tdskip Posted November 16, 2019 Report Share Posted November 16, 2019 (edited) It’s been quite a while since I’ve been out of here, hope everyone is well. I have a JDM S14 SR20DE with a Wiring Specialists harness and am wondering what engine motoring signal would be stock for that? Finding info has been rough since it is an older set up now. For example - I know I have have oil pressure signal but would that be for an idiot light or actual pressure? Any coolant temp monitoring or would that have been separate? Thanks! Edited November 17, 2019 by tdskip Quote Link to comment
Spiff Posted November 17, 2019 Report Share Posted November 17, 2019 Oil pressure switch for an idiot light. It would most likely have two sensors for the water temp, a one wire sensor for the dashboard gauge and a two wire sensor for the ecu. Quote Link to comment
Stoffregen Motorsports Posted November 17, 2019 Report Share Posted November 17, 2019 Most PSI senders are a potentiometer of sorts, so the sender will likely work for both idiot light and PSI gauge. Quote Link to comment
tdskip Posted November 17, 2019 Author Report Share Posted November 17, 2019 Thanks guys, so in theory if it’s acting as a warning light it’s binary, in other words it either sends a signal or it doesn’t so I could wire up a white to serve as a warning? I imagine that the wiring would take power from the switch and then I would ground it? Thanks! Quote Link to comment
Spiff Posted November 17, 2019 Report Share Posted November 17, 2019 No the oil pressure switch grounds through the block. So the ground wire of the oil light would go to the oil pressure switch. Quote Link to comment
tdskip Posted November 19, 2019 Author Report Share Posted November 19, 2019 OK, got it. So I should have two idiot lights, one for coolant temp and one for oil pressure. It looks like both of those would need power to a warning light, and then connection back to the gauge which would at least give me some indication of whether I’ve got an issue. Granted-by the time I see those lights I’ve likely got a very unwell engine but it’s better than no monitoring ... Thanks! Quote Link to comment
paradime Posted November 21, 2019 Report Share Posted November 21, 2019 Are we talking about "Engine Monitoring" for the ECU or dash indicator lights for idiots? If the later, remember there were many JDM cars and mini vans that had the S14 SR20DE all with different dash gauges and ECUs. With a custom harness and unknown donor, I'd be cautious making any wiring assumptions. Use the ECU ID (usually a white label with big red letter and number) to google it's pinouts, and that will show you what you need to be sure. As for gauges and idiot lights on a stock dash, although nice to have they're only a crude way of watching what's going on with the engine, and then only if you're paying attention. When you think about it, besides monitoring engine conditions via coolant temp knock sensor and O2 sensor, the ECU reads it in relation to the MAF, throttle position, RPM, gear position, and speed to adjust ignition, mixture, VVT. And it does all that in real time. Anything in that system stops working or gets too far out of wack the ECU will let you know as soon as it happens. Best life hack for avoiding a very unwell engine is to have the signal to the check engine light also trip a loud buzzer. I also have a great hack for keeping flannel shirts from getting pilly, but thats for another forum. Quote Link to comment
tdskip Posted November 21, 2019 Author Report Share Posted November 21, 2019 Good morning and thanks for the response. Sorry for not being clear enough, looking to monitor the engine health rather than muck about with the ECU. Basically wanting to make sure that I have oil pressure and good coolant temp. It appears that the recommendation is to pull the oil pressure idiot light and use a proper gauge that indicates actual pressure. Where can/should I pick up actual coolant temp? Thanks, and will come back on the flannel shirts later. 😁 Quote Link to comment
demo243 Posted November 22, 2019 Report Share Posted November 22, 2019 Definitely better to run separate gauges - coolant temp, oil temp, oil pressure are priorities. Not sure about the SR, but the KA has two temp sensors in the outlet from the head, one is for the ECU and the other is a simple single wire for the dash gauge. You can use the single wire one to wire in an after market temp gauge. For Oil Pressure and Temp it will depend on what you have for outlets- again not sure what the SR has, but the KA has two off of the oil filter bracket, SR should be similar. If you have two and they both will clear the sending units you can run pressure off of one and temp off the other , the other option is to add a T fitting or get one of the oil filter spacers with additional sending unit mounts. I prefer electronic sending units/gauges, the mechanical temp gauges will likely require a bunch of adapters to run.... Speedhut has some nice gauges for pretty good prices and they come with sending units. Quote Link to comment
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