need help with diagnosis
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need help with diagnosis
Thank you for your time, I will start searching as soon as I get this posted, in the hopes someone may recognize the symptoms. 1994 f 150 5.0 automatic, a/c
178,000 miles. normally truck runs perfect, never a hiccup, with the exception of high idle at start up that slows to normal after a few. Now starts with low idle and stays low, seems to try and find shift points up and down, dieseling during acceleration, but can limp home. My thought would be one of the sensors. Any suggestions?
178,000 miles. normally truck runs perfect, never a hiccup, with the exception of high idle at start up that slows to normal after a few. Now starts with low idle and stays low, seems to try and find shift points up and down, dieseling during acceleration, but can limp home. My thought would be one of the sensors. Any suggestions?
Fleet Owner
Joined: Oct 2005
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From: Kentucky
Your search should have resulted in hundreds of the same reply: "Check for codes!"
Warm up the engine then do this: Fuel Injection Technical Library » How To Run a Self-Test
Or purchase a code reader such as the Equus 3145.
Warm up the engine then do this: Fuel Injection Technical Library » How To Run a Self-Test
Or purchase a code reader such as the Equus 3145.
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Your search should have resulted in hundreds of the same reply: "Check for codes!"
Warm up the engine then do this: Fuel Injection Technical Library » How To Run a Self-Test
Or purchase a code reader such as the Equus 3145.
Warm up the engine then do this: Fuel Injection Technical Library » How To Run a Self-Test
Or purchase a code reader such as the Equus 3145.
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Okay, I disconnected both battery terminals and charged the battery for 20 min or so while letting the ecm lose memory. cleaned and reconnected battery, went for a ride and same symptoms seems to limp only. runs fine at idle. I jumpered the 2 connectors and did the koeo check. I came up with 1 122 122 1 122 332 122 332. Not an easy task to count and write with out looking and losing count.
Fleet Owner
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From: Easton,Ks
The one wire plug (STI) is either grounded to the NEG post of the battery or jumped to pin #2 of the self-test plug.
Then when the key is turned on the self-test KOEO test will start and you can count the flashes on the CEL/MIL lamp in your cluster.
The frame is not a ground point and may or may not be grounded depending is the right NEG ground cable was replaced or not.
Then when the key is turned on the self-test KOEO test will start and you can count the flashes on the CEL/MIL lamp in your cluster.
The frame is not a ground point and may or may not be grounded depending is the right NEG ground cable was replaced or not.
Fleet Owner
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From: Easton,Ks
The first set 122 is KOEO, the second set 122, 332 is the CM codes.
KOEO:
DTC 122 indicates the Throttle Position (TP) sensor signal is less than the Self-Test minimum value.
Possible causes:
TP sensor may not be seated properly (tightened down).
Damaged TP sensor.
Open harness.
Grounded harness.
Damaged Powertrain Control Module (PCM).
CM:
CONTINUOUS MEMORY DIAGNOSTIC TROUBLE CODE (DTC) 122: MONITOR TP CIRCUIT UNDER SIMULATED ROAD SHOCK
Connect VOM or Super Star II Tester to STO.
Observe VOM or listen for beeper to sound on Super Star II for indication of a fault while performing the following:
Move throttle slowly to WOT position.
Release throttle slowly to closed position.
Lightly tap on TP sensor (simulating road shock).
Wiggle TP harness connector.
Continuous Memory DTC 332 indicates the EGR valve did not open with the engine stabilized and the EVR solenoid duty cycle present sometime during vehicle operation.
Possible causes:
Obstructed or cracked hose to EGR valve.
Icing.
Damaged EGR valve.
Damaged EVR solenoid harness.
Key off.
Disconnect vacuum hose at EGR valve and connect a hand vacuum pump.
Apply 10-20 in-Hg (34-67 kPa) to EGR valve.
Does EGR valve open and maintain vacuum?
KOEO:
DTC 122 indicates the Throttle Position (TP) sensor signal is less than the Self-Test minimum value.
Possible causes:
TP sensor may not be seated properly (tightened down).
Damaged TP sensor.
Open harness.
Grounded harness.
Damaged Powertrain Control Module (PCM).
CM:
CONTINUOUS MEMORY DIAGNOSTIC TROUBLE CODE (DTC) 122: MONITOR TP CIRCUIT UNDER SIMULATED ROAD SHOCK
Connect VOM or Super Star II Tester to STO.
Observe VOM or listen for beeper to sound on Super Star II for indication of a fault while performing the following:
Move throttle slowly to WOT position.
Release throttle slowly to closed position.
Lightly tap on TP sensor (simulating road shock).
Wiggle TP harness connector.
Continuous Memory DTC 332 indicates the EGR valve did not open with the engine stabilized and the EVR solenoid duty cycle present sometime during vehicle operation.
Possible causes:
Obstructed or cracked hose to EGR valve.
Icing.
Damaged EGR valve.
Damaged EVR solenoid harness.
Key off.
Disconnect vacuum hose at EGR valve and connect a hand vacuum pump.
Apply 10-20 in-Hg (34-67 kPa) to EGR valve.
Does EGR valve open and maintain vacuum?
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The first set 122 is KOEO, the second set 122, 332 is the CM codes.
KOEO:
DTC 122 indicates the Throttle Position (TP) sensor signal is less than the Self-Test minimum value.
Possible causes:
TP sensor may not be seated properly (tightened down).
Damaged TP sensor.
Open harness.
Grounded harness.
Damaged Powertrain Control Module (PCM).
CM:
CONTINUOUS MEMORY DIAGNOSTIC TROUBLE CODE (DTC) 122: MONITOR TP CIRCUIT UNDER SIMULATED ROAD SHOCK
Connect VOM or Super Star II Tester to STO.
Observe VOM or listen for beeper to sound on Super Star II for indication of a fault while performing the following:
Move throttle slowly to WOT position.
Release throttle slowly to closed position.
Lightly tap on TP sensor (simulating road shock).
Wiggle TP harness connector.
Continuous Memory DTC 332 indicates the EGR valve did not open with the engine stabilized and the EVR solenoid duty cycle present sometime during vehicle operation.
Possible causes:
Obstructed or cracked hose to EGR valve.
Icing.
Damaged EGR valve.
Damaged EVR solenoid harness.
Key off.
Disconnect vacuum hose at EGR valve and connect a hand vacuum pump.
Apply 10-20 in-Hg (34-67 kPa) to EGR valve.
Does EGR valve open and maintain vacuum?
KOEO:
DTC 122 indicates the Throttle Position (TP) sensor signal is less than the Self-Test minimum value.
Possible causes:
TP sensor may not be seated properly (tightened down).
Damaged TP sensor.
Open harness.
Grounded harness.
Damaged Powertrain Control Module (PCM).
CM:
CONTINUOUS MEMORY DIAGNOSTIC TROUBLE CODE (DTC) 122: MONITOR TP CIRCUIT UNDER SIMULATED ROAD SHOCK
Connect VOM or Super Star II Tester to STO.
Observe VOM or listen for beeper to sound on Super Star II for indication of a fault while performing the following:
Move throttle slowly to WOT position.
Release throttle slowly to closed position.
Lightly tap on TP sensor (simulating road shock).
Wiggle TP harness connector.
Continuous Memory DTC 332 indicates the EGR valve did not open with the engine stabilized and the EVR solenoid duty cycle present sometime during vehicle operation.
Possible causes:
Obstructed or cracked hose to EGR valve.
Icing.
Damaged EGR valve.
Damaged EVR solenoid harness.
Key off.
Disconnect vacuum hose at EGR valve and connect a hand vacuum pump.
Apply 10-20 in-Hg (34-67 kPa) to EGR valve.
Does EGR valve open and maintain vacuum?
in regards to the egr, mine looks like if I was to just replace it would be the egr valve and valve position sensor. I will check the vacuum first, but I need to go buy a vac pump before i can check. I do not see an egr solenoid.
Thank you for a perfect straight forward answer. I have been on other forums where the answer tends to be "do a search".
Last edited by christo651; Dec 16, 2013 at 10:31 AM. Reason: new info
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Fleet Owner
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From: Easton,Ks
The EGR solenoid that operates the EGR valve is on the drivers side by the ignition coil.
Some auto part stores will rent you a hand vacuum pump.
The TPS is used by the PCM Computer to select gears in the transmission.
Some auto part stores will rent you a hand vacuum pump.
The TPS is used by the PCM Computer to select gears in the transmission.
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upon closer inspection of the egr I noticed the vac line was disconnected and plugged by the previous owner, Guess that solves that part, must need either solenoid or valve. I guess the vac pump will tell if it is the valve. Is there a way to check the solenoid?
Still though these were present in the truck for years, if the tps completely crapped out would it give me the symptoms I am describing, dieseling with throttle, gear searching, and low power.
Still though these were present in the truck for years, if the tps completely crapped out would it give me the symptoms I am describing, dieseling with throttle, gear searching, and low power.
Fleet Owner
Joined: Aug 2005
Posts: 23,668
Likes: 301
From: Easton,Ks
I am not sure what you mean by dieseling. You have a 5.0L fuel injected engine and the fuel is shut off to the engine when the key is turned off. So I do not see how it could diesel.
Here is some information on the EGR solenoid and it is sometimes call the EGR Vacuum Regulator (EVR):
Fuel Injection Technical Library » EGR Vacuum Regulator (EVR)
Here is some information on the EGR solenoid and it is sometimes call the EGR Vacuum Regulator (EVR):
Fuel Injection Technical Library » EGR Vacuum Regulator (EVR)
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New User
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I am not sure what you mean by dieseling. You have a 5.0L fuel injected engine and the fuel is shut off to the engine when the key is turned off. So I do not see how it could diesel.
Here is some information on the EGR solenoid and it is sometimes call the EGR Vacuum Regulator (EVR):
Fuel Injection Technical Library » EGR Vacuum Regulator (EVR)
Here is some information on the EGR solenoid and it is sometimes call the EGR Vacuum Regulator (EVR):
Fuel Injection Technical Library » EGR Vacuum Regulator (EVR)
Fleet Owner
Joined: Aug 2005
Posts: 23,668
Likes: 301
From: Easton,Ks
When you say dieseling I think you mean pinging or knocking.
The PCM is getting bad information from the TPS when you start it and there for it is not opening the IAC valve at start up. So you are getting low idle.
I do not know if the TPS is bad or the plugs and wiring between the TPS and the PCM.
Here is some information on the TPS:
Fuel Injection Technical Library » Throttle Position Sensor (TPS)
/
The PCM is getting bad information from the TPS when you start it and there for it is not opening the IAC valve at start up. So you are getting low idle.
I do not know if the TPS is bad or the plugs and wiring between the TPS and the PCM.
Here is some information on the TPS:
Fuel Injection Technical Library » Throttle Position Sensor (TPS)
/
Thread Starter
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New User
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When you say dieseling I think you mean pinging or knocking.
The PCM is getting bad information from the TPS when you start it and there for it is not opening the IAC valve at start up. So you are getting low idle.
I do not know if the TPS is bad or the plugs and wiring between the TPS and the PCM.
Here is some information on the TPS:
Fuel Injection Technical Library » Throttle Position Sensor (TPS)
/
The PCM is getting bad information from the TPS when you start it and there for it is not opening the IAC valve at start up. So you are getting low idle.
I do not know if the TPS is bad or the plugs and wiring between the TPS and the PCM.
Here is some information on the TPS:
Fuel Injection Technical Library » Throttle Position Sensor (TPS)
/
Fleet Owner
Joined: Aug 2005
Posts: 23,668
Likes: 301
From: Easton,Ks
Yes check the plugs and wiring around the TPS.
Back probe the TPS plug for the 5 volt dc from the Computer and check it to the SIG RTN on the same plug.
Then check the TP wire voltage at closed throttle, mid throttle and WOT.
Back probe the TPS plug for the 5 volt dc from the Computer and check it to the SIG RTN on the same plug.
Then check the TP wire voltage at closed throttle, mid throttle and WOT.