Thread: Advice on Hard Cold Start

I'm not confident that was conclusive, I need to retry on a colder day. It didn't start on the first try every time either methods. Colder it is the more attempts it takes so I need to try those on a colder night/morning to really know. I have an IACV and AaC inbound so I'll be able to rule those out this weekend. Then I'll focus on fuel, but if injector resistance is good, not leaking and pump holds/delivers correct pressure, what am I looking at? (an ecu is good)

The car don't like you an u should sell it lol

Since you have another IACV-AAC on the way, maybe you don't want to troubleshoot
it, but if so, there is a procedure in the FSM, synopsis below.
Replacing the IACV-AAC will not rule out continuity issues in harness and other connectors.

For the IACV-AAC valve troubleshooting, see FSM EF & EC-121.
- warm up engine
- check idle speed, 800+-50 RPM
- without a consult, disconnect IACV-AAC valve harness connector, make sure idle speed drops
- next check power to IACV-AAC. Disconnect harness connector, should be battery voltage between terminal A and ground.
If not, check harness connectors as listed in FSM; check 10A fuse; check continuity between IACV-AAC valve and fuse.
Next check circuit between ECM terminal 113 and terminal B.
If no good, check harness connectors as listed in FSM, and harness continuity between ECU and IACV-AAC valve.

To check the AAC valve, see FSM EF & EC-184:
- Disconnect IACV-AAC valve harness connector,
measure resistance. Should be about 10 ohms.
- check plunger for seizing or sticking
- check for broken spring

I think its mad that I parked it for winter. Cause it was all good till I woke it back up. Must be pissed off, but its for its own good. I dont want it running around all hours of the night on those streets with those awful salt crystals hanging around. They are a bad influence.....



Well I have consult and it does show valves on the AAC, so I assume that connection was good because otherwise i assume it would just be 0 like it wasnt running. I have unplugged it numerous times while running, sometimes i notice idle change, but other times I didnt.......I do when I adjust the idle screw as well. But doesnt the ECU auto adjust for idle if you arent in timing mode usually? Cause I know you have to warm up the car, turn off, disconnect the TPS, turn on adjust the screw, then plug the tps back in to actually adjust anything or you are just fighting the ECU? No?

Some notes from today after getting my wideband in (its installed in the 2ndary but i had to use a 45 degree adapter cuz of the stablizer bar being in the way so it might not be dead accurate (but thats ok for now cuz i dont have a tuneable ecu in it yet). But after start up it was reading around 12.X i cant remember but it was def not lean. Starter fluid sometimes will help boost the start up, but although it may not kill the engine, the RPMs will still dive down low before recovering to a normal idle.

Car wasnt fully warmed up (not sure if that chances this test) but I unplugged the ACC (brown plug) and Idle didnt drop or change really at all. When the car was cold before I started it, i just turned it to the ON position before crank, put a multimeter on the (brown) plug. I grounded the multimeter to the battery ground and put it first on the red wire (got .001 or something like that) and then put it on the other wire (forget color) and got .13 i believe. I had it on DC voltage (20). This is also a harbor freight multimeter so it could be fucky but im not sure if that helps with the info.

I'll be swapping the IACV under the intake manifold on friday or sat first then testing. If no change i'll be changing the IACV-AAC shit on top passenger side (with the idle screw..etc) as well and we'll see whats up. If no change i'm out of ideas completely and open to the idea it could be fuel, however i'm not sure what other test I could do via the fuel system to troubleshoot.........

Sorry, that's not how easy it works... The values are only what the ECU sends out, what actually reaches the solenoid can be a whole different story. Do the wire test!



A "proper" set up manifold/idle should result in the car STALLING when the IACV is disconnected. I know that our cars are getting old, leaky tb's, uncalibrated idle duty% etc, so this is not true for all. But it's what you should strive for, resulting in a much better idle.

Start with the wire check. I doubt it's fuel related.

The wire test being checking voltage from the harness plug? I checked the brown plug (with the car to the on position not running) when it was cold assuming i'd get a battery voltage type value but grounding the ground and positive to the other 2 terminals one terminal showed .001 and the other .13 IIRC. I'm not exactly sure what those values represent....does the car need to be full warmed up when i test them. As for resistance, am I testing the AAC itself? Cause its hard to get anything on that terminal being its a highport and that plug is facing towards the ground......

Okay, let me try to set up an extremely easy way to test this. Note that it's dangerous to check continuity if you don't know what you are probing, very easy to burn fuses!

You want to check the wires and ECU PWM output. We will not follow the FSM here, this is a faster way:

-Unplug connector to IACV
-Set multimeter to voltage test (20V)
-Key to IGN
-One multimeter probe to chassis GND, other to IACV connector. Check which pin is feed.
-If you get +12V on one of these pins, the fuse and wiring for this pin is OK. Mentally make note that this pin is +12V.
-Focus your attention on the other pin, (PWM GND). Remove multimeter.
-Set multimeter to continuity mode.
-Connect multimeter to chassis ground, and the other lead to PWM GND
-Start the car. Do you get continuity? If you get continuity, both ECU and wiring is fine.

Report back soon! This will simplify this heaps!

You are talking about the brown connector correct, I just wanted to make sure. Also where is the fuse for the IACV, I just wanna keep an eye on it but I forget where it was

I am talking about the harness side IACV/ACC plug. I dont know if it's brown, might be. But there is no need to even check the fuse, just probe the harness using the above mentioned method. If it fails on finding +12V, then you can start to search for the fuse.