My Car Is Slow.. What Else To Try To Fix It

[GTAAAH]

Heyy, Ive been having missfiring issues and all sorts of crap with my car since i got it

There fixed now but it lacks performance (after i got new fuel pump it was really quick for about 3 days, then i left it overnight and next morning it was slow) Basically at the moment boost kicks in at 3krpm and holds all the way to 6, no real pushback in seatage. It used to Die out at 4krpm then kick in at 6krpm alot. But for a while there(after i got new pump), boost was kicking in at 3, building then at 4 it really pushed u back into your seat and.. i want it to do that again.

Tell me if above isnt clear, ill re-write it

Anyway so here what ive tried:

Clean AFM with metho (was already clean)

Full ECU diagnostics (got code 55 which means all ok)

02 Diagnostics (light was on slightly longer than off, so its running pretty good, slightly rich)

Replaced Fuel pump with a walbro (old one wasnt flowing anywhere near enough) (helped with missfire)

Replaced Fuel filter

Ran some injector cleaner through

Regapped Spark plugs to .8m (helped finish off the missfiring prob)

Tested voltages on Coil packs, got from 1.3-1.9 so pretty normal, checked contacts to

Re-checked all intercooler hoses

Tried various Boost controller settings

Can any one suggest something else to try on it please?

(ive tried some other things but i cant remember em all)

[lingeringsoul]

possibly get a tune first and see what power its running?

[GTAAAH]

Hmm, well its like couple of hundred bucks for that and i need to get it re-mapped/tuned after new turbo so if that was the only solution, itd have to wait till 33 turbo went on

anything else?

[xRHETTx]

Take the boost controller out maybe? At least it will rule that out as the source of the problem.

Go to a dyno day, for about $50 you'll get a much better idea of what is happening.

[Links]

maybe the boost cut (afm detecting too much air flow) is kicking in if you have it cranked up to much.. what boost are you running? Is it a stock ECU or aftermarket?

[GTAAAH]

Hmm i dont think itd be the boost controller and its a pain to take out, but its a decent suggestion, when i get a spare 4 hours ill take it out. Such a fiddly device and enclosed space T_T

Erm any idea where to find out about these "dyno" days?

Its a standard ecu, and its running 10 psi atm, but makes no differrence if its on 12

Any other suggestions?

Edited July 7, 2006 by r32 gts-turbo

[jap32r]

Heyy, Ive been having missfiring issues and all sorts of crap with my car since i got it

There fixed now but it lacks performance (after i got new fuel pump it was really quick for about 3 days, then i left it overnight and next morning it was slow) Basically at the moment boost kicks in at 3krpm and holds all the way to 6, no real pushback in seatage. It used to Die out at 4krpm then kick in at 6krpm alot. But for a while there(after i got new pump), boost was kicking in at 3, building then at 4 it really pushed u back into your seat and.. i want it to do that again.

Tell me if above isnt clear, ill re-write it

Anyway so here what ive tried:

Clean AFM with metho (was already clean)

Full ECU diagnostics (got code 55 which means all ok)

02 Diagnostics (light was on slightly longer than off, so its running pretty good, slightly rich)

Replaced Fuel pump with a walbro (old one wasnt flowing anywhere near enough) (helped with missfire)

Replaced Fuel filter

Ran some injector cleaner through

Regapped Spark plugs to .8m (helped finish off the missfiring prob)

Tested voltages on Coil packs, got from 1.3-1.9 so pretty normal, checked contacts to

Re-checked all intercooler hoses

just a suggestion ry a different afm i don't think it's recomended to use metho to clean them.

Tried various Boost controller settings

Can any one suggest something else to try on it please?

(ive tried some other things but i cant remember em all)

[GTAAAH]

hmm metho's not very harsh and doesnt leave residue, um i think phat32 used it so i stole his idea

Dunno where to get a different afm from, but tomorow ill open it up and check the connections. Any 1 wana lend me a afm? In melbourne area, ill come to your house try it on then bugger off

Edited July 7, 2006 by r32 gts-turbo

[Adriano]

I would do a compression test, check ignition timing and then cam timing, but for $50 get a power run on a dyno, maybe you are axpecting too much, if it is a standard r32 gtst, they arent rockets.

[RANDY]

Fuel pressure ok? I mean.. if it was great one day, then bad the next, and that was after a fuel pump went in.... you could have a fuelling problem perhaps?

I dunno that a dyno thrash is a great idea if you have unknown issues. I guess it could finish the job and then you'd REALLY know what the problem is! ;op

Standard ECU eh? See if you can borrow someone's laptop and consult cable too.. it'll give you an idea of what your injectors are doing, and whether the ECU thinks you're lean or rich when you put the boot in. Might be useful.

[GTAAAH]

The o2 sensor test isnt a good enough indication of whether the car is running rich or lean?

The fuel presure is cool since the new pump, he tested it all out again after the install so that couldnt be the prob

Perhaps a 14 second car does feel this slow, i dunno, but i swear its gotten significantly slower.

Its funny you should mention cam timing, because my mechanic said my ??VAC?? pressure was a bit low and that can be a indication of my timing belt being off by a tooth so.. Thats what he seems to think is the problem but well its not constant only happens sometimes so i cant see how it could be that.

The ignition timing is cool, he re-did it for me so no problems there

Some one else suggested a compression test to, but i need 2 people to do one unfortunately

Thanks guys

[HRthirtyone]

get it on the dyno, and get your fuel pressure checked. If there is a blockage, it would have killed the fuel pump both times, with the old one and the new walboro. im pretty sure there will be a blockage. I have seen this happen before, bits of the petrol tank or lines breaking down and getting caught in the lines. it will still run, and to someone who doesnt know the car, would have no idea, but it could be down 20rwkw or so on power aswell

[philta]

might be stupid comment but keep ur eye on ur boost gauge, might be a boost leak, BOV? maybe?

best thing is to get it on a dyno and check out the graphs

[GTAAAH]

nah no bov and no spiking

After the mechanic installed the walbro, he re-did the tests for puel pressure and said they were fine, but i suppose your right and something could have slipped off an old pipe or something. I dont know him very well and i know if i go back and ask for him to re-do the fuel pressure test, hell just laugh it off and ill come back with something else new so.. Is there a tool or a way to check the fuel pressure?

[Haysey]

i know it may sound obviuos but you have reset the computer?

[GTAAAH]

well yeh i have done that (unplug battery, press brakes, left for some hours) but from what i know it makes very little difference any way

Any1 else?

[Haysey]

well yeh i have done that (unplug battery, press brakes, left for some hours) but from what i know it makes very little difference any way

Any1 else?

weird, my car runs like a non turbo for around 15kms untill it relearns all the fuel maps etc then its a rocket again for a few more months till i have to do it again..

im stumped. sorry

[Cubes]

weird, my car runs like a non turbo for around 15kms untill it relearns all the fuel maps etc then its a rocket again for a few more months till i have to do it again..

im stumped. sorry

]

Its definitely impossible as the r32 and r33 ecu's don't learn anything to do with ignition, afr's or where detonation occurs. Its not within their capabilities.

All they do is sense detonation pull timing and drop a little added fuel in at that given time, it doesn't remember anything.

I had mine on the dyno some time ago when I had the stock ecu running ~1bar, did back to back with an ecu reset, zero difference.

[GTAAAH]

Took it to doctor drift friday night (felt a lil weird rocking up to a r31 skyline club do in a 32 but meh) and got it dynoed. Put out 135.8 rwkw and the doctor drift bloke who did the dyno said theres nothing wrong with it or the performance, so im just tripping out i guess hehe. Oh well, i got a quote on a 33turbo install.. Cheap + he rkns 30kw's is pretty easily attainable so allll good

[Cubes]

Post the dyno sheet. If its dieing off after 4k and then picking up after 6k it will reflect.

But your right.. I remember when mine was making 140rwkw or there abouts.. It felt slow. Only when it started cracking 160rwkw did it start feeling decent.

Be aware dyno's read differently but mine at 12psi (stock ecu, stock IC, 3" exhaust) made 152rwkw with ~11.5:1 afr's.

100% stock on the same dyno it made 115rwkw.