92 F-150 351 Base curb idle low, out of spec
08-29-2011, 04:38 PM
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92 F-150 351 Base curb idle low, out of spec
Hi, my name is Craig and the specs of the vehicle are below:
1992 Ford F-150 XLT 2WD V8-351 5.8L Windsor 265,000 Miles
The base curb idle speed is too low. Kept thinking to myself, the base idle sounds lower than it should and consequently, the vehicle is idling at 600RPM according to the cheapest $35 tach recently purchased at O' Reilly's.
This is my dad's truck and he mentioned that he adjusted the throttle stop screw counterclockwise (decrease idle) several years ago. My assumption was to circumvent a high idle do to a vacuum leak on MAP systems. Now that I rebuilt the upper engine and replaced all vacuum lines, the vehicle now has a very low idle.
Here are my questions:
1) In this situation, do I turn the throttle stop screw clockwise until I get to 750-800RPM? Since I cannot find a base curb idle specification and only get the answer that it is computer controlled, is the reason why the Air Bypass Valve Assembly cannot compensate is because the Throttle Position Sensor is out of range or the ABVA is stucking?
2) If the TPS is out of range, wouldn't I be reading a KOEO and/or KOER code specifying the TPS is out of range?
3) The SPOUT connector is intended to be connected at all times, correct? If it is, that explains why it is unresponsive due to retarded timing and having no cold fast idle sequence.
My initial testing/T+s=Time elapsed in seconds
SPOUT connector shorting bar connected
Start vehicle
T+0=idle 700RPM
T+5s=1600RPM (cold fast idle)
T+30s=1300RPM
T+15s=850RPM Regardless of engine speed, timing mark on damper (harmonic balancer) remains the same @ 20°BTC which verifies the EEC (engine module) and TFI (ignition module) is advancing beyond initial base timing as intended.
Disconnected SPOUT connector shorting bar
T+5s=900RPM T+10s=650 RPM @ 10°BTC (Previously timed vehicle to 650RPM before obtaining tach)
----This is the end of post, the rest is what was gathered from @LLD@T@ if you need it----
"Idle Speed: Adjustments
NOTE: The curb and fast idle speeds are controlled by the e EEC-IV processor and the Air Bypass Valve Assembly. The Air Bypass Valve Assembly is not adjustable. A large increase or decrease in closed plate airflow from the calibrated level will not allow this device to control the speed. The idle speed setting procedure has been revised considerably to reflect the expanded application of the Self-Test idle speed options and because the throttle body incorporates an orifice in the throttle plate to control idle airflow as part of the sludge tolerant design. A change in idle airflow can occur not only at the throttle body but other areas as well. You should enter the idle speed procedure only after other possible causes in the following areas are eliminated.
RPM TOO LOW Do not clean the throttle body, Check the plate orifice plug. If there is no plug, turn screw counterclockwise until conditions in Step 4a are satisfied. If there is a plug from previous service remove plug then adjust screw in either direction as required. Screw must be in contact with the lever pad after adjustment. Step 4a- Specifies using a dealership STAR scan tool because the idle speed is computer controlled and a scan tool is required for adjustment.
Ignition Timing: Specifications Initial Timing=10ºBTC Before Top Dead Center
NOTE: Initial timing is measured with engine at normal operating temperature and Spark Output (SPOUT) connector disconnected or shorting bar removed.
Ignition Timing: Adjustments
INITIAL TIMING
Attachment 54022
1992 Ford F-150 XLT 2WD V8-351 5.8L Windsor 265,000 Miles
The base curb idle speed is too low. Kept thinking to myself, the base idle sounds lower than it should and consequently, the vehicle is idling at 600RPM according to the cheapest $35 tach recently purchased at O' Reilly's.
This is my dad's truck and he mentioned that he adjusted the throttle stop screw counterclockwise (decrease idle) several years ago. My assumption was to circumvent a high idle do to a vacuum leak on MAP systems. Now that I rebuilt the upper engine and replaced all vacuum lines, the vehicle now has a very low idle.
Here are my questions:
1) In this situation, do I turn the throttle stop screw clockwise until I get to 750-800RPM? Since I cannot find a base curb idle specification and only get the answer that it is computer controlled, is the reason why the Air Bypass Valve Assembly cannot compensate is because the Throttle Position Sensor is out of range or the ABVA is stucking?
2) If the TPS is out of range, wouldn't I be reading a KOEO and/or KOER code specifying the TPS is out of range?
3) The SPOUT connector is intended to be connected at all times, correct? If it is, that explains why it is unresponsive due to retarded timing and having no cold fast idle sequence.
My initial testing/T+s=Time elapsed in seconds
SPOUT connector shorting bar connected
Start vehicle
T+0=idle 700RPM
T+5s=1600RPM (cold fast idle)
T+30s=1300RPM
T+15s=850RPM Regardless of engine speed, timing mark on damper (harmonic balancer) remains the same @ 20°BTC which verifies the EEC (engine module) and TFI (ignition module) is advancing beyond initial base timing as intended.
Disconnected SPOUT connector shorting bar
T+5s=900RPM T+10s=650 RPM @ 10°BTC (Previously timed vehicle to 650RPM before obtaining tach)
----This is the end of post, the rest is what was gathered from @LLD@T@ if you need it----
"Idle Speed: Adjustments
NOTE: The curb and fast idle speeds are controlled by the e EEC-IV processor and the Air Bypass Valve Assembly. The Air Bypass Valve Assembly is not adjustable. A large increase or decrease in closed plate airflow from the calibrated level will not allow this device to control the speed. The idle speed setting procedure has been revised considerably to reflect the expanded application of the Self-Test idle speed options and because the throttle body incorporates an orifice in the throttle plate to control idle airflow as part of the sludge tolerant design. A change in idle airflow can occur not only at the throttle body but other areas as well. You should enter the idle speed procedure only after other possible causes in the following areas are eliminated.
- Contamination within the idle speed control device OK
- Lack of fuel system control (excessively rich or lean) OK
- Throttle sticking or binding. OK
- Engine not reaching operating temperature OK
- Incorrect ignition timing CHECK
- Incorrect or clogged PCV system OK
- Vacuum leaks (intake manifold, vacuum hoses, vacuum reservoirs, power brake booster, etc. OK Manifold Absolute Pressure (MAP) systems will increase idle with vacuum leak and Mass Air Flow (MAF) will decrease idle with vacuum leak)
RPM TOO LOW Do not clean the throttle body, Check the plate orifice plug. If there is no plug, turn screw counterclockwise until conditions in Step 4a are satisfied. If there is a plug from previous service remove plug then adjust screw in either direction as required. Screw must be in contact with the lever pad after adjustment. Step 4a- Specifies using a dealership STAR scan tool because the idle speed is computer controlled and a scan tool is required for adjustment.
Ignition Timing: Specifications Initial Timing=10ºBTC Before Top Dead Center
NOTE: Initial timing is measured with engine at normal operating temperature and Spark Output (SPOUT) connector disconnected or shorting bar removed.
Ignition Timing: Adjustments
INITIAL TIMING
- Place transmission in NEUTRAL or PARK with Air Conditioning/Heater in OFF position. CHECK
- Connect an inductive timing light. CHECK
- Disconnect the single wire in-line Spark Output (SPOUT) connector or remove the shorting bar from the double wire SPOUT connector located near distributor. CHECK
- Start engine and allow to reach operating temperature. CHECK
- With engine at timing rpm, check or adjust initial timing to specification. ?
- Reconnect single wire in-line SPOUT connector or reconnect shorting bar. CHECK
- Check timing advance to verify distributor is advancing beyond the initial setting. CHECK If it does not, perform EEC IV Quick Test
- Remove test instruments." -@LLD@T@
Attachment 54022
Last edited by bluecar5556; 08-29-2011 at 07:52 PM.
08-29-2011, 05:10 PM
#2
That was a helluva lot to read. Let's see...RPM and Timing don't necessarily have any correlation and your timing (stock) should be 10*BTDC. With that, you only check your timing with the SPOUT plug -out-. So you can have a 10*BTDC and idle at 600 or 700 or 800 RPM since one doesn't necessarily affect the other. Hold one...should have quoted...need to go back and read again...
08-29-2011, 05:26 PM
#3
Originally Posted by bluecar5556
Hi, my name is Craig and the specs of the vehicle are below:
1992 Ford F-150 XLT 2WD V8-351 5.8L Windsor 265,000 Miles
I'm having base ignition timing issues. Kept thinking to myself, the base idle sounds lower than it should and consequently, the vehicle is idling at 600RPM according to the cheapest $35 tach recently purchased at O' Reilly's.
This is my dad's truck and he mentioned that he adjusted the throttle stop screw counterclockwise (decrease idle) several years ago. My assumption was to circumvent a high idle do to a vacuum leak on MAP systems. Now that I rebuilt the upper engine and replaced all vacuum lines, the vehicle now has a very low idle.
Here are my questions: 1) In this situation, do I turn the throttle stop screw clockwise until I get to 750-800RPM? Since I cannot find a base curb idle specification and only get the answer that it is computer controlled, is the reason why the Air Bypass Valve Assembly cannot compensate is because the Throttle Position Sensor is out of range or the ABVA is stucking? 2) If the TPS is out of range, wouldn't I be reading a KOEO and/or KOER code specifying the TPS is out of range? 3) The SPOUT connector is intended to be connected at all times, correct? If it is, that explains why it is unresponsive due to retarded timing and having no cold fast idle sequence.
My initial testing/T+s=Time elapsed in seconds
SPOUT connector shorting bar connected
Start vehicle
T+0=idle 700RPM
T+5s=1600RPM (cold fast idle)
T+30s=1300RPM
T+15s=850RPM Regardless of engine speed, timing mark on damper (harmonic balancer) remains the same @ 20°BTC which verifies the EEC (engine module) and TFI (ignition module) is advancing beyond initial base timing as intended.
Disconnected SPOUT connector shorting bar
T+5s=900RPM T+10s=650 RPM @ 10°BTC (Previously timed vehicle to 650RPM before obtaining tach)
Manually increased engine speed via throttle body to 750RPM=20°BTC
"Idle Speed: Adjustments
NOTE: The curb and fast idle speeds are controlled by the e EEC-IV processor and the Air Bypass Valve Assembly. The Air Bypass Valve Assembly is not adjustable. A large increase or decrease in closed plate airflow from the calibrated level will not allow the diveci to control the speed. The idle speed setting procedure has been revised considerably to reflect the expanded application of the Self-Test idle speed options and because the throttle body incorporates an orifice in the throttle plate to control idle airflow as part of the sludge tolerant design. A change in idle airflow can occur not only at the throttle body but other areas as well. You should enter the idle speed procedure only after other possible causes in the following areas are eliminated.
[*]Contamination within the idle speed control device OK[*]Lack of fuel system control (excessively rich or lean) OK[*]Throttle sticking or binding. OK[*]Engine not reaching operating temperature OK[*]Incorrect ignition timing CHECK[*]Incorrect or clogged PCV system OK[*]Vacuum leaks (intake manifold, vacuum hoses, vacuum reservoirs, power brake booster, etc. OK Manifold Absolute Pressure (MAP) systems will increase idle with vacuum leak and Mass Air Flow (MAF) will decrease idle with vacuum leak)
RPM TOO LOW Do not clean the throttle body, Check the plate orifice plug. If there is no plug, turn screw counterclockwise until conditions in Step 4a are satisfied. If there is a plug from previous service remove plug then adjust screw in either direction as required. Screw must be in contact with the lever pad after adjustment. Step 4a- Specifies using a dealership STAR scan tool because the idle speed is computer controlled and a scan tool is required for adjustment.
Ignition Timing: Specifications Initial Timing=10ºBTC Before Top Dead Center NOTE: Initial timing is measured with engine at normal operating temperature and Spark Output (SPOUT) connector disconnected or shorting bar removed.
Ignition Timing: Adjustments
INITIAL TIMING
[*]Place transmission in NEUTRAL or PARK with Air Conditioning/Heater in OFF position. CHECK[*]Connect an inductive timing light. CHECK[*]Disconnect the single wire in-line Spark Output (SPOUT) connector or remove the shorting bar from the double wire SPOUT connector located near distributor. CHECK[*]Start engine and allow to reach operating temperature. CHECK[*]With engine at timing rpm, check or adjust initial timing to specification. ?[*]Reconnect single wire in-line SPOUT connector or reconnect shorting bar. CHECK[*]Check timing advance to verify distributor is advancing beyond the initial setting. CHECK If it does not, perform EEC IV Quick Test[*]Remove test instruments." -@LLD@T@
1992 Ford F-150 XLT 2WD V8-351 5.8L Windsor 265,000 Miles
I'm having base ignition timing issues. Kept thinking to myself, the base idle sounds lower than it should and consequently, the vehicle is idling at 600RPM according to the cheapest $35 tach recently purchased at O' Reilly's.
This is my dad's truck and he mentioned that he adjusted the throttle stop screw counterclockwise (decrease idle) several years ago. My assumption was to circumvent a high idle do to a vacuum leak on MAP systems. Now that I rebuilt the upper engine and replaced all vacuum lines, the vehicle now has a very low idle.
Here are my questions: 1) In this situation, do I turn the throttle stop screw clockwise until I get to 750-800RPM? Since I cannot find a base curb idle specification and only get the answer that it is computer controlled, is the reason why the Air Bypass Valve Assembly cannot compensate is because the Throttle Position Sensor is out of range or the ABVA is stucking? 2) If the TPS is out of range, wouldn't I be reading a KOEO and/or KOER code specifying the TPS is out of range? 3) The SPOUT connector is intended to be connected at all times, correct? If it is, that explains why it is unresponsive due to retarded timing and having no cold fast idle sequence.
My initial testing/T+s=Time elapsed in seconds
SPOUT connector shorting bar connected
Start vehicle
T+0=idle 700RPM
T+5s=1600RPM (cold fast idle)
T+30s=1300RPM
T+15s=850RPM Regardless of engine speed, timing mark on damper (harmonic balancer) remains the same @ 20°BTC which verifies the EEC (engine module) and TFI (ignition module) is advancing beyond initial base timing as intended.
Disconnected SPOUT connector shorting bar
T+5s=900RPM T+10s=650 RPM @ 10°BTC (Previously timed vehicle to 650RPM before obtaining tach)
Manually increased engine speed via throttle body to 750RPM=20°BTC
"Idle Speed: Adjustments
NOTE: The curb and fast idle speeds are controlled by the e EEC-IV processor and the Air Bypass Valve Assembly. The Air Bypass Valve Assembly is not adjustable. A large increase or decrease in closed plate airflow from the calibrated level will not allow the diveci to control the speed. The idle speed setting procedure has been revised considerably to reflect the expanded application of the Self-Test idle speed options and because the throttle body incorporates an orifice in the throttle plate to control idle airflow as part of the sludge tolerant design. A change in idle airflow can occur not only at the throttle body but other areas as well. You should enter the idle speed procedure only after other possible causes in the following areas are eliminated.
[*]Contamination within the idle speed control device OK[*]Lack of fuel system control (excessively rich or lean) OK[*]Throttle sticking or binding. OK[*]Engine not reaching operating temperature OK[*]Incorrect ignition timing CHECK[*]Incorrect or clogged PCV system OK[*]Vacuum leaks (intake manifold, vacuum hoses, vacuum reservoirs, power brake booster, etc. OK Manifold Absolute Pressure (MAP) systems will increase idle with vacuum leak and Mass Air Flow (MAF) will decrease idle with vacuum leak)
RPM TOO LOW Do not clean the throttle body, Check the plate orifice plug. If there is no plug, turn screw counterclockwise until conditions in Step 4a are satisfied. If there is a plug from previous service remove plug then adjust screw in either direction as required. Screw must be in contact with the lever pad after adjustment. Step 4a- Specifies using a dealership STAR scan tool because the idle speed is computer controlled and a scan tool is required for adjustment.
Ignition Timing: Specifications Initial Timing=10ºBTC Before Top Dead Center NOTE: Initial timing is measured with engine at normal operating temperature and Spark Output (SPOUT) connector disconnected or shorting bar removed.
Ignition Timing: Adjustments
INITIAL TIMING
[*]Place transmission in NEUTRAL or PARK with Air Conditioning/Heater in OFF position. CHECK[*]Connect an inductive timing light. CHECK[*]Disconnect the single wire in-line Spark Output (SPOUT) connector or remove the shorting bar from the double wire SPOUT connector located near distributor. CHECK[*]Start engine and allow to reach operating temperature. CHECK[*]With engine at timing rpm, check or adjust initial timing to specification. ?[*]Reconnect single wire in-line SPOUT connector or reconnect shorting bar. CHECK[*]Check timing advance to verify distributor is advancing beyond the initial setting. CHECK If it does not, perform EEC IV Quick Test[*]Remove test instruments." -@LLD@T@
That being said, you're NOT SUPPOSED to adjust the screw in the first place. The screw is basically attached to the throttle. When you turn the screw either way its like pressing or releasing the throttle. You aren't really adjusting the RPMs per say, you're just giving it more throttle or letting off the throttle.
Yes the SPOUT plug is intended to be in at all times, with the exception of adjusting the timing. In that instance you remove it to check/adjust the timing. Adjusting your timing with it IN just throws your computer off and your truck will run like ****.
You would know if the IAC/IAB was sticking. If it were sticking closed your truck probably wouldn't run very well, if at all, at idle. Yes, if the TPS was out of range you SHOULD get a code/codes. Just as you SHOULD get codes if your EEC couldn't control the RPMs.
Not sure why you put all that stuff on the bottom, its just making your post longer and is information that YOU should be looking at if you think it necessary to solve/fix your issue.
08-29-2011, 06:51 PM
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RPM and Timing don't necessarily have any correlation and your timing (stock) should be 10*BTDC. With that, you only check your timing with the SPOUT plug -out-. So you can have a 10*BTDC and idle at 600 or 700 or 800 RPM since one doesn't necessarily affect the other. Hold one...should have quoted...need to go back and read again...
That being said, you're NOT SUPPOSED to adjust the screw in the first place. The screw is basically attached to the throttle. When you turn the screw either way its like pressing or releasing the throttle. You aren't really adjusting the RPMs per say, you're just giving it more throttle or letting off the throttle.
Yes the SPOUT plug is intended to be in at all times, with the exception of adjusting the timing. In that instance you remove it to check/adjust the timing. Adjusting your timing with it IN just throws your computer off and your truck will run like ****.
You would know if the IAC/IAB was sticking. If it were sticking closed your truck probably wouldn't run very well, if at all, at idle. Yes, if the TPS was out of range you SHOULD get a code/codes. Just as you SHOULD get codes if your EEC couldn't control the RPMs.
Not sure why you put all that stuff on the bottom, its just making your post longer and is information that YOU should be looking at if you think it necessary to solve/fix your issue.
Last edited by bluecar5556; 08-29-2011 at 06:58 PM.
08-29-2011, 07:04 PM
#5
Originally Posted by bluecar5556
Didn't make sense at first but when all computer advancing is disabled, RPM is irrelevant. It remains the same at all times.
The idle speed sounded much better before rebuilding the upper end and replacing the vacuum lines, although I never checked with a tach or vacuum gauge beforehand. I guess my question now is, what RPM should the idle speed be set to and why is the ECC not compensating with the IAC right now?
Right, the sticker on the TB that states such is still on there but it is too late for that, unfortunately.
Thank you for clearing that up, it no longer exists on the truck, to my knowledge, for some mysterious reason. FORD is a little different compared to what i'm used to working on. I was puzzled why @LLD@T@ never stated to disconnect the SPOUT connector at the end... Everything makes sense now.
Ahh, good point, you're exactly right about the sticking. As far as the codes, perhaps i'll check them again.
Too much info is better than too little I say, then again it DOES make the post ridiculously long. Put a dotted line at the end of the actual post, shouldn't hurt to leave it in case someone else needs and stumbles across it?
The idle speed sounded much better before rebuilding the upper end and replacing the vacuum lines, although I never checked with a tach or vacuum gauge beforehand. I guess my question now is, what RPM should the idle speed be set to and why is the ECC not compensating with the IAC right now?
Right, the sticker on the TB that states such is still on there but it is too late for that, unfortunately.
Thank you for clearing that up, it no longer exists on the truck, to my knowledge, for some mysterious reason. FORD is a little different compared to what i'm used to working on. I was puzzled why @LLD@T@ never stated to disconnect the SPOUT connector at the end... Everything makes sense now.
Ahh, good point, you're exactly right about the sticking. As far as the codes, perhaps i'll check them again.
Too much info is better than too little I say, then again it DOES make the post ridiculously long. Put a dotted line at the end of the actual post, shouldn't hurt to leave it in case someone else needs and stumbles across it?
08-29-2011, 07:44 PM
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Yes, the SPOUT short bar is missing so I think i'll make one with blade connectors soldered on a wire. I adjusted the timing to 10°BTC with the SPOUT connector disconnected then reconnected it afterwards. Then after turning the TB stop screw clockwise 1/2 turn with a 5/16" socket, noticed the orange paint on the bolt and TB aligned PERFECTLY while watching the tach @ approx. 750RPM. Woohoo, it idles and drives like it's being pulled at the same time! Very satisfied with the results, thank you Forge-World-FORD for all your help!
Last edited by bluecar5556; 08-29-2011 at 07:50 PM.
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08-29-2011, 08:55 PM
#8
Originally Posted by bluecar5556
Yes, the SPOUT short bar is missing so I think i'll make one with blade connectors soldered on a wire. I adjusted the timing to 10°BTC with the SPOUT connector disconnected then reconnected it afterwards. Then after turning the TB stop screw clockwise 1/2 turn with a 5/16" socket, noticed the orange paint on the bolt and TB aligned PERFECTLY while watching the tach @ approx. 750RPM. Woohoo, it idles and drives like it's being pulled at the same time! Very satisfied with the results, thank you Forge-World-FORD for all your help!
08-29-2011, 10:25 PM
#9
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Check your manuals, idle speed is controlled by the ECU, PCM, computor or what ever you want to call it, thru the use of the IAC. The screw is to set the base engine idle to 400-500RPM with the IAC unplugged. When plugged in the computor takes over and does all the work, whether its cold high idle or warm normal temperature idle. Check a good FORD manual, not the aftermarket gypo crap. Someplace here on the internet is Helm Inc. they print all for Fords publications, I believe they have an on site pay as you use policy. Am not sure if the material can be copied or not. I believe the minimal time usage is like 3 days.
Last edited by Good old Bill; 08-29-2011 at 10:28 PM.
08-29-2011, 11:29 PM
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That's right, I remember someone stating that from UTI now that you mention it. I found someone who wants to sell me a Helm's ford factory service manual for year 1996. Do you know if there is a lot of differences between 1992 and 1996 or would it be better to wait until the 1992 manual from helminc.com becomes in stock?
EDIT: Started the vehicle with the IAC disconnected and it idled at 500RPM in Park and in gear. Turn ignition off and reconnected IAC, idles at 750RPM in Park/In gear.
EDIT: Started the vehicle with the IAC disconnected and it idled at 500RPM in Park and in gear. Turn ignition off and reconnected IAC, idles at 750RPM in Park/In gear.
Last edited by bluecar5556; 08-30-2011 at 12:09 AM.