[ab85]

Hey all. Recently Ive been having some weird issues my my 1jz swapped sc300. Its been developing the worst misfire ever, at random. Its always cyl 1 and 4, that go out, but sometimes its a lot worse than other times and it feels like maybe 1 or 2 extra cylinders are out. from searching on here and doing some checks myself on the car, it seems that it is could be the ecu causing the injectors not to pulse. But whats weird is that the problem is completely intermittent, sometimes it will start and run perfectly, and sometimes it will sound like a WRX, and sometimes it will sound like a harley...

the ambient temperature seems to have a lot to do with how it starts also, if the windows are up and its parked in the sun and 9000 degrees in the car, then it will run like **** until i pull it into the garage and let it cool off... that was the rule until today. its been in the garage for a few hours now, nice and cool and it is still running like a soft tail! what could be causing this? TPS? ECU? MAP sensor?

any suggestions?

 

[jamis]

heat will kill an ecu quickly. do you have yours mounted in the stock location? do you have a buddy you could swap ecus with? that would be the easiest way to find out.

 

[jza71]

It's the begining of the end for the ECU.

 

[di_rosa]

^agreed. that's what happened to mine. 1&4 went out..........order the capacitors and spend a couple of hours swapping in the new ones.

in regards to the ambient temperature trouble, pop off the connector for the intake air temp sensor and you should see it idle normally (after you fix the ecu of course). damn heat soak, worst place to put the air temp sensor. mine is really bad cause i have my intake powdercoated, so it can't dissipate the heat as well.

 

[ab85]

Ok, i'll see about fixing the caps in the ecu. it is mounted in the stock location, but its about 97+ and humid as hell on a daily basis. its impossible to avoid the heat and humidity! unfortunately im the only person i know of with a 1jz... so i cant really swap to see if it is the problem.

where is the intake air temp sensor? i bought my car with the swap already done, and i dont see any sensor near my intake. The car idles and drives just fine once its been running for a bit and up to temperature, or if i let it sit in the garage and let the interior to cool down, then it will run fine, but it is always cyl 1 and 4 that crap out.... damn gremlins...

guess its time for a new ECU then...

 

[di_rosa]

when it's running like crap, pull the #1 and #4 plug, if they're black (from being flooded with fuel), then yeah, it's your caps for sure.

don't worry about the intake temp sensor, fix they caps first.

 

[OneJSupra]

Ok, i'll see about fixing the caps in the ecu. it is mounted in the stock location, but its about 97+ and humid as hell on a daily basis. its impossible to avoid the heat and humidity! unfortunately im the only person i know of with a 1jz... so i cant really swap to see if it is the problem.

where is the intake air temp sensor? i bought my car with the swap already done, and i dont see any sensor near my intake. The car idles and drives just fine once its been running for a bit and up to temperature, or if i let it sit in the garage and let the interior to cool down, then it will run fine, but it is always cyl 1 and 4 that crap out.... damn gremlins...

guess its time for a new ECU then...

I got a good and in working condition jza70 ecu for sale. Pm me if you're interested.

 

[ab85]

when it's running like crap, pull the #1 and #4 plug, if they're black (from being flooded with fuel), then yeah, it's your caps for sure.

don't worry about the intake temp sensor, fix they caps first.

yeah, when its running bad the plugs are black. not sure if its fuel or oil though. if it is the ecu crapping out though, what would explain the issue fixing its self after a few miles of driving? are the capacitors just leaking, due to heat and not being used for a few hours; and then refilling up once the car has been running for a bit?

I got a good and in working condition jza70 ecu for sale. Pm me if you're interested.

I might be interested in that. I work at a helicopter squadron in the navy, so the "trons" might have a test bench and some spare capcitors laying around.

 

[di_rosa]

i noticed with mine when the caps went bad, it would run like ass for about 20 minutes, and would kind of get better after that. i don't know why, maybe the ecu was compensating by leaning it out cause the o2 sensor was reading an overly rich mix