turbo? Knock sensor? running lean?

[west_side_supra]

ok well ill start off by mentioning what modifications i have done

Shimmed the wastgate 4 washers
lightweight flywheel
Stage 3 clutch
muffler
New spark plugs/wires

Now for the Diagnostic's results
it flashes 5 times then a pause then flashes 2 times

what is happening
if i drive it normal i have no problems

when i drive it hard enough for the turbo to kick in the check engine light will turn on. There are no noises and i dont smell any burning. the exhaust smells fine at least rich. but it does feel like its running lean possibly it feels like theres a low response to throttle like a lag or its holding back from power.

the car drives fine even with the light on. it still is boosting past stock so 10-11psi im lost

what i think it might be
from codes knock sensor? Oxygen sensor? lean sensor?

what you guys think

[SideWinderGX]

the code is 52, so looking here: http://www.cygnusx1.net/Supra/Librar...ion=FI&Page=28 gave me a Knock Sensor Signal. apparently, it could be either of the two knock sensors or the ECU. and i know theres a post around here with the knock sensor locations, i posted on it yesterday...got it. http://www.toyota-supra.info/forums/...ead.php?t=6577

im not a supra wizard, so thats all i know haha, maybe someone else will post here with more information on what it could be. thats a start though.

[west_side_supra]

what does the knock sensor do exactly? why would it cause it to feel like its looseing power or dragging behind like im towing somthing.

also i have mixed gas for the first time
Safeway gas 92 octane 1/2 Tank of gas
chevron 92 octane w/techron 1/4 tank of gas
could this be causeing the issue

and one last possible the BOV might be leaking from the IC i can feel vacume when i put my hand on the seal.

[SideWinderGX]

im not an expert, but as far as i know, this is all close to correct:

knock is the preignition of gasses in a cylinder. instead of the piston compressing the gases and having the reaction occur, they combust prematurely, backfiring, and slow the pistons down. hence, they could slow the car down if bad enough. it happens if you ahve too high of an octane in your car, or if you mix them.

although, i dont think mixing gas matters as long as its the same octane. maybe it was a bad batch from one station that messed up yoru entire system.

um, if the blow off valve is leaking, thats obvoiusly not a good thing, although im not sure how that would relate to knock or anything messing up.

[west_side_supra]

sweet deal, so im going to wait for my tank of gas to empty out and im gonna stick with my usal safeway 92octane since i know that works fine no issues, or maby ill just stick with the lowest i dont know they all work fine from safeway damn chevron . well thanks ill keep posted once i do a refill

[marc]

nope, a code 52 signlas that the wires running from ur knock sensors to the ecu has shitted out. u need to cut the wires and resolder new wires in their place. i used microphone wire becazuse its the same shielded wire.

[IHateHacks]

Marc, usually when that happens the CE light stays on as long as the engine is running.

west_side_supra said: "if i drive it normal i have no problems
when i drive it hard enough for the turbo to kick in the check engine light will turn on."

And he said "is boosting past stock so 10-11psi"

I personally think the knock sensor is doing its job, and detonation robs you of power so that would explain your "dragging behind like im towing somthing."

When the ECU detects knock, it retards the timing like a mofo and performance goes way down.

Why don't you try lowering the boost, and take a few "shims" out of your wastegate. Or put a walbro 255lph fuel pump in it. 550's wouldn't hurt either.

[west_side_supra]

well its been running fine untill a couple days ago when i mixed to diffrent gas stations. so ill still try to run outa gas and refill and try it from there if all goes wrong still ill go and see about getting a new pump. but for now im driving it nice

[jfunez]

you may want to do a back pressure test on your cats, ...if you have any....!! on my case I did not have a code 52 since I had repaired that wiring problem when I installed the JDM engine. but I had shimmed the wastegate like you have done ,4 washers.., but every time that I would boost at or past 8 psi I would get this "lean gases smell "in the cabin and noticed that the supra would not increase speed as fast as it should... "Mustangs passed me for example" also there was a lot of lag on boost. This weekend I took it to the muffler shop and did what I"ve been wanting to do for a long time. I got the first cat removed. "the second one was allready removed" what I found out un-intentionally was that the cat was partially plugged and that the flex part of the downpipe had a long crack on it.

now the supra KICKS ASS and boosts a whole lot faster, the sound on the exhaust is great and throaty, get nice fireballs and backfires....er.. the good kind when down-shifting... top end response is way better and also low and top end acceleration.

I am a happy supra owner now and have discovered new abilities and posibilities for my supra.

moral of the story....cut the cats if posible, if not replace them with High flow ones.

[west_side_supra]

well from what i know the first cat is for cold start emissions, wich i dont have to do. i do need to do regular stick the thingy in the tailpipe emmsions, but yea. i was thinking of taking off the first one eventually. and replacing it with a straight pipe. then maby put in a hi flow for the second one. i have been hearing a little rattle and possible leak by the cats though. but its hard to tell because there is a little exhaust leak at the top of the new muffler.

well whenever i get my damn garage back ill be working on it more.