08/12/17 12:51 AM
Hesitation / CEL / smoke

Hi I have a 99' galant vr4. My car has developed a problem after I gave the throttle body, IACV (throttle body cleaner) and MAF sensor (CRC MAFS cleaner) a clean. The car was driving fine before the clean, the reason for cleaning was the rev seems to drop very slowly after I rev the engine in neutral (no biggie but I thought I could make it run better).
After the cleaning the car seems to be idling and rev'ing fine in neutral whether engine is cold or warm. The problem only arises when I put it in gear. The car will shake, idle at about 600 rpm (much lower than usual), CEL comes on and thick smoke from tailpipe and exhaust manifold. Strong smell of unburnt gas.
Prior to cleaning out the throttle body, IACV and MAF I changed the transmission oil and transfer case oil. Took it for a drive after changing fluids and seems to drive fine so I doubt this is the cause.
Any help is appreciated.

08/12/17 04:52 AM
Re: Hesitation / CEL / smoke

Would anyone be able to tell me what could be wrong? I am suspecting I might have killed the MAF sensor as this makes the most sense why it is acting up, make sense? Also would anyone be able to tell me if a MAF from a v6 non-turbo galant work on a VR4? or even from a 1.8L 4cyl?

(Doesn't Match Anything)
08/14/17 10:59 AM
Re: Hesitation / CEL / smoke

The simple answer to using cleaners on a MAS sensor like Mitsu uses, is that you will either kill it there and then, or soon after.
You generally cannot clean MAS/MAF sensors.

When cleaning an IAC, unless you remove the bits and only handle the tip and clean it this way, you can get cleaner into the electrical mechanisms behind the internal seals, IE spraying while the engine is running or with it off and the cleaner going into the IAC bore/seat areas. Simple as that.

Replace the MAF with an identical MAF, and see what happens, after the engine is allowed to relearn it's idle. Go from there.

("Just to be pedantic!")
08/14/17 11:13 AM
Re: Hesitation / CEL / smoke

Kia ora bro. Welcome to the Galant VR-4 forums.

First thing's first - this forum caters primarily to the '87 to '92 shape 6th generation Galant VR-4 only, and more specifically the USDM market.

Secondly - you have a Mitsubishi with a karmann vortex MAF which generally doesn't need cleaning unlike the hot-wire MAF's that you'll find in the likes of Nissans etc. It does sound like you damaged it by cleaning it. It might come right with time, but I would say the damage has been done permanently.

Lastly - on the MAF is a three digit number above the Mitsubishi part number, like 707, 309, 609 etc. You need another MAF to match that number. No, a N/A V6 or 1.8 GDI MAF definitely wont work. From a quick google search your MAF number is a 005 which doesn't appear to be shared with anything else. You will need another MAF with the same number.

08/17/17 02:51 AM
Re: Hesitation / CEL / smoke

Thank you for response.
I have bought and replaced the MAF with same three digit number 005 (second hand), unfortunately my car is still doing it. There is a chance this is a bad MAF, but most likely not.
Cold start seems and sounds very normal. But as soon as I put it in gear the car starts playing up, or turning it off and back on again and it is a little bit harder to start and then cars shaking, smoke from tailpipe that smells gasoline, CEL.
I pulled out the IACV from the car, spray it down with throttle body cleaner, and wipe the gunk off it and let it dry for 30mins before reinstallation. Dont think I did something that I shouldnt do?
To reset the ECU I am assuming we disconnect the battery terminals and reconnect it after 10-15mins, yes?
I did not know the car has a different type MAF, lessen learnt. I was intending to clean the throttle body and IACV and while the MAF is out I thought why not clean that as well.

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