It has nothing to do with “improved airflow”, it has to do with a change of the air how it flows over the MAF sensor. The MAF sensors are very sensitive, so just changing the filter from a panel version to a cone one, WILL change the flow over the MAF, which then gives different signal to the ECU which doesn’t match for what it has been designed with.

The next change is the tub where you fit in the MAF, I would guess it doesn’t 100% match the old one, so there again you will get a different reading from the MAF again.

This all can be easily tested, so I would ask 1st how much it alters to Mina, they surely must have tested this, so at least you know what the deviation is over a standard setup. This is very simple to test via monitoring the fuel trims which should be around 0 for different speeds for a good setup.

I would suggest you do the same now with your stock box, check it, to see where the fuel trims are now. It may well be that they are at 15% now, which will not set a code, but is already not good. Then when adding the mina kit it could go to 21%, which will set a code as 20% is the threshold. This is just an example, guessing on the forum will not help; you just need to measure it.

It would also be helpful if others who have the kit now also do the fuel trim measurement that will help in understanding what the deviation can be.

Here is how you do it:
Engine must be at operating temp, than check the values for Bank 0 and 1:
At idle, wait until the values stabilize, and write them down
Drive 30 mph, put it on cruise, drive a short while stable, and write the numbers down.
Drive 60 mph, put it on cruise, drive a short while stable, and write the numbers down.

 

Robert, follow Avos's diagnostic path. You may have a vaccume leak that when combined with the Mina intake takes the threshold over 20%. A bunch of us have experienced this and proven with smoke tests and/or fitting with new vaccume lines and gaskets.

 

Still waiting to pull the trigger on this mod until I read a few more "no problem" installs from fellow forum members.

 

Tommy, the Mina intake is completely safe, effective, and properly calibrated to the STR MAF sensor. Those having CEL w/RP have other issues to sort through, mainly vaccume leaks.

 

Have to admit I feel the same way - if there are vacuum leaks, they only seem to show up when the Mina is fitted, so they must somehow be caused by fitting the Mina, or be due to a fault in the Mina itself. Not to mention the ill-fitting cone filter problem. Chris is really a nice guy, but it all sounds like too much potential hassle.

Avos, I'm going to buy a bigger piggy bank, it's twin-screw or nothing. Did I once see an estimated time of end-April 2013? Rough idea of cost? Could really use another 100+ HP without having to fret about the MAF and without any ECU re-programming.

 

The Mina intake doesn't cause a CEL w/RP, it merely exacerbates an already present vaccume leak, etc.

 

I'm not convinced we KNOW that, though it's plausible.

Why anyone spending many $$$ on mods doesn't first buy a cheap OBD tool and check the car is running properly is beyond me - FOLKS BUY AN ELM327 AT LEAST and look at fuel trims.

 

Ok so lets take a step back a moment. I love to drive my car and it has always ran very well in deed. Now the Mina is $150 and I have issues so no biggy, I have a code reader with live feature so I can do what Avos suggests, Thank you by the way for spending the time to pass on your Knowledge. When I get the chance to have one of my buddies come over for an afternoon I will put the Mina back on and do the prescribed tests. As of today I have no time to do them or search for a solution as I am arranging a return to the UK. The Mina is a good unit and I am sure that if I spent enough time I would sort it out. The Jag does seem to be temperamental when it comes to modding and I would be a bit more annoyed if I had paid out thousands of dollars on mods and had problems but at $150 as I said no biggy and I will get round to it. Thanks for all the comments and suggestions and the time you give up to post. As soon as I have the time an constructive support form my mates (as long as they bring beer) I will pass on what we find.

 

1st test your stock setup now, then afterwards the Mina setup so you can compare and see where the issue lies.

 

+1 because you may well find your stock setup has trims it ought not to have.

 

Ok Avos I have some data, now I am a novice so bear with me. I put the stock box back on with the K&N panel with my Metal intake pipe, I ran this system fine for 6 months with no known faults, have had this set up back on for a week with no problems or codes. This morning on start up restricted performance and codes all lean on both banks. At idol 659 revs, short term trim on both banks 25% long term trim on both 19.5% Maf figure was .56 all data collected on a Actron CP9580. So I have problems at idol straight from start up.

 

Was the engine fully warmed up? Did you wait a little after that until the ltft figures settled?

Then please do now the other 2 measurements, then I can give you my thoughts.

 

Yes Engine was at operating temp and yes I waited for figures to stabilize. I will do the other readings when I can.

 

19.5% LTFT warmed up at idle - you have quite an air leak unless it doesn't drop if you rev to (say) 2500.

 

Robert,

I hope you don't mind, but I'm using one of your pictures for reference. I started installing my Mina Intake today and noticed that the silicone coupling is too large for the MAF tube (see the circle I added to Robert's picture). Since we both have the Qwiketz intake tube, the coupling goes from 3" to 3.25" to fit over the MAF connector from the stock airbox. I'm wondering if that's where you're getting your leak. I'm going to replace my 3-3.25" coupling with a straight 3" coupling before firing my STR up bought wanted to post my initial observation.

 

Hi go blue, there was no gap as my MAF tube had a rubber gasket on that end which compressed completely with the clamps so no gap there, we then tried another MAF housing sent from Mina with the same results. The codes that are happening now are with the Stock box back on with the elbow so the Mina is no longer involved even. What I am trying to find out now is why my car will no longer run without codes or restricted performance which it did before.

 

Post #94 - what happens when revved?

 

Vaccume/air leak.

 

Just finished installing my Mina intake...







I replaced the 3/3.25" coupler with a 3/3 and enlarged the hole in the heat shield a little. Overall it was an easy install. I drove it around the neighborhood and so far no Cel... Will go on a more spirited test drive later this evening.

 

So avos I did the tests with interesting results.
30 MPH on cruise RPM 1295
Maf 2-3
STFT 1 and 2 -25- 9 fluctuating
LTFT 1 and 2 19.5

60 on cruise control RPM 1406
MAF 3-16 fluctuating
STFT Bank 1 0-1.6 Fluctuating
STFT Bank 2 0
LTFT Bank 1 7-19.5 fluctuating
LTFT Bank 2 5.5-19.5 Fluctuating
No Codes or Engine light on test run.
Later in the day started car again and Codes and restricted performance right away.
Any thoughts?