Car Not Accelerating Properly

[Zell]

looks like mine is a fuel problem cos my car has big trouble starting now if i get it going tried to start it this arvo and first try it chugged a bit and died, second try the chugging got slower then died, third time i got nothing at all lol. a mate of mine reckons my aftermarket fuel pump has died, not sure when it was fitted as i bought the car with it on.

my mods are FMIC, cat back exhaust, bigger fuel pump, electronic boost controller, K&N filter and runs about 13psi but cant hold it the whole way so drops to 11psi and greddy bov.

the car goes into hyperdrive in 2 weeks to see if they can find the problem. any ideas or info would be greatly appreciated!!

[Wogan]

My mods are only pod filter, 3" cat back exhaust and just installed an fmic... the popping / spitting / misfiring i described in my previous post seems to have begun since i installed the fmic.. don't know if they are related or whether the better air flow has just allowed something which wasn't working properly to have it's weakness exposed.

Missed with stock coils at around 4500 rpm (PFC) - like hitting the limiter, it pops and misses etc

have to admit this sounds most like my problem. Hoping it's not coz i don't have a spare $500 on me at the moment. Could the same issues be caused by something as simple as shitty spark plugs or plug leads?

Do speedworks have a dyno? may need to put the car on the dyno to diagnose it since the problem only happens under load.

[ix9]

before you spend the money on coil packs make sure it is the coilpacks first... as it sounds more like a blocked fuel filter to me.

Agreed

[Wogan]

Update on my car's issues:

Upgraded fuel pump to one from an R33 GTR - no change

Replaced spark plugs - no change

i don't regret doing either thing though because the better pump will be good for future tuning and the spark plugs really did need replacing..

one thing i learnt from the old spark plugs is that they look as if the engine has been running on the leaner end of the scale.. suggests towards a fuel issue rather than ignition.. Gonna check the fuel pressure regulator tomorrow to see if that's all working fine... if i can't find out i'll probably book it in at speedworks and get them to diagnose it.. either the engine is not getting enough fuel or it's not igniting while under boost. Pop pop.

can't shake the feeling in my gut that it's coil packs though.

[Wogan]

Is it normal to have some oil coming through my air pipes after the turbo, and how much is normal?

i don't think i have a lot coming through, but when i was changing my intercooler i had some dripping out of a disconnected pipe (like 5 or so drips) and one of the new cooler pipes which wasn't tightened properly for a lil while had oil come through the leak.

could this be the source of my problem? is my turbo screwed? .. it appears to be working fine.. still get about 12 psi or so

[Ant97GTR]

Is it normal to have some oil coming through my air pipes after the turbo, and how much is normal?

i don't think i have a lot coming through, but when i was changing my intercooler i had some dripping out of a disconnected pipe (like 5 or so drips) and one of the new cooler pipes which wasn't tightened properly for a lil while had oil come through the leak.

could this be the source of my problem? is my turbo screwed? .. it appears to be working fine.. still get about 12 psi or so

Mate thats probably just blow by and as long as there is not a lot of oil (5 or so drips is nothing) it isn't much to worry about.

[WA_R32]

hey guys i have tried a few things with my car to try and fix the problem but it seems to be worse now all of a sudden the car will start jerking back and forward usually around 2500 - 3000 rpm i have bought and installed splitfire coilpacks as well as install a bosch 040 and new fuel filter and cleaned out the afm with electrical contact cleaner, after i cleaned the afm it ran really well for about half a day then started screwing up again could it possibly be that my afm is screwed?

[maka]

hey guys i have tried a few things with my car to try and fix the problem but it seems to be worse now all of a sudden the car will start jerking back and forward usually around 2500 - 3000 rpm i have bought and installed splitfire coilpacks as well as install a bosch 040 and new fuel filter and cleaned out the afm with electrical contact cleaner, after i cleaned the afm it ran really well for about half a day then started screwing up again could it possibly be that my afm is screwed?

Dude,

its your AFM, have a look, I posted a similar problem about 6 months or so ago...

Although I have an R33gtst.

Have a look at what type of air flow meter you have, and borrow one off someone to try... I think the RB25 has 3 different stickers on them a pink, yellow and green.. I could be wrong with the colours.. but yeha mine had a pink one.. I borrowed an AFM, put it on my car, and she was sweet.. Then had a look on the for sale section and managed to get one for $100.. The car never missed a beat after that... I would also suggest having a look at the posts about coilpacks. and how to fix em.. i found mine had some of those hairline cracks.. also worth doing...

I tried cleaning the AFM before too, and it worked for a little while.. but after realising the way a AFM works, I realised the thermistor had just got old, and needed replacing.. if you wanna pull your AFM apart, check for dry joints, there is a thing on the forum on how to do it.. But yeah I donno if it is possible to get the thermistor specs for that type of AFM.. I mean you could measure it, but I doubt you'll be able to match it..

The AFM should solve your issues for now though..

Good luck

Cheers,

maka.

Edited January 29, 2008 by maka

[WA_R32]

thanks mate bubba said i could borrow his to see if that fixes just waiting to hear back from him, it if it does ill see if he will sell it to me if he wont ill upgrade to a z32 afm

cheers again

[maka]

thanks mate bubba said i could borrow his to see if that fixes just waiting to hear back from him, it if it does ill see if he will sell it to me if he wont ill upgrade to a z32 afm

cheers again

Sweet, no probs. see how you go.. But isnt Bubba running a RB30/25 or something in those lines?

Yeah, as long as it is the same one, you'll be ok.. I mean if worst comes to worst, you can just get another 3 pin AFM, find out the pin config, and put that on.. I remember using a AFM of some sort of subaru... was a lot larger than the one that is standard on the 33.. Car took forever to get up to speed, but it proved the AFM was an issue...

Cheers.

[Wogan]

hey guys i have tried a few things with my car to try and fix the problem but it seems to be worse now all of a sudden the car will start jerking back and forward usually around 2500 - 3000 rpm i have bought and installed splitfire coilpacks as well as install a bosch 040 and new fuel filter and cleaned out the afm with electrical contact cleaner, after i cleaned the afm it ran really well for about half a day then started screwing up again could it possibly be that my afm is screwed?

I had exactly the same issue.. Turned out to be the crank angle sensor.. it definately is possible that it's the AFM, but there are a few sensors that can cause these sorts of problems.

Allstar Garage did a great job of diagnosing it.

[WA_R32]

yeah im going to borrow bubbas afm on sat to see if that is the problem hopefully this will fix it cause its really frustrating having to baby my car around everywhere ill let you know how it goes

[lcy]

i reckon its the sparkplugs....

have u change it yet??

if not, i think its time u change it.....

if problem is still there, most probally the coilpacks....

[WA_R32]

Problem is now fixed turns out it was the afm so have swapped it over and it is running fine now thanks everyone for your help

[SKYRYAN]

Aww such a cute, happy, little ending.. just precious

[WA_R32]

happy endings are always the best

[Nick033]

the solder points inside the afm probly broke apart, same thing was happening to me i wud be driving along and then car wud shudder and jerk back and forth under acceleration,(r33 tho)

dont throw the afm out dude, it can be fixed

u have to get a stanly knife and cut the silicon seal around the side cap out, take that off and u shud see a copper plate, remove that and u will be able to see the circiut board and there will be three metal pins that join up to another set leading down to the fillament, the solder used to join these is shit and breaks easy, so just get some more and resolder them, i made sure ther were lots of solder on each connection so they dont break again, then just put the copper plate back in, put the side cap on and reseal it with silicon again (i used sensor safe black rtv silicon) and voila car drives normal again.

[WA_R32]

the solder points inside the afm probly broke apart, same thing was happening to me i wud be driving along and then car wud shudder and jerk back and forth under acceleration,(r33 tho)

dont throw the afm out dude, it can be fixed

u have to get a stanly knife and cut the silicon seal around the side cap out, take that off and u shud see a copper plate, remove that and u will be able to see the circiut board and there will be three metal pins that join up to another set leading down to the fillament, the solder used to join these is shit and breaks easy, so just get some more and resolder them, i made sure ther were lots of solder on each connection so they dont break again, then just put the copper plate back in, put the side cap on and reseal it with silicon again (i used sensor safe black rtv silicon) and voila car drives normal again.

okay i might do that tonight then and keep it as a spare cheers

[Black_CSR]

Aww such a cute, happy, little ending.. just precious

I think u've been hanging around ur GF too much hehe

[bubba]

Sweet, no probs. see how you go.. But isnt Bubba running a RB30/25 or something in those lines?

Yeah, as long as it is the same one, you'll be ok.. I mean if worst comes to worst, you can just get another 3 pin AFM, find out the pin config, and put that on.. I remember using a AFM of some sort of subaru... was a lot larger than the one that is standard on the 33.. Car took forever to get up to speed, but it proved the AFM was an issue...

Cheers.

Indeed I am, but I am also running a z32 afm and have lots of RB20 crap lying around