Truck won’t run after new maf and CAI

Hey guys I just threw on my new af dynamics intake and a new maf sensor earlier tonight and I fired it up after the install only to find out that it won’t run now. It’s around 15 degrees Fahrenheit here so as every 3rd gen 3.5 owner knows the trucks have a initial spike in idle when cold starting.

But after the install the truck fired up and didn’t rev up as usual, then after a couple seconds it started stuttering so I tapped the throttle and it just choked and died. I shut off the ignition and went over everything with a fine tooth comb and swapped back in the original maf sensor (it is fine besides one of the ears being broken) and it still won’t run. With the original sensor it’s actually a little worse it only idles for a couple seconds then dies.

So I unplugged the maf and it fires right up and runs like a top, besides being in limp mode. Idle spikes as usual and it idles smooth. It will also take as much throttle as limp mode will allow it to and it doesn’t stutter or miss whatsoever.

I am baffled guys I’ve double checked all my clamps and boots and the maf is installed correctly (arrow points to the throttle body) and ive got nothing. I forgot to mention that I also pulled the battery terminal for a minute to reset the computer.

I’m beginning to think maybe one of the maf wires cracked from being moved around in the cold and shorted or something. If anybody knows the maf pin out on the 2grfks would you post it so I can attempt to check for shorts or broken wires? Also I’m open to any other suggestions because I need to get this sorted ASAP.

 

How big is the intake tube? If it's too oversized you may need an airflow straightener, or a MAF calibrator.

With my setup I usually have to start it at least twice if not three times give it a little gas to keep it from dying and it takes a couple minutes of low rough idle before it figures out its trims.

 

Thanks for the reply, it’s a regular old 3 inch tube so nothing crazy. And I had a 3 inch home made setup on there with a cone filter before so I figured that it would be about the same but maybe not. The setup I made consisted of a generic intake tube with a maf adapter coupled together and it was fine. I just wanted a solid unit with a heat shield that looked cleaner.

I’ll try to give it some gas to keep it going and see how it goes. But out of the 7 or so times I started it yesterday it didn’t seem to want any sort of throttle input whatsoever. I’m gonna try techstream lv reset when I get home and see if that helps. I also have ovtune so if all else fails I’ll datalog and post the results

 

Where did you get your MAF. Hoping it is genuine OEM. Off market MAFs are notorious for failing out of the box. MAFs are one of the sensors you need to spend the OEM $$ on... Highly doubt it has anything to do with the CAI. Good luck.

Assuming your old MAF was not known to be bad, I'd reinstall it and see what you get.

 

Yes it was a cheap maf and your right, definitely hit or miss. But i took a chance on it just to see if I would get a good one. My factory maf is absolutely fine one of the ears cracked and fell off though. But it will still seat and hold with one bolt on it. So I figured worst come to worst I get a bad aftermarket sensor and I can still just use my factory one with one bolt until I can get a good oem replacement.

But that was the first thing I did, I swapped my oem original sensor in and it didn’t help a bit, it actually doesn’t even want to idle with the factory sensor.

The new “aftermarket” sensor at least allows it to start and idle. But the idle is still pretty rough and lopey like the ecu is confused. So maybe I just didn’t give it enough time to learn the new setup

 

If the aftermarket pipe isn't exactly the same diameter as the factory pipe where the MAF sensor goes it's not going to work correctly without a calibration change in the tune of the ECU.
MAF sensors are tuned and calibrated for the size and flow characteristics of the pipe that they are in, any change to pipe diameter or flow characteristics will skew the MAF reading.

 

The tube diameter hasn’t changed between the setup I have now and my last setup, but the bends and breather hose location have changed drastically. The last setup I was running had the crankcase breather down on the filter end a few inches upstream of the maf. So I’m sure that’s altering the airflow in some way. Also when I was pulling off my old intake to install the new kit I realized that the clamp on the throttle body was a little on the loose side so there very well could have been a small leak there. I hadn’t thought about that until now, so if there was a leak there and the new kit is airtight that would probably be my issue. I would assume that the computer would compensate over time for a slight leak behind the maf, and ultimately richen up the tune.

All that makes perfect sense honestly and I really didn’t give it much of a chance to make corrections. I just have never had any issues throwing on a cai on any of my other Tacoma’s with the 2.7 or 4.0 so I got a little worked up about it and kept shutting it down. But the 3.5 is quite a different animal so I guess I’ll reset my lv’s and try to give it a chance to run and relearn. I still haven’t got time to mess with it. I’m getting over covid at the moment and I’m constantly dizzy and foggy minded so I haven’t had the motivation.

I appreciate you guys for your input, I get that it’s an odd situation with a ton of different variables but I figured making a thread wouldn’t hurt. Also I apologize if I’m not explaining things the best, I haven’t exactly been all there this week! Haha

 

Alright guys so it warmed up the other night and I ran home, grabbed the laptop, and reset my dtc’s and reset my learned values. Sure enough when I turned the key the truck fired up and all was normal. I left it run for 15 minutes and took it for a drive and it’s running just fine. It’s still learning but it’s actually running better than ever so I beleive I did have a leak downstream from the maf somewhere. Thanks for your input guys! And I hope someone stumbles upon this thread in the future and gets the answers their looking for.

For anyone that doesn’t have access to a tactrix cable and techstream (or vf tuner) you should be able to reset your learned values if you leave the battery disconnected for awhile. I used to beleive that 30 or so seconds was enough but it wasn’t in my case. I probably would’ve got the same results if I would’ve left the - terminal off longer but I decided to use my laptop.

One last thing, the cheap maf was not a good one. It will idle just fine but it leans out like crazy under throttle enough to cause the engine to cut out. This was not the cause of the issues as I swapped my oem back in right off the bat and still got nowhere. But I figured I would post my experience with the maf gamble I took.