Problem: FC NA, Hesitation/No fire

[evil_as_skeletor]

Hi, im looking for advice on an issue I am experiencing with my FC (Aus deliv, NA).

Sometimes on start up, if left for a few hours, it will not start, it will crank like crazy (with my monster battery i can probably just drive using the starter!!), but no fire.
I dont know if its an issue from the coil, or somewhere else, possibly the CAS not sending signal to the coils...

It is also noticable at warm driving (initially) in first gear, second gear, as a stutter or 'choking' feeling, at around 2000rpm (as well as at 3800, but thats probably a characteristic). It is a similar feeling to running low on fuel or a shot coil feeling, like it has no power.
Its pretty friggen dangerous when trying to cross lanes or intersections, when it feels like its gonna cut out.

I have a feeling it could be the CAS, could i be correct, has anyone had a similar issue with the CAS failing?

Ive taken it to mildren($$$) and they are incapable of finding the issue.
I have had them install a Cat Converter ($500), feeling it was a 5th/6th port issue which only accentuated it, and also, was told "its not doing it now so we cant test anything" when it wasnt starting during the day there.
I told them it was happening earlier than 3800 (2500) and was responded with, "no its at 3800, its the actuators". All this after a rebuild, where before it was fine (and not smoking on startup). If anything, the rear (6th??) port actuator feels a little tight and gets stuck. I have mentioned this and they said that they checked it and it was OK.........

Im sure something is wrong.
Please help, any advice is good.

Cheers, ERIN

[Rota_boy]

Sounds very similar to what happened to Kats FC. I would try and get a new CAS line it up and give that a shot.

[evil_as_skeletor]

Cheers, ill try that. Its all a bit tricky with rotas, ill have to refer to the manual that i Dld.
Hopefully i will here a bit more advice then i can go down that path.
Thanks.

[chaos99]

I had an issue with my JDM S4 turbo with loose wires on the leading coil under the cover.

it took a while to find the problem cause would only play up every now and again.:dodgy:

Stole some pics from another site to show the wires.

Worth a look:)
[attachment=17]
[attachment=18]

Cheers Greg

[evil_as_skeletor]

Cheers. Ill look at them, i think i am looking at an earthing/grounding issue. Ill trace some earths and see if anything is untoward.
Thanks guys.

[evil_as_skeletor]

The contacts mentioned look to be ok on both sets of coils. nice and tight.
I have a few checks, ie TPS, Timing, and general Idle and AFR checks before i go down any other path i think.
Maybe it aint the CAS at this stage....

[FIX_my_ROTA]

Probably a wild shot but have you tried your fuel filter and pump. My old s2 use to run fine cold but when it warmed up the pump use to cut out hard an i couldnt get the car past 100km's... Just a thought....

Will it rev out further than 3800 if you slowly squeeze the throttle rather than 3/4 to full acceleration...?

[evil_as_skeletor]

Checked all the above and nothing showed up.

Oh it revs out all the way, just first gear (higher demand on electrics/ignition) where the flat spot occurs.
It may be a fuel issue, but as the motor was just rebuilt, surely MRE would have looked into replacing fuel filter if it was cactus, right?
Anyone know anything about the secondary injectors, and whether or not the NA 13b has them? I cant find any definitive answers on that. It could be that the higher demand on ignition draws current from the secondary coils at the RPMs that they are activated in? Making me think that I may have an earthing issue or CAS signal issue....?

[rxfc3s]

i had a similar problem with my first fc turbo when i first got it. it turned out to be an earthing issue, if i remember right i had to earth a wire to the body from the boost pressure sensor on the rh side strut tower. Not sure if your NA FC would have it? That fixed it, i then installed an aftermarket computer and ran fresh positive and negative wires to power the computer, removed that wire and i had no problems. Its a common problem with them lol just type "FC 3800rpm hesitation" in google

As far as no firing issue, i had a similar problem, it was firing however just flooding really easy. I installed a fuel pump kill switch near my ignition which i would leave off, crank the car till it started, then flick the fuel pump switch on. Again this problem was rectified when i installed the microtech.

Andrew

[evil_as_skeletor]

i had a similar problem with my first fc turbo when i first got it. it turned out to be an earthing issue, if i remember right i had to earth a wire to the body from the boost pressure sensor on the rh side strut tower. Not sure if your NA FC would have it? That fixed it, i then installed an aftermarket computer and ran fresh positive and negative wires to power the computer, removed that wire and i had no problems. Its a common problem with them lol just type "FC 3800rpm hesitation" in google

As far as no firing issue, i had a similar problem, it was firing however just flooding really easy. I installed a fuel pump kill switch near my ignition which i would leave off, crank the car till it started, then flick the fuel pump switch on. Again this problem was rectified when i installed the microtech.

Andrew


Cheers Andrew, yeah i'll check earths this weekend. I am going about replacing the cheap sensors on the engine just to make sure its not something dodgy and also to have new sensors.... I have researched the 3,800 hesitation and found stuff like soldering the ECU so i thought that i was going up the wrong path.

As for the kill switch, i have a pump one installed, i dont think its flooding, i think rather, that it is an ignition issue. As there isnt that strong smell of fuel and it would at least sputter and not magically come back to life after a bit!

Ill check earths, i reckon thats going to be it.
It might just be something MRE left off when they removed the motor and g/box.

Cheers, ERIN

[evil_as_skeletor]

Anyone got a new(ish) TPS they dont want anymore? I am thinking this could be shagged.

[Rags]

my s4 on hot days after a drive if left for 1/2 hr will flood, i just pull the injector fuse out crank it put the fuse back and crank again, away she goes pain in the ass and it takes a min to get the revs stable because it feels like it takes a gob of hot air.

[Rags]

but i have a problem with earthing at the moment my left light is dim (recent) and dash lights will turn off if i hit bumps,wipers only work on hi, int main light just works int now as well, and i lost around 10 to 20% power and delay as well.
its like the elecrtics are slowly craping them self.
is it just my s4 7

[evil_as_skeletor]

Hey there.
After millions of dollars spent at mildrens, they seemed to have found the issue. I was having minor electrical issues too. They got a guy named Gianni in who was an auto elecy, he spent a little bit of time on it, after wiring in a Microtech for diagnostic purposes before removing it after finding out what was wrong, it appeared to be a Voltage Regulator module inside the vehicle apparently. Meh, whatever, the car is fixed and i can drive it.
Maybe give Greg at Mildrens a call and see whether your symptoms fit. Might be beneficial for you.
Alternatively call Gianni first hand, i can PM you his number if you want, he is really good and knows his stuff.
PM me and ill get it to you.

[evil_as_skeletor]

Gianni also rebuilds wiper and headlight switches (units) which may be what you are after. They crap themselves a bit i hear.
He is reasonably priced considering the work he puts in.

[evil_as_skeletor]

My car is back at MRE for a really bad hesitation, running way lean. (could be related).

They have checked most sensors and ECU and they have not come up with anything.
Greg has checked CAS scope patterns and injector condition and pulsing etc.

It is basically bucking and hopping and no power at all. It just isn't driveable.

They have run out of ideas after almost 6 months now, but they reckon it may be sorted by installing a Microtech.

The motor has been rebuilt and it was fine for ages after that, then all of a sudden it started to lack power etc when foot was planted a bit.

I must admit, I drive it pretty tamely, but when I put my foot down to cross traffic or speed up to overtake or take off from lights it almost feels as if the ignition coil(s) has gone or the fuel pump, and there is no power at all, in fact i have to back off the throttle to get it to move.

The fuel pump has been replaced as part of their repairs and they have extensively tested things and dynoed, even going to the extent of getting an 80 year old dude to bring his 40K old Na FC in to compare.

They have checked charging, CAS scope patterns, AFM, injector circuits, pulse width, voltages at the ECU etc and nothing has become obvious. They also checked boost and Atmo sensors. Greg also fiddled with resistors on the AFM etc and essentially 'remapped' the points in the AFM.

I have recently (past year) replaced battery and alternator (as it shit itself), but that's not to say that they aren't now playing up.

They sent it to the auto eleccy (Isaacs) and he apparently went through all the earths and cleaned them and whatever he did.

I thought the TPS could be poo, but they said it has tested ok, expecially since replacing it is a bit pricey.

They replaced the cat, thinking that it was the cause of the 3800 hesitation, but that didnt seem to improve things too much, and after that this problem slowly arose.

They made a breakout box also for testing between the ECU and Harness to test signal volts.

It isnt being too fruitful, but I am adamant that i do not want to go down the aftermarket ecu path, it just doesnt seems warranted as the ECU was ruled out a while ago by their diagnosis.

Any help would be greatly appreciated.

Thanks.