rb20 doesn't run when warm

[Shift]

I've recently swapped an rb20 into my 240sx. It ran great, with a high idle, for a couple months or so after the swap then I had to park it for about a month.

In that time I've changed the ecu and the maf (had to return borrowed items)

Now the problem that I'm having is that it's taking forever to get it to start (cranks fine just doesn't turn over), still has a really high idle, it's missing slightly at idle and badly under any throttle and it won't run for more than a few seconds at a time once it gets warm.

As far as I can tell everything has been wired right since it was running decently before (I'll be going over all the harness modifications again) and everything else is like it was before I parked it.

Any ideas or suggestions on what it could be or where to start would be greatly appreciated. I'm completely new to rb's and have little to no idea where to start with these things.

TIA

[Skym]

Ignition module (black box that's located on top, back of engine) can make engine stall after 10 minutes of driving. Let ignition module cool for 10 minutes and engine starts, runs for another 10 minutes or so, then same problem. Missing is another symptom of faulty ignition module. Also check ignition module earth, as could blow fuse if not connected. And fuelpump earth, etc.

If it did it when cold, hot, misadjusted or faulty TPS, dirty or faulty AACV. Faulty CAS is another cause of hard starts when cold or hot, but would have CAS error code on ECU.

[gtrjon]

check ecu for codes

[Shift]

Ignition module (black box that's located on top, back of engine) can make engine stall after 10 minutes of driving. Let ignition module cool for 10 minutes and engine starts, runs for another 10 minutes or so, then same problem. Missing is another symptom of faulty ignition module. Also check ignition module earth, as could blow fuse if not connected. And fuelpump earth, etc.

If it did it when cold, hot, misadjusted or faulty TPS, dirty or faulty AACV. Faulty CAS is another cause of hard starts when cold or hot, but would have CAS error code on ECU.

It seems to run fine when cold but the idle is really high. Idle drops to something much more decent if I unplug the AACV, could it be stuck open? I'll check the ignition module tomorrow and do what you've suggested. Thanks for the tips.

check ecu for codes

All my ecu gives me is a solid red which I've been told is an indication of a check engine light and a code 55 (all good?)

[markc32]

coolant sensor?

[DylanArmstrong]

It can't be your coolant temp sensor. I had the same problem in the past with my rb and your CTS will run your car when its cold on its own MAP and once it warms up it will run off your other sensors such as Your MAF and Your O2 Sensor, i would check both these sensors along with the wiring going to them as your car will not start when warm and if it does it will run like ****. Mine was running this way due to wiring.
As far as your igniter chip i've never heard of that affecting your car when its warm? its worth a try though!

GoodLuck

[Shift]

Alright so today I found out my tps is garbage. at closed throttle its at .5-6v and will go all the way to 4v just before WOT anything after including WOT and it drops to .4v. Gives me a start anyways.

It can't be your coolant temp sensor. I had the same problem in the past with my rb and your CTS will run your car when its cold on its own MAP and once it warms up it will run off your other sensors such as Your MAF and Your O2 Sensor, i would check both these sensors along with the wiring going to them as your car will not start when warm and if it does it will run like ****. Mine was running this way due to wiring.
As far as your igniter chip i've never heard of that affecting your car when its warm? its worth a try though!

GoodLuck

It should run with a dead o2 though, just really rich. Also wouldn't a faulty MAF cause it to go into limp mode? I can free rev above 3500rpms although it misses. Worth a look though. Thanks.

[Shift]

Alright so found out that my temp sensor isn't reading the same at the ecu, probably a break in the wire. Tomorrow a new wire will go in.

[markc32]

my car had hard start n likes to stall when really warm......coolant sensor was the only problem

if the cts is bad....ur car will stall when hot coz the ecu cannot get an accurate reading n now it thinks its gonna over heat...run rich as well with miss

[Skym]

There should be 2x CTS, one for dash temp gauge, one for ECU.

Should get a CTS error code for ECU CTS if it's faulty. ECU does make engine run richer when it overheats (from memory, 110 degrees+). Also ECU runs engine very rich with anything below 0 degrees.

[Shift]

Alright so a little update:

I've had almost no time at all to work on my car between getting laid off, job hunting, going back to school, homework etc etc.

But I did manage to get my car running enough to get it home from the shop. I disconnected the tps at the ecu and my car went into limp mode and

it was good enough I could drive it. So now my question is does anyone know what sensors are still being used in limp mode if any? I'm hoping it'll

help me narrow down some gremlins.

Thanks.

[Shift]

so I did a little work today. re-wired the coolant temp senor and now i have 2.5v at sensor and ecu when cold so that seems to be good. I connected the tps wire at the ecu and my car has the weakest idle and pretty much stalls right away.

I checked for continuity between the 1&2 terminals on the throttle switch and I have nothing. So i'm hoping is the tps thats effin' my stuff up.

I'll update again when the part comes in (if i can get it ordered...damn useless stearlerships)