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Surging

Mick

By Mick,
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Mick Mentor

Mick

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I have an R33 Gtst s2 and a few weeks ago i went to pick up my girlfriend from the airport and since i live in ballarat it is a long drive there and back so i filled up my tank almost full and since then the car has been surging, i never normaly put that much fuel in the tank and its usually half full as a maximum cos i dont drive much so i thought it might have something to do with filling the tank full cos it may have had some crud buildup higher up on the tank that isnt usually disturbed but it could be anything really, i filled up at the usual place and i put the 91 octane stuff in cos the car runs rich so since it wastes alot of fuel it makes sense to put the cheaper stuff in. Anyways i have just put new plugs and a fuel filter in and it didnt fix it and i just put some injector cleaner in it and im going to give it a big long drive tomorrow. It seems to only surge when im accelerating so if im sitting on the freeway its good but if im just getting onto the freeway and accelerating upto speed it will surge, does anyone have any hints on what could be the oroblem or can tell me what i can check next

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niZmO_Man Grand Master

niZmO_Man

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I have an R33 Gtst s2 and a few weeks ago i went to pick up my girlfriend from the airport and since i live in ballarat it is a long drive there and back so i filled up my tank almost full and since then the car has been surging, i never normaly put that much fuel in the tank and its usually half full as a maximum cos i dont drive much so i thought it might have something to do with filling the tank full cos it may have had some crud buildup higher up on the tank that isnt usually disturbed but it could be anything really, i filled up at the usual place and i put the 91 octane stuff in cos the car runs rich so since it wastes alot of fuel it makes sense to put the cheaper stuff in. Anyways i have just put new plugs and a fuel filter in and it didnt fix it and i just put some injector cleaner in it and im going to give it a big long drive tomorrow. It seems to only surge when im accelerating so if im sitting on the freeway its good but if im just getting onto the freeway and accelerating upto speed it will surge, does anyone have any hints on what could be the oroblem or can tell me what i can check next

I'm assuming standard ECU, injectors, pump, AFM, boost.

You should be putting 98RON fuel in. Otherwise, the ECU retards the engine because it'll ping.

What spark plugs did you put in? Gap? It could be hitting R&R (too much boost), could be bad AFM (replace/solder fix AFM), could be bad fuel pump. First thing I'd do is drain the fuel tank and put 98 RON fuel in.

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Plattsy Grand Master

Plattsy

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yep. problem is 91. 95 is fine. 98 is better.

for now disconnect you r battery for 24 hours, to reset the ecu. it swill remapp itself and may get out of trouble for now.

but id start adding 98ron as soon as possible.

once all the 91 is gone reset the ecu again to remap for better fuel

as a start.

as niz said above you could have a problem too.

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Dose Pipe Sutututu Grand Master

Dose Pipe Sutututu

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yep. problem is 91. 95 is fine. 98 is better.

for now disconnect you r battery for 24 hours, to reset the ecu. it swill remapp itself and may get out of trouble for now.

but id start adding 98ron as soon as possible.

once all the 91 is gone reset the ecu again to remap for better fuel

as a start.

as niz said above you could have a problem too.

ECU doesn't remap shit.. it has a pre-defined ignition & injection table.. the only closed loop is the idle & knock feedback.

If you insist in running 91RON, just retard the base timing like 4~5 degrees so at idle it's at 11 degrees BTDC

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Mick Mentor

Mick

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UPDATE

after changing all that stuff it ended up being the injectors, they were clogged from running that cheap 91 octane crap, i put a bottle of injector cleaner in it and its all good now. I only started putting it in a year ago cos the car is running so rich and dumping most of the good 98 out the exhaust so cos of that i used 91 and that dirty crap clogged up everything.

Let this be a lesson to anyone else running rich and thinking of putting the cheap crap in cos its spittin your good unburnt 98 out the rear, its not worth it, get your car tuned instead cos it will save you alot of headaches

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