Apexi Afc

[skyliner33gurl]

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?

[Mr Italy!]

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.

[skyliner33gurl]

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.

[SLIPPERY]

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 June 15, 2006 by SLIPPERY

[Phantom32]

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

[SLIPPERY]

woops i read it as Power FC, not AFC...disregard my post

[MerlinTheHapyPig]

unlikely to be fuel pump. it sounds afm related, so i'd be finding out what settings were changed on the SAFC that started this happening. Or get the mechanic who changed it to take a look.

[brett33]

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.

[Phantom32]

i had a similiar problem with my car a lil while back and when i upgraded the fuel pump it sorted itself out.

I'm no expert when it comes to cars, just throwing out some suggestions to look at.

[lineskee 33]

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

[Mr Italy!]

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.

[skyliner33gurl]

Yeah, thanx for all your comments. When I am cruising, I am not even switching the boost switch on.

[Phantom32]

boost switch?

do u have a hi-lo switch to control your boost? If so, which setting is the AFC tuned for?

maybe just tune it for one setting and leaving it at that?

[SLIPPERY]

have you checked for dirty injectors at all?

[700HP-GTR33]

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 June 20, 2006 by 700HP-GTR33

[skyliner33gurl]

Thanks dudes. I have called someone who sounds pretty trustworthy and has a fair few experiences with skylines so will get this done and advise what the problem is for others.