Jump to content
The mkiv Supra Owners Club

Something isnt right!


ADD
 Share

Recommended Posts

Havin 3 problems with my AFR's,

NUMBER 1 when ive got the car running under 1.2 bar and im WOT the afr's are about 11...now as soon as i go over 1.2bar to say 1.3bar the afr's are straight down to 10 and if im really booting it into 100+ leptons the car starts to hesitate and almost start to pop and backfire. It is exactly the same for 1.4bar but worse.

NUMBER 2 if ive been driving the car around 90 for more than 30 mins the afr's shoot down to between 11 and 12 from 15ish for no apparent reason. just cruising.

NUMBER 3 when the car has been driven for a while and im at a junction or T/L the afrs go down to between 11 or 12.

Im gonna change the plugs tomorrow but can anybody shed some light on what i should do? extremely worried im gonne screw it up.

cheers ad

Link to comment
Share on other sites

Is this that same issue we saw where you'd get mad rich AFRs for no apparent reason or am I thinking of a different car?

 

For issue one, having a look at one of your datalogs, 4th gear pushed 11.0:1 at 1.4bar but even so you'd have to hit low 10's to 9's to get hesitation and misfires... Something might be up, or it may be something we never got to on the day. Can you get a datalog for me to compare?

 

Number two and three certainly aren't mapping issues , that sounds like the random richness I recall?

 

-Ian

Link to comment
Share on other sites

Is this that same issue we saw where you'd get mad rich AFRs for no apparent reason or am I thinking of a different car?

 

For issue one, having a look at one of your datalogs, 4th gear pushed 11.0:1 at 1.4bar but even so you'd have to hit low 10's to 9's to get hesitation and misfires... Something might be up, or it may be something we never got to on the day. Can you get a datalog for me to compare?

 

Number two and three certainly aren't mapping issues , that sounds like the random richness I recall?

 

-Ian

 

Ian yes mate it seems to still be happening, but then it will suddenly be fine and go back to normal.

how to i get you a datalog mate?

cheers

ad

Link to comment
Share on other sites

How are you monitoring the AFRs? Could it possibly be the gauge you are using?

 

No, it's definitely the car going wibbly-woo, it did it while I was there and I had to use the laptop in realtime to control the fuelling to get us back to base as it had completely lost the plot!

 

I think it's probably still something up with the vac hosing, although I'd expect it to go worryingly lean up top rather than super rich. Hmmm. Drop me a PM and I'll go through the datalog procedure with you - you have got a laptop right? ;)

 

Did you ever get piccies of that wierd boost gauge wiring/hose behind your dash by the way?

 

-Ian

Link to comment
Share on other sites

No, it's definitely the car going wibbly-woo, it did it while I was there and I had to use the laptop in realtime to control the fuelling to get us back to base as it had completely lost the plot!

 

I think it's probably still something up with the vac hosing, although I'd expect it to go worryingly lean up top rather than super rich. Hmmm. Drop me a PM and I'll go through the datalog procedure with you - you have got a laptop right? ;)

 

Did you ever get piccies of that wierd boost gauge wiring/hose behind your dash by the way?

 

-Ian

 

Ian sorry for mega late post, that pipe from existing boost gauge goes under the dash through to pasenger footwell and into a box which is linked to my boost controller, it stays as a pipe and not as a electrical wire as i thought.

Ill pm ya now!

ad

Link to comment
Share on other sites

  • 4 months later...
Does issue 2 happen by any chance when you are only just on the throttle, sort of feathering it?

 

yes mate correct! its issue 1 thats the worse now, whenever i boot it and it reaches anywhere near 1 bar it hesitates so badly, but not when the exhaust bung is in, it only stars to shit itself at above 1.3 bar

Link to comment
Share on other sites

OK i have found that on very fine throttle openings or slight throttle on and off, for some reason the ECU goes very rich, but as soon as a steady throttle opening is held its fine, and I'm afraid i cant find a solution yet, throttle position sensor has been suggested but mine checks out fine so I'm still looking,

Issue 2 is i would say down to to rich a mixture, if mine goes into the 10s or below at more than 1.0 BAR it will miss, due to over rich, i have actually wondered if you need a colder plug, unless you boost to over 1.2 BAR, anyway try leaning it our a bit.

Link to comment
Share on other sites

OK i have found that on very fine throttle openings or slight throttle on and off, for some reason the ECU goes very rich, but as soon as a steady throttle opening is held its fine, and I'm afraid i cant find a solution yet, throttle position sensor has been suggested but mine checks out fine so I'm still looking,

Issue 2 is i would say down to to rich a mixture, if mine goes into the 10s or below at more than 1.0 BAR it will miss, due to over rich, i have actually wondered if you need a colder plug, unless you boost to over 1.2 BAR, anyway try leaning it our a bit.

 

Thank you for that mate, im doing a datalog for the mapper sometime next week so it can shed some more light on the matter if its mapping issues.

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.