[mmnewcomb]

Having trouble finding a solution here. My '13 EB has new plugs and new coils, cleaned TB and MAPs, new PCV, but I'm still having a rough idle, low vacuum and really poor LTFT on Bank 2.

RPMs stumble from 580-620 at idle, I'm showing at most 11-13 inHg vacuum, and my LTFT on Bank 2 is -24% while Bank 1 is -10%. I've gone all over the engine and can't find any vacuum leaks. Any suggestions where to go next?

 

[dezman2]

Bad cat on drivers side?

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[mmnewcomb]

I don't think so based on what I can see. No rotten eggs, temperature between both cats is the same, around 700 degrees F when idling. One thing I did notice is that at full operating temp, my O2 Bank 2 Sensor 2 stayed steady at 0.075v to 0.105v while my Bank 1 Sensor 2 fluctuated from 0.095v to 0.760v at a standard interval. Could that point to a bad O2 sensor?

 

[dezman2]

I don't think so based on what I can see. No rotten eggs, temperature between both cats is the same, around 700 degrees F when idling. One thing I did notice is that at full operating temp, my O2 Bank 2 Sensor 2 stayed steady at 0.075v to 0.105v while my Bank 1 Sensor 2 fluctuated from 0.095v to 0.760v at a standard interval. Could that point to a bad O2 sensor?

Not sure. Was just wondering if a cat was clogged up a bit and messing with things.

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[SrpRacing]

When was the last time the O2 sensors were replaced? Not a bad maintenance item.

Also I’d do a kam reset following all those changes. Then do an idle relearn.

What do the STFTs look like? I imagine after those changes they are probably still adjusting.

 

[mmnewcomb]

I just replaced the Bank 2 Sensor 2 O2 sensor. The old one was definitely not operating properly based on the live data so that's one good thing.

I still think I have a vacuum leak somewhere on top of the motor but I just can't pinpoint it.

I did the relearn, but I've done that a few times and it never seems to really do a relearn. LTFT's for both banks stayed relatively the same. Bank 2 went from -24% to -22% after the O2 replacement. Will see if anything changes after driving a bit.

 

[SrpRacing]

A vacuum leak would cause the LTFTs to trend positive not negative and the idle rpm would be higher.

It’s sensing a rich condition or not enough airflow.

Do the fuel trims trend towards 1 when accelerating? Is this the same tank of gas?

When a kam reset is done properly you’ll notice both LTFTs be at 1 and the STFTs move to either positive or negative.

 

[mmnewcomb]

That’s good to know. I do smell fuel on a cold start so the rich condition could make sense.

I’ll do another kam reset tomorrow and see what the fuel trims show me.

 

[SrpRacing]

These engines do run rich on a cold start. So smelling a bit of fuel is quite normal.

 

[mmnewcomb]

The amount of gas I smell is a new phenomenon with this truck. I've owned it for 2 years and never had it smell like this.

I just did a kam relearn and did some testing with Forscan and can't find any faults or any issues with anything. I'm attaching a screenshot of my fuel trims. I'm just at a loss. I can't figure out why it would be sensing a rich condition.

EDIT: I did forget to mention, I monitored actual fuel rail pressure vs. expected pressure. Actual was ~1500kPa, while expected was 1360kPa. Not sure what that could point to.

 

[SrpRacing]

This may be a stupid question but when was the air filter last replaced? Check to make sure all pipes are tight.

Do the LTFTs move toward 1 when accelerating and driving around?

Some catch cans impede the airflow leading back to the intake which can skew the LTFTs a tad.

11-13inhg is normal when idling. It will be higher when decelerating.

Make sure you have the correct motorcraft PCV valve installed and that the passenger side is the only side with a check valve.

Also is this the same tank of gas? How long has it been doing this?

 

[mmnewcomb]

Air filter is a year old I'd guess but looks like new. All pipes are tight.

I don't have a catch can installed.

PCV valve is a brand new Motorcraft valve picked up yesterday. It's the newer brown one that was part of the TSB for fuel getting into the oil.

The one thing that hasn't changed is that this is the same tank of gas since the problems started. They didn't start right when I filled it up, and I'm down to about a quarter tank left now. I'll probably fill up today and see if that affects anything. I'm going to monitor the LTFT when I take a ride in a few minutes and see what it does upon acceleration.

The issues have been going on for about a week so far. I filled this tank about 3 weeks ago.

 

[SrpRacing]

Sounds like it could definitely be the fuel. You may have a gotten an ethanol free blend.

 

[NickG80]

Negative fuel trims means rich and it is taking away fuel. Plus the O2 sensor shows that it is rich. I’d guess a stuck open injector.

 

[mmnewcomb]

Negative fuel trims means rich and it is taking away fuel. Plus the O2 sensor shows that it is rich. I’d guess a stuck open injector.

I thought about an open injector at first, but there hasn't been any type of smoke coming through the exhaust. I guess it could be a leaky injector and maybe it's just not pumping out enough to cause smoke but enough to force the engine to run lean. Is there an easier way to test for that without pulling the manifold off? I'm assuming not.

 

[SrpRacing]

It’s by looking at the Fuel trims when driving. Not idling. That will give a better answer on what’s going on.

 

[mmnewcomb]

Alright so I did a short trip last night and monitored the trims.

At idle, bank 1 LTFT was -10% and bank 2 was at -25% like I said before. Under load around 2500rpm (short trip, didn't get above 25mph) both banks settled around -6% and were both pretty much following each other exactly.

So I'm thinking that I need to be looking for a leaky injector in bank 2. I watched a video of a guy doing a cold flood crank test so I guess I'll start there and see if I find anything.

 

[SrpRacing]

It’s not an injector if both banks trim at 6% under load. If it were then one would be trimming far less than the others while in OPEN loop. It sounds like Ethanol free fuel. Have you tried filling up with a new tank?

The -25% at idle could be an exhaust leak. Make sure the coupler on the downpipe is seating the turbo all the way. That would explain the growing fuel smell on cold start.

When was the last time the oil was changed? Fuel dilution can also affect fuel trims while in closed loop.

If anything fill up with some high quality fuel, go for a nice highway drive, and get the truck hot.

 

[mmnewcomb]

It’s not an injector if both banks trim at 6% under load. If it were then one would be trimming far less than the others while in OPEN loop. It sounds like Ethanol free fuel. Have you tried filling up with a new tank?

The -25% at idle could be an exhaust leak. Make sure the coupler on the downpipe is seating the turbo all the way. That would explain the growing fuel smell on cold start.

When was the last time the oil was changed? Fuel dilution can also affect fuel trims while in closed loop.

If anything fill up with some high quality fuel, go for a nice highway drive, and get the truck hot.

Alright so I got a new tank of fuel and drove a 100-mile round trip yesterday. Since the idling issue began the truck still always ran great under acceleration and cruising. The main issue is the stumbling idle and the long crank times which I'm still experiencing. Also to answer you previous question, the oil was changed about 500 miles ago.

So after the 100-mile drive yesterday (mainly highway) I stopped at my buddy's house and hung out for a couple hours. When I was leaving I got in the truck and started it. It cranked for 5 full seconds, and then barely started like it was in limp mode. I hit the accelerator and it then kicked on to a regular start. So I am really confused as to what the issue is. Still zero codes.

 

[SrpRacing]

Could your hpfp be going out? The truck needs a certain amount of fuel pressure before lighting off the mixture.