Rough Idle on Cold Start
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Member
Joined: Feb 2020
Posts: 16
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From: Sydney
Rough Idle on Cold Start
Hey, I'll introduce myself as I'm new here. My real name is Daniel, I have a 1998 Ranger 3.0 4x4 and I'm from Cape Breton Nova Scotia.
Anyway, I'm having a issue with my ranger. When I start the truck up (especially cold start) the idle goes real rough for the first little bit after starting the truck it will idle at about 1500 rpm and every 5-10 seconds or so it will drop right down, Also sometimes blowing black smoke. The first time I scanned the truck and I got codes for bank 1 and bank 2 too rich, also a code for evap. I cleared the codes and the cel came back on, now when I try and scan the truck I get "OBD 2 not ready". My evap canister fell off last winter and I lost it, so I ran a vent line for the fuel tank and blocked the vacuum hose that goes to the intake. I'm not sure if that has something to do with my issue or not.
So far I have tried new down stream o2 sensor, maf, plugs, wires, PCV valve, air filter, coolant temp sensor, fuel filter, and resetting the computer. The plugs and wires seemed to help with the smoke but the rough idle is still there. When I pull the new plugs they are black.
So I was wondering if anyone else has experienced this issue on a 3.0 and what the fix was? I'm thinking it could be a fuel pump or possibly the upstream o2's. I'd like to have a second opinion before I spend more money on parts I may not need. Any help would be greatly appreciated. Thanks.
Video of the truck running:
Anyway, I'm having a issue with my ranger. When I start the truck up (especially cold start) the idle goes real rough for the first little bit after starting the truck it will idle at about 1500 rpm and every 5-10 seconds or so it will drop right down, Also sometimes blowing black smoke. The first time I scanned the truck and I got codes for bank 1 and bank 2 too rich, also a code for evap. I cleared the codes and the cel came back on, now when I try and scan the truck I get "OBD 2 not ready". My evap canister fell off last winter and I lost it, so I ran a vent line for the fuel tank and blocked the vacuum hose that goes to the intake. I'm not sure if that has something to do with my issue or not.
So far I have tried new down stream o2 sensor, maf, plugs, wires, PCV valve, air filter, coolant temp sensor, fuel filter, and resetting the computer. The plugs and wires seemed to help with the smoke but the rough idle is still there. When I pull the new plugs they are black.
So I was wondering if anyone else has experienced this issue on a 3.0 and what the fix was? I'm thinking it could be a fuel pump or possibly the upstream o2's. I'd like to have a second opinion before I spend more money on parts I may not need. Any help would be greatly appreciated. Thanks.
Video of the truck running:
Welcome to the forum
The Downstream O2 is there to test if Catalytic converter is working to clean the exhaust, so it being good or bad can't effect engine operation
Upstream O2s are used AFTER warm up, to set correct air/fuel mix, these would set Rich codes, or Lean codes
O2 sensors last about 125-150k miles, after that they run out of the chemical needed to detect oxygen in the exhaust, MPG would start to go down as that happened but no lean or rich codes because O2s are used to detect that, and BOTH sides wouldn't fail at the same time
O2s need to be above 650degF to work so computer ignores them until engine/coolant temp is above 150degF
So O2 would cause cold start issues as they are not being used.........................unless ECT(engine coolant temp) sensor is failing
ECT sensor tells the computer the engine temp, this is different that dash temp gauge, only the computer uses the ECT sensor
This sensor is use to tell computer if the start up is a restart, after getting gas or running into the store, or is this a COLD start, so ignore O2 sensor
But you changed this sensor, what BRAND did you use?
But the fact engine idles high, 1,500, on cold start means ECT is working at least a bit
Lean codes can be a sign of fuel flow issues, i.e. pump and filter, not Rich codes
The black smoke means engine is running Rich, so Rich codes are not an error
So you could have a leaking fuel injector
Test for that using Clear Flooded Engine Mode
Warm up engine FIRST
Turn engine off then turn on the key
Press gas pedal down to the floor and HOLD IT DOWN ALL THE WAY
Now crank engine to try and start it
It should NOT start, it should not even fire, the fuel injectors are shut off
If engine just cranks and doesn't start then injectors are not leaking
If it fires or starts then you will need to investigate further
As soon as you release gas pedal injector will start up again
I use this every morning to start my high mile 4.0l engine, I want to circulate the oil BEFORE engine starts up
Computer on(key on), RPMs at 0 and gas pedal to the floor(TPS at 4.5volts) = Clear Flooded engine mode so computer turns off fuel injectors but spark is still on
The Downstream O2 is there to test if Catalytic converter is working to clean the exhaust, so it being good or bad can't effect engine operation
Upstream O2s are used AFTER warm up, to set correct air/fuel mix, these would set Rich codes, or Lean codes
O2 sensors last about 125-150k miles, after that they run out of the chemical needed to detect oxygen in the exhaust, MPG would start to go down as that happened but no lean or rich codes because O2s are used to detect that, and BOTH sides wouldn't fail at the same time
O2s need to be above 650degF to work so computer ignores them until engine/coolant temp is above 150degF
So O2 would cause cold start issues as they are not being used.........................unless ECT(engine coolant temp) sensor is failing
ECT sensor tells the computer the engine temp, this is different that dash temp gauge, only the computer uses the ECT sensor
This sensor is use to tell computer if the start up is a restart, after getting gas or running into the store, or is this a COLD start, so ignore O2 sensor
But you changed this sensor, what BRAND did you use?
But the fact engine idles high, 1,500, on cold start means ECT is working at least a bit
Lean codes can be a sign of fuel flow issues, i.e. pump and filter, not Rich codes
The black smoke means engine is running Rich, so Rich codes are not an error
So you could have a leaking fuel injector
Test for that using Clear Flooded Engine Mode
Warm up engine FIRST
Turn engine off then turn on the key
Press gas pedal down to the floor and HOLD IT DOWN ALL THE WAY
Now crank engine to try and start it
It should NOT start, it should not even fire, the fuel injectors are shut off
If engine just cranks and doesn't start then injectors are not leaking
If it fires or starts then you will need to investigate further
As soon as you release gas pedal injector will start up again
I use this every morning to start my high mile 4.0l engine, I want to circulate the oil BEFORE engine starts up
Computer on(key on), RPMs at 0 and gas pedal to the floor(TPS at 4.5volts) = Clear Flooded engine mode so computer turns off fuel injectors but spark is still on
Thread Starter
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Member
Joined: Feb 2020
Posts: 16
Likes: 4
From: Sydney
Hi, thanks for the help. The engine coolant temp sensor I used wasn't brand new but it came out of a truck that was running perfect before it was parted out. After I swapped the ECT it had no effect at all so I ruled that out.
After the truck warms up it will sit there and idle at 900 RPM all day. Is that normal for a 3.0?
I took the truck for a test drive and it runs fine but one thing I noticed is every now and then while I'm cruising at around 1800 RPM it's almost like the truck has a miss fire that comes and goes.
I will test for a leaking injector and check back in with what I find.
After the truck warms up it will sit there and idle at 900 RPM all day. Is that normal for a 3.0?
I took the truck for a test drive and it runs fine but one thing I noticed is every now and then while I'm cruising at around 1800 RPM it's almost like the truck has a miss fire that comes and goes.
I will test for a leaking injector and check back in with what I find.
Thread Starter
|
Member
Joined: Feb 2020
Posts: 16
Likes: 4
From: Sydney
Welcome to the forum
The Downstream O2 is there to test if Catalytic converter is working to clean the exhaust, so it being good or bad can't effect engine operation
Upstream O2s are used AFTER warm up, to set correct air/fuel mix, these would set Rich codes, or Lean codes
O2 sensors last about 125-150k miles, after that they run out of the chemical needed to detect oxygen in the exhaust, MPG would start to go down as that happened but no lean or rich codes because O2s are used to detect that, and BOTH sides wouldn't fail at the same time
O2s need to be above 650degF to work so computer ignores them until engine/coolant temp is above 150degF
So O2 would cause cold start issues as they are not being used.........................unless ECT(engine coolant temp) sensor is failing
ECT sensor tells the computer the engine temp, this is different that dash temp gauge, only the computer uses the ECT sensor
This sensor is use to tell computer if the start up is a restart, after getting gas or running into the store, or is this a COLD start, so ignore O2 sensor
But you changed this sensor, what BRAND did you use?
But the fact engine idles high, 1,500, on cold start means ECT is working at least a bit
Lean codes can be a sign of fuel flow issues, i.e. pump and filter, not Rich codes
The black smoke means engine is running Rich, so Rich codes are not an error
So you could have a leaking fuel injector
Test for that using Clear Flooded Engine Mode
Warm up engine FIRST
Turn engine off then turn on the key
Press gas pedal down to the floor and HOLD IT DOWN ALL THE WAY
Now crank engine to try and start it
It should NOT start, it should not even fire, the fuel injectors are shut off
If engine just cranks and doesn't start then injectors are not leaking
If it fires or starts then you will need to investigate further
As soon as you release gas pedal injector will start up again
I use this every morning to start my high mile 4.0l engine, I want to circulate the oil BEFORE engine starts up
Computer on(key on), RPMs at 0 and gas pedal to the floor(TPS at 4.5volts) = Clear Flooded engine mode so computer turns off fuel injectors but spark is still on
The Downstream O2 is there to test if Catalytic converter is working to clean the exhaust, so it being good or bad can't effect engine operation
Upstream O2s are used AFTER warm up, to set correct air/fuel mix, these would set Rich codes, or Lean codes
O2 sensors last about 125-150k miles, after that they run out of the chemical needed to detect oxygen in the exhaust, MPG would start to go down as that happened but no lean or rich codes because O2s are used to detect that, and BOTH sides wouldn't fail at the same time
O2s need to be above 650degF to work so computer ignores them until engine/coolant temp is above 150degF
So O2 would cause cold start issues as they are not being used.........................unless ECT(engine coolant temp) sensor is failing
ECT sensor tells the computer the engine temp, this is different that dash temp gauge, only the computer uses the ECT sensor
This sensor is use to tell computer if the start up is a restart, after getting gas or running into the store, or is this a COLD start, so ignore O2 sensor
But you changed this sensor, what BRAND did you use?
But the fact engine idles high, 1,500, on cold start means ECT is working at least a bit
Lean codes can be a sign of fuel flow issues, i.e. pump and filter, not Rich codes
The black smoke means engine is running Rich, so Rich codes are not an error
So you could have a leaking fuel injector
Test for that using Clear Flooded Engine Mode
Warm up engine FIRST
Turn engine off then turn on the key
Press gas pedal down to the floor and HOLD IT DOWN ALL THE WAY
Now crank engine to try and start it
It should NOT start, it should not even fire, the fuel injectors are shut off
If engine just cranks and doesn't start then injectors are not leaking
If it fires or starts then you will need to investigate further
As soon as you release gas pedal injector will start up again
I use this every morning to start my high mile 4.0l engine, I want to circulate the oil BEFORE engine starts up
Computer on(key on), RPMs at 0 and gas pedal to the floor(TPS at 4.5volts) = Clear Flooded engine mode so computer turns off fuel injectors but spark is still on
Yes, it could be, but FIRST check throttle cable, if it can't open the throttle all the way, then no Clear Flooded Engine Mode
Key off
Put something on gas pedal to push it down all the way, like a stick against the seat
Then open the hood and see if throttle will open more, if so then cable has stretched, do Throttle Cable Mod
Release gas pedal, then put a zip tie, or two, on the end of the throttle cable above gas pedal, you will see where to do it, it tightens the cable so you get full throttle back
Picture here: https://www.therangerstation.com/tec...tle-cable-mod/
Then repeat test
Key off
Put something on gas pedal to push it down all the way, like a stick against the seat
Then open the hood and see if throttle will open more, if so then cable has stretched, do Throttle Cable Mod
Release gas pedal, then put a zip tie, or two, on the end of the throttle cable above gas pedal, you will see where to do it, it tightens the cable so you get full throttle back
Picture here: https://www.therangerstation.com/tec...tle-cable-mod/
Then repeat test
Thread Starter
|
Member
Joined: Feb 2020
Posts: 16
Likes: 4
From: Sydney
Yes, it could be, but FIRST check throttle cable, if it can't open the throttle all the way, then no Clear Flooded Engine Mode
Key off
Put something on gas pedal to push it down all the way, like a stick against the seat
Then open the hood and see if throttle will open more, if so then cable has stretched, do Throttle Cable Mod
Release gas pedal, then put a zip tie, or two, on the end of the throttle cable above gas pedal, you will see where to do it, it tightens the cable so you get full throttle back
Picture here: https://www.therangerstation.com/tec...tle-cable-mod/
Then repeat test
Key off
Put something on gas pedal to push it down all the way, like a stick against the seat
Then open the hood and see if throttle will open more, if so then cable has stretched, do Throttle Cable Mod
Release gas pedal, then put a zip tie, or two, on the end of the throttle cable above gas pedal, you will see where to do it, it tightens the cable so you get full throttle back
Picture here: https://www.therangerstation.com/tec...tle-cable-mod/
Then repeat test
And the truck fires when gas pedal is down to the floor and starter motor is engaged?
If so, then when engine is cold get your spark plug wrench out
Unplug the coil pack, so no spark
Do the clear flooded engine test but crank for a full 10 count
Now start pulling out the spark plugs
ALL should be dry as a bone, except if that cylinders injector was leaking
If they are all WET then not sure what to say
All Ford computers have clear flooded engine mode
If so, then when engine is cold get your spark plug wrench out
Unplug the coil pack, so no spark
Do the clear flooded engine test but crank for a full 10 count
Now start pulling out the spark plugs
ALL should be dry as a bone, except if that cylinders injector was leaking
If they are all WET then not sure what to say
All Ford computers have clear flooded engine mode
Thread Starter
|
Member
Joined: Feb 2020
Posts: 16
Likes: 4
From: Sydney
And the truck fires when gas pedal is down to the floor and starter motor is engaged?
If so, then when engine is cold get your spark plug wrench out
Unplug the coil pack, so no spark
Do the clear flooded engine test but crank for a full 10 count
Now start pulling out the spark plugs
ALL should be dry as a bone, except if that cylinders injector was leaking
If they are all WET then not sure what to say
All Ford computers have clear flooded engine mode
If so, then when engine is cold get your spark plug wrench out
Unplug the coil pack, so no spark
Do the clear flooded engine test but crank for a full 10 count
Now start pulling out the spark plugs
ALL should be dry as a bone, except if that cylinders injector was leaking
If they are all WET then not sure what to say
All Ford computers have clear flooded engine mode
Thread Starter
|
Member
Joined: Feb 2020
Posts: 16
Likes: 4
From: Sydney
Don't mean to bump this thread, but I still can't get to the bottom of this. I would really like to figure this out in the next few days as my 6 month licence suspension is going to be finished on the 21st lol. I tried checking for leaking injectors and the truck does not start when held at wot. I have a feeling it's the maf causing the issue. When I unplug the maf the truck runs better. Even though it is basically new? It is a walker brand maf. What I dont understand though is I replaced the maf over a year ago and it ran fine. (When I said new maf I meant there's about 1500km on it) And now after sitting it is running horrible. I forgot to mention also that all these issues happened after the truck sat for 5 months. It was started and allowed to run every week though. If I can't figure it out I'll take it somewhere to get scanned with a better scanner than I have.
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