afm/maf issue

[I A Motorsport]

OK after solving my odd problem i now have another..

everything is fine .. and tunning as planed . built boost upto o.8 bar making a nice 230 fwhp ..

the car is a Ca18det stock with a cam mod on the inlet side a gt28rs, and now running a r33 afm .. its also been recalibrated using the nistune tool for different maf's so i would asume read alot higer?

now ive discovered my afm reaches 5 voltes before then end of the map and wont read higher.. and tp reads 88 and flat lines im sure this is a simple fix but cant seem to find it. or is it just a recalibration ?

log below


ragards ian

[Matt]

if your MAF is reaching 5 volts and you can see a flat line along your logging then you have maxed this one out also. the R33 ones will read more flow, but perhaps not enough for that setup???

[I A Motorsport]

something must be wrong ... its only making 0.8 of a bar and 220 ish hp..

im basically getting to load site 90 at 0.8 and it wont go any further no matter how much boost i put through it .. ive taken it to 1.0bar and it still only goes to load site 90.. if it would go to the end of the map im sure it would be perfect.. would you like me to post up the map ?

regards ian

[Matt]

00:17.2 6037 5.078 80 0 112 13.8 4.06 84 __ __ NT __ __ 4.57 13 22528 [88]

it cant really get any more voltage from the AFM to get higher than 22528 [88] on the TP scale most likely

TP = AFM * K constant * map value + coefficients basically

if your AFM voltage is about 0.5 v at idle and 5.07 now then getting close to the top of the VQ map

what is the scaling on your map. if you want to go to the end of the map and it isnt because your scaling is too big, then reducing the numbering on your scaling

[I A Motorsport]

ive taken another look at this and it seems my AFM/MAF is reading 1.1 volts when at idle..

and then maxing out way to quickly

is there a fix for this ?

thanks

[I A Motorsport]

if this isnt the issue can you suggest some things to check?

this car should be able to run much higher hp and boost levels before maxing out the afm .. its no very highly tuned to flow that much air..

afer all is a 4 cyl stock bore and stroke ca18det.

im must be doing something wrong..

is there anything i can supply that will help the search ?

regards ian

[Matt]

nothing in the ECU you can do. that is quite a high voltage reading which you can only rescale your fuel/timing maps around

try another AFM would be my suggestion. trying to remember what the idle voltage would be, need to check but 1.1 seemed a little high

[I A Motorsport]

i have cleaned the afm (but im sure this would do the oposite and increase the voltage)

i have also swaped it out for another r33 gtst afm both run he same voltage..

just out of intrest i pluged nistune it into my ps13 sr20 just to see the afm voltage and on idle when warm the afm reads 1.6 volts ..?

could it be the wiring to the afm (maybe somehow its been done wrong or .. as its been soldered maybe causing high resistance.?
could it also be possible to have interferance ? but i cant see how this wold increase the voltge going throught he afm

changing the address file or base image wont affect anything like this ?

what about if the car has a manual ecu in a auto car/loom

[I A Motorsport]

the fact that its at 5 volts means the airflow meter wont see any more flow past this point so even if i do rescale it will only read upto 0.8 of a bar boost before we max readable flow ..

rescaling wont allow more boost to be addded or are we talking about a different scale ?

[Matt]

if you rev the other car with the SR20 you should see the voltage increase. okay so 1.5 volts is about normal idle voltage (i thought it was lower but I also have a bad memory!)

but hitting 5 volts means you've maxed that sensor out regardless of tune

you wont see that going any higher so load will not be measured any higher

rescaling wont allow more boost to be added, just changes the reference points of there TP will reach on the maps

[Legionnaire]

I'm sorry for breaking into this conversation, but just to make sure - you said that you are running R33 afm. As fas as I know there are two AFMs on R33, I cannot remember exact year when they swapped one for another, but the difference can be easily seen - they have different sticker color and different P/N.
S1 green sticker MAF has p/n 22680-02U00 and if you are using it, 230 wheel hp is a bit low (I don't know your transmission losses), but generally sounds right, as they are known to reach 5v at about 300-310 crank hp.
After 95 they used MAF with purple sticker, p/n 22680-31U00 or -31U05. This MAF was also used on R34 'lines, cefiros and whole lot of other engines including V8s. If you have this latter one, it should not max out before ~360-370 crank hp, which covers the abilities of GT28RS.

Petros.

[I A Motorsport]

its the early s1 green sticker afm and its not making 230 whp thats flywheel hp

but that doesnt bother me, its the fact itonly making 0.8 bar boost before it maxes itself. as this is for a 6 cylinder car running 0.7 bar boost just doesnt make sence..

i realise pressure is not flow but you can see the issues ? lol

can i have a list of ideas / reasons it would be maxing out early maybe ive missed something really simple?

could it be wiring ..this is what ive done ..

ca18det loom with plug pin for referance / to pin and wire colour Rb35 maf

A: green with yellow stripe / not used (cut and taped )

B:+12v Black with white stripe / +12v black with white stripe (E)

C:Ground black wire / signal wire ground White blue stripe (d)

D:Air flow signal out Green with black stripe / signal orange with black stripe (B)

On the gtst rb25 maf there is also a 12v ground this goes to the engine ground ..

if this is wrong please let me know ...

ecu codes

23710 ff410
mec-doo6 C1

manual ecu i beleive, the car has an auto wiring loom but a manual engine and engine loom.

could someone also confirm what address file i should be using and base image .. i know this is simple stuff but there mus be a problem somewhere.

regards ian

[Legionnaire]

OK after solving my odd problem i now have another..

everything is fine .. and tunning as planed . built boost upto o.8 bar making a nice 230 fwhp ..

ragards ian

Silly me confused front wheel hp with flywheel hp Sorry then.

Does your maf work fine with RB25?

[I A Motorsport]

ok well this is just getting more and more odd..

ive sawped out the afm for a running gst rb25 one and its seems to have kinda done the trick... now it reardds 1.1v at idle and readds up to 3.9 so far..

issue 1
my tp seems to max out as in flat line at 88 as the afm reaches 3.6 volts then it satys there even though the afm voltge goes up..

now as tp doesnt increase it mean it stops the map from reading past a certin load point about 3/4 of the way up load...

so my quession is does the tp vrs afm need re doing ? or should i be reading higher TP as im sure here are people reading over 100tp


and how can uncheck knock sensor as its reaading 192 all the time and then randomly goes up and down as it feels .. like it gets stuck

[I A Motorsport]

ok well this is just getting more and more odd..

ive sawped out the afm for a running gst rb25 one and its seems to have kinda done the trick... now it reardds 1.1v at idle and readds up to 3.9 so far..

issue 1
my tp seems to max out as in flat line at 88 as the afm reaches 3.6 volts then it satys there even though the afm voltge goes up..

now as tp doesnt increase it mean it stops the map from reading past a certin load point about 3/4 of the way up load...

so my quession is does the tp vrs afm need re doing ? or should i be reading higher TP as im sure here are people reading over 100tp


and how can uncheck knock sensor as its reaading 192 all the time and then randomly goes up and down as it feels .. like it gets stuck