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Discussion Starter · #1 ·
Hey guys/girls, I'm trying to figure out possible causes for my low airflow mass lb/min. Every now and then (VERY rarely) I can get 27.01, but most of the time i'm in the 24 to low 25's. So far i've removed all the MAP/MAF/TMAP sensors and cleaned them with the proper cleaner, removed all charge pipes; checked and re-tightened them, checked all vacuum lines that I can think of/see, checked intake manifold and throttle body for leaks, checked intake for leaks, checked all exhaust from DP back, and changed out my turbosmart BOV with the stock BPV. Anyone have any clue what it could be or what I should be looking for? Thanks!
 

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Hey guys/girls, I'm trying to figure out possible causes for my low airflow mass lb/min. Every now and then (VERY rarely) I can get 27.01, but most of the time i'm in the 24 to low 25's. So far i've removed all the MAP/MAF/TMAP sensors and cleaned them with the proper cleaner, removed all charge pipes; checked and re-tightened them, checked all vacuum lines that I can think of/see, checked intake manifold and throttle body for leaks, checked intake for leaks, checked all exhaust from DP back, and changed out my turbosmart BOV with the stock BPV. Anyone have any clue what it could be or what I should be looking for? Thanks!
Not sure why you think 27 lbs/min is low; for a stock turbo car that's fine. I've gotten a little over 28 during the winter with good gas.

Hope that helps,
Mark
 

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Discussion Starter · #3 ·
Hey Mark, thanks for the response. I don't think 27 is low, I would be pleased if I was getting that regularly. My issue is that I rarely ever see 27 or above. I'm usually maxed out at around 24.3 to 25.2 or so. I can't seem to figure out what it is that is keeping me from getting 27 and 28 consistently. I've tried open airbox and sealed airbox with no difference between the two. My boost always builds and holds pretty strong, between 22.8 and 23.7, so I don't think I have a boost leak. I'm kind of at a loss.
 

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Hey Mark, thanks for the response. I don't think 27 is low, I would be pleased if I was getting that regularly. My issue is that I rarely ever see 27 or above. I'm usually maxed out at around 24.3 to 25.2 or so. I can't seem to figure out what it is that is keeping me from getting 27 and 28 consistently. I've tried open airbox and sealed airbox with no difference between the two. My boost always builds and holds pretty strong, between 22.8 and 23.7, so I don't think I have a boost leak. I'm kind of at a loss.
Have you replaced the factory FMIC?

At the end of the day, it's all about mass (not volume). Lower your charge air temps and you'll increase your airflow mass/minute.

Mark

P.S. You may want to put your mod list in your signature... :)
 

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Discussion Starter · #6 ·
Have you replaced the factory FMIC?

Yeah, I'm running the 3.5" Depo Racing IC along with the catless DP. Sorry about the mods list in the signature. I've updated it. Like CVPI was saying, do you think the sensor itself could be an issue? Is there a way to test the sensor voltage?
 

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Have you replaced the factory FMIC?

Yeah, I'm running the 3.5" Depo Racing IC along with the catless DP. Sorry about the mods list in the signature. I've updated it. Like CVPI was saying, do you think the sensor itself could be an issue? Is there a way to test the sensor voltage?
Well, now that I see you are tuned by Stratified, I'd suggest emailing Alex (or reply to the email in which they sent your tune file) with your order # and just ask if you should be expecting a few more lbs/min of mass airflow. You might also want to send them a log of a pull at the same time; Alex has a very specific list of parameters to log, available on their web site.

In my experience sensors don't go slightly out of calibration generally; they just fail outright or go so far out of range the ECU throws a code either way.

One thing you could do while you are waiting is to clean up your grounds. Not only the battery ground wire on the top of the strut tower, but also the several on the driver's frame rail under the airbox. There are two more under the battery too that to get to will require you to remove the battery and its tray. And don't forget the motor side of the engine-to-chassis ground wire as well.

Lastly, check the resting voltage of your battery after it's been sitting overnight, before you start the car first thing. If it's in the very low 12s, your battery could be getting tired. Check the running voltage after driving around for 20-30 minutes and you should be in the high 14s. If you are still above 15V, go to AutoZone or similar and have them do a load test on the battery. Our cars can do weird things with weak batteries sometimes...

Hope that helps,
Mark
 
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Discussion Starter · #8 ·
Well, now that I see you are tuned by Stratified, I'd suggest emailing Alex (or reply to the email in which they sent your tune file) with your order # and just ask if you should be expecting a few more lbs/min of mass airflow. You might also want to send them a log of a pull at the same time; Alex has a very specific list of parameters to log, available on their web site.

In my experience sensors don't go slightly out of calibration generally; they just fail outright or go so far out of range the ECU throws a code either way.

One thing you could do while you are waiting is to clean up your grounds. Not only the battery ground wire on the top of the strut tower, but also the several on the driver's frame rail under the airbox. There are two more under the battery too that to get to will require you to remove the battery and its tray. And don't forget the motor side of the engine-to-chassis ground wire as well.

Lastly, check the resting voltage of your battery after it's been sitting overnight, before you start the car first thing. If it's in the very low 12s, your battery could be getting tired. Check the running voltage after driving around for 20-30 minutes and you should be in the high 14s. If you are still above 15V, go to AutoZone or similar and have them do a load test on the battery. Our cars can do weird things with weak batteries sometimes...

Hope that helps,
Mark
Thank you so much Mark. I went out and turned on the Accessport without starting the car and checked the battery voltage. It read 10.6 I drove around for a while and other that immediate start up (14.5-14.7) it hovered around 14.1 The 14.1 looked ok to me but the 10.6 while off was a little concerning. Is that normal?
 

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Thank you so much Mark. I went out and turned on the Accessport without starting the car and checked the battery voltage. It read 10.6 I drove around for a while and other that immediate start up (14.5-14.7) it hovered around 14.1 The 14.1 looked ok to me but the 10.6 while off was a little concerning. Is that normal?
10.6 is very, very low for a battery, and indicates that at least one cell has failed. It shouldn't get below 11.6 with a heavy load, and 12.1 with no load.

Does your car exhibit any of the symptoms of the ground splice TSB? You may want to check that out; almost all the engine sensors go through those splices, and a high-resistance ground will cause low readings. I fixed mine because of the stumbling and was shocked to find that slight/partial-throttle power shot way, way up. I was not expecting that at all, and I suspect the sensors weren't reading quite right. It was like a whole new car...
 

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Thank you so much Mark. I went out and turned on the Accessport without starting the car and checked the battery voltage. It read 10.6 I drove around for a while and other that immediate start up (14.5-14.7) it hovered around 14.1 The 14.1 looked ok to me but the 10.6 while off was a little concerning. Is that normal?
I've found the AP to read voltage pretty accurately when the car is running, but I've never compared when the car is off. As Kranny says, use a multimeter at the battery to be sure.

But, 10.6 is pretty bad for all the reasons hawkeye18 mentions.

If it were me, I'd take it to AutoZone or similar and let them do the load test. Then you'll know for sure. And if it's bad... >> http://www.focusst.org/forum/focus-st-maintenance/46089-odyssey-pc1200t-battery-installation.html

All the best,
Mark
 
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Discussion Starter · #12 ·
Thanks so much guys! I drove it from upstate South Carolina to Florida today without any issues.... with the exception of one thing. After getting back into the car from a rest area, I noticed that the dome lights would not shut off. No doors were open and the hatch wasn't open. I wound up having to turn the car off completely and after restarting, the lights went off. I'm starting to worry that I might have some gremlins in the electrical system. Maybe something like @hawkeye18 was talking about with the TSB? I will definitely get the battery load tested as soon as I get a chance. I might run up to an Advance I saw just up the road from where i'm staying and have them check it.
 
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