RX74Life

Hi all! My s4 haven't run for some time now, so I decided to buy this s5 in the for sale section on the forum. Of coarse It has a few issues.

1. The temp gauge doesn't work at all.

Update:it was a broken connector at the sending unit.FIXED

2. The oil pressure gauge shows normal pressure at startup (about 20-30) but drops almost completely to the bottom after just a couple minutes.

I connected a 100ohm resistor to the lead wire and it only read about 30. 100ohm should have put it above 60 according to the FSM. Maybe a bad gauge? I may have to buy a mechanical pressure gauge.

Now this is the one that I'm really posting for:
3. The "not your usual" bouncy idle. Only after the car is warmed up and it seems to get better after idling for a while(goes from a 600-1000 bounce to a 700-800 bounce). But wait, there's more!

I've dealt with the bouncy idle before on my s4, so I thought that this would be the easy part. I still had my homemade test LEDs so I proceeded to warm up the engine, shutdown, connect the LEDs and turn the key to the on position. No lights turned on but I heard a strange popping noise coming from the drivers side of the engine bay. I investigated it and found that it was coming from the cluster of, what I believe are the solenoid valves, with the vacuum hoses just behind the crank angle sensor. I decided "one thing at a time" and proceeded back to the already connected test lights.

Both LEDs were off so I pushed the throttle linkage by hand and one of the LEDs blinked on and off followed by the other LED doing the same further into the throttle linkage movement. Neither of them ever maintain a solid state just one blinked on and off followed by the other, not simultaneously. After I let the linkage go one of the LED's kept blinking. Here's what I find unusual, the LED is blinking along with the popping noise. perfectly in sync almost like Morse code.

Has anyone else experienced this? I guess if I find the source of the popping noise I'll have my solution, so any help would be appreciated. I'm happy to be back and look forward to everyones input. Thanks in advance.

SonicRaT

iTrader: (6)

I've always had good success warming the car up completely, turning it off, and using an ohm meter to get it the TPS to around 1K. Disconnect/reconnect the battery and away I go.

RX74Life

Why the disconnect/reconnect battery SonicRaT? That's the first time that I've heard that. Also, is there a difference between the s4 and s5 as far as the TPS connector? It looks different that I remember. Can you, or anyone, point me to a resource that shows which wires to connect my multimeter to?

RX74Life

OK, good old pre-4th of July freedom bump.

I searched and found the disconnect/reconnect thing, as well as the difference between the s4 and s5 harness.

The popping noise is still a mystery. It sounds like an electrical clicking noise. Like somethings being switched on and off repeatedly. Does this sound familiar to anyone?

Roen

iTrader: (2)

s5 ecu learns the tps. by disconnecting the battery for a min of 5 minutes, you wipe its memory and force it to re-learn. Works sometimes.

RX74Life

Cool, I'll give that a try. Any idea on the popping noise. It sounds like an electric component clicking on and off constantly while the car is off but the key is in the on position.

HAILERS

The TPS sends a voltage to the ECU. This voltage input tells the ECU to put a ground on either the RELIEF or SWITCHING solnoid (Blue and Grey colored plugs).

The sound you hear is one or the other solenoid having a gnd put on it by the ECU, nence the click.

It's one of the Primary functions of the TPS, to control those two solenods. One of the TPS functions, not the end all. Personally I don't think it has much of anything to do with maintaining an idle at all, unless unplugged which defaults the TPS signal in the ECU to ??????? memory says full throttle. I'm too lazy/disinterested, to look.

The only other function of the narrow range TPS is to cut fuel when letting off the throttle. The Full range is dedicated to the electric omp. Frankly anybody that can list anything else a narrow range tps does........have at it.

RX74Life

Thanks for the good info HAILERS. So the sound that I'm hearing is by design or is it a defect in the ECU, solenoid, etc...?