For a while now, my 2000 corolla has been throwing a p0420 and a p1315 for a while. I replaced the #4 coil pack and the p1315 went away and I thought this may have fixed the p0420 as well due to the misfiring. p0420 is back, and i'm thinking it may be the cat? the car used to burn a quart of oil about every 300 miles or less. in short, it now has a new block with maybe 10,000 miles on it now. my tps reads 10.58% at idle and only 76% at wot...shouldn't it be 100%? I think this is the problem with my stumbling acceleration and being SLOW. I'm probably going to the junkyard in the morning to get a tps...is it true that the stock catalytic converter on the matrix xrs is high flow? Thanks.
all catalytic converters are meant to have high flow, if you hold it up to an image you can see the image right through it. Buying something like a high performance cat means nothing like buying high performance spark plugs-_- Also your TPS could be the problem judging by those readings. Doesn't it usually give you the readings in Voltage? like 0V when it is at WOT and 5V when it is at idle(closed throttle)? What does that particular code mean and if changing the TPS fixes the problem that would be pretty sweet:P good luck
those are normal tps readings, sounds like theres a misfire and either a lean or rich condition causing the cat to not be able to work correctly and flagging up the catalyst as being bad. fix the stumbling issue and i'll bet the cat itself is fine.
however with oil consumption that high you may have indeed fouled out the cat.
the scanner i was using showed the throttle position in percentage. I thought if it was at wot it should be 100%? I'm going to change the rest of the coil packs today...as well as change the maf sensor. BTW, the cylinder numbers are listed from left to right, correct? The reason i think the tps could be the culprit is because it's at a certain throttle position where the stumbling occurs. about when i hit half throttle, I sometimes lose power and it will accelerate in pulses. I'll be really excited when this issue is fixed...
Update: changed the other coil packs, put a maf from a celica. I cleaned the maf first with acetone, started the car and everything was running good. took off down the road, stomped it in 1st at about 15 mph and the tires broke loose. ran fast for a while till the car was completely warmed up and driven for a bit, then it seems like i lost a lot of power. tires would break loose when i hit 2nd anymore. hmmmm....would the resistance of the tps change when it's warm?? i'll change that next. I forgot to mention that with the p0420 code, when the fans kicked on when the motor was hot the car would start missing like crazy, sometimes actually stalling out.
Well, I'm not getting the bogging issue anymore. But i'm wondering why there is such a power difference between driving at one point and 5 minutes later. feels like a 20whp difference...my clutch isn't that great and the tires still broke loose in second when i first took the car out. I haven't tested to see if the fan problem still occurs...i'll do that after work tonight.
I unplugged both fans and the car still ran fine. I unplugged the tps (used to give me a gain in power) and it gave me less power. Looks like maf/coil packs fixed the problem. I have a lot better gas mileage too! I'm still wondering about the P0420 though...seems that the code always pops up at low rpm (2200 range) is what the freeze data said. Could someone tell me why full throttle only goes to 76% where % is out of a scale of 100?
hahaha man, that wouldn't have been good. i think i'm going to go unplug the battery and let the ecu reset for the new coil packs and maf. I'll be sure to see if the valve is opening all the way. thanks for the feedback guys.
^^^ For the seemingly increase in power - that is a known "trick". If you reset the ECM, the car will run off of a preset A/F and timing map. In many cases, if you immediately dyno'd the car, would show a significant gain in power.
Once the car "relearns' the proper fuel trims, it will scale the timing and A/F to optimize running conditions - meaning better mileage, better driveability. The pre-set maps are hit or miss, some cars run great, some don't - but they are set to a "safe" values to make sure that the engine doesn't run too lean while the ECM is relearning.
If you want to really tailor the running of the engine - run a wideband and a piggyback EMS - that way you can see exactly what the engine is doing and can squeeze as much power as possible for your setup. Constantly resetting the ECM is a poor way to handle this, plus in many states that smog, you will automatically fail the test (I/M readiness is never set).
I just tested to see if when the fans kick on, the car still misses. As soon as the fans kicked on, the car just idled up like it should. Where could I get a piggyback EMS? I've searched and searched for them for the 1zz-fe corolla and couldn't find anything. Why can't you use an ECU from a celica (140 hp, stock rather than 125 from the corolla)? I understand that the ECU from the celica ups the rev limiter to 6600, changed the advance in spark and alters the A/F ratio for the extra 15 hp. does the valve timing have anything to do with this? Car is still running tip top. I am running 92 octane and some fuel system cleaner to ensure everything is up to par and still no p0420...I've only driven it 10 miles since reset though.
The ECM from a Celica takes into account the slight differences in the head (valve size) and differences in induction and exhaust.
As for EMS system, you can find them everywhere - Megasquirt, Apexi, Greddy, AMS, Camcon, etc. Each one will have to be tuned to your particular application. have to get the appropriate wiring harness as well (i.e., don't chop into the OEM harness, that is just asking for problems).
Really no turn key, plug and play solution - unless someone was running the exact same mods on their engine. Option is to pick up one from MWR with a "baseline" tune - then go from there. Being programmabe is part of their "charm" - be it good or bad.
Hmmm, that's more work than I feel like doing right now- I have a 1974 vw beetle that is my real project and consumes most of my money. Is there not a power programmer available? Jet chip apparently has one...but I don't know if I trust it. i doubt there is any real tune on it.
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