Jump to content
The mkiv Supra Owners Club

HKS FCD STD wiring on a VVTI... Plug into MAF or MAP? Misfire and vvt malfunction


bluecoupe46
 Share

Recommended Posts

Hi Guys,

 

I've been converting my supe to BPU (well stage 2 anyway). My car is a VVTI jspec auto.

 

Having followed the instructions as best I could (in Japanese... Useful!), I wired the FCD into the MAF.

 

Having driven the car for 10 minutes give or take and letting it warm up on idle for another 5-10 minutes it started misfiring badly :mad:

 

I would like to know whether I was right to wire the fcd into the MAF rather than the MAP (remembering the car is a VVTI)?

 

It seems strange to me, as the car was misfiring badly before I installed any bpu mods, I replaced the plugs, cleaned the plug well thoroughly, cleaned the coil packs and tightened the rocker cover bolts to spec as they were hardly even hand tight. After that the idle misfire went away, but i didn't drive it, so I don't know if the plugs fixed the original misfire...

 

If I have done the correct thing by wiring the fcd into the maf pin on the ecu instead of the map, then what could be the cause of the misfire? I did a quick code check and it came back with maf and vvt system malfunction. The car only has 75k genuine miles on the clock with regular service history and the cleanest engine oil i have ever seen, so i can't see it being a ocv filter problem. As far as I can see it would have to be an electrical problem...

 

Any ideas guys?

 

Regards,

Alex :thumbs:

 

p.s. I have tapped into the Turbo pressure sensor hose to run the boost gauge... is this also going to cause a problem? If so where's best to tap into? Being the vvti, none of the threads i have found have a diy for the vvti, they just state tap into the y splitter which I haven't got. :/

Edited by bluecoupe46 (see edit history)
Link to comment
Share on other sites

What make of FCD? The Yanks sometimes try and clamp the air flow metering signal, but I have never seen this work properly, we over here (I have no idea where "Top Secret" is, or why people are so secretive), clamp the MAP sensor signal. wiring is in this thread and elsewhere:

 

http://www.mkivsupra.net/vbb/showthread.php?273315-Fitting-FCD-into-a-VVti&highlight=fcd+fitting+vvti

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. You might also be interested in our Guidelines, Privacy Policy and Terms of Use.