Jump to content
SAU Community

Recommended Posts

I will try and explain this as thoroughly as possible cause it is a little hard if you haven't experienced the problem yourselves. I had an apexi AFC installed and tuned about a year ago. From the dyno tune, the power which was produced was 250 hp (roughly 160 kw). That was with a boost control, intercooler, greddy bov, turbo back exhaust installed. Bearing in mind, it was boost was only adjusted at 8psi.

Now, recently I have had a problem driving on freeways at approximately 100km when the car starts to kind of stop start. It feels like the something is pulling it back and only last a couple of seconds and then will happen again at the same speed. I previously had a service and the guy who serviced my car adjusted the fuel cut defender on the apexi and that seemed to be ok but over 100km, it still gives me the pits. I rang up a dyno tune guy (another one, not the one that tuned my car) and told them and they said that the apexi afc is not really compatible with the skyline r33 95 model's standard computer and suggested I remove the apexi and boost control to make it more efficient. Now that doesn't seem right considering many posts on this forum tend to express how great the afc is. I don't want to bring it back to the original guy because it is too far and I really don't have time but I am not too sure what the other one is talking about either so does anyone have any ideas?

Does anyone have this problem with their car underperforming?

Link to comment
https://www.sau.com.au/forums/topic/122261-apexi-afc/
Share on other sites

I've got an SAFC2 and its on 93 R33 with no problems.

I'm just taking a wild guess but it may have something to do with fueling. As in, is the flow of fuel. Maybe the fuel pumps shitting itself?

I'm taking a stab in the dark but i would want a 2nd and 3rd oppinion from dudes who work exclusively on imports before you do anything to the SAFC.

Oh and lastely, has anyone ever messed with the AFC itself? Could be messing with your tune if they've messed around with it.

Link to comment
https://www.sau.com.au/forums/topic/122261-apexi-afc/#findComment-2257268
Share on other sites

I've got an SAFC2 and its on 93 R33 with no problems.

I'm just taking a wild guess but it may have something to do with fueling. As in, is the flow of fuel. Maybe the fuel pumps shitting itself?

I'm taking a stab in the dark but i would want a 2nd and 3rd oppinion from dudes who work exclusively on imports before you do anything to the SAFC.

Oh and lastely, has anyone ever messed with the AFC itself? Could be messing with your tune if they've messed around with it.

No messing around, not that I am aware of. I really do think it just needs to be re-tuned and also the fuel pump just can't handle it....will need to check that out. Thanks for the advice.

Link to comment
https://www.sau.com.au/forums/topic/122261-apexi-afc/#findComment-2259016
Share on other sites

check the other thread on the same subject in the 'forced induction' section. its titled something along the lines of 'Mysterious power FC missfire'

the power FC is known to 'cut out' for a brief micro second while cruising.

Edited by SLIPPERY
Link to comment
https://www.sau.com.au/forums/topic/122261-apexi-afc/#findComment-2260353
Share on other sites

yo, ure using a afc right?

I reckon its the fuel pump not running right atm. Maybe its been tuned to run well and effiecient at the lower rev ranges but up high its leaning out.

Wat happens when u stretch the gears ou and ay given speed? Does it still shudder?

If yes, i'd say it def a fuel issue. Get an import mechanic to take it for a drive, they'll figure it out in now time.

good luck mate

Link to comment
https://www.sau.com.au/forums/topic/122261-apexi-afc/#findComment-2260391
Share on other sites

Hi, I really can't understand how it could be the fuel pump. At 100kph my car used to (with stock injectors) run at 6 to 7% injector duty cycle. Not a lot of work for the fuel pump I would think. I did also have AFM problems but was flat out getting to 40kph and 2500rpm. Which is about the stock ecu limp mode.

Link to comment
https://www.sau.com.au/forums/topic/122261-apexi-afc/#findComment-2260464
Share on other sites

i have the exact same problem with mine at the moment. have u turned up the boost by any chance? im pretty sure its fuel cut in my opinion not the fuel pump but the fuel pump can contribute if running higher boost. if u turn your boost rite down to around stock psi and give it a run on the highway and see if it still does it. i just put in a SAFC2 and its getting dynoed very soon, so that should fix the prob for me. another option is to go out and spend heaps on a power fc, or a mines ecu which is way cheaper and it has fuel cut defender built in along with a few other goodies. or u could get a fuel cut defender and have it tuned by someone who knows what they are doing.

its so obvious too. the guy adjusted your fuel cut defender when it last got serviced. theres the answer. i suggest going to another person who really knows how to specifically tune your car/afc.

well thats my opinion anyway, feel free to correct me if im wrong because i am no expert at this. i hope u fix the problem soon. good luck

Link to comment
https://www.sau.com.au/forums/topic/122261-apexi-afc/#findComment-2263646
Share on other sites

i have the exact same problem with mine at the moment. have u turned up the boost by any chance? im pretty sure its fuel cut in my opinion not the fuel pump but the fuel pump can contribute if running higher boost. if u turn your boost rite down to around stock psi and give it a run on the highway and see if it still does it. i just put in a SAFC2 and its getting dynoed very soon, so that should fix the prob for me. another option is to go out and spend heaps on a power fc, or a mines ecu which is way cheaper and it has fuel cut defender built in along with a few other goodies. or u could get a fuel cut defender and have it tuned by someone who knows what they are doing.

Its obviously not high boost related. If you actually read her post you would have read that its only on 8psi.

And why would she be on full boost doing 100km's on a highway anyways? If she's cruising at 100km's and its doing it what does boost have to do with any of it.

Link to comment
https://www.sau.com.au/forums/topic/122261-apexi-afc/#findComment-2263866
Share on other sites

have you checked for dirty injectors at all?

Hello,

Not that iam a expert at these things...but

Alot of things can do this to you, faulty coils,faulty injectors,faulty fuel pump or regulator,

even the AFM if faulty.The problem is at that speed, something is not working right

Suggest you get it checked by someone who knows what there doing,then you have someone to blame...

Good luck

Edited by 700HP-GTR33
Link to comment
https://www.sau.com.au/forums/topic/122261-apexi-afc/#findComment-2272154
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • Even more fun, leave all the ADAS stuff plugged in, but in different locations, hopefully avoid any codes!   And honestly, all these new cars with their weird electronics. Pull all the electronics out Duncan, and just shove an aftermarket ECU and if needed a trans controller in, along with a PDM. Make it run basic but race car styled!
    • To follow up a question from earlier too since I had the front bar off again (fking!) This is what is between the bumper and the drivers side wheel And this is the navigator side, only one thing but its a biggy! So basically....no putting coolers in the wheel arches without a lot of moving other stuff. Assuming I move to properly race prepping this car I'll take that job on and see how the computers respond to removing a whole bunch of ADAS modules
    • So I prepped the car for another track day on Wednesday (will be interesting to see coolant temps post flushing out and the larger reservoir, with a forecast of 3-14 being 20o cooler than last time I took it out). Couple of things to mention; since I am just driving the car and not taking a support vehicle, I took the rear seats out and just loaded the back up Team Trackday style. Look at all that space! To cover off removing the rear seat....it is weird (note the hybrid is probably different because it wouldn't have folding rear seats) Basically, you remove the lower seat base, very similar to a r series but it is a clip that pulls forward to release the base rather than it being bolted down. Easy Then, you need to remove the side section of the rear seat on each side. There is a 14mm head nut at the bottom of the side piece, the it slides upwards off a hook at the top to release; you also need to unhook the seatbelt from the loop at the top. Then the centre piece is weird. You need to release/fold the seats forward with the tab in the boot on each side From there, there are 2,x12mm headed bolts holding the rear of each seat to the folding bracket, under the trim between the rear seat and the boot (4x christmas tree clips there, they suck). The seat is out but you can see where the bolts attach to the bracket
    • As discussed in the previous post, the bushes in the 110 needed replacing. I took this opportunity to replace the castor bushes, the front lower control arm, lower the car and get the alignment dialled in with new tyres. I took it down to Alignment Motorsports on the GC to get this work done and also get more out of the Shockworks as I felt like I wasn't getting the full use out of them.  To cut a very long story short, it ended up being the case the passenger side castor arm wouldn't accept the brand new bush as the sleeve had worn badly enough to the point you could push the new bush in by hand and completely through. Trying a pair of TRD bushes didn't fix the issue either (I had originally gone with Hardrace bushes). We needed to urgently source another castor arm, and thankfully this was sourced and the guys at the shop worked on my car until 7pm on a Saturday to get everything done. The car rides a lot nicer now with the suspension dialled in properly. Lowered the car a little as well to suit the lower profile front tyres, and just bring the car down generally. Eternally thankful for the guys down at the shop to get the car sorted, we both pulled big favours from our contacts to get it done on the Saturday.  Also plugged in the new Stedi foglights into the S15, and even from a quick test in the garage I'm keen to see how they look out on the road. I had some concerns about the length of the LED body and whether it'd fit in the foglight housing but it's fine.  I've got a small window coming up next month where I'll likely get a little paint work done on the 110 to remove the rear wing, add a boot wing and roof wing, get the side skirt fixed up and colour match the little panel on the tail lights so that I can install some badges that I've kept in storage. I'm also tempted to put in a new pair of headlights on the 110.  Until then, here's some more pictures from Easter this year. 
    • I would put a fuel pressure gauge between the filter and the fuel rail, see if it's maintaining good fuel pressure at idle going up to the point when it stalls. Do you see any strange behavior in commanded fuel leading up to the point when it stalls? You might have to start going through the service manual and doing a long list of sensor tests if it's not the fuel system for whatever reason.
×
×
  • Create New...