R33 Problem

[Nige1]

I have an r33 skyline 1994, it has a bad case of backfire, it has very poor acceleration and when i accelerate it gets stuck at 3 rpm backfiring really bad, i have check spark plugs, fuel filter, coils, afm, vacuum leaks, i have cleaned throttle body, afm, aac valve ive had a mechanic check it he cldnt find problem, its undrivable and check engine lights on, timing strts up at 20 on strt up and slowly decreases to 15 as car warms up. Mods are

Splitfire coils.

550cc fuel pump.

3 inch turbo bAck exhaust

High flow turbo

Apexi pod filter

Apexi fc commander

Boost Gauge

Front intercooler

Boost controller

Lowered 1.5 inchs

Short shift gear box

What di you guys think

[jjman]

Even though you have splitfires in there it sounds like textbook coilpacks.

Try some other known working coilpacks in it.

Otherwise you say you have only 'checked' sparkplugs and 'cleaned' the AFM.

Id go for changing spark plugs to the tried and tested bcpr7es .8 gap. Also 'check' that you dont have a dry solder on your afm or some other problem/damage in it.

That timing seems normal but otherwise when was the last time it was tuned/ PFC checked?

good luck. Nothing worse than a case of the missfires/backfires.

Edited March 12, 2013 by jjman

[GTSBoy]

How many of these threads do we need?

[Nige1]

I changed sparkplugs to those ones clned maf the joints look fine but it could be i unplug maf while car was running it stalled strted it up with maf unplugged idled shit we tested coils by unpluging one at a time while car was running

[jjman]

coils will often work fine at idle and low rpm/throttle levels, but then loose their shit at higher rpm, that 3-4000rpm range as you hit peak boost...

But yes, overall doesnt point directly to coils.

[Nige1]

Ill try reheat the solder joints and see if tht changes

[Dose Pipe Sutututu]

wonder if your CAS is cactus, they sometimes fuark up too

[Nige1]

Resoldered the amf made no diff

[blind_elk]

Lack of power can be attributed to the cams being "off" (generally retarded).

"Check engine" suggests maybe a collapsed / collapsing catalytic converter.

[Nige1]

The mechanic said he checked exhaust ill check tomorow ill put it on jack stands and try

[Jayden.K]

mate it seems at peak boost is when your problem is, has to be either afm or coils/plugs. very sure of it. i put to much oil on my air filter once and when it hit boost at around 2600rpm it hit a wall, point being afm wasnt reading correctly. and coil packs bring on the engine light. on standard computers anyway not to sure about pfc in how it stores trouble codes if it has any

[Nige1]

Its undriveable, i cant drive without it just hitting a wall of backfire we tested coils thywhere good

[Nige1]

Cld a vac leak cause backfire, no power, high idle?

[BLITZ-26]

Yes but not what your describing..... what boost is it reaching ? It's not over boosting is it ?

Change afm with known working one as with coils

[Nige1]

(Update) buzzing noise coming from cat

[BLITZ-26]

Buzzing ...... pull your cat off and see if part of your turbine wheel is playing hide and go seek in there

[Nige1]

This will be fun lol

[R33 Eddy]

wonder if your CAS is cactus, they sometimes fuark up too

This, had same problem when my cas stuffed up, wouldn't go anywhere on WOT.

[Nige1]

I think my catylac is f**ked from all the backfiring, ill check cas nxt thn inevitably hve to either sell it as wrecking or project or leave her in the shed til i can afford mechanic

[DVS JEZ]

Is it building boost?

Can u free rev it or drive off boost above 3krpm?