Idle issue

Pentalab

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The FRPP T-body is way too massive for a NA car. The FRPP Manifold is also huge. You're sacrificing a grip of low-mid power for virtually no top end gain. You have huge air volume and low air velocity, and no cubic inch to back it up. That setup needs a blower huffing into it to make use of it.

Regardless, the T-body would be a possible idle issue component. The movement of a t-body that large would have to be extremely small at idle and have huge effects if the movement weren't tight enough. Abormalities in TPS voltage alone would cause significant idle hunting. Particularly if having alternator issues as well.

I have the FRPP twin 62mm TB on my 2010 auto ( with small roush M90 blower). The idle is superb, doesn't budge. The FRPP twin 62mm TB is made by acufab, same outfit that makes the oem twin 55mm tb. The FRPP twin 62mm TB won't buy you anything on a NA car, but it won't screw up the idle either.
 

Pentalab

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I asked about fuel pressure because I saw in your other video the pump duty cycle was showing .24. This translates to 48% in percentage value which is high for an idling engine. I think mine was at .15-18. The throttle hesitation could be from a dirty in-line fuel filter and/or a dirty pre-filter attached to the fuel pump which would explain the high duty cycle.
But it could also be a bad throttle position sensor. Usually people replace the whole TB when diagnosing throttle related problems.

As for TPS voltage, there should not be any fluctuating at all if the throttle is staying in one position.

My 2010 ( with m90) fuel rail pressure is 40 psi, and fluctuates between 39.8 and 40.2 psi..at idle. It's like that whether idle or 6 krpm with blower on full bore boost.

My Fuel pump duty cycle is 38-40% at idle. Rises to 80% at 6 krpm with blower on full tilt. ( that's with the 10 gauge wire mod from battery to trunk, to reduce fpdc, when blower used)

A few years ago, one day... ONLY when trying to get into boost, the eng would gag. Just fine if not into boost. When it gagged, the Fuel rail pressure dropped to just 5 psi ! Fuel pump duty cycle was sky high just a couple of weeks before, like 98% at wot. Turns out the problem was the sock filter, that goes on the bottom of the oem fuel pump. Once that was cleaned, everything was back to normal..and FPDC is 38-40% at idle. Once the FPDC (at idle) starts to creep up a bit, then I know the sock filter is starting to clog up..again.

There was all sorts of crap floating around the bottom of the tank on driver's side. That was the 7th instance, locally of clogged sock filters. Only thing in common between us was using chevron 94 ( and mustangs of course)...go figure. Fuel filter was previously swapped out, made no difference. I was at my wits end till a local buddy mentioned the pre-sock clogging issues local folks were having.

But even when sock filter was clogged up... I still had a solid idle, didn't budge.
 

07gts197

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Ive been having problems loading forscan files on my phone and my computer keeps freezing after it updated. Ill try to get it straightened out Im curious to see what that file has in it.
 

Clown9

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I'm going to warn you it is a loooooong datalog.
Think I may do another one tonight and let the car idle in my driveway for about 5-10 minutes.

Which I should add, I really appreciate the help anyone and everyone posting here. Thanks.
 

702GT

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I have the FRPP twin 62mm TB on my 2010 auto ( with small roush M90 blower). The idle is superb, doesn't budge. The FRPP twin 62mm TB is made by acufab, same outfit that makes the oem twin 55mm tb. The FRPP twin 62mm TB won't buy you anything on a NA car, but it won't screw up the idle either.

I'm not questioning the quality or performance of the throttle body. I spoke in reference to voltage issues in concert with the throttle body. The larger the throttle body, the more pronounced the effect. Regarding idle hunting, if the voltage from the TPS fluctuates, the throttle body over compensates. Thus, idle hunting.
 
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07gts197

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If you can record the screen like you did with the other one. Im not in town and wont be back until tomorrow night.
 

Clown9

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First video is cold start. letting engine warm up, and some in town driving. I forgot RPMs in the first one so my bad.
Second video is in town driving with some highway driving.
Also apologize for the messenger pop up. Didn't realize it had popped up til I came to a stop.


 

redfirepearlgt

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This may sound very layman of me but has the KAM been cleared and the idle relearn process performed? You may wish to try this and then relog to see if your STFT/LTFT's are more stable at idle. See the video below.
https://www.bing.com/videos/search?...A48DDCD35BF8F3C73AB0A48DDCD35BF8F3C&FORM=VIRE

If this has already been done, the thing I would be concerned with is the lack of ability of the Fuel Rail pressure to reach/stay at 40psi at idle. As I understand it Fuel Rail Pressure is suppose to be maintained at 40psi (min) at idle by most Fuel Injector manufacturers correct??? I don't see your datalog ever reaching 40psi. I would expect that to be varying slightly above and below 40psi as it maintains it based on Fuel Rail pressure feedback from the FRPS. So don't lose sight of the FRPS if the FR pressure is where I believe it should be on a 3V setup.

The alternator is fine BTW with regard to your readings. AC ripple can only be measured accurately with the car running. AC power of any kind is generated from a rotating device, I.E. your alternator or the big ass generator at a power plant. A battery is incapable of storing AC just as a Capacitor (which is a form of battery) cannot store AC. (25+ years in electrical, electronic, and electromechanical experience backs this). 5-10% AC ripple vs the DC output is the rule of thumb on a DC buss using AC to DC rectification. There are exceptions to this rule in the industry but they are extreme sensitive circuits and aren't the norm. Your readings are well within the 5% and more conservative side of diagnosis.
 
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Clown9

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This may sound very layman of me but has the KAM been cleared and the idle relearn process performed? You may wish to try this and then relog to see if your STFT/LTFT's are more stable at idle. See the video below.
https://www.bing.com/videos/search?...A48DDCD35BF8F3C73AB0A48DDCD35BF8F3C&FORM=VIRE

If this has already been done, the thing I would be concerned with is the lack of ability of the Fuel Rail pressure to reach/stay at 40psi at idle. As I understand it Fuel Rail Pressure is suppose to be maintained at 40psi (min) at idle by most Fuel Injector manufacturers correct??? I don't see your datalog ever reaching 40psi. I would expect that to be varying slightly above and below 40psi as it maintains it based on Fuel Rail pressure feedback from the FRPS. So don't lose sight of the FRPS if the FR pressure is where I believe it should be on a 3V setup.

KAM has been reset and battery unplugged for more than 30 minutes multiple times with each time having the car go through the relearn process. No luck.

I do not know anything about the FRP needing to be steady or not but in very first video a page back the FRP did vary from I believe it was ~38psi to ~41psi.
 

redfirepearlgt

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Check this out. Using your short term and long term trims may help you. They seem to me to be erratic. I'm comparing to my 14 GT Coyote so maybe they are fine since the 05-09 3V uses a narrow band O2 rather than a WB version as in 11+ vehicles. This could be leading me to a false conclusion so forgive me if I am mistakenly comparing apples to oranges. Either way the document below may help you to confirm if you have a vacuum leak using Fuel trims. At least that will help eliminate the vacuum leak concern if there isn't one. I trouble shoot everyday in my job. If I cannot eliminate a probable fault from the equation completely I cannot move to the next probable fault in diagnosing. Assuming something is fine and going on has bit me more times than not. Just decades of advice. Sorry I can't be of more help but hope to hear the cure for this problem.

http://www.easterncatalytic.com/education/tech-tips/fuel-trim-can-be-a-valuable-diagnostic-tool/
 

Pentalab

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Your fuel rail pressure could be a hair higher, like 40 psi. Your FPDC analog gauges on the 2nd video reads in 6 psi increments, moot point, since it also displays the absolute reading. Mine will vary from 39.9... up to as high as 40.1 psi... whether at idle... or 6 krpm.

I did notice your battery voltage went as low as 13.29 vdc... plus it wandered about. Mine stays put at 14.4, whether at idle or high rpms.

Your alternator, or the internal regulator inside the alternator, may be fried.

You might want to start with a known good alternator, with a solid 14.4 vdc output, then re-test everything from there.
 
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Pentalab

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Your fuel rail pressure could be a hair higher, like 40 psi. Your FPDC analog gauges on the 2nd video read in 6 psi increments, moot point, since it also displays the absolute reading. Mine will vary from 39.9... up to as high as 40.1 psi.

I did notice your battery voltage went as low as 13.29 vdc... plus it wandered about. Mine stays put at 14.4, whether at idle or high rpms.
I suspect that is part of your issue.
 
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Pentalab

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[QUOTE

The alternator is fine BTW with regard to your readings. AC ripple can only be measured accurately with the car running. AC power of any kind is generated from a rotating device, I.E. your alternator or the big ass generator at a power plant. A battery is incapable of storing AC just as a Capacitor (which is a form of battery) cannot store AC. (25+ years in electrical, electronic, and electromechanical experience backs this). 5-10% AC ripple vs the DC output is the rule of thumb on a DC buss using AC to DC rectification. There are exceptions to this rule in the industry but they are extreme sensitive circuits and aren't the norm. Your readings are well within the 5% and more conservative side of diagnosis.[/QUOTE]
.06 vac = 60 millivolts
.04 vac = 40 millivolts
.028 vac = 28 millivolts.

I think those readings are in the typ normal range with a good alternator. I will try and dig up my old notes on this, which depict the max allowable.

With eng off, your readings should drop to 0.000 AC volts.
With eng on /off, polarity of leads should make no difference, there is no polarity per se, when using a DVM in AC mode.

.06 vdc / 14.0 = .4% ripple.....which is dick. But your battery in parallel with the alternator's DC output, is acting like a big capacitor ( albeit with a much higher effective series resistance)... which will further reduce the AC ripple... like way down... vs just the raw output of the alternator by itself. To test that theory, temp disconnect the positive lead at the battery. Then re-measure the AC ripple at the output of the alternator (between temp disconnected positive lead and chassis).

This is with eng on, and idling.
 

redfirepearlgt

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[QUOTE

The alternator is fine BTW with regard to your readings. AC ripple can only be measured accurately with the car running. AC power of any kind is generated from a rotating device, I.E. your alternator or the big ass generator at a power plant. A battery is incapable of storing AC just as a Capacitor (which is a form of battery) cannot store AC. (25+ years in electrical, electronic, and electromechanical experience backs this). 5-10% AC ripple vs the DC output is the rule of thumb on a DC buss using AC to DC rectification. There are exceptions to this rule in the industry but they are extreme sensitive circuits and aren't the norm. Your readings are well within the 5% and more conservative side of diagnosis.


.06 vdc / 14.0 = .4% ripple.....which is dick. But your battery in parallel with the alternator's DC output, is acting like a big capacitor ( albeit with a much higher effective series resistance)... which will further reduce the AC ripple... like way down... vs just the raw output of the alternator by itself. To test that theory, temp disconnect the positive lead at the battery. Then re-measure the AC ripple at the output of the alternator (between temp disconnected positive lead and chassis).

This is with eng on, and idling.[/QUOTE]

AAHHHH! Never factored the battery having filtering effect on AC ripple. Makes sense. Thanks for correcting that. I troubleshoot from the perspective of a rectified DC power supply output feeding I/O devices or CPU circuit boards, etc. No battery to factor into the equation there. Never crossed my mind to factor that in though I realize a battery is a giant cap. Even at my age I am still learning. Dad always said if you want to live forever learn one thing new each day.
 

Clown9

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Alright so not be an insufferable douche, but um could one of you summarize exactly what you two are saying I should do?
Kind of lost in all the multiple posts and botched quotes lol

I understood: Turn on car, disconnect positive battery cable, test AC voltage from alternator.

Is that correct or am I missing something?
 

Pentalab

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Alright so not be an insufferable douche, but um could one of you summarize exactly what you two are saying I should do?
Kind of lost in all the multiple posts and botched quotes lol

I understood: Turn on car, disconnect positive battery cable, test AC voltage from alternator.

Is that correct or am I missing something?


Correct. Other end of alternator output will be the temp disconnected lead ( aka positive battery cable).
 

redfirepearlgt

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You're not being insufferable or a douche.

My only way of doing this safely is as follow. Pentelab may have a trick up his sleeve for an easier means of isolating the two from each other and the car still run.

For the car to remain running to perform this you will need to disconnect the feed cable at the alternator side at . It will have to be isolated in a way that it cannot touch ground with ANYTHING METAL.

HOWEVER: to make this as safe as possible disconnect the red + cable terminal on the battery first and isolate. This minimizes shorting to ground and possibly blowing the fusable link between the alternator and the battery inside the cable run while removing the cable at the alternator end (C102-B). Then reconnect the battery cable so the car will start.

The car will be running only on the battery power. A CEL or idiot light may pop up which may or may not require being reset later. At idle place your red voltage probe lead on the output post of the alternator where you disconnected the cable. Place the black probe on the negative post of the battery. Record VDC reading. Then switch the voltmeter to AC and record the same. THis will give you the true unfiltered AC ripple reading.

Shut the car off, disconnect the positive battery post again, reconnect the alternator cable and reconnect the battery. The schematics for the charging system are below.

http://iihs.net/fsm/?d=40&f=Charging System.pdf&p=2
 

07gts197

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I agree with the others about the battery and alternator. I would just go ahead and get them both tested to rule them out.

As far as all the other parameters they look fine. But J did notice a rough correlation between app and rpm. In the begining when youre idling for some reason the accelerator position keeps changing like youre pushing and letting off the throttle slightly. It shouldnt change when idling.

There are 2 other things Id like you to try. Remove the harness and turn the car on. If it idles (which Im not sure it will) it should go into limp mode and idle at a pre determined rpm. If it idles fine without fluctuating then youve narrowed the problem. Also do the same test but with the tps unplugged instead of the accelerator. It should do the same thing. The idea is to get the ecu to disregard the tps and/or accelerator position sensor to see if it can control the idle. If it idles fine youll know those sensors are contributing to the problem.
 

Clown9

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You're not being insufferable or a douche.

My only way of doing this safely is as follow. Pentelab may have a trick up his sleeve for an easier means of isolating the two from each other and the car still run.

For the car to remain running to perform this you will need to disconnect the feed cable at the alternator side at . It will have to be isolated in a way that it cannot touch ground with ANYTHING METAL.

HOWEVER: to make this as safe as possible disconnect the red + cable terminal on the battery first and isolate. This minimizes shorting to ground and possibly blowing the fusable link between the alternator and the battery inside the cable run while removing the cable at the alternator end (C102-B). Then reconnect the battery cable so the car will start.

The car will be running only on the battery power. A CEL or idiot light may pop up which may or may not require being reset later. At idle place your red voltage probe lead on the output post of the alternator where you disconnected the cable. Place the black probe on the negative post of the battery. Record VDC reading. Then switch the voltmeter to AC and record the same. THis will give you the true unfiltered AC ripple reading.

Shut the car off, disconnect the positive battery post again, reconnect the alternator cable and reconnect the battery. The schematics for the charging system are below.

http://iihs.net/fsm/?d=40&f=Charging System.pdf&p=2

Just got home from work, will be trying this out.

I agree with the others about the battery and alternator. I would just go ahead and get them both tested to rule them out.

As far as all the other parameters they look fine. But J did notice a rough correlation between app and rpm. In the begining when youre idling for some reason the accelerator position keeps changing like youre pushing and letting off the throttle slightly. It shouldnt change when idling.

There are 2 other things Id like you to try. Remove the harness and turn the car on. If it idles (which Im not sure it will) it should go into limp mode and idle at a pre determined rpm. If it idles fine without fluctuating then youve narrowed the problem. Also do the same test but with the tps unplugged instead of the accelerator. It should do the same thing. The idea is to get the ecu to disregard the tps and/or accelerator position sensor to see if it can control the idle. If it idles fine youll know those sensors are contributing to the problem.

Will do that as well.
One thing I should mention is when I drive I have the terrible habit of pushing on the gas for a bit then letting go. I can't help it, I love listening to the exhaust when I let off the gas y'know :/

*BUT* when I am idling, I do not touch the gas pedal. I should have logged speed as well *facepalm*
 
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07gts197

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I know what you mean but I like to hammer the gas to hear my exhaust haha! I have no axle backs so its like having my m80s dumped and it sounds mean, I love it. Im going to swap to actual dumps soon. If it sounds good Ill keep it.

I figured as much, its odd if you watch the act_ect the voltages go up and down quite a bit for some reason while idling. As far as adding speed it helps but so far youve done well supplying us with what we need. Forscan is a great app, I highly recommend using it to figure out its full potential. It now has a test feature where you can test certain things (Ive only used it once). It scared the crap out of me because it started to tuen on and off things like interior lights then the horn honked and all my neighbors looked at me like wtf lol.
 

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