1999 Carrera EVOM Cold Air Intake Car runs Awful after install? Help

Hello I have a 1999 Carrera and I purchased a Evolution Motorsport Cold Air Intake. First off I have to say I know the HP is BS, but after installing it Im really wondering why I wasted money. This thing fits horrible, it does not line up or really sit well in here at all. But beyond that, the car will not even run unless I hold the gas now. Is it possible the MAF got dirty? I mean this isn't my first rodeo and I was extremely careful as always, to the point I can 100% say nothing touched it or brushed against it, I took it out and put it back in 10 minutes later. But now the car when you turn the key will not start, unless you give it gas, will not hold an idle or stay running unless you give it gas. Any ideas?

You're sure MAF is installed in the right orientation, and connector is seated properly? If all yes, then I guess put it back to stock and see if it still runs okay.

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Sounds like there was a difference in the MAF "housing diameter" between what you installed and what you took off. The fuel trims need to reset. To help them reset, disconnect the battery for 10min, then reconnect a run at idle A/C off, then ON, then road test at different RPMs. Of course you should also clean the TB. You will also have to reset radio code, and reset power windows and sunroof as per owners manual.

I appreciate it, I bought this used off eBay, I ordered a new Filter from Evolution Motorsport like 3 weeks ago that hasn't even been shipped yet, and Ironically they are located about 3 miles from my shop. I have done, wheels, coil overs, headlights, taillights, I have the GT2 Bodykit Im installing and painting the car as well this week. I wanted to add some bolt-ons because this car will be for-sale and I know that will be the first question most potential buyers ask, but honestly this box is garbage and not a good fit at all. Im pulling it out and putting the factory one back in. But thank you for your help.

Yea, sounds like a piece of junk. You better take it off before your car adapts to it. If you leave it on too long your car will adjust fuel trims to it, and you will experience the same or similar problem when you go back to original..

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Lol no the Porsche is one of my projects it's not driving anywhere. I pulled the Evom out, and called it a night. Tomorrow in going to look at a c10 and after that I'll put the factory air box back in and see how it runs. The car ran beautifully until this so maybe the MAF, I'll narrow it down tomorrow.

I had an EVOM on my 2000 with no issues. Loved the howl under acceleration. I did get a CEL code once, but reset and it was done.

Did you have these issues with a new filter on it or was the old one stuffed? I just put a K&N on for ****s and giggles and it sounds amazing not to mention it revs up quicker (maybe my old filter was dirtier than it looked).

I havent received the new filter yet that I ordered 3 weeks ago from 3 miles away so I really never got that far, but I cleaned this one before I even installed it and it wasn't bad to begin with. As for the "sound" I would be willing to bet that if some actually did a dyno this would lose HP not gain. It's not a good fit at all and honestly a hot air intake if anything.

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There was some temp testing and you'd be surprised...Once airflows, temps stabilize and if you raise the spoiler there's a significant drop in temps. I do recall some dyno testing that showed a drop in HP, how much is the question. The stock airbox has a bunch of holes in the bottom the lets hot air in too so it would be interesting to see real world numbers.

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Hi Hangar13, I just sent you an email regarding the order. I will get you squared away with a filter ASAP...we are actually in the process of moving from Phoenix to Seattle, so it's a little further than that at the moment but I'll be back in town on Tuesday and would be happy to meet up and get you a filter and see what's causing the running issue. Regarding the poor fitment, when new this kit includes a bracket that relocates the secondary air pump further into the engine bay and out of the way of the airbox. That bracket is almost never removed and included on used kits since it looks almost factory, and without it the airbox barely fits in the engine bay. Sounds like you need that bracket and everything should fall into place. Regarding the running issue, unfortunately it sounds like you need a MAF sensor. If the sensor is original to the car, they tend to be very fragile due to age and simply handling it during the install might have been the nail in the coffin. I've dealt with this a few times on older 996 and 986 service cars; removing the stock airbox to change the filter can be enough to kill the sensor and give the same symptoms you're seeing. Our intake is well designed in that it uses the same diameter MAF housing as stock, and there's a perfect straight shot from the air filter to the MAF housing with no bends or sharp edges to disturb the airflow into the sensor. Fuel trims should be very close to stock, there's no real adaption needed to get it to run right. Regarding results--I just had to go through this this week with a 997 C2S we'd tuned up here that had some odd running problems. The car was running another brand's aftermarket intake that has a simplistic carbon fiber heatshield between the engine and air filter, and a carbon fiber intake tube with the MAF sensor installed in the middle of a bend in the tube (!). I baselined the car and found a couple of things. RKAT idle fuel trims were around -1.6, which is notable as they're quite elevated (ideally want these to be close to zero) and they're almost never negative on these cars--which means the ECU was leaning out the mixture to achieve its air:fuel targets from what the MAF and fuel tables indicated they should be. Modern cars almost never run rich, almost every type of wear or problem that can happen results in a lean condition which causes the ECU to add fuel with a positive fuel trim. Ambient temperature during the test drive, which included two 5min stretches of open freeway and 10min of sitting in traffic with low speed driving, was 20C (around 70F) but during every portion of my road test whether it was on the highway, stopped at a long light, wing up, wing down, etc. intake temperatures (measured by the MAF) were consistently and invariably 35-38C (95-100F). Lastly, there was weird inconsistency in the powerband which came down to the car pulling timing during some runs, which kills power. We ended up swapping on a stock airbox and repeating the same test, then a V-Flow almost identical to what Hangar13 has. The stock airbox corrected EVERY abnormality noted above. At the end of the 20min test drive, without clearing adaptions first, RKATs were back to +0.2-0.3 on both banks which is completely normal, the powerband came back and timing pull was almost completely gone, and while intake temps would rise when stopped at a light (to a maximum of 30C on the same 20C ambient temp), once driving and especially with the decklid raised they dropped down to 23-25C, just above ambient and as good as you'll ever see in a car. There was a roughly 3% loss in load at peak torque, which is either a sign of a slight drop in airflow or a result of a faulty MAF reading due to the position of the MAF sensor in the carbon fiber intake, but the car ran better and more consistent due to the lower intake temps and better timing figures. We then installed the V-Flow. RKAT trims were 0.3-0.4, so slightly changed but very close to stock. Intake temps reached slightly higher than stock, with a max of 34C stuck at a stoplight, but once moving dropped down to a typical value of 24-26C. So the cold air ducting worked and hot air intrusion from the engine bay is minimal--especially compared to the other intake. Load came back up by around 3%, and timing was as consistent as stock. No loss or change in behavior compared to stock, but slightly more load measured on the engine (indicates more air into the cylinders) and the great sound came back which is a win for this upgrade. Sam