Detonation or running rich...not good options

[Sprint]

I'm having a issue I jsut can't seem to figure out. The engine is a built 12:1 LLO with SDA cams (02 block, 01 head, 96 crank, forged rods/pistons), stock PCM for timing and fuel. Plugs are NKG's two steps colder with accel coils and SPS wires. Rockin the auto for now. Heres the issue: If I run anything less then 94 in it I get missing and detonation. It will surge and buck, especially under part throttle cruise. But when like this I throw no codes and my check service engine light will be off. If I put in 100+ (Usually run 1 gal toluene with 94 octane) I get almsot no misses/detonation, still some hessitation on launch but only because its idling low with the loppy cams. BUT I throw a "too rich" code. I've gone through and switched from a tank of 93 octane and had no codes then 94+toluene withthe code and back and forth again to make sure thats what it is. I have a emmissions test in three months I'd like to pass and they will fail me instantly if I have a engine code in the PCM. What could be causing this? I mean I dont want to run the lower gas because it runs horribley...I really thing its going to destroy something. Any ideas? Next step after a manu swap if its still doing this is to use the MegaSquirt for the injectors and hopefully lean it out but I don't see why its throwing a too rich when its definately running better. Any suggestions?

-Allan

[S.Bretz]

Try usingthe stock coils and a set of stock or regular OEM replacement wires. The ODB2 has a ion senseing curcuit built in that monitors off the number 4cyclinder. If the stock resistance in the primary and secondary curcuits had been altered, then the timing will be off and cause it to run lie but.

[Sprint]

Try usingthe stock coils and a set of stock or regular OEM replacement wires. The ODB2 has a ion senseing curcuit built in that monitors off the number 4cyclinder. If the stock resistance in the primary and secondary curcuits had been altered, then the timing will be off and cause it to run lie but.

No change. I've tried two ignition modules, a stock set of wires, and a total of 4 stock coils. It runs good with the Accels but throws the rich code.

[nefarious]

hows your fuel pressure?

[S.Bretz]

SOunds like you need a way to tune it then.

[Sprint]

I just dont understand why running crappy = PCM happy and running good = PCM unhappy. I'll see if the manual swap and a slight increase in the idle helps before I start tuning. I've had the MegaSquirt in for a while just as a super data logger, maybe I'll have to use it for tuning if the other things don't help.

[S.Bretz]

WHen you get detonation, the NOx and COx levels change alot, so the change in the chemical levels after might be changing what the sensor "thinks" is happening.

[Sprint]

Heres a new twist. Filled her up again, 8 gal 93 octane + 1g toluene + 4 oz ATF + 3 oz mineral spirits. Driven it 4 times, almost no miss/det and no light yet. Man she's finicky but she likes this blend. Maybe I just need to keep the much higher octane (>100). Oh and best part is I'm getting 30 mpg......hi compression FTW!

[omgitselvisc]

boost ftw [img]{SMILIES_PATH}/biggrin.gif[/img] <3

[DTDSasquatch]

Heres a new twist. Filled her up again, 8 gal 93 octane + 1g toluene + 4 oz ATF + 3 oz mineral spirits. Driven it 4 times, almost no miss/det and no light yet. Man she's finicky but she likes this blend. Maybe I just need to keep the much higher octane (>100). Oh and best part is I'm getting 30 mpg......hi compression FTW!

If that doesn't quite work out for you, try toluene + acetone.

[Jeremy]

manual swap.

[S.Bretz]

I have never heard to add ATF to the gasoline mixture. Is it to help clean stuff out or something?



This may sounds dumb, but I have seen it a couple times.....Ckeck your plug order....it should be 4-1-2-3 on the coil packs, If you mix either or both coils up, then it will run, but it will be finicky like you are describing.

[saturnspeed_12]

man allan, thats one hell of a mixture. i think you just need to get the manaul swap going and hook up the megasquirt. if i have any days off when you plan the manaul swap, ill be there.

[S.Bretz]

Another question...You don't have one of those super leet IAT mods in do you?

[Sprint]

I have never heard to add ATF to the gasoline mixture. Is it to help clean stuff out or something?

This may sounds dumb, but I have seen it a couple times.....Ckeck your plug order....it should be 4-1-2-3 on the coil packs, If you mix either or both coils up, then it will run, but it will be finicky like you are describing.

ATF helps with lubrication, have seen it in a couple different "make your own octane booster" guides out there and the car seems to like it. I've also double checked the coil packs so many times its ridiculous.

Another question...You don't have one of those super leet IAT mods in do you?

Nope. And all the sensors are reading good (IAT/CLT/TPS/etc). Got one of those little scantools.net boxes so I have verified all the values are good.

Just went thorough my third tank of the 93+tolune+ATF+Mineral spirits mix and my engine light hasn't come on in the last 7 or 8 startups. Runs a lot better too. That mix burns real hot though...last I pulled the plugs they were shiny like new except a bit of glazing. Looked good overall though. I'm gonna recheck the PCM for codes and if there isn't any I'm gonna get it emission tested while the weather is cold and its running good.

man allan, thats one hell of a mixture. i think you just need to get the manaul swap going and hook up the megasquirt. if i have any days off when you plan the manaul swap, ill be there.

Yes I def. need a manual. If I can run a 16.1 with the auto, 90+ degree IAT's, and the street cams I think I can break into high 14's with a manual, cold IAT's, and the race cams. I got my XRC shaker scoop sitting in the basement and most of the manual swap parts....just need to find some motivation.

-Allan