dicer

Since the temp sensor single wire for gauge is easy to get to I did a ripple test on it with a scope.
I got a dirty looking 18 ish milli volts, the car runs okay though I don't drive it a lot because the front suspension needs some attention. So what do you think of checking at that point?
To get to ECT connector its getting a lot of stuff off to properly remove the spark plug wire conduits and access it.

Yamae

Sorry that I haven't tried that. Unfortunately I can't confirm that since there isn't any UCF10/11 any more here. Why don't you try to check and confirm?

cgawelko

Yamae - Does the Alldata page I gave you my access to not list the proper readings for this??

Also - Dicer - its a $20 sensor. If you question it - slap a new one in and be done.

dicer

WHAT? I guess you don't understand. The sensor is fine, I'm checking for the ECU ripple voltage at the connector. No reason to slap a new one in.

cgawelko

If its a 93/94 I have a spare ECU you can slap in then. lol I have not done this ripple test personally. LScowboy still rebuilds them - and John Heard does as well but idk his CL name.

I ran through my Alldata and I dont see anywhere that would instruct on the ripple for any specific values so its down to A) testing another car known to be fine. B) Asking LScowboy. C) trying a known functioning ECU.

Yamae

Generally speaking, a single wire gets electromagnetic interference quite easily. The engine compartment room has full of noises. The ignition noise, injector noise, variety of noises from solenoids and others are there. As long as a single wire works as an antenna, you can't expect it a lot to check ripples and noises.

Without confirming it comparing with the ripple at the Diag. connector, I have no idea to recommend to use it.

Yamae

Thanks for the advise, cgawelko, but the issue dicer mentions is totally different from the sensor itself. The issue needs to have the knowledge and skills about "EMI" (ElectroMagtenic Interference) which requires an iNARTE engineer level.

I hope dicer is OK to pass it. Many years have passed since I got the licence. It was NARTE and i (International) was not included at that time though.

dicer

Engine was not running for the test. It showed no DC component that needed a blocking capacitor. The wave form had some high frequency noise like what ever processor speed is? And the ripple was choppy and around
18 millivolts.
So when using the ECT connector do you check across the 2 terminals then? Not one of them to ground?

Yamae

Sounds like you don't know the basic to measure high frequency signals. What is the difference between the normal mode and the common mode measurement? Without your understanding of this, it's impossible for me to explain you.

dicer

Since those terms relate to signals across 2 wires I don't know how to answer it. I was checking a 1 wire system.
I wasn't looking for and did not have a good probe to look for HF. I actually used a DMM to check it first and got 19 millivolts. It was not a sinusoidal ripple I have no idea if it supposed to be with bad caps or not.
And yeah I am very rusty on the stuff, as I don't do it like you do. And its been at least 25 years since I was really into it. If you don't use it you lose it.

Differential voltage from noise is normal mode.
Same polarity is common mode
But still its across 2 wires to ground.

And yeah if I don't know something that is why I am asking the expert, that is you.

Yamae

I'm sorry that I'm not good at explaining a person who is not good at the basic of the interference.

dicer

I feel the same way about ones that don't know basic automotive mechanics.