I6 300 ROUGH IDLE

[Mhfco6]

I’ve been trying to chase down a rough idle and need some help please. I’ve cleaned the IAC, replaced TB with a Delphi sensor, blocked EGR valve then unblocked and replaced gasket, unplugged 02 sensor while running but nothing has helped.

1987 F150
Codes are 41 63 and 32

Inline6 300 Rough Idle

m.youtube.com

 

[RonD]

Double check firing order, then have a friend check it, lol

You should always look up codes on a full list FIRST, like here: https://www.therangerstation.com/tech/obd-i-diagnostic-trouble-code-dtc-applications-2-digit-ford-codes/

Reason being is that there are usually several codes the computer can chose from for any device, sensor or system, so the codes it DID NOT chose can tell you what its NOT, so narrowing down the field of what it might be

32 EVP – (R) EGR not responding properly during test
This means when computer activated the EGR solenoid(sent vacuum to valve) the EGR sensor did not show the EGR valve opening
Not sure what EGR sensor is used on your model, a pressure sensor(DPFE) or physical movement sensor on the EGR valves shaft


41 (R) System lean – Fuel control
This means O2 sensor was reporting higher Oxygen Level in exhaust so computer is having to add more fuel than calculated for RPM and engine load
Can be from a vacuum leak, dirty MAF sensor(MAP sensor issue), steady misfires, exhaust manifold leak(it sucks in air), low fuel pressure

63 Throttle Position Sensor (TPS) signal too low TPS
TPS is a 5volt sensor, has 3 wire connector, center wire is the "return voltage" to computer to tell it the position of throttle plate, foot on the gas pedal
Key on engine off
Center wire should show 0.69v to 0.99volt, under 1 volt
At WOT the center wire should show 4.5volt
Code 63 would indicate center wire is under 0.69v on start up, foot off gas pedal
Could be just mis-adjustment or a dead spot in TPS, you will need to test it with volt meter
Could also be corrosion on a connector, its lowering voltage enough to set the code
Test 3 wire connector for 5volt, top wire and ground, lower wire

Warm up engine, let it idle
Unplug the two wire connector on the IAC Valve, it should close
RPMs should drop to 500 or engine may even stall either is good it means no vacuum leaks
If idle doesn't drop then there is a vacuum leak, find it

 

[bobbywalter]

Did you wet test the plug wires?


What did the plugs look like?


What does the vacuum look like?


Is there vacuum signal to the egr solo?

 

[Mhfco6]

Double check firing order, then have a friend check it, lol

You should always look up codes on a full list FIRST, like here: https://www.therangerstation.com/tech/obd-i-diagnostic-trouble-code-dtc-applications-2-digit-ford-codes/

Reason being is that there are usually several codes the computer can chose from for any device, sensor or system, so the codes it DID NOT chose can tell you what its NOT, so narrowing down the field of what it might be

32 EVP – (R) EGR not responding properly during test
This means when computer activated the EGR solenoid(sent vacuum to valve) the EGR sensor did not show the EGR valve opening
Not sure what EGR sensor is used on your model, a pressure sensor(DPFE) or physical movement sensor on the EGR valves shaft


41 (R) System lean – Fuel control
This means O2 sensor was reporting higher Oxygen Level in exhaust so computer is having to add more fuel than calculated for RPM and engine load
Can be from a vacuum leak, dirty MAF sensor(MAP sensor issue), steady misfires, exhaust manifold leak(it sucks in air), low fuel pressure

63 Throttle Position Sensor (TPS) signal too low TPS
TPS is a 5volt sensor, has 3 wire connector, center wire is the "return voltage" to computer to tell it the position of throttle plate, foot on the gas pedal
Key on engine off
Center wire should show 0.69v to 0.99volt, under 1 volt
At WOT the center wire should show 4.5volt
Code 63 would indicate center wire is under 0.69v on start up, foot off gas pedal
Could be just mis-adjustment or a dead spot in TPS, you will need to test it with volt meter
Could also be corrosion on a connector, its lowering voltage enough to set the code
Test 3 wire connector for 5volt, top wire and ground, lower wire

Warm up engine, let it idle
Unplug the two wire connector on the IAC Valve, it should close
RPMs should drop to 500 or engine may even stall either is good it means no vacuum leaks
If idle doesn't drop then there is a vacuum leak, find it

Other than the pulley/belt squeak this test checks out.

 

[RonD]

Yes, not a vacuum leak

 

[Mhfco6]

Did you wet test the plug wires?
Yes I did, no sparks at night.


What did the plugs look like?
Haven’t pulled them yet


What does the vacuum look like?
Here is a R134 gauge, but you get the point.


Is there vacuum signal to the egr solo?
Have a feeling this is important but not sure how to perform this test. Bobby, can you please help explain how?

Hey Bobby, the answers to your questions are below.

Did you wet test the plug wires?
Yes I did, no sparks at night.


What did the plugs look like?
Haven’t pulled them yet


What does the vacuum look like?
Here is a R134 gauge, but you get the point.

I6 300 Vacuum

m.youtube.com

Is there vacuum signal to the egr solo?
Have a feeling this is important but not sure how to perform this test. Bobby, can you please help explain how?

 

[bobbywalter]

Well ..it sounds ok for a 300 in the vid.


The vac is solid .. but seeing flutter on the setup you gave there over a typical automotive unit ... Can't say if it will tell much.


Look at your vac label. Make sure all is lined out.

 

[rusty ol ranger]

Dude that idles about like any other early EEC IV ford. I wouldnt worry.

 

[Mhfco6]

Well ..it sounds ok for a 300 in the vid.


The vac is solid .. but seeing flutter on the setup you gave there over a typical automotive unit ... Can't say if it will tell much.


Look at your vac label. Make sure all is lined out.

I just replaced all the vacuum lines last year and followed all of them. This idle issue just started.

 

[Mhfco6]

Dude that idles about like any other early EEC IV ford. I wouldnt worry.

My 91 ranger doesn’t run like this, it idles smooth. This truck never ran like this till recently. Something is off, it shouldn’t run up and down and either have a high idle or idle so rough that it dies. I usually get phenomenal info here!

 

[rusty ol ranger]

My 91 ranger doesn’t run like this, it idles smooth. This truck never ran like this till recently. Something is off, it shouldn’t run up and down and either have a high idle or idle so rough that it dies. I usually get phenomenal info here!

I didnt hear that in the video. All i seen was the tremors they all do.

You spray ether around the intake manifold?

 

[Mhfco6]

I didnt hear that in the video. All i seen was the tremors they all do.

You spray ether around the intake manifold?

Did you watch the video I linked in the first post? Got all this hurricane rain coming in here but I’ll try the ether this weekend and let you know what it does.

 

[Mhfco6]

I sprayed brake cleaner everywhere and the only spot that changed idle was the EGR gasket, so I installed one and it didn’t react to the brake cleaner anymore.

 

[4x4prepper]

Ditto on everything RodD posted, especially about #63.

I have worked on many I-6 300s and owned them, you should not have a rough idle. A ticking, yea, maybe, the older 1980s and 1990s ticked right from the factory sometimes.

Assuming you do not have a voltage problem, I would do a stone cold and then hot compression test (WOT) and make sure you do not have a dead cylinder or weak cylinder. It is one of the easiest engines to do a compression test on unless it is an inline 4 such as in a 1980s Jeep.

Prime example: A guy called me to fix his marine Chrysler 318 in dual inboard engine 1965 Marienette (sp?) that had a rough idle, and they had thrown everything at it, including a new carb. The first thing I did was I put a vacuum gauge on it, saw the dip and jump, so then I did a compression test and one cyl was completely dead. I could take a picture of the actual hole in the piston with my cell phone, inside a crammed engine compartment, it was that obvious a blunder of the previous mechanics.

imho, Do the compression test first so you are not chasing your tail. A bad plug will be obvious. Then worry about the #63 code.

 

[Mhfco6]

Ditto on everything RodD posted, especially about #63.

I have worked on many I-6 300s and owned them, you should not have a rough idle. A ticking, yea, maybe, the older 1980s and 1990s ticked right from the factory sometimes.

Assuming you do not have a voltage problem, I would do a stone cold and then hot compression test (WOT) and make sure you do not have a dead cylinder or weak cylinder. It is one of the easiest engines to do a compression test on unless it is an inline 4 such as in a 1980s Jeep.

Prime example: A guy called me to fix his marine Chrysler 318 in dual inboard engine 1965 Marienette (sp?) that had a rough idle, and they had thrown everything at it, including a new carb. The first thing I did was I put a vacuum gauge on it, saw the dip and jump, so then I did a compression test and one cyl was completely dead. I could take a picture of the actual hole in the piston with my cell phone, inside a crammed engine compartment, it was that obvious a blunder of the previous mechanics.

imho, Do the compression test first so you are not chasing your tail. A bad plug will be obvious. Then worry about the #63 code.

When I cold start this truck even in the summer it idles high and knocks for 1-2 seconds then goes away. I thought it was due to a new oil filter so I tried a different one, but same thing. I tested my new Delhi TPS and confirmed it wasn’t installed properly. I reset it and am getting .9 at rest and 4.6 at WOT - KOEO. Today I tested the EGR valve, pulled a vacuum on it and plugged the air intake valve with my finger. This did not change the idle or performance. Could this be my issue, it should be spitting and sputtering, correct?