94 bronco doesn't want to shift

I just bought a 94 bronco with 217xxx miles on it. I bought this one because it was in perfect condition. Only problem is it doesn't want to change gears. It will rev up, but I have to let off the gas before it shifts. If I floor it, it just slows down. I pulled the codes and one of them was for the TPS. That was my first guess anyways so I replaced it and it didn't change anything. What would you guys suggest I check next? Seem like a common issue?

Yo,

Welcome!

The throttle position sensor is a potentiometer that is mounted on the throttle body on gas applications and on the fuel injection pump lever on diesel applications. The throttle position sensor detects the position of the throttle plate or lever and sends this information as a voltage signal to the powertrain control module.

If a malfunction occurs in the throttle position sensor circuit, the powertrain control module will recognize that the throttle position sensor signal is out of specification. The powertrain control module will then operate the E4OD transmission at a higher line pressure to prevent transmission damage. This high line pressure causes harsh upshift and engagements. Used as an input to determine shift scheduling and electronic pressure control.

Symptoms: Harsh engagements, firm shift feel, abnormal shift schedule, abnormal or no torque converter clutch operation. May flash transmission control indicator lamp.

Diagnostic Trouble Codes: 121, 122, 123, 124, 125, 167.

What is the code?

DTC 121, 122, 123, 124, 125 & P0122 and P0123 in TSB 94-26-4; "...The following is a list of vehicle symptoms which have been associated with the TPS, but can also be related to other vehicle components. Check engine light, Stalls, quits, hesitation/stumble, fast idle;

***To minimize the replacement of good components, be advised that the following non-EEC areas may be the issue: Excessive blow-by, PCV malfunction, Vacuum leaks, Fuel pressure, Throttle sticking or linkage binding.***

Following in upper case is by Ford, not me.

MANY VOLTMETERS WILL AUTOMATICALLY CHANGE RANGES WHEN MEASURING TPS OUTPUT FROM IDLE TO WOT. WHEN A VOLTMETER IS USED TO MEASURE TPS OUTPUT FROM IDLE TO WOT, THE METER SCALES OR CHANGES RANGES AUTOMATICALLY. THERE MAY BE AN ERRONEOUS METER DISPLAY UNTIL THE VOLTMETER HAS LOCKED TO THE APPROPRIATE VOLTAGE READING. THE ERRONEOUS METER DISPLAY DOES NOT REPRESENT A DEFECTIVE TPS. NOTE: IT IS RECOMMENDED THAT THE "RANGE LOCK" FEATURE ON MANY METERS BE SET FOR CHECKING TPS VOLTAGE..."

Test, Operational Description & Parameters

Source: by Ryan M (Fireguy50) at http://web.archive.org/web/20101201014211/http://fordfuelinjection.com/index.php?p=30

One test is for vacuum leaks, see my diagnosis in post #20 @ http://broncozone.com/topic/23994-90-58l-getting-continuous-code-33-and-running-code-44/?p=125535

One indicator of a leak is "...The air handling system is designed to provide defrost when no vacuum is applied to any of the three air door vacuum motors. This is done to prevent a situation where defrost cannot be obtained due to a system vacuum leak. Instead, a leak in the vacuum control circuit will send all airflow to the defroster outlets. This condition may occur during acceleration (slow leak), may exist at all times (large leak) and may happen only when certain specific functions are selected, indicating a leak in that portion of the circuit. ..."

Yo,

In order to get you more attention, will move this thread to 80-96 Ford Bronco Tech Support.

These are the codes I pulled when doing the key test.

17

2

53

217

25

38

Yo,

Your year will produce only 3 digit codes. 217 is for later year Fords with coil on plug ignitions.

Do you have a helper to do the code test?

This is the only Ford tps diagnosis that I have,

Throttle Position Sensor (TPS) Function & Diagnosis TSB 94-26-4 for 93-95

@

http://web.archive.org/web/20101224145551/http://www.tccoa.com/articles/mn12-techinfo/tsb/tsb-94-26-4.pdf

I will try to find a pin-point test, but chances are that I won't.

Forgot to mention the pin point testing is in the 94 Ford Bronco Powertrain Control/Emissions Diagnosis (PCED/EVTM) Manual.

Here is the PCED EEC-IV Diagnostic Trouble Code (DTC) Chart, BUT THE TPS CODES have dead links to the tests. One more thing is that most electrical pin point tests cite use of the Ford break out box that is obsolete, but available on eBay bay. There is a workaround though using

so, as I mentioned in another thread here; In place of the break-out box, Substitute EEC connector pin Number for breakout box number.

http://www.thedieselstop.com/faq/9497faq/maint/vra/vra02040.htm

Usually available on eBay. My 96 manual would not run on WINDOWS 8, 8.1 or 10, but did run on XP.

Fords publisher Helm sells the manual in print form:

1994 Powertrain Control/Emission Diagnosis Manual Set

Price: $180.00

In Stock

Qty:

Add to Cart

Pkg Qty: 1

Media: Paper

Language: English

Item/Part #: FPS1210694

Models and Years Covered

Information contained within this official Ford Motor Company reference manual provides the user a step-by-step approach for diagnosing drivability, emission and power train control system symptoms. This manual should be used in conjunction with the Shop Manual and Wiring Diagram.

Description:

Instructions And Procedures For Routine Repair Adjustment Maintenance Work Diagnosis/Testing And Removal/Installation Of Parts For Various Vehicle Systems.

Your purchase consists of, and included in the above price.

(1) FPS1210694AL - 1994 On Board Diagnosis I Looseleaf

(2) FPS1210694BL - 1994 On Board Diagnosis II Looseleaf

(3) FPS1210694C - 1994 Villager Powertrain Control/Emission Diagnosis Shop Manual

(4) FPS1210694A1 - 1994 OBD Supplement

(5) FCS1210694D - 7.3L Di Powertrain Control/Emission Diagnosis Sect: 18A Supplement

(6) FPS1210694AT - 1994 On Board Diagnosis I Tabs

(7) FPS1210694BT - 1994 On Board Diagnosis II Tabs

(8) FCS12106 - Powertrain Control/Emissions Diagnosis Car And Truck Binder

http://www.helminc.com/helm/product2.asp?Make=FRD&Model=BRON&Year=1994&Category=&class_2=FRD&mk=Ford&yr=1994&md=Full-Size+Bronco&dt=&module=&from=result&Style=helm&Sku=FPS1210694&itemtype=K

Update: right after I changed out the TPS it didn't change anything. But now 1 day later, I can't get it above 1 gear. And the rpms pulsate as I drive. And if I punch it the nose dives and just gives up. Could I have put the sensor on backwards? I was an idiot and forgot to check which direction the old one was before I ripped it off.

yo,

http://www.supermotors.org/getfile/266547/fullsize/8%20Vac%20Hoses%20-%20IAC.JPG

"...INSTALL: Prior to removing the TPS, remove the negative battery cable. Some truck years will require that you scribe a mark across the sensor and the TB to ensure that the new sensor is installed in the same exact location. I was not sure about my truck so I did it anyway...

...

New sensor should be positioned the same as the old...wiring harness pointed away from the IAC. Engage the tangs of the sensor with the throttle shaft blade, then rotate it clockwise to align the reference marks before installing the screws..."

by Xris







***

By Ford...

"Secure throttle position sensor to throttle body with two retaining screws. Tighten to 2-3 Nm (18-27 lb-in) on 4.9L engines. On 5.0/5.8L, tighten to 1.2-1.8 Nm (11-16 lb-in)...

http://www.diesel-dave.com/vehic/manual/stj/images/v4797j.gif

Item Part Number Description

1 9424 Intake Manifold, Upper

2 9E936 Throttle Body Gasket

3 9F715 Idle Air Control Valve

4 9E926 Throttle Body

On a 5.0L and 5.8L engine, position the throttle position sensor so that the pigtail points toward the idle air control valve (IAC valve)..."

Ok so I flipped that TPS sensor back around and boom it works! So now it drives. Problem was it idles real high! I checked the forum and decided it was the IAC. That helped but it also wasn't shifting very good and did not want to shift back into 1st when starting. So I checked again and I replaced the MAP sensor. After trying several time I finally was able to figure out how to pull the codes. This is what comes up now. What's weird is it starts with a 4 and then nothing for like 30 seconds then a 1 then 30 seconds then a 1 then 30 more seconds then a 1 then 30 more seconds then a 2 then the normal reading as follows

18. 25. 38. 53. 66. 32. 12. 11. 72. 53. 85. 36. 63. 2. (Engine running)

11. 21. 12. 11. 12. 21. 28. 11. 32. 12. 81. 72. (Engine off)

1 Now it kinda lags when you press the gas before it goes.

2 Doesn't like starting in 1st gear.

3 If I romp on it once I get to like 30mph it kind of stalls but doesn't shut off, then I have to wait a couple seconds before I can give it gas.

4 I can smell gas so I'm guessing it's running rich

I ran the codes 2 times and had different numbers. The beginning is what's throwing me off.

Any help would be awesome!

Yo,

Toss those codes. You should see just 3 digit codes.

Call ļocal mom and pop parts stores and ask if they can scan the codes for your year, make and model for free. Chain parts stores scan just 96 Broncos and later for free.

The 4 is the Engine Identification Codes (ID Code)

Engine ID codes are issued at the beginning of the Engine Running Self-Test and are one-digit numbers represented by the number of pulses sent out. For gasoline engines, the engine ID code is equal to one-half the number of engine cylinders (i.e. 2 pulses = 4 cylinders). These codes are used to verify the proper PCM is installed and that the Self-Test has been entered.

Do you have someone to help with the test?

My much better half saves me from going off track a lot now.

See this pced section for the self test, I can not open Joe's page..

http://www.thedieselstop.com/faq/9497faq/maint/vra/leftside=vras5al.htm&rightside=vras5ar.htm

Alright here it is one last time. I think I got it this time

Engine off

121. 122. 128. 172.

Engine running

121. 171. 172. 411. 412. 536. 538. 633.

Yo,

121 &122

TPS Overview & Testing; "...The TPS is a three wire sensor that measures the throttle plate opening and its rate of change. This sensor is a variable resistor, also called a potentiometer, that is directly linked to the throttle plate shaft. The TPS outputs a voltage directly proportional to the throttle opening. As the accelerator is depressed the throttle plate opens and the TPS voltage increases. The TPS assists the PCM in determining transmission shift points, converter lock-up and along with the MAP and MAF sensor are main PCM indicators of acceleration and load. In other words, the PCM looks at these sensors to calculate engine operation upon acceleration. Let me preface by saying I do not believe that any Ford TPS requires adjustment unless you have played with your Throttle Plate Set ***** or have a performance application. The procedure is not mentioned in any Ford Factory or Engine, Emissions-Diagnosis Manual that I have seen. If you require an Adjustable TPS you must set it just below 1v, ideally between 0.96v-0.98v. This is because the PCM is programmed to observe the TPS Signal Voltage in three modes: Idle Mode, Less than 1v. Part Throttle Mode, Greater than 1v. WOT Mode, Greater than 3.7v (Breakpoint is Plus 2.7v). The 0.96v-0.98v. setting has been determined to be optimal as it minimizes time delay between Closed Throttle and Part Throttle which increases performance. This is where general TPS Adjustment Settings Instructions are directed and many mistakenly think it is all inclusive. The shop modification of drilling out the ***** holes for additional adjustment is directed at people that use the incorrect TPS or cannot achieve the setting parameters due to intentional Throttle Body variences. On the other hand, EEC-IV Broncos use a Non-Adjustable TPS. Each time the key is turned on the PCM reads the Closed Throttle TPS voltage and places it in KAM memory as TPREL PID (or Ratch) Voltage. Ratch Voltage then becomes the baseline for Idle where the PCM assumes 0% Throttle Opening. The PCM is programmed for a voltage stairstep, (or Ratch), to Part Throttle and Wide Open Throttle (WOT) values. These stairstep values are based on the initial Closed Throttle readings and are determined each time the ignition key activates the PCM and TPS. Ratch Values: Closed Throttle, Initial Voltage Setting. Part Throttle, +0.02v above Closed Throttle. Wide Open Throttle, +2.71v above Closed Throttle. Even though the PCM determines Ratch Voltage with key on, there are different vehicle specifications for TPS Settings. This is to ensure that your TPS can operate within the full range of it's mechanical/electrical capability (In the case of my 1990 5.8L Bronco, this range is 0.34v-4.84v between 0-85 degrees rotation). As long as your settings are within the factory specified range, such as listed below, your TPS will be correct. TPS Settings: 1990 Bronco 4.9L - 0.73v to 1.22v. 1990 Bronco 5.0L - 0.73v to 1.22v. 1990 Bronco 5.8L - 0.73v to 1.22v. 1995 Bronco 4.9L - 0.65v to 1.28v. 1995 Bronco 5.0L - 0.65v to 1.28v. 1995 Bronco 5.8L - 0.65v to 1.28v. In either case, the PCM generally operates in Open loop on cold Start-up, Closed-Loop on warm idle/low-load cruising and Open-Loop during WOT. Open-Loop refers to shutting down the EGR, ignoring O2, ECT, ACT Sensor Input and relying upon programmed fuel maps. The TPS is advising the PCM through throttle modes when to go into Open or Close Loop Operations. And, as the TPS is an electrical/mechanical device, the TPS Sensor can wear out by developing dead spots which cause idle problems or hesitation usually in the most used lower range. Finally, Curb Idle and Fast Idle are controlled by the PCM and IAC and are not adjustable. This means adjusting your Throttle Plate Set ***** from the factory calibration will not allow the IAC to effectively control the rpm. This changes the Throttle Plate position potentially causing it to stick in the bore and it alters the TPS settings by either telling the PCM that you are always at Part Throttle or pushing it outside of setting specification. The Throttle Body Return ***** adjusts the Throttle Plate for Minimum Air Rate, which is the minimum amount of air required to maintain idle with the IAC unplugged. Plug the IAC in and the PCM is in control of your Idle. This means that you should not have to touch the Throttle Plate Set ***** unless someone has played with it or if you have a performance application which requires a higher Idle air flow. That is where you must adjust your TPS back to factory settings to compensate for the change in Throttle Plate position. As the Minimum Air Rate, Engine Load, TPS Sensor and the IAC are very closely linked, they must all work together to maintain a good idle. Idle problems can be caused by a myriad of other issues which should always be looked at first. These include ignition, fuel, spark, EGR,vacuum and PCV to name a few. Then the KOEO TPS Harness may be tested for Reference Voltage. The KOEO TPS Voltage may be back probed for baseline setting and a smooth increase thoughout the Throttle rotation. The unplugged TPS Sensor may be tested for Resistance also throughout the Throttle rotation. KOEO TPS Testing: KOEO TPS Reference Voltage, 5v (VREF/SIG RTN). KOEO TPS Signal Voltage, Less than 1v to 4.5v (TP SIG/SIG RTN while rotating Throttle). Unplugged TPS Resistance, Less than 4k ohms, Greater than 350 ohms (TP SIG/SIG RTN while rotating Throttle)..."

Source: by Seattle FSB (SeattleFSB) at FSB http://www.fullsizebronco.com/forum/blogs/seattle-fsb/681-throttle-position-sensor-management.html

****

128 indicates the MAP sensor vacuum has not changed more than 2 in-Hg (7 kPa) during normal vehicle operation.

Possible causes:

MAP sensor vacuum supply hose improper routing, blockage and/or linkage.

MAP sensor leak.

•Key off.

•Check vacuum hoses for proper routing. Refer to VECI decal. Check MAP sensor vacuum supply hoses for disconnections, kinks or blockage.

Are vacuum hoses OK?

read more at

http://www.thedieselstop.com/faq/9497faq/maint/vra/vra06022.htm#pptdf11

***

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

Source: by Ryan M (Fireguy50)

DTC 172 lean Heated O2; "...Backprobe the MAF (+) and MAF-RTN (-) lines with a DVOM. You should see ~1.0V or slightly less at warm idle. If not, check the +12V and GND lines to make sure there's battery voltage between those terminals with the ignition key turned ON. You also may want to try using the proper spray cleaner on the MAF wires, especially if you have a K&N oily filter (in which case I can almost guarantee there's oily junk on your MAF's wires). Also make certain that the tube(s) leading from the MAF to the throttle body are 100% intact. The red wire (on the right in the first above picture) is supposed to have battery voltage with the key on. Measure between that wire and the one right next to it. You measure the MAF voltage at idle, because the MAF voltage is what's interpreted by the PCM..."

Source: by SigEpBlue (Steve)

DTC 172, 173 or 41 for HO2S Failure Or Fuse \"E\" Inoperative, ABS Light On, Back-Up Lamps Inoperative, Daytime Running Lamp (DRL) Inoperative, MIL On, Inadvertent Self-Test, Speedometer Inoperative & Trailer Battery Charge Relay Inoperative in TSB 95-5-21 for 92-95 Bronco & F Series; "...the HO2S wires in the 12A690 (subassembly of the 14B060 battery cable) harness may become chafed and the vehicle could exhibit any one of the following conditions....Lack of proper HEGO operation may cause, or be the result of a rich or lean fuel condition, which could cause additional heat in the catalyst. Perform self test KOEO and KOER, service any codes. CHECK FOR PROPER HEGO GROUND. If the HEGO ground is good, the following areas may be at fault: ..." READ MORE

Source: by Ford via Steve

http://api.viglink.com/api/click?format=go&jsonp=vglnk_146861476483511&key=6ed47b392b9edfe394b9e89b72717104&libId=iqo78r1501000bgv000MAbcnv3fdb&loc=http%3A%2F%2Fwww.fullsizebronco.com%2Fforum%2F7-1980-96-bronco-tech%2F420577-dtcs-found-advise-procedure-please.html&v=1&out=http%3A%2F%2Fwww.supermotors.net%2Fregistry%2Fmedia%2F646262&ref=https%3A%2F%2Fwww.google.com%2F&title=DTCs%20found...advise%20on%20procedure%20please%20-%20Ford%20Bronco%20Forum&txt=1983%20Ford%20Bronco%20TSBs%20%26amp%3B%20FSAs%20(Recalls)%20for%20%2783-96%20Broncos%20%26amp%3B%20F150s%20picture%20%7C%20SuperMotors.net

***

DTC 411 Idle speed system not controlling idle properly (generally idle too high); "...DTC 411 indicates a dirty/ bad or connector issue w/ Idle Air Control valve (IAC). inspect it for crapola. Some can be cleaned. But our's shouldn't since the TSB says; "...Cleaning is not required on sludge tolerant throttle body designs released for 1991 and newer model years...." in Idle Air Control (IAC) Sludge; Poor Idle TSB 91-25-07 for 85-92 Bronco & F Series & many others; "...Hard cold starts, hesitation and stalls on initial start-up or during idle or decel may be caused by sludge in the throttle body and/or idle by-pass valve. Sludge deposits or oil film on the throttle body bore and plate or the idle air by-pass valve may cause one or more of the following conditions. Hard Cold Start, Stall On Initial Start-Up, Stall During Idle, Stall During Decel, Rough Idle, Rolling Idle, Hesitation During Acceleration. A new idle air by-pass service kit (F2PZ-9F939-A) is now available for service use to correct sludge contamination concerns of the throttle bore and plate only. It eliminates the need to clean the majority of past model throttle body applications. Cleaning is not required on sludge tolerant throttle body designs released for 1991 and newer model years..."

***

DTC 412 Cannot control RPM during KOER self-test high RPM check. \"...indicates that during the Engine Running Self-Test, engine rpm could not be controlled within the Self-Test upper limit band. Possible causes: Open or shorted circuit. Throttle linkage binding. Improper idle airflow set. Idle Air Control (IAC) solenoid contamination. Items external to Idle Air Control system that could affect engine rpm. Damaged IAC solenoid. Damaged Powertrain Control Module (PCM). Turn the key \"OFF\", connect a tachometer. Then start the engine and disconnect the Idle Air Control (IAC) harness connector. Does the rpm drop or engine stall? If it does, turn the key \"OFF\" and disconnect the IAC. With an Digital Volt/Ohm Meter (DVOM) check the resistance of the IAC solenoid. It should be between 6.0 and 13.0 ohms. Due to diode in the solenoid, place the DVOM (+) lead on the VPWR pin and the (-) lead on the IAC pin. If it is not within specification, replace the IAC solenoid..." miesk5 Note; Ford says the range is 7-13 ohms

***

--

DTC 538 Insufficient RPM change during dynamic response test. "...This is another code generated when the dynamic response or "goose" test as some refer to it is not performed during the KOER test. The KOER test requires that after a certain length of time the throttle be opened to bring the idle above 2000 rpm for a short period of time. If the dynamic response test is not performed or the rpm's do not peak ABOVE 2000 rpm's this code will be generated. (Computer needs to compare changes in sensor readings at different RPM's to determine system operation and efficiency)..." IGNORE this DTC FOR NOW

***

DTC 536 - Brake On/Off circuit failure / switch not actuated during KOER test or shorted to ground. IGNORE this DTC if brake pedal was not ppressed during self test

***

DDTC 632 - OD cancel switch not changing state. "...During the KOER test, AFTER the initial recognition code is generated, the brake pedal must be applied, the OD switch must be turned off and then back on and finally the "goose" test must be performed. This code is generated when the person performing the KOER test fails to deactivate and reactivate the OD cancel switch at the end of the shift lever. It does NOT indicate a problem unless the switch WAS INDEED deactivated and reactivated and the code still came up. (Computer needs to know if the tranny is in OD or not)..."

IGNORE this DTC if OD switch was not activated aand ...

****

633 4x4L switch should be in 4×2 or 4×4 high for the self test

I've looked everywhere. I don't think I have a MAF sensor

And the TPS. If I put a brand new one on there could it possibly be a faulty part? And no vacuum leaks on the MAP sensor. Put a brand new on on there and the one line that comes from the sensor is on tight and no cracks in the line.

Yo,

OK, forget about the MAF sensor.

If the TPS is not a Ford Motorcraft unit, then it needs to be tested.

For example Duralast TPS sensors have been reported by Bronco owners to be Defective after a month to a year of use.

Well took the bronco to local shop that had a scanner and they checked and saw that the TPS was stuck at 2 amps. So when I put it on backwards I must have messed it up. Going to replace it in the morning and see if that fixes everything

Yo,

Thanks for the info. GL!

Alright it all went good and it cleared most of the codes. Only one left while running and not is 172. I bought 2 new O2 sensors. Think I should just replace them as that is what the code is about? And that code has been there from the beginning.

Thanks

Sam

Yo Sam,

Most shops & technical sites suggest replacing the o2 sensors @ 30k miles.

Testing; "...You can test them, but usually if there's more than ~30k miles on them, I wouldn't bother. I treat them just like spark plugs, as they DO wear out and stop performing like they're supposed to. In fact, the EEC is programmed to observe the HEGO signal and count crossovers to determine the relativistic age of the sensor, and to compensate for it. Usually the cost of HEGOs is more than paid for in terms of mileage and driveability increases, at least IMHO. MANY reference literatures state that you can test them with a voltmeter and a heat source such as a propane torch, or even right in the vehicle. This is bull to me; HEGOs generate voltage through a galvanic reaction, and it's nothing like a DC source such as a battery. They 'swing' high to low, and 'center' around a value to tell the EEC what the mixture is approximately. Also, HEGOs are accurate only within a very very narrow range, something on the order of 14.2:1 to 15:1 (don't have my references here in front of me, sorry). So that bench testing crap won't fly too well. The real problem is reading what the HEGO is outputting without that special circuitry. Many people make do with a resistor (or shunt of some sort) and a DVOM, but it's not accurate enough for ME to accept as reliable..."

I have replaced 2 out of the 3 since new. BUT only when they failed and I tested the circuit and looked for burnt wires near exhaust manifold, cat. converter, etc.