outlet of the pump, good enough for now. I put the gauges back in, and can't remember if I mentioned the bulb was pulled out for the CEL:smilie_slap and fired it up......:rockon we have oil pressure!!! and the Tachometer stopped freaking out on me and is now nice and stable, it rips around fully on start-up but then returns to normal, again good for now. I'm stoked things are coming around!!

Took it for another test drive and was hoping that it would shift but no luck still stuck in first. On a good note I do have a functioning speedometer now, so all the gauges are functioning properly. I had pulled the codes last night after I fixed the CEL and got a few, they remained the same after todays test drive so I'm dealing with them now. codes are as follows:

KOEO -
54 oc ACT indicated -40�C (-40�F)/circuit open
81 o Air Management 2 (AM2/TAD) circuit failure
82 o Air Management 1 (AM1/TAB) circuit failure

CM-
54 oc ACT indicated -40�C (-40�F)/circuit open
29 c Insufficient Vehicle Speed Signal (VSS) input

KOER-
98 r Hard fault present
54 oc ACT indicated -40�C (-40�F)/circuit open

I looked them all up and wrote them down. I am wondering if I should reset the computer and see what comes back or is that a bad idea? Also I understand the KOEO and CM tests but during the KOER test does the computer require any driver input? I didn't seem to find anything indicating it did so I wanted to verify. Also at the end of the KOER test the RPM bucks and then the CEL comes on steady and remains on, is that all normal? Thanks again!
 
#20 ·
There is no "reset". And you shouldn't clear adaptions unless there's a DAMNED good reason - just clear the codes. But when you post codes, post the COMPLETE definition for each one so we don't have to re-look them up after you already did. Click this, read the whole caption, and follow the link to the complete procedure:

 
#21 ·
So after reading what you have instructed me to do so, I corrected my prior post to include definition of the codes.

First when you say "clear adaptations" I am assuming you mean disconnecting the battery completely for five minutes. When you say " just clear the codes" that would mean in my case removing my paper clip jumper in my EEC-IV test terminals during my KOEO test, this I will do this morning.

I am going to test my resistance of my IAT/ACT-7 to 13 ohms, and take a reading from cold start to operating temp for voltage decrease verification.

Don't know where to start with the other codes so I'm going to start by "clearing " them and seeing if anything comes back during my IAT/ACT test.

Thanks for the guidance!
 
#22 ·
yo, Some info for now;
DTC 54; the Intake Air Temp (IAT), (Air Charge Temperature [ACT] prior to 1992)
Source: by miesk5 at Ford Bronco Zone ForumsOverview & Testing; "...
The ambient temperature should be above 50�F (10�C) to receive acceptable input from the Air Charge Temperature (ACT) sensor during the KOEO and KOER Self-Test. To accomplish this, the engine should be at normal operating temperature.


This measures the temperature of the air entering the engine. Which impacts the fuel ratio; the cooler the incoming air is the denser it is. Denser air can utilize more fuel, giving us even greater accuracy in obtaining our desired air to fuel ratio. Before you start blaming the air charge temperature sensor and replacing it make sure the rest of the coolant system is in good condition. All of the following items will affect the ACT; Coolant level, Radiator Fan, Engine Temperature, and more; Values were calculated for VREF=5.0 volts.These values may vary 15 percent due to
sensor and VREF variations
..." READ MORE
Source: by Ryan M (Fireguy50) at http://oldfuelinjection.com/?p=29


Symptoms; Check Engine light is on continuously, hesitation, poor mileage or rich exhaust odor, poor performance and economy. Inspect for damage or corrosion on terminals. Check sensor for carbon accumulation or contaminants which can cause false readings.


-----------
In following Pin-Point Testing, where Breakout Box is cited; go to the EEC IV Pin instead;

EEC
IV Connector Pin Depiction Pic by Ryan M (Fireguy50)

EEC IV Connector Pin Legend by Ryan M (Fireguy50) @ http://oldfuelinjection.com/truckpinouts.html

Wiring Diagram in an 89 (From TAD & TAD to EEC IV)

Source: by SeattleFSB (Seattle FSB) at SuperMotors.net

DTC 81/553 and 82/552 indicate voltage output for secondary air injection solenoid did not change when activated. Possible causes for this fault are:

• AIRB/AIRD circuit(s) shorted or open.
• Fault in solenoid or PCM.

Disconnect both solenoid connectors. Turn ignition on. Measure voltage between VPWR terminal of wiring harness connector and battery ground for both solenoids. If either voltage reading is less than 10.5 volts, repair wiring harness open circuit, and repeat QUICK TEST. If both readings are 10.5 volts or more, go to step 9).

9)Measure Solenoid Resistance :
Turn ignition off. Leave solenoid connectors disconnected. Measure resistance of both solenoids. If either reading is not 50-100 ohms, replace solenoid assembly and repeat QUICK TEST. If both readings are 50-100 ohms, go to step 10).

10) Check Circuit Continuity :
Leave ignition off. Disconnect PCM 60-pin connector. Inspect terminals, and repair if damaged. Install EEC-IV Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Measure resistance between AIRB test pin and AIRB terminal at wiring harness connector. Measure resistance between AIRD test pin and AIRD terminal at wiring harness connector. If either reading is 5 ohms or more, repair open circuit and repeat QUICK TEST. If both readings are less than 5 ohms, go to step 11).

11) Check For Short To Ground :
Leave ignition off and solenoids disconnected. Measure resistance between test pin No. 51 and test pins No. 40, 46 and 60 at breakout box. Measure resistance between test pin No. 11 and test pins No. 40, 46 and 60. If any reading is less than 10,000 ohms, repair short to ground and repeat QUICK TEST. If all readings are 10,000 ohms or more, go to step 12).

12) Check For Short To Power Circuit :
Turn ignition off. Measure resistance between test pin No. 51 and test pins No. 37 and 57 at break-out box. Measure resistance between test pin No. 11 and test pins No. 37 and 57 at breakout box. If any resistance is less than 10,000 ohms, repair short to power and repeat QUICK TEST. If code is repeated, replace PCM. If all resistances are 10,000 ohms or more, replace PCM and repeat QUICK TEST.

I'll post up for now; expecting a replacement Comcast Modem now to alleviate pre 1996 download speeds
 
#23 ·
yo,

DTC 27, 29, 452, P0502, P0503, PO716, PO718; Insufficient input from Vehicle Speed Sensor (VSS); also called RABS Sensor & Differential Speed Sensor (DSS)

"...A more difficult problem to identify is a VSS that works, but sends out the wrong signal for a given vehicle speed. In some cases, a wrong reading from the VSS may still cause a code to be set. For example, if the VSS signal tells the computer the vehicle is traveling 60 miles an hour, but the throttle position sensor and MAP sensor tell the computer that the engine is idling, the computer will be confused. And a confused computer should set any of the following codes: 27, 29, 452. ..." read more
Source: by wells @ http://www.wellsve.com/sft503/Counterpoint4_2.pdf
read more

VSS pic for a 90 (at transfer case);

Steve83 wrote, "...Its magnets & tone ring are all inside that sensor body. The plastic gear drives the sensor's shaft, and that shaft drives the speedo cable. Pull the C-clip off the gear and then pull the gear off the sensor..."
by SeattleFSB (Seattle FSB) at SuperMotors.net

Wiring Diagram in a 90 (SEE RABS) 1400 Ohms across the pins

Source: by Seattle FSB (SeattleFSB) at SuperMotors.net

==============
DTC 98 Hard fault present; "...Failure Mode Effects Management (FMEM) FMEM is an alternate system strategy in the PCM designed to maintain vehicle operation should one or more sensor inputs fail. When a sensor input is perceived to be out-of-limits by the PCM, an alternative strategy will be initiated. The PCM will substitute a fixed in-limit sensor value and will continue to monitor the faulty sensor input. If the faulty sensor operates within limits, the PCM will return to the normal engine running strategy. Engine Running DTC 98 or 998 will be displayed when FMEM is in effect. The Malfunction Indicator Lamp (MIL)/Message will remain on when FMEM is in effect. The MIL will come on while the engine is operating in Failure Mode Effects Management (FMEM) or Hardware Limited Operation Strategy (HLOS) modes. The light will stay on for at least 10 seconds, then stay on as long as the fault causing it is present. If the MIL flashes quickly (less than 10 seconds), the MIL circuit should be checked for concerns. Refer to «Quick Test». In FMEM mode, the PCM is receiving a sensor signal that is outside the limits set by the calibration strategy. In this mode, the PCM uses an alternate engine control strategy to maintain reasonable vehicle operation in spite of the fault. The DTC associated with this fault is stored in Keep Alive Memory (KAM). If the fault is no longer present, the light will turn off and the vehicle will return to the normal vehicle strategy. The DTC stored when the light was on is kept in Continuous Memory for the next 80 warm-up cycles (40 cycles on some applications) and then erased. This Continuous Memory DTC can be accessed by running the Key On Engine Off Self-Test. It should have some code(s) come up that will help narrow this down. 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." by miesk5 at FSB...http://fullsizebronco.com/forum/showthread.php?t=201804

DTC 98 in KOEO Electronic pressure control driver open in EEC (E4OD). this circuit fails line pressure should go to full at all times. The full line pressure puts a good deal of extra load on the engine, and will usually effect the idle. It is especially noticeable if your engine is already in need of a tuneup. You will need to check the electronic pressure control solenoid and its wiring. Either of these could be causing the EPC code. Open circuit causes maximum EPC pressure, harsh engagements and shifts. EPC Solenoid/WIRING OR MAP SENSOR. by miesk5 at Ford Bronco Zone Forums
 
#24 ·
DTC 98 in KOEO Electronic pressure control driver open in EEC (E4OD). this circuit fails line pressure should go to full at all times. The full line pressure puts a good deal of extra load on the engine, and will usually effect the idle. It is especially noticeable if your engine is already in need of a tuneup. You will need to check the electronic pressure control solenoid and its wiring. Either of these could be causing the EPC code. Open circuit causes maximum EPC pressure, harsh engagements and shifts. EPC Solenoid/WIRING OR MAP SENSOR. by miesk5 at Ford Bronco Zone Forums
I am noticing that it feels like I'm at the tractor pulls with a lead sled behind the truck when I test drove the two times I mentioned. I have been putting a 350 together and working on other cars so I didn't get to the bronco today. But... when I sat down tonight to review the info you provided again, I remembered about the grounds I found that are not terminated, three into one around the engine harness connectors. Maybe they are part of my Air injection system codes I have. I am going to hook those up in the morning first thing. When I did all the KOEO and KOER tests the truck was up to temp. Long day, I'm beat, thank you for the help I really appreciate it.;)
 
#25 ·
I have made some more progress, I am down to the following codes:

KOEO------

81 - AIRD solenoid - Solenoids and Air Injection
82 - AIRB solenoid - Solenoids and Air Injection

The diverter Valve at the back of the motor is not hooked up to the pump or the small black round "POT" mounted on the passenger fender well like my 90 is. will these hoses missing from the valve cause these codes to be triggered? I did complete the OHM tests on both solenoids, 75 OHMS--- Good. I tested the circuits for shorts to power and ground and neither problem exists. I'm thinking it may be because the hoses are missing.


CM ------

18 - Ignition TACH signal erratic - Ignition Systems
54 - Intake Air Temperature (IAT) or Vane Air Temperature (VAT) signal high -
IAT VAT

The tach was all over the place but now seems to be functioning properly.
the ACT sensor did not have any power going to it due to wiring loom issues, I repaired that problem and I can tell that the ACT is working now, the engine runs much better. Please clarify for me, because these two codes, 18 & 54 are registering in the CM portion of the test does this mean that they are not currently present, just stored in memory?


KOER------

41 - System lean - Fuel control
33 - ALL - EGR did not open/ respond during test or if memory code, did not
open intermittently - EVP EVR PFE

Am going to check fuel pressure this afternoon.
Sucked on the EGR valve......my vacuum pump broke:smilie_slap, and it operates properly, stalled the engine, I am going to test the sensor and continue troubleshooting, any advice or tips are appreciated, thanks for all the help up to this point!!
 
#26 ·
yo wrenchhead427,
81 - AIRD solenoid - Solenoids and Air Injection
82 - AIRB solenoid - Solenoids and Air Injection
Both pin point tests address electrical issues; I have not seen that vac leaks or vac hoses not connected will trigger the 2 codes.
But, after you get it hooked up, we'll see what happens.

The two codes, 18 & 54 are stored in Keep Alive Memory (KAM). If the fault is no longer present, the CEL will turn off and the Bronco will return to the normal vehicle strategy. The DTC stored when the light was on is kept in Continuous Memory for the next 80 warm-up cycles (40 cycles on some applications) and then erased. Continuous Memory DTCs are accessed by running the Key On, Engine Off Self-Test

The Continuous Memory DTCs must be retrieved within 80* engine temperature warm up cycles. On the 81st or 41st Engine Temperature cycle, the DTC will be automatically erased. The Continuous Memory DTCs can also be erased by deactivating Self-Test while the DTCs are being outputted

DTC 41, 42, 91, 92, 136, 137,139, 144, 171, 172, 173, 175, 176, 177 & some Possible Causes for Rich & Lean HEGO The engine temperature must be greater than 50°F (10°C) to pass the KOEO Self-Test and greater than 180°F (82°C) to pass the KOER Self-Test. To accomplish this, the engine should be at normal operating temperature
So rule that out since you had it @ norm op temp during Self-Tests

DTC 41; "...KOEO; No HEGO sensor switching detected or disconnected. HEGO is bad, not connected, or missing. KOER; HEGO sensor indicates system lean. HEGO is going bad, missing." read more on testing Source: by miesk5 at FSB http://fullsizebronco.com/forum/showthread.php?t=155932&page=2


DTC 33 is triggered when the EVP sensor is not closing; so EZiest & cheapest checks are to inspect & repair/replace repair any bad vac lines.
Miesk5 note; da TAB & TAD again; so repair those vac lines 1st

=

You are doing it well!
And you have saved boo-koo $$$!
 
#27 ·
Dropped the transfer case and trans to discover the block plate was bent around the starter hole, which the weight on the flex plate was hitting while running, so I found my knocking/clunking. While I had the trans out I flipped it over and pulled the valve body. After inspection I found the 1-2 shift valve sticking and the 3-4 shift/3-4 tv cable valve also sticking(cant remeber the exact name of it). So I freed them up and they are nice and loose now. Dropped the pan and did a rear main seal while I was at it. dropped the exhaust to get the pan off easier and discovered a hole in the top portion of the exhaust tubing right next to the O2 sensor so Im going to weld that up and put everything back in. I also discovered an orange wire exiting the loom at the same place as some different wires that go to a sensor on the rear top of the block. It has a ground looking terminal on it so I am going to look through Steves or Miesks diagrams and see what it is. I would swear its a ground but the orange wire is throwing me off. On a different note, I got my EEC-IV connector in the mail today for my Actron scanner so I'm excited about that and am hoping it will aide in my further diagnostics. will update soon, Ive been busy, I wont abandon this thread until I have everything perfect!! Thanks for the help so far!:rockon
 
#30 ·
Progress....

Well the tranny shifts now so progress had been made. As previously stated I acquired an EEC-IV cable for my actron scanner. Can someone tell me exactly what the difference is between FAST CODES and SLOW CODES? I brought the truck up to temp and chose the KOEO FAST CODES option:

067 Neutral safety circuit failure. A/C circuit was on during KOER Self-Test.-----
The gear shift and linkage is sloppy so I think this is why this code was thrown, tested later it was gone. Dash switch for A/C is in off position.

081 TAD circuit failure

082 TAB circuit failure

054 ACT sensor signal is greater than the Self-Test maximum of 4.6 volts.

033 EGR valve opening not detected.

I was a little concerned that the truck may not have been completely hot enough since it was cooler yesterday, so I ran it for a bit longer and pulled KOEO FAST CODES again, the thermostat opened this time for sure. This was the second set of results:

024 ACT sensor out of self test range 0.3 to 3.7 volts.

081 TAD circuit failure

082 TAB circuit failure

054 ACT sensor signal is greater than the Self-Test maximum of 4.6 volts.


Next I selected the KOEO SLOW CODES, this is what I got:

081 TAD circuit failure

082 TAB circuit failure

011 System pass


Next I chose KOER FAST CODES, the results:

042 No HEGO switching detected always rich (right side).


033 EGR valve opening not detected.


Then I chose KOER SLOW CODES, and the results:

042 No HEGO switching detected always rich (right side).


033 EGR valve opening not detected.


There as also an option for computed timing under KOER TESTS, I initialized it and came back with these results: TIMING IS NOW FIXED AT BASE TIMING PLUS 20 DEGREES PLUS OR MINUS 3 DEGREES

I wasn't sure where to start, the truck bucks like a stinkin horse when you drive it so I thought well maybe the computer is operating the EGR and since it apparently cannot see it opening, it keeps opening and closing it and maybe that is what is causing the bucking, i don't know but it seemed a place to start. So I disconnected the vacuum line from the EGR solenoid and the valve, tested the line and it holds vacuum. Hooked the EGR solenoid back up to the tubing and tested the line with the solenoid hooked up, i notice that it wont hold vacuum, so apparently the solenoid is leaking, I believe it has a small filter underneath so is solenoid supposed to bleed off with the engine and key off? that would explain the "leaking". I also checked the EGR valve itself and it operates with vacuum applied and holds. Turned the key on and tested the EVP sensor voltage. With EGR at rest, I have 5V on the VREF wire, the EVP pin wiring increases voltage from .4 closed to 4.3 with valve full open. On the top pin which is SIG RTN, I am getting a ground signal from my power probe, meaning it is grounded, I never see voltage on it, am I supposed to? I am going to try and stick with this code and fix it first then I will move to another unless someone may think that the computer of messed up, I don't know what to think. Thanks again for any help.
 
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