- My model of MX-5 is: 2013 Sport Graphite 2.0
- I’m based near: Manchester
- I’m looking for technical help or recommendations on: Persistent Engine light after clearing DTC.
Hi all, I’m having trouble with my NC after replacing the stock airbox to a Direnza air intake.
When i first fitted this intake i had no issues but after turning the car off and driving it again shortly after the engine light will come on, despite clearing the code and buying a replacement MAF.
I’ve tried clearing this code and refitting this intake I don’t know how many times but nothing seems to change.
Once the engine light comes on it’s instantly down on power, chugging when slowly accelerating and almost stalling.
Advice?
Have you code read the issue to see what the ecu thinks is wrong ?
Check the loom under the air filter box ,i had a similar issue where some critter had damage the wiring .
Yes, these were the codes.
|POM|P0171–|
|OBDI|P0171-C|
Another thought - assuming there is no damage as suggested by Jamesy1 - did you let the ecu re-learn the maf/throttle body after fitting ?
The relearn procedure is :
- Turn the ignition to ON without starting the engine for one minute, then turn it to OFF.
- After one minute has passed, start the engine.
- Turn off any electrical load, including the A/C, with the shifter in Neutral or Park position.
- Warm up the engine at idle speed until the cooling fan starts operating or until the coolant temperature reaches 90°C or higher.
- Let the engine run for five more minutes.
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I haven’t checked this no, but I will first thing tomorrow.
No I haven’t tried this. I’ve seen and heard people talk about relearning the ECU but I haven’t tried it myself, but tomorrow I will follow those steps after clearing the codes for the thousandth time. Hopefully this does the trick.
So the ECU thinks too much air is entering the engine and causing a lean condition.
Apparently so, might explain my 25mpg no matter how I drive 
Is that an OILED filter like a K&N ?
If yes - I wonder if oil has been pulled passed the filter and coated the MAF
You could try giving the MAF a good clean with MAF cleaner or brake cleaner to remove any oil deposits so it can sense airflow properly.
No I dont think so anyway. And I stupidly bought a new one thinking I had damaged the original when changing over the stock airbox to this new intake but that seems to have changed nothing. I think relearning the ECU is the solution. I hope so anyway.
The MAF is plugged in to the outlet of the std airbox.
Are you sure there is the same seal between the maf and the new air filter ?
Also - I notice on the Direnza air intake - that the flange of the MAF mount hole seems wider than the OEM airbox - could it be blocking the vent holes under the MAF ?
Have you considered putting it back to ‘standard’ to see if this clears your problem?
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Please let us know when you find the solution @dbowers14.
I was just about to order that kit!
Yep try the stock airbox again, after disconnecting the battery to clear the fuel trims.
Moving the location of the MAF within the airstream will affect how it reads. If your fuel trims go outside of tolerance (usually around +/-25%) the car will think there is a running problem a throw a MIL. The way around this is a remap, or revert back to standard.
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Hi all, just cleared the codes and am not waiting for it to warm up and waiting the 5 minutes as per @CBRDEANO , hoping this does fix it or I think I will take the suggestion of returning it to stock to fix the issue.
@PuffyPinkPanda honestly it’s a really nice bit of kit and was so easy to fit but I think I’ve jumped the gun and just took it out for a rip without relearning the ECU. I’d suggest this intake over the very small amount that are on the market especially over the ram air kit as that is a pain to fit, believe me.
Will update after waiting the five minutes and taking for a spin.
Yeah I’ve taken out and replaced the old MAF and the new one I don’t know how many times but it definitely seems to fit flush so there shouldn’t be an air leak there anyway or a blockage.
Yeah very true, I think a remap that takes into account that the MAF has more air going through is definitely what it needs but I’m trying to avoid having to get it retuned as I bought the versatuner ‘DIY’ tune a couple of weeks ago and that makes a huge difference.
Standard is not an option now 
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Fingers crossed! It does look like a far better setup than having to take the bumper off every time you want to service the filter.
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Understood!
The MAF won’t have any more air going through it, just the relocation upsets the calibration so you will need to rescale the voltage vs airflow table, using logged data.
If you want some help with VersaTuner feel free to give me a shout, I am one of their approved tuning agents (and only a few miles North of Chorley).
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