R33 Misfire/backfire/not Running That Sweet

[HEAPHO]

Hey Everyone Just wondering if anyone can help me out i have a 98 Series 2 R33 Skyline and just recently the car started popping and backfiring a bit when I was driving home down the freeway. Before that It wouldn't start after I had sat in the sun on a hot day but I replaced the spark plugs and that seemed to have fixed that as the old ones were black and dirty. So far Im just trying to find out what the problem is with the backfire and It not running right It started to blow a bit of black smoke and i was revving it to keep it running was a bit scared to let it idle as I didn't want it to stop at the lights. Managed to get it home and now I have done the following. Turbo still spools up and make boost cars running 0.5 bar at the moment and has a BOV POD filter FMIC and boost tap.

Pulled off the front mounted Intercooler piping and joiners and cleaned everything and put them all back on a tightened the clamps and checked joiners for splits they all seemed to be ok.

Replaced the spark plugs

Cleaned and checked the coil packs for hairline cracks looks like the factory one am keen to buy Splitfire coils but am going to wait to see if I need new ones to solve the problem.

Cleaned the AAC valve

Cleaned the AFM ( air flow meter ) had Oil from K&N filter all through it so cleaned that and got a new dry pod filter. Just wondering If it need to be hooked up to a diagnostics computer to check for any trouble code on the computer.

Checked vacuum lines for splits but I may have missed one but seems ok

So am thinking maybe fuel pump and filter need to be replaced or something to do with the injectors ? put 98 in the gas tank and a bottle of wynns injector cleaner

maybe AFM needs to be rebuilt or buy a new one ?

also whats the deal with the different spark plug gaps ?

Any help will be much appreciated don't want to buy new parts till I know whats wrong going to take it to the mechanic soon to get checked out just seeing If there is something I can do to fix it first.

cheers

Tom

[SECURITY]

try a 0.8mm spark plug gap. also make sure your AFM is plugged in properly. failing those, you can open up the AFM using a stanley knife and re-solder the pins, there is a bit of sealant around the square part on the AFM that you can cut to open it up. just make sure you re-seal it.

funnily enough, if your car is backfiring you will actually make more boost.

[DVS JEZ]

if a mate has another stock AFM that you can try that will help with diagnosis, if that doesnt work, try another ecu.

where are you located?

[The Mafia]

hhmm.. Symptoms. Car missfiring. Spark plus black and fouled, changing them fixed the problem.

Then I see it has a BOV.

Keep spending your money, spend thousands. I keep repeating myself. ATMO BOVs do this.

They are just going to keep fouling your plugs and making your car fail.

Why do people see the f**king need to put a BOV straight on these things where there is a perfect, NON constant leak one plumbed back and all neat and tidy. Don't say noise, because that just means you're a full on wanker.

[Dose Pipe Sutututu]

Get rid of that wank valve, put the stocker on or buy a plumb back BOV.

[DVS JEZ]

hhmm.. Symptoms. Car missfiring. Spark plus black and fouled, changing them fixed the problem.

Then I see it has a BOV.

Keep spending your money, spend thousands. I keep repeating myself. ATMO BOVs do this.

They are just going to keep fouling your plugs and making your car fail.

Why do people see the f**king need to put a BOV straight on these things where there is a perfect, NON constant leak one plumbed back and all neat and tidy. Don't say noise, because that just means you're a full on wanker.

i do agree with you but there is a lot of skylines running stock ecu and atmo BOV without any issues

[SKITTLES]

I've got a non-turbo R33 doing a similar that.

It's backfiring, causing loss of power.

Suggestions given by friends: timing chain and injectors.

If my Consult cable would hurry the f**k up and arrive, I'd probably be able to read out the errors but NOOOO dealextreme is taking forever

[Rolls]

timing chain??

[Fat_Tony]

i do agree with you but there is a lot of skylines running stock ecu and atmo BOV without any issues

I was under the impression a AFM system must be completely sealed behind the AFM. If there is a air leak to atmo there would be to much fuel entering the system.

[HEAPHO]

Hey thanks for the replies as for the BOV carry on It was already on the car and the car was running fine with that on its an HKS SSQV and I don't have the stock one. The AFM is sealed off it has an intake pipe to the turbo with silicone joiners on both ends then the AFM then an air filter clamped to the AFM. I think It need to have a diagnostics session with the auto sparky to see if any thing pops up on the ecu trouble codes. Kinda is making the same problems as my old 96 WRX did when the airflow meter was on its way out. Do the RB's run a timing chain or cam belt ? Also do you just buy spark plugs gapped to 0.8mm ? cheers Tom

[Rolls]

If you retune a car after adding an atmo bov you can get rid of most of the backfiring and stalling, but with the stock tune it will never play nice.

Eg the redtop rb20dets that had no bov, they get crazy reversion and don't backfire or stall.

[DVS JEZ]

i know of heaps of cars running atmo BOV's with out over fueling issues, yes sometimes they try to stall but never over fueling issues.

OP see if you can borrow an air flow meter off a mate or on a cruise night etc, this is the best way to diagnose if its the cause

[HEAPHO]

Think I may have found part of the problem was just look around the engine bay and found a small vacuum hose has one split on the end and the other has snapped off now where did it come from its a small 4mm inside diameter hose its black and has a green strip on it any one know what that hose is ?? i found it near the front of the intake plenum.

[DVS JEZ]

make sure the fuel reg has the vaccuum line connected to it, check for anywhere that loose line can reach too,

[HEAPHO]

Had a look around still cant find where the vacuum line came from its black with a faint green stripe down the side of it one end is broken/hard and dry and one end has been over a nipple but has a split on it the bit i have is about 300mm any body know what that hose mite be ? i hope this will fix my problem

[SECURITY]

where is it? what is it connected to? what side of the motor? picture?

your description is shit.

edit: yes, that is definitely capable of causing the problem you are describing. replace the hose.

Edited February 7, 2011 by SECURITY

[HEAPHO]

Thats the thing I don't know where I came from is there a type of pressure test to do on the vacuum system ? if so how do you do it ? Ill take a pic of the hose but it could have just been replaced earlier on and some one just left it there ??? ill put a pic up soon cheers

[Rolls]

Think I may have found part of the problem was just look around the engine bay and found a small vacuum hose has one split on the end and the other has snapped off now where did it come from its a small 4mm inside diameter hose its black and has a green strip on it any one know what that hose is ?? i found it near the front of the intake plenum.

sounds like the fuel reg or the boost guage line.

any vac leak will make it run like shit though, look harder, you'll find it eventually.

[DVS JEZ]

get a smoke test done on the intake, will find the leak

[HEAPHO]

where abouts is the fuel reg vacuum line located ? not to sure as its the first skyline ive owned cheers