Vic'89

I know for a fact that my car was BONE stock, the original owner didnt do anything to it. It even had a paper air filter when I purchased it.

This was backed up by a 13.87 run at 98 mph with no mods. I do agree that some car are faster than other right from the factory, but all of these L98 will respond to exhaust and intakes mods.

Vic

stevec4

Hmm, actually yes I do. I have spent 4 years analysing ECU systems and have written a 600+ page web site about a specific European vehicle which includes extensive analysis of engine performance and OBD2 systems. I also have access to the Ford Motor Company archives and databases. All I'm saying is that I'd like to think that I know a little about what I'm talking about.

My data logging equipment is probably rather more powerful than most too and I can record engine parameters when driving the vehicle to monitor mixture and other sensors.

This thread went this way because you proclaimed that Bosch Platinum plugs were 'Junk' - I disagreed and told you why I disagree. I still do. You claimed that your car ran so rich that it caused Bosch Platinum plugs to foul up after 6k miles but your AC Delcos are just fine. I stated that is not normal and there must be another factor involved.

You then added that you have LT headers with an unheated O2 sensor - now I know why you killed your Bosch Platinums - you never reached CLOSED LOOP and so your car would run very rich - go figure.

stevec4

Hmm, and I'll bet they were 2 stroke motors

4 stroke motors do not carbon up when the engine is cooling - there is nothing in the cylinder to cause carbon to form. 2 strokes have residual oil in the cylinder that burns onto the plugs.

4 stroke motors carbon their plugs when they are running very, VERY rich or when they are burning oil. In fact they would have to be so rich that they would wreck the cat due to unburnt fuel igniting inside, leave black soot up the pipe and all over the rear bumper and you would sure as heck fail sniffer tests.

formul89

Tha would kill any spark plug plus your cat-converters after a while.

Mad-Mic

go figure then why when the car was BONE STOCK it did this? after opening her up to breath some i get a constant 12.9:1 AF Ratio? i didn't mod this car till alittle over a year ago. it had a 3 year 36k bumper to bumper warrenty. i didn't add the headers till last spring. bosch platinums was on my first tune up at 34k in original miles. so yes i stand by what i said. Bosch Platinums are Junk. oh did i mention these were +4's? suppose to be the best. i'd buy a 99 cent AC Delco plug over a Bosch Platinum plug any day of the week. you have your opinions and i have mine and i back mine up with real world data, not theory.

BTW you questioned me where i got my information and i answered. your information does not support what you are trying to debate about plug fouling. AF Ratio on a dead idling car with 0% throttle is high enough so no plug should ever foul. so where does fouled plugs come from if the combustion temps are so high to burn any excess fuel off?

Mad-Mic

with a code 34 and the problems i'e been having with the non heated O2 sensor these were my readings with a gutted cat.

state standards Inspection readings

hydrocarbons
220 ppm 531 ppm fail

carbon monozide
1.20 pct 1.11 pct pass

carbon dioxide
6.0 pct 13.38 pct pass

when i go back this month i'm sure she'll pass right through even with 12 degrees timing. once i finish the 388 up i'm putting 2 3" hi flow bullet cats cause i'm going with an LT1 style true dual setup.

now i'm curious how much did the MAF relays and the O2 threw it off by. i'll keep you informed.

cplonner

how can you tell what gear ratio your rear end is? and with a torque converter how does a higher stall speed help your car? i dont know exactly how the torque converter works

stevec4

We should probably let this thread die as neither of us is going to agree - I like my Bosch Platinum+4s because they suit my Vette and you prefer Delcos cos they suit yours. I just guess that the motors are different in some way.

By the way, if you are getting a constant 12.9 AF ratio then you have a problem as the ECU constantly varies the AF ratio between rich and lean - this is necessary for emissions and longevity of the cat. If you map the AF mixture over time it should show a regular square wave - if you had a post-cat O2 sensor then that should flatline showing that the cat is doing what it is supposed to.

By the way, this is a trace of O2 sensors - the top one is showing a working sensor the bottom one is a dying sensor that throws an error code.

formul89

I have run the regular Bosch 1 prong Platinums for years. Never tried the Plus 2's or 4's as I have heard mixed reviews on them.

hippy

Not on a dyno. Full throttle, remember?

stevec4

Agreed - at WOT the mixture is rich.

Mad-Mic

agreed that is a great graph! last nov before scanning the car i changed out the O2 sensor and she ran like a scolded dog for about 2-3 weeks then back to the Rich condition. i finally got my friend to wire in a serial port cable to the aldl cable for data logging. i wish i would of known about needing a heated O2 sensor along time ago! Funny thing was i was talking to Phil aka Wheelsup about this since i bought the headers from and am buying some other go fast parts from said "If ya would of asked me about the O2 i would of told ya!" damn that made me mad cause i asked him every other question about the installation process.!

Steve you are a wealth of information but not every car is the same. most of our cars run super rich from the factory. i believe the +4's gunk up alot more is due to the burn flame and the explosion of the fuel is shielded by the prongs of 4 resistors and this may enhance the Rich situation. this is only a theory as like i've shown on the original Stock O2 sensor from date of purchase ran fine all the way upto the point of my header install and 3 days later confirmed with the AF Ratio sheet from the dyno run. at WOT atleast my car ran pig rich as most do. now after i find some time to put this heated O2 sensor in this week i'll let you know the results.