DRFT103

iTrader: (3)

Yea, that's what I thought.... I'm doing extensive research on this.... some say its behind the crank, some say it's not... I even called up the toyota dealer to check for a crank position sensor for a 94 sc300, and he said that I have one behind the crank pulley wtf....?

I'm pretty sure my timing isn't off... I've set it a bunch.

Also... if this helps... the car sometimes goes really rich or really lean randomly at idle... sometimes at idle it will flood itself out, and sometimes it will go so lean that it dies.....

stockhatch

iTrader: (12)

I still say it sounds like the piggyback. As much trouble as it will be to run on a stock ecu again, that is what I would try. Unless you have a friend with mapecu2 you can try swapping in.

stockhatch

iTrader: (12)

You can also try adding dedicated chassis grounds to the battery, engine, and ecu(s). Have you checked resistance on your ground points?

DRFT103

iTrader: (3)

Well running on the stock ECU isnt an option, I already wired in 580cc injectors with a mk4 resistor and piggy tails ect... and the fact that it's converted to map ecu I have eliminated my KVF, so it would also have no way to read airflow.

mapecu checked it out and said it was good... there's got to be something being over looked here... I've been trying to diagnose this problem for a year now....

DRFT103

iTrader: (3)

I thought about that was well, adding more grounds... I checked for resistance on most parts, but not all.

If it's a ground problem in the wiring.. would adding more grounds solve this?

stockhatch

iTrader: (12)

It may fix it in a workaround kind of way. You really want to verify all factory paths to ground are good. Start changing flow paths to ground and I imagine there could be some ill effects depending on how many devices are hanging off of any particular ground. I would try adding grounds in a pinch if I was out of other options.

Check the ground points on the engine, especially the intake manifold ones. The EFI ground pigtails bolt to the intake. Take them loose, wire brush them really good, and make sure the bolt is clean and tight when you reassemble.

Then check for continuity between that bolt head and the battery negative. And also between that bolt head and the chassis of the car.

99SC42

iTrader: (44)

You do not i repeat do not have one behind the crank pulley, if you have one it will be on the oil pump and you have a 94 SC300 only 96-97 SC300 have a crank sensor behind the crank pulley but it's not functional trust me on this .
92-97 they all pick up the signals fro the distributor, the guy from lexus doesn't know what he's talking about.

Worse case i would remove the map ecu just to eliminate the possibility....

sayayin

iTrader: (2)

i have mapecu2 with a 1jz, check if you have a vacuum in the line for the mapecu2 or maybe kink, check your setting and maps, here is another one, on my turbo the compressor side had to much play back and front that on idle sometimes or when i go in to boost the turbine was hitting it the inside of the funnel and my car dies, luckily I found the problem replace turbo so far is being running great.

DRFT103

iTrader: (3)

First of all, I'd like to thank everyone for their help with this... I know it sucks to read about someones problems when there are much more interesting things going on in the forums... so thanks, I really appreciate it.

Ok, so today I inspected my wiring harness while doing a wire tuck at the same time, killing two birds with one stone, the harness checked out fine.... I tucked it under the runners for the intake manifold out of sight. I was even able to add an extra 4 gauge ground from the block to chassis.

I crank it up, it idles for two minutes, perfect AFR's, perfect volts, then shuts off fast. I crank it back up, starts fine. runs for about 5 minutes then dies again with no sputtering or anything. I crank it back up after having to give it a good bit of gas, then attempt to drive it... I go down my road, turn around, ease into boost, then let off and it dies, this time it won't start back up...

So in attempt to diagnose in "no start mode" as suggested, I checked for fuel, I removed my charcol canister, so my tank is not pressurized, I removed a fuel line and attempted to start and fuel was definatly flowing.

Next I checked for spark, I put the number one spark wire on the shock tower ground and it was defiantly getting spark.

I pulled the number one plug and it was soaked, I put it back in, came back to the car 20 minutes later, cranked it, and drove it back into the garage.

I'm seriously stumped... It seams like the no start problem is only when the motor is hot, yet it randomly kills at idle still when it's not warmed up yet.

anyone have an idea of what to check that might cause this?

I know the cam/crank sensor is in the distributor, I changed out the distributor with the one from my daily with no luck. same issues.

1WILLY1

iTrader: (9)

i hate seeing people go through these issues.

im sorry i have no advice for you but i am rooting for you to figure it out.

good luck

DRFT103

iTrader: (3)

Yea it just sucks because I've had the issue for over a year now, and posted multiple threads on various forums on the subject and no one seams to have the answer. I'm sure it's something small and simple

1WILLY1

iTrader: (9)

yes i went through something like this once and it drove me crazy

my problem tunred out to be the cam sensor was loose-----tookm me four or five mechanics and a thousand dollars to figure that out


check all your plugs and sensors make sure everything is plugged in tightly.

considering you have swapped out almost everything im not sure what it could be.


did u find out if your car has a cam and crank sensor---im sure it does-----did u check them?

DRFT103

iTrader: (3)

Yes, The GE ecu reads cam/crank position threw the distributor, I swapped out the distributor with the one from my daily, and I had the same issue.

DRFT103

iTrader: (3)

Ok, now that I think about it.... is it possible to melt a ground?

when my car was running great about a year ago, I bought an AEM tru boost gauge and wired it up to the same ground wire on the ECU that my map ecu and AEM wideband, so I had two digital gauges AND the MAPECU running off the same little 16ish gauge ground wire to the ECU. The car ran fine for a day, the next day I noticed little hiccups at full boost, the hiccups got progressively worst over the next few days to the point where my car barely started..

Since then I've wired the gauges to the radio where my MAPECU was the only thing running off of that wire.

It started up and drove much better than before, yet it wasn't all the way fixed, because i'm still having these problems.... Could I have messed up that one ground wire somehow?

FatBrian81

iTrader: (2)

Its very possible to have overloaded a small wire. Check around for burnt or melted insulation.