Air/Fuel/Igntion Questions - Toyota Nation Forum : Toyota Car and Truck Forums

IMPORTMyth01 · 05-10-2004, 06:48 AM

Whats Up TN,

A couple of questions about some different problems...
I remember hearing a while back that you could run 16psi on stock everything on 91 MR2 3SGTE. Is that possible bone stock or was there any upgrades at all? Because I ran about 13-15 PSI and everytime it seems like halfway down the track the ECU picks up the knock sensor signal and the knock sensor burns out. I was just wondering if it was just my car or if running a better fuel pump and a fuel pressure regulator would help any?

And is stock ignition good enough to handle 16psi?
What kind of ignition upgrades is everyone running? Plugs, wires, MSD?
What kind of fuel upgrades? Pump, regulator?

Last question have a HKS EVC boost controller and it seems that when at full wide open throttle it will boost to 15psi at about 4000rpm's and by 7000rpms it will go back down to about 11psi? Just wondering if that is just because it is an internal wastegate or was there something I could do to make it stay there?

Thanks for any input,
Raymond

***MRQtwinturbo*** · 05-10-2004, 07:23 AM

OEM plugs/wires are best for 3SGTE.....stock fuel system is good for up to 300rwhp....are u sure ur not hitting boost cut (12psi)...how do u know its the knock sensor??..are u getting a CEL (check engine lite)??....max effiency of ct-26 is 16psi....u can run this safely without any major upgrades but an upgraded IC would be optimal......

IMPORTMyth01 · 05-10-2004, 12:58 PM

yes I have a check engine light and the code is 52 which is the knock sensor...but the funny thing is is that all I do is get a new knock sensor and the light goes away and car starts running back to normal again. I have an HKS FCD and I have a AFC. I havent been able to get the car tuned with the afc yet and so I have all the setting set to "0". When I have the AFC hooked up there are no problems but as soon as I unhook it the knock sensor faults out. Thanks

JekylandHyde · 05-10-2004, 02:01 PM

What octane gas are you running?
What gap on your plugs?

... I would recommend getting new Toyota cap, rotor and wires ... along with some NGK copper plugs (6097) and gap them to .28.

IMPORTMyth01 · 05-10-2004, 03:04 PM

thanks for the insight on the plugs...know of anyone having a knock sensor problem?

Piddy · 05-10-2004, 03:49 PM

Quote:

Originally posted by JekylandHyde
What octane gas are you running?
What gap on your plugs?

... I would recommend getting new Toyota cap, rotor and wires ... along with some NGK copper plugs (6097) and gap them to .28.

Is .28 the standard gap?

JekylandHyde · 05-10-2004, 05:40 PM

Standard gap is .30-.32
For 15 psi or so .. you should close the gap down .28-.29
I gap mine to .25.

Piddy · 05-10-2004, 05:58 PM

Okay.... I could have sworn it was .32. At least I know I'm not going crazy.

IMPORTMyth01 · 05-10-2004, 11:52 PM

I am running 93 octane gas (the best I can get) but running a US Spec ECU so it 93 should be fine, right? I know running a JDM ECU I would have to run at least 110? would it make a difference with a JDM motor running on a US ECU? EGR Make a difference?

Piddy · 05-11-2004, 01:17 AM

110 Octane? Do they even make that? I run 91 Octane (highest I can get) on my JDM.

JekylandHyde · 05-11-2004, 05:23 AM

The 3sgte Gen II calls for 93 octane (regardless of JDN or USDM).
the 3SGTE Gen III found in the later years in Japan calls for 110 RON octane (that is their measurement over there).
I believe it is equivalent to our 94-96 or so.

*I could be wrong on that.

110 octane (our rating) does exist here, but it is leaded.
I run 94 octane exclusively on the street and I race with the 110 leaded.

Leaded fuel will kill your cats and O2 sensors.
It will kill your cats fast and make your car undriveable.
I have no cats and my car was modified for GM O2 sensors which are much cheaper than the Toyota ones.

At any rate, for those of you in California and can not get hgher than 91 octane, I highly recommend getting a water injection system. Do a google search for "aquamist" and see what I am talking about. I have been running WI for over 2 years now.

IMPORTMyth01 · 05-11-2004, 07:01 AM

ok I have a concern now I just realized that before I installed a Top End Performance Downpipe my Air/Fuel Ratio Stayed on "Rich", and I never had a problem (I ran 18lbs on accident one time). Then when I installed the new downpipe I also installed a new Bosch 02 that came with it. But now it jumps back and forth lean to rich. But isn't that right?...The knock sensor only started coming on after the 02 change. Would that be a concern?

JekylandHyde · 05-11-2004, 09:39 AM

If you are watching an A/F gauge, it should fluctuate form rich to lean at idle and cruise. That is 100% normal.

If your old 02 read rich all the time, it was probably coated to a disgusting level and was not reading right

IMPORTMyth01 · 05-11-2004, 12:44 PM

one more question...oil...what grade/weight/amount does everyone use?? Because I heard a bunch of different, synthetic/10w-40/4 quarts, and even just regular 40/5 quarts. Just wondering if it would make a difference and if will make my car quit smaoking a little. Thanks

JekylandHyde · 05-11-2004, 12:47 PM

I use Castrol Syntec 10w30.