used unleaded instead of premium.

[LastTemptation]

(r33 rb25det)The other day i filled up on plain unleaded cos i wasnt paying attention. today i filled up on ultimate 98 and reset the computer. Now i have a problem with reving. on warm idle it jumps between 680 to 1300 just bouncing around. it even does it while im in gear driving. i can also hear a ticking from the engine. when i check it out i can smell like a electrical burn smell.. i dunno if this is the injectors or or plugs. also my car idled at 800rpm in neutral still dont know if that is normal. im going to check out the spark plugs tomorrow cos it was pinging abit the other day.

not sure on wat to do at this moment. did take it for a drive hoping it would go away and did reset the ecu a few mor times. any help guys?

[The Dan]

Check or replace your fuel filter and check other items such as coil packs and plugs. If you want to find out if the coil packs are crossfiring, get one of those water sprayers (like hairdressers use) and spray a fine mist over the top while it is running. You will see the sparks arcing across. And don't worry, a little water mist will not do any damage as long as you don't drown them. Just a couple of squirts.

Also check the earth wire to the ignition module and ensure it is tight. Try removing the AAC valve and inspecting it for cleanliness.

[LastTemptation]

Will do tomorrow, thanks for the info. I'll let you know if it works.

[LastTemptation]

Checked throttle body, clean.. cleaned spark plugs, cleaned AF meter, checked coil paks all is good. i think i should run some injector cleaner threw it. i want to change fuel filters. how many does the r33 have? i can only see the one in the engine bay. is there one in the tank??

[Al]

I really hope you were not driving it hard on the std unleaded fuel. I know of a person that blew his motor doing this very thing.

Once you noticed that you filled up with std unleaded, did you add octain booster to bump up the octain? That $16 for a bottle would have saved you all this aggravation.

[Col-GTSX]

Just the one fuel filter needs replacing in the engine bay... Make sure you get the right one not a universal type.

[LastTemptation]

yer Al, should have done that, but something inside of me also wanted to see what would happen, experiment? it actually didnt run that bad.. wont be doing it again tho. i think it might have done something to the gunk in the bottom of the tank loosened it or something. but dont see how that could happen.. will hunter a new filter down on thursday.

the revs are just fluctuating while on idle or when im rolling out of gear.. mainly low revs.. im pretty sure it is injectors. might test out some injector cleaner

[GTS4dood]

I really hope you were not driving it hard on the std unleaded fuel.  I know of a person that blew his motor doing this very thing.

Once you noticed that you filled up with std unleaded, did you add octain booster to bump up the octain?  That $16 for a bottle would have saved you all this aggravation.

would it do any damage to the engine adding the octane booster when already filling up with 98 octane fuel. would run a bit faster and cleaner???

[ferni]

Mate blew his RB25DET by putting normal unleaded and giving his car stick...

GTS4dood: nope it won't... I always run 98ron and usually ad a bottle of octane boost on trackdays - mainly for saftey. I don't think you'd see any performance gain, just a bit of saftey if your cars tune is on the edge or you're giving it a flogging.

[LastTemptation]

Used a bottle of injector cleaner, did 100kms, no change.. Changed the fuel filter the other day still no change. The revs seem to slow down instead of fluctuating from 1000 - 500 it goes to around 710 - 780 searching for a good rev. i dont understand. you can hear the car from outside idling up down. this only happens when im not accelarating. Some body said i should clean the ACC. What exactly is this? I dont know what it stands for but im sure, i know what it is.. anybody explain this to me. thanks..

[TracidTrax]

hmmm dont know much about this, let us know if u have solved the problem

[ylwgtr2]

sometimes you have to teach the ecu the engine speed.....how we do this when a vehicle has a delco efi system is erase all codes the start the engine and hold the revs at 2000rpm for about 2 minutes

[ylwgtr2]

aac is the auxillary air control valve.....some vehicles(mitsubishi's especially)when they have aac valve problems they roll at idle....on evo's when they are stuck open the revs go to increase and the ecu pulls the power from the injectors,revs drop below the excessive idle speed which is programed into the ecu and it opens up the power to the ecu again revs go up again and rolls(it knows your not on the throttle coz the tps is closed)

[LastTemptation]

will defenatly let you guys know whats going on. been pm'ing people that have had similar problems. tomorrow will carby clean the TPS and AAC or ACC valve, what ever its called.

also today when the engine was warm, oil pressure dropped in between 4 and 0 on idle, is this normal? ive always seen the niddle just below the 4? not sure what its meant to sit on.

keep the ideas coming guys. you guys are great. THANKS

[LastTemptation]

well oil pressure sits on 4 for sum reason today.. cleaned out the TPS and AAC and it aint that.. can anyone tell me how i can test coil packs? i tried that mist spray with water thing but i didnt get any respons last time. one of them might not be firing right.

[LastTemptation]

i get a big gurgle, drowning popping noise when down gearing.. very confusing.. could this be injectors or coil packs.

[Jax]

Can someone tell me,technically and factually, just what 'blows up' an engine, hard worked or not, if running on lower octane fuel than it was tuned on ? And , What 'lets go' or fails?

This is a serious question. I must admit, I can't see it myself, but I'm certainly open to facts, and to be convinced.

[Kaz200]

Adding more octane to premium wouldn't hurt it.. but you'd have less combustion and reduce your power so no, it's more likely to run slower than 'faster'.

However, one of our friends in Brisbane added 2 bottles of octane booster "need more POWAH" to his v8 commodore or whatever he owns and it wouldn't start.. so I wouldn't recommend it

[ylwgtr2]

Can someone tell me,technically and factually, just what 'blows up' an engine, hard worked or not, if running on lower octane fuel than it was tuned on ?   And , What 'lets go' or fails?

This is a serious question. I must admit, I can't see it myself, but I'm certainly open to facts, and to be convinced.

what breaks is the ring lands on the pistons or the big end floggs out from the engine trying to fire backwards

[Jax]

WHY is the engine trying to fire backwards? Are you saying it's 'detonation', or pre-ignition? Does'nt the Engine Management cope with this [mixture or timing ] If not, why not, and certainly on Standard Specs road engines, even though the recommended fuel is 98?