siikduke

iTrader: (5)

I'm having some issues cold stating with my RX7. NA to JDM T2 Swap. I got rid of all the vacuum leaks, TPS is good, Emissions have been removed, BAC is still on the car, just replaced the water thermo sensor, and she still chokes out when starting cold. The only way to get her to keep running is to hold the throttle down until she warms up, then she holds an idle fine at 1k, no surging.

Mods:
Racing Beat Rev II Exhaust System.
AEM Wideband
Fuel Cut Defender
ECU is possibly "chipped" by Knight Sport. I have not confirmed this yet.
Blitz BOV on compression tube.
Emissions Removed, BAC still on the car.
Stock 550cc injectors all around.
Koyo Radiator

Here's what I noticed so far:
When I had a narrowband O2 gauge hooked up, I noticed that the car would not hold an idle until the O2 sensor was warmed up, because until that narrowband moved and got a signal from the O2 sensor, it would choke out everytime.

When I installed my AEM Wideband, when starting to warm up, idle is very very lean, not even registering on the digital meter, when it is warm and she idles at 1k fine, the AFM is anywhere from 14.8-16. I have the wideband to report to the ECU as a non-linear (0-1v) emulation. So if it's reporting immediately, then what I noticed above with the stock O2 sensor has nothing to do with the cold start I assume? Unless, the non-linear emulation is the wrong signal to send, and I should send a linear (0-1v) signal, but I mean, after warmed up, she idles fine, perhaps I'm just over-thinking the O2 signal issue.

Highway driving under boost is great! Lots of power, no hesitation, and does not run lean at all.

Anyways, do you guys have any thoughts about this? I've been trying to troubleshoot this for the past 3 months since I got the swap done. It's been kind of annoying having to hold the throttle down every morning until she warms up and then I can get out of my car. I've searched the forums all over, read multiple threads, and tried all that I can think of so far on my car, now I need some more input.

satch

iTrader: (1)

The o2 sensor is only used in cruising instances so it should not be a factor in starting or idling. I gather that the JDM engine is not equipped with the Thermowax Fast Idle Cam component to help the car warm up? If so then that removes an additional item to help warm the car in a slow and meticulous manner which it seems would help your apparent problem. I'm sure others will chime in to lend some assistance and get you pointed in the right direction. Lastly, with respect to the Thermosensor did you get a pin reading at the ECU and if so what did it show upon a cold start?

HAILERS2

Water thermosensors don't go bad unless you pry on them or hit them with a hammer.

You need to see if the sensors signal is getting to the ECU....or not. Sounds like the case is NOT.

While there make sure the Start signal is there when the key is HELD to START.

The START signal is seen on pin 3B when the key is HELD to START and should show approx 9-12 when the key is HELD to START.

The water thermo sensor should read approx a half volt if the car is fully warmed up. If cold the figure should be b/t 2-3 vdc and if you see a figure of 4.5 to 5vdc.............the signal is NOT getting there.

Either of these two items will cause a difficult COLD start. A digital meter is required.

3B is on the small ECU plug and is black/blue in color.

3I ...the middle plug on the ECU is green/white.

All plugs must be connected to the ECU to read the voltage on the wire.

canonize-ryda

on cold start my 7 would die over and over if i didnt rev it for a few seconds to let it catch, so i picked up some dollar store injector cleaner and few days later after running it threw the tank i no longer have to start it over and over, it starts up nice by itself now, maybe your injectors are dirty....