Author Topic: Cold Air Intake (CAI) Problems (Read 10040 times)

DeepBlueGXP · « **on:** February 05, 2009, 07:45:30 PM »

Certain CAIs have been causing problems and the GMPP CAI Kit is ok, my son has it installed on his. I did some research and found that the CAIs made by Fujita and Dejon differ from the GM stock and GMPP CAI. I don't know what the new DDM Works CAI measurements are since I haven't seen one directly. Anyway here are the dimensions on the intakes:

Stock tube on stock intake - 3.14" OD / 2.90" ID - area = 6.60 sq/inches
Dejon Intake - 2.72" OD / 2.595" ID - area = 5.29 sq/inches
Fujita Intake - 2.73" OD / 2.596" ID - area = 5.29 sq/inches
GMPP Intake - 3.015" OD / 2.89" ID (estimated based on .065" wall thickness) - area = 6.59 sq/inches

What the smaller diameter intakes will do is make the computer think more air is passing the Mass Air Flow (MAF) sensor than actually is passing and cause the ECM to have to use the short and long term fuel trims to try to adapt to it. Some cars will not be able to adapt and these are the ones that have had problems with the intakes. Especially during transitions. This means that the fueling could be off by as much as 25%. That is why several of you have experienced the check engine lights (CEL).

If you have had issues, speak up and tell us which system you have installed.

snaponbob · « **Reply #1 on:** February 05, 2009, 08:37:34 PM »

I cobbled together a CAI but it didn't work properly. Seems that a CAI does need to be necked down at the Mass Air Flow sensor. That said, how are you establishing a 25% fueling error? I don't know what the fkuid dynamics would be for the sq." difference but I would think that a computer read out as well as a 4 or 5 gas analyzer would be needed to really know what is coming out of the engine. If there were large fuel delivery errors one would think that the engine would go quite lean (THAT could be ugly) or rich. Yes? No?

BTW, sure makes a case for either a stock intake with a modded air box or a GMPP system.

baconbits · « **Reply #2 on:** February 05, 2009, 09:05:18 PM »

Do the codes explain what the problem is with the mass flow sensor (too high volume air flow..) or are the codes just reference for techs to swap out sensors.. Is that parameter set in the ECU and if it is is it able to be cracked and edited within the confine of a tune..
Just wondering
Bacon

snaponbob · « **Reply #3 on:** February 05, 2009, 10:45:20 PM »

Having sold diagnostic equipment for nearly two decades, I can tell you that the question just asked is SO important that it can't be over emphasized. A trouble code means ONLY that there is a problem in the effected CIRCUIT, NOT the sensor. A code is the BEGINNING of the troubleshooting process, NOT the indicator of what is wrong. Example - an O2 sensor code does NOT mean that the sensor is bad. WAY too many techs (over used term) just use a code for an opportunity to start throwing parts at a problem. Dealerships are THE worst at this.

Bottom line - a code is ONLY an indicator that something is OUT OF SPEC, but not WAHT is wrong. Too many mechanics actually AVOID troubleshooting because it can be time consuming. They would rather throw parts at a problem and get paid on the labor. Be aware of this. Be VERY aware. There ARE some great techs and diagnosticians out there, but not nearly enough.

Divingsolo (formely Randy@DDM) · « **Reply #4 on:** February 05, 2009, 11:05:41 PM »

Some good observations here.

MAF sensors are finicky little creatures. In the OLD days of Fuel injection, Air flow sensors where either a flapper valve style or a heated wire. Either way, the units had a specific calibration as a unit. In the early 90's, Mass air flow sensors came in a specific sized enclosure or built directly into the Throttle body. Then a few years ago, GM started using the slot MAF sensor. These were in variably sized housings, and can be accordingly scaled in the ECM. The MAF sensors produce a frequency output back to the ECM based on the amount of air. The size of the tube/housing affects this output. This way a single sensor can be used across mutiple flow ranges/platforms. Each Engine/car type is given a specific lookup table in the ecm based on the frequency response of that MAF in a SPECIFIC size enclosure/tube. If you change the size of the tube, it will not report the actual air flow. You have to give the ECM a new adjusted lookup table to accurately fuel the engine. This is a major part of tuning a car.

Plus, MAFs are extremly sensitive to turbulance. and can give false readings in turbulant air. In the 90's GM put a fine mesh screen in front of the sensor to "filter" and smooth the air. Performance guys would always remove these, because it's a "restriction", and it actually was, but the cost was rough or unstable idle and inaccurate MAF readings.

Ok enough with the history lesson....

If the size of the intake tube is changed from what came with the car, it will cause inaccurate air readings...Period! The car can adjust for it up to a point. The GXP can adjust about +/- 35% in fueling and the NA can do about 20% with out setting a check engine light. Some cars, in certain climates and such can live fine with the adjustments...others can not and will cause problems as we've been seeing on the boards. The very first batch of Fujita's caused codes on every car. They redesigned them, but not correctly, and it's a 50/50 shot as to seeing a light.

Our Mach II system uses a 3.00" OD with a 2.87" OD....very close to stock. But even though we're off a little, we compensate for this because unlike the other intake systems, ours is a matched kit: Intake, Pipes, Intercooler, and a TUNE. The system is only sold as a kit. It would probably work just fine on a stock setup. It's certainly the closest aftermarket system to the stock sized MAF tube.

jrsno1fan · « **Reply #5 on:** February 06, 2009, 12:03:44 AM »

2500 miles now on my MACH II setup no problemo!

lil goat · « **Reply #6 on:** February 06, 2009, 12:28:35 AM »

The Dejon when it came out threw codes too, Dave put a "fin" in the tube and it quit getting codes, Lyndon put the stock and both Dejon versions on a flow bench and said the corrected Dejon flowed very well, and actually flowed better than the stock one with the filter removed. I look forward to the DDM Works CAI, as none of the others are CAI's they are just intakes. But anyway they all suck.....

LatinVenom · « **Reply #7 on:** February 06, 2009, 01:40:30 PM »

Let's also not forget that on the GM GMPP intake the sensor was relocated.

Unclefester · « **Reply #8 on:** February 06, 2009, 04:04:42 PM »

I have had my DEJON on for 6 months and zero codes. I've put at least 8000 miles on her with the CAI on.

Divingsolo (formely Randy@DDM) · « **Reply #9 on:** February 06, 2009, 04:14:51 PM »

Quote from: Unclefester on February 06, 2009, 04:04:42 PM

I have had my DEJON on for 6 months and zero codes. I've put at least 8000 miles on her with the CAI on.

As stated above in a couple post. The Stock ECm can adjust a great deal. But when you start pushing the performace edge with Tunes and Intercoolers, and certain environmental conditions, it reaches the limits of how much it can adjust.

Also, it's not about the Flow rate. It's about accuratly reporting the Air Mass that causes the problem.

Deep-GXP · « **Reply #10 on:** February 06, 2009, 06:30:35 PM »

I've had codes since installing the dejon cai. I already had a Westers tune for my 08 gxp Manual with Dejon IC. Westers said i need to retune. I put the stock air box back in until i get an Hp Tuners.

spicy3480 · « **Reply #11 on:** February 06, 2009, 07:08:47 PM »

I had codes with both the Fujita and Dejon CAI's. The GMPP CAI that I have now hasn't given me any issues. MACH II going on next!

PubliusE · « **Reply #12 on:** February 06, 2009, 08:59:59 PM »

This is an interesting thread. I never read that the after market CAI were throwing codes. I'm glad I spent the extra $$ and went with the GMPP. I had one on the NA and now on the GXP.

Lucy'sDaddy · « **Reply #13 on:** February 07, 2009, 07:38:52 AM »

We've had the complete Dejon system and the Wester's tune on for almost a year now. Probably about 13,000 miles, and never once thrown a code.

lil goat · « **Reply #14 on:** February 07, 2009, 05:49:41 PM »

Lyndon Wester has the Dejon on his 2008 GXP, he has not had any issues with it. He has a Dejon intercooler and Solo catless downpipe and Street Race exhaust, need I say he has a tune as well. The thing with all of them except one that RPI put out and the soon to be released DDM Works is that they are NOT CAI's, not even the GMPP. They are performance intakes but they draw hot air from under the hood, not cool fresh air, therefore they are not Cold Air Intakes, DDM Works and RPI make the only CAI's available for our cars, and they all still suck...

jrsno1fan · « **Reply #15 on:** February 07, 2009, 08:54:54 PM »

<---------- Pic of a TRUE CAI

DeepBlueGXP · « **Reply #16 on:** February 07, 2009, 11:09:22 PM »

Kim, I hate to inform you but yours isn't a true CAI since it draws warm air from under the hood. Actually quite close to the engine. DDM is working on a True CAI and the pic is here

Howster · « **Reply #17 on:** February 08, 2009, 02:59:55 AM »

My '07 GXP has quite a few mods, which include a Dejon CAI ( I know. I know. NOT a CAI.) I have had it on since last spring and it has never thrown a code... BUT the car runs like total crap with it on the vehicle. My Wester tune was to blame in the beginning and I had the ECM retuned three times. (Lyndon has been great just so you know). I finally just put the stock air filter box back on and the car runs like a mad-man. If only I would have known this way back when. I also had tons of problems with the Dejon IC pipes, and after a lot of grief from Dejon, I returned them for a refund. The only folks I feel are up to the task (for me anyway) is Dave and the gang at DDM. Dave and Randy seem to have their stuff together, and if customer service is all they ever have, that would be my reason for buying from them. I have been waiting for their new IC system to come out and will have it on post-haste once it is out and ready to unpack. So there ya have it. My thoughts-good or bad. Now I wanna go and take a drive. See ya.

Howster

jrsno1fan · « **Reply #18 on:** February 08, 2009, 04:38:33 AM »

Quote from: DeepBlueGXP on February 07, 2009, 11:09:22 PM

Kim, I hate to inform you but yours isn't a true CAI since it draws warm air from under the hood. Actually quite close to the engine. DDM is working on a True CAI and the pic is here

(Image removed from quote.)

The only thing that's different on mine is the missing airbox (which Dave is going to be delivering). The right side tube couldn't be any colder if you placed ice cubes on it! Who's Sol is this? Very nice!

lil goat · « **Reply #19 on:** February 08, 2009, 11:49:29 AM »

It's the air box that makes it a CAI, you are almost there, and it will still suck...

spicy3480 · « **Reply #20 on:** February 08, 2009, 12:59:35 PM »

That Sol belongs to ducksol. This kit is coming to me very soon!

jrsno1fan · « **Reply #21 on:** February 08, 2009, 01:46:14 PM »

Ohhh I didn't recognize it without the powder coating!

Goat - you still crack me up

Sly Bob · « **Reply #22 on:** February 17, 2009, 10:10:27 PM »

That DDM CAI airbox really is sweet looking. I have no doubt that a few people are anxious for them to get it up on their site so it can be ordered.

spicy3480 · « **Reply #23 on:** February 18, 2009, 07:39:22 PM »

I am very excited to get mine...still awaiting a big package!! HA HA

Cheers · « **Reply #24 on:** February 18, 2009, 11:47:49 PM »

Any mention of PRICE????

Not to mention DATE???

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Author Topic: Cold Air Intake (CAI) Problems (Read 10040 times)

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