tune or something else?

pass1over

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Ever since I put long tubes on my car and had AM adjust the tune, I have been having an idle issue that I can't figure out and they can't tune for. I just want to make sure I'm not overlooking something mechanical on my end.

While driving, if I push the clutch in the car will idle down to around 800 or so, then fall to 500 for a little bit, can hear/feel it struggling, then bounce back up to 800/900. It doesn't do it all the time and is worse when engine is cold.

I have cleaned throttle body, MAF and air filter multiple times. I replaced all gaskets on the CAI and replaced the breather tube from drivers valve cover to CAI. All clamps are tight and sealed. What else can I look at or is this a tune issue?
 

pass1over

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I never had an issue with their tune until this. I figured they probably didn't need to change much for the long tubes anyways.
 

pass1over

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You would think it would be an easy fix. Almost as easy as providing some helpful constructive information about this topic. Like I've said before in this post ... 9 years and almost 173k miles and never had an issue with their tune on my car.

So I'm guessing that's a No, you can't think of anything else mechanical for me to look at before placing the issue purely on the tune?

Lito doesn't tune 5.0's last I read/heard.
 

Laga

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[QUOTE="pass1over, post: 2514234, member: 12464. 9 years and almost 173k miles and never had an issue with their tune on my car.

.[/QUOTE]
And none of those miles with the long tubes. Find a better tuner.
 

pass1over

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Long tubes do not need a tune. Go back to your old tune and see if you still have the issue. If not then you know its something in the new tune.

loading the tune pre-LT's now. This was my idea as well.
 

Dino Dino Bambino

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Long tubes do not need a tune.

From an airflow standpoint, you're correct as the MAF sensor inputs adjust for changes in airflow but there are two other factors to consider:

1. The primary header tube length and how much further away from the cylinder head exhaust ports the upstream O2 sensors need to be placed. On cold starting it doesn't matter as the ECU is in open loop. However when it transitions into closed loop, this can cause the engine to run lean and hesitate as the O2 sensors may not yet have warmed up. This may not be an issue on warm summer days but on cold winter days it could be more problematic. The simple solution is to adjust the tune to extend the cold start open loop operation.

2. If you're using an off-road mid-pipe behind the long tubes, you need to have the downstream O2 sensors disabled in the tune to prevent the CEL from flashing up. A CEL tripped by the downstream O2 sensors doesn't affect driveability in any way though.

@pass1over which LT headers do you have, and do you have a catted or off-road midpipe?
Did you retorque the header bolts after running the engine for a couple of heat cycles?
Since the problem dates back to when AM adjusted the tune, that's most likely to be the source of your problem. One way to find out is to reload your pre-LT tune (which you already thought of) and see if the idle improves. If AM had only made one or both of the adjustments I mentioned above to your previous tune, there shouldn't have been any problem.
If your previous tune doesn't solve the erratic idling problem, the next step would be to look for a vacuum leak. When the idle drops to 500rpm and the engine's on the verge of stalling, this indicates that it's momentarily running lean.
If it does solve the idling problem, you could either leave it alone or have it optimized by reputable Coyote tuners like Lund Racing or VMP.
 
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Juice

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I can tell you first hand, just installing LTs and not updating the tune worked fine on mine. I started adding transport delay for the headers with no noticable drivability effect. Only had a small impact on fuel trims.

Your idle stumble sounds very similiar to my idle issues when I first got mine running. Changes to the predicted throttle angle table was my solution.(returned to 100% stock) I think this was altered some for throttle response. I have confirmed this to be the case. Running a stock TB and using the Ford stock data, zero idle issues. Couldn't see anything in the logs, no codes were tripped.

Coyote pcm has the ability to learn the LT headers, but it is not enabled by default. I found one of the settings, and SCT is kind enough to note that other setting changes are needed to enable learning of transport delay, but neglected to list them in the notes.

I do feel that disabeling fore-aft fuel control is better for LTs. That is how I have mine now. Without changes to O2 transport delay.
 

pass1over

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I have MBRP long tube headers, with an off road X pipe. Rear o-2's are still installed as AM will no longer disable them. I was getting a code for rear o2 left bank, but I found one of the clamps had slipped and there was an exhaust leak. I fixed that and code has not returned. I'm not sure how much the front o2's actually moved, as I didn't need a harness extension. It was awhile ago, but it almost seems like they stayed in roughly the same spot as original. I could be wrong though, too many projects.

When the car idles down to 500rpm, I noticed on my WB that it goes rich. I was seeing it dip down to 12.0-13.4 and then shoot up to the mid 15's before settling back around stoich. No codes are present when any of this happens, and no codes on the car.

Only other thing besides tune I can think of is vacuum leak like you suggested. At this point, I think a smoke test would be the only thing that could help me out.

I'll post back results after a pre-LT tune drive. Thanks for the ideas!

edit: I forgot to mention, I did re-torque the headers after a few heat cycles. I don't hear or smell any exhaust leaks, but I might throw it back up on the lift and check them again.
 
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GlassTop09

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Ever since I put long tubes on my car and had AM adjust the tune, I have been having an idle issue that I can't figure out and they can't tune for. I just want to make sure I'm not overlooking something mechanical on my end.

While driving, if I push the clutch in the car will idle down to around 800 or so, then fall to 500 for a little bit, can hear/feel it struggling, then bounce back up to 800/900. It doesn't do it all the time and is worse when engine is cold.

I have cleaned throttle body, MAF and air filter multiple times. I replaced all gaskets on the CAI and replaced the breather tube from drivers valve cover to CAI. All clamps are tight and sealed. What else can I look at or is this a tune issue?
Hi pass1over,
From reading your symptoms you posted (assume that you have a Coyote thus Copperhead PCM), this reads to me like you may be having issues w\ your WB O2's heaters keeping the elements hot enough for the WB's to respond fast enough to maintain AFR during throttle transitions (you pushing in clutch while driving means you've also fully released the accelerator pedal as well....right? If so then this action puts the PCM in DFCO--deceleration fuel cut off, a normal operation of an electronic fuel injection system--until the engine RPM's drop below a certain RPM along w\ the VSS showing the vehicle speed to be below a certain MPH setting--typically 1,000 RPM's for the engine but this can be set in tune at a lower RPM as well--before the PCM reenables the fuel injectors. While this is going on the engine is essentially pumping air only thru the exhaust which is cooling the WB's elements & can shut them down--stop putting out current--unless the WB's heaters can maintain enough heat in the elements by themselves to keep the WB's functioning thruout this process. You won't see any DTC due to the PCM is ignoring these during this episode. Then when PCM turns the injectors back on & engine is now burning fuel, if the WB's are slow to respond the PCM will think the fueling is rich due to WB's showing low\no current thus lean out the fuel causing your issue until the WB's wake up & react showing high current now thus PCM thinks fueling is lean thus reacting to correct back to stoich since by now the WB's have woke up & are functioning normally & since they woke up before the WB testing time span counted off the PCM didn't flag a DTC), depending on what speed you're moving when you initiate this process. The WB heater issue can also cause what you're seeing during cold starts as well (WB's too slow to start operating before PCM switches from OL to CL operation, again causing the exact same operational pattern as mentioned above), depending on where the initial ambient temp is at when cold start is initiated. You can run tests on these to see if this is what's going on before you buy anything using a generic OBDII scan tool that can display live data (set up scan tool to view custom data to look at the B1S1, B2S1 WB sensor current output PIDs along w\ the fuel system 1 PID which shows OL to CL status during a cold start to see if\how fast the WB's start sending current outputs before the status switches from OL to CL....essentially from being cold to being heated up which will also be the case during a DFCO event while driving).

This really should be checked out if for no other reason to ensure that all this is operating properly.....don't wait for a MIL to do this.
Also, this issue can be caused\aggravated by the install of LT's which will move the existing WB's being used further down the exhaust system from the closest engine exhaust port, depending on how well\poor the WB's heaters are operating. A properly operating O2 sensor heater, regardless of whether a WB or a NB design, should be capable of heating up the sensor's element w\o any assist from engine exhaust temp to start sensor operation within 100ms time span. This capability\lack of will also affect the O2 sensor's overall accuracy so shouldn't be taken lightly IMHO........ If you do decide to replace both WB's I suggest to replace only w\ OEM Ford WB O2 sensors regardless of the cost.

Something to think about & consider since you haven't posted anything to suggest to me that you have checked this potential cause & verified this to not be the cause of your issue.

Hope you get all resolved.
 

pass1over

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I have and SCT and livewire I can datalog on my laptop and check out those PID's. I was thinking that something was going on with the DFSO possible, but hadn't thought of it being an o2 sensor issue. I've messed around a lot on my pushrod 5.0 swapped '66 tuning, just not this one so much.

I'm in Florida and even the "cold" temps in the mornings are mid 70s.


Thank you for pointing this out.
 

pass1over

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It did not like the pre-LT tune, it stayed way too lean everywhere. I was just easy on it on the drive home and am uploading one of the LT tunes I have.

Also waiting on the car to cool down so I can datalog the o2's and OL/CL status.
 

pass1over

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One thing I forgot to add, AM has asked me a few times about my mods. They first wanted to verify my mod list as if something was missed and stumping them. Then they asked if my CAI was a series 1 or 2. Lastly, they asked if I had a ram air hood by chance. All of which I thought was a bit odd, any idea what they could be seeing on their end?

I might pull the o2's and look at them before I order new ones, maybe they got messed up somehow during install. But yea, I'll get FoMoCo ones when/if I need them.
 

Juice

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One thing I forgot to add, AM has asked me a few times about my mods. They first wanted to verify my mod list as if something was missed and stumping them. Then they asked if my CAI was a series 1 or 2. Lastly, they asked if I had a ram air hood by chance. All of which I thought was a bit odd, any idea what they could be seeing on their end?

I might pull the o2's and look at them before I order new ones, maybe they got messed up somehow during install. But yea, I'll get FoMoCo ones when/if I need them.
They asked because some mods need to be tuned for, like a "tune required" CAI.
They want to make sure all the applicable value files have been added to your tune. This works most of the time, and the pcm learns the difference. Once they get someone like you, who's car isnt happy with just the value files, they are lost. And this one of the most difficult strategies to tune.
 

pass1over

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Interesting. This is the third change I've made to the car needing them to tune it and every other time is was spot on.

I don't know, at 173k, the original o2's might have had their last dance.
 

Juice

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Interesting. This is the third change I've made to the car needing them to tune it and every other time is was spot on.

I don't know, at 173k, the original o2's might have had their last dance.
Thats a lot of miles, maybe.
Have you cleaned the throttle body? I know Ford says it should never be done (and there is logic in the pcm to deal with it). I still clean mine.
Note: this operation can damage the throttle body if the blade is forced open. Key on, engine off, helper holding foot to floor while you clean is the safe way. At that many miles, anything can fail at any time. Just to be clear.
 

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