lotus7racer

I think you gave me a hint.
No! the fuel pump is not control by the ECU. I made my own manual switch to
turn the fuel pump on and off (as I said the S2000 engine installed in a racing car).
When I turn the ignition off, I also turn the fuel switch off. Perhaps, turning the switch off late, enough fuel dumping in the cylinder to diesel.
The car is using stock ECU, security like immobilizer are bypassed and other stuff that will trigger limp mode (such as VSS).


I will check the vacuum too for hi-idle. I eliminated a lot of vacuum hoses but they are blocked. Do you think something to do with those vacuum I eliminated (hi-idle problem)?

SgtB

I think it's either a vacuum leak, or you don't have the sensors correct that tell it when to switch out of warm-up mode. What CEL's are you showing right now? A simple trick to check for vac leaks is the spray a light mist of carb cleaner around the intake. If it's leaking you'll find it. It's probably the sensors though. Honda's tend to fluctuate their idle bad with a vac leak because the IACV fights it. If you have any temp sensor or IACV errors, that would explain the idle.

like you said on the switches, I'd cut fuel, let it die, and then kill the power.

lotus7racer

Hmmmmmm, another hint you gave me.
Where is this coolant sensor (IACV) located ? (edit) I FOUND IT!!

Yeah I changed two sensors, the oil sensor and the coolant temp sensor (the one below or under the air pump diaphram unit). The reason I changed the sensors is because of my Race technology gauge. I hope this is not the one you are talking IACV. If it is, you are probably right again. The ecu does not see it and the idle goes up to 3,000rpm. The idle is constant 3,000 not fluctuating...indication that ecu does not see signal.

The ecu needs the coolant temp. If I decide to bring that wire back to the ecu, do you know which color wire IACV I need to connect? There are 3 plugs at the ecu A-B-C.

I guess, worse to worse (since this application is only for racing), I can manually turn the idle lower and not depend on the ecu?

I've been looking around but I can't find any vacuum hose that are open.

SgtB

EDIT: NOTE: This information is incorrect. I'm leaving it for continuity, but my correction is here.

This is the IACV:


The IACV is the Idle Air Control Valve. It takes air from the "out" line, and meters it out to the "in" line( it's backwards, but I'm too lazy to fix it ). If you follow the out line, it connects to a hard line at the throttle plate.

If you don't mind, let's try one more thing before I send you off rewiring things. Take the intake off at the throttle body. Inside is a small hole where that hardline enters the housing. Put your finger over it while the engine is running. This will scare the bageesus out of you, but will not pull the skin off your finger. If the idle drops to normal, or the engine dies, the IACV is the culprit. That's not to say it's broken, it may be, but it also could be a system malfunction.

I'm looking for the wire colors right now, and will post them up soon. The manual is pretty big, and for some reason I'm haveing trouble finding that one connection. If you have a code reader it would help a lot. The ECU is pretty good at telling you why it's acting up.

lotus7racer

Thanks SQTB--- I appreciate your help. I will test them tomorrow when not raining. Right now its raining hard and I cant ran my racing car with no top.
I think the culprit is the input wire going to ECU from that IACV. I don't remember feeding the wire with value (C101 blue plug) has been cut.
But I will try to test it tomorrow. I can still bring it to the ecu if I can identify the wire I cut from C101 light blue plug.

By the way, can you take a look at one of my thread. I think maybe something to do with this hose that I blocked and uplugged.

https://www.s2ki.com/forums/index.php?showtopic=688759

SgtB

If that's a vacuum line, and isn't plugged, it will raise the idle a lot. you still need the IACV hooked up for smooth idle, but that's not helping.

On a side note: you need to be careful with deleting electronics off the motor. The F has very few thing that aren't needed. It's 50/50 whether that motors going to run right without everything in place. The ecu is very picky. I actually haven't seen anyone do this with a stock ecu. Not saying its bad,but you may hit a few walls. Just my $.02

Now, the coolant sensor and the iacv aren't connected right now?

SgtB

Ok, finally found my helm. I'm assuming you know the connectors and pin order. If not let me know. The iacv is driven off of connector B, pin 23 (black/red). The coolant sensor (ECT) is on connector C, pin 26 (red/white). The ECT is just a thermistor, so make sure your gauges don't inject voltage into that line.

I also looked more into that vac hose. It connects to a small purge valve mounted to the firewall of the s. it's emissions related and can be deleted. I'd pull the hose off the T and cap it.

lotus7racer

OK--I will pull or plug that hose. I think I know what that purge valve you are talking. I deleted that too because its for emission.
I will check the connector B pin 23 (black/red) also the C connector pin 23 (black/red). I have the C101 schematic and the ECU so I will be able to verify it carefuly.

It's hard to work in my little car. You need someone who can do a contorshonist position. The ecu is under that little cave.

I will let you know sometimes.

Thank you.

SgtB

No problem. The S is about the same engine wise. Anything under the IM is pretty much inaccessible.