The sensors are different:
* Gauge sender is a simple variable-resistance type (1-wire)
* Temperature sensor for fuel system is a precision voltage type (2 or 3 wire)

You want to measure water temp at the engine because it's a regulated temperature, while the temp in the radiator and radiator hoses is unregulated and can vary wildly.

Nissan Water Temp Sensor, bolts to the cylinder head or coolant passage of intake manifold



Water Temp sensor on factory A14 EFI manifold (B)



ECUs use different temp sensors: Some use water temp sensor, other use intake air temp sensor (IAT), some use both. Datsun EFI had an air temp sensor in the airflow meter, while the ECU read the water temp sensor. Modern mass airflow sensor doesn't need to know air temp. So what you need all depends. Modern ECUs like MegaSquirt and Haltech can use both temp sensors (water and IAT). They can both use either Nissan or GM sensors.

With a DIY ECU, most people use a GM Intake Air Temp sensor, just poke a hole in the air duct and insert the IAT. Nissan IAT sensors bolt into the inlet.

Pardon my ignorance can you use the same temp sensor you'd use to run a temp gauge in the same position in the head and just aplice the wiring?

Where would the best spots for each of the sensors be?

Yeah your absolutely correct, I'm not here to argue,
Just pointing out various efi options/ systems.

It all depends on the ECU. Some can fire individual coil packs, and some do not.


Quote:Actually many EFI systems do not use a crank position sensor. It's only needed for spark but the Datsun ECUs do not control spark, but only the fuel injection. And cam sensor is used for Sequential injection, many systems are not sequential. Cam sensor also used for individual coil packs, but not required for dual-coil packs. Starting around 1984 Nissan added spark control to the ECUs. Before that it used a tach signal for engine RPM.

But isn't Sequential EFI so much better than non-sequential? Not really. HP levels are about the same. Fuel economy might be a little better. Emissions are a little better which is why some OEM setups use it. There is nothing wrong with SEFI, it works fine.

might be limited for room between the thottle body and strut tower for an airbox?
with my quad throttle bodies i only have those ram sox,maf or map sensors arent a necessity if you haved the right ecu. my motec only used ambient air temp, lambda, coolant temp,crank and cam angle and all efficiency calculations were made/adjusted by a combination of lambda value and throttle position, no actual intake pressure sensor. but hey mine are quad throttle bodies and laptop programmable expensive ecu, all of which are good systems,(hyundai, megaquirt, custom throttle bodies. id stay with the hyundai stuff to keep costs as low as possible

Are the Hyundai cars MAF or speed density systems? If they are MAF, i`d recomend you get a manifold to work first. Then use the complete engine wiring loom, engine sensors and ECU from a manual hyundai doner car.

You would need:

Water temp sensor
Air temp sensor (probably buit into the MAF sensor if its MAF based)
MAF or MAP sensor
TPS (throttle position sensor, will be on the TB on the manifold)
CAS (crank angle sensor)
Sync sensor (driven on camshaft)
Oxygen sensor
Baro sensor if fitted
Ign coil/s and modules

You will have to run a return fuel line to the tank from the pressure regulator
and mount a high presure fuel pump.

The hardest bits will be to modify the manifold to fit and mounting the crank and cam positon sensors.

If the doner car is MAF it may run OK. If its MAP(speed density) you probably wont get it to run very well without a lot of headaches or changing to an aftermarket ECU.
Im not sure if its possable to reflash the Hyundai ECU`s

hey mate im about to finsh fuel injecting my a14, as for your sensors/ecu, if all the hyundai sensors are used you should be able to get some noise out of it. as for your coil packs a camshaft position sensor is needed to fire them correctly, now of course you need a crank position sensor aswell (all efi systems do) a chopper disc mounted to the crank pulley is probly the easiest and quickest way. but what i used for a cam position sensor is an electronic a series distributor, grinded 3 points off the reluctor inside the distributor so it suplies one single pulse the the ecu per every tdc on cylinder #1 compression stroke (or every 720 crankshaft degrees). that way you are abloe to run fully sequential injection and your 4 individual coils.
i have done some extensive research on this and feel free to ask any other question mate, too happy to help, go the datto

Ok so iv started gathering bits lol 4 coil packs only 2wire one lol now to figre out what eles I need...

For MegaSquirt, click this link: MegaSquirt.

If you use the Hyndai injectors and sensors, it should run very well. You won't need to get it tuned. Just make sure it's running the hyundai spec fuel pressure.

Same with the Datsun ECU, with Datsun parts and spec fuel pressure, it will run correctly.

The factory ECUs are smart enough to adapt themselves.

thats why you get it dynoed. i think an A12 would handle that size injector no problem. if not you would get a new set for a few hundred there abouts