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Do you mean that there was no signal at the speed sensor? Or where at?
You also need to explain how the mechanic make it send the signal to the cluster? You need to specify the amplitude, the frequency and the impedance of the signal source. Without details, I have no idea to give you any.
The signal was not being generated by the sensor but sensor is new.
Then you should analyse why the signal is not generated although the sensor is new. You need to step ahead more when the symptom is confirmed.
Is the sensor not driven mechanically?
Is the sensor not driven electrically being the voltage is not supplied from the cluster? See attached. The speed sensor needs the voltage supply from the gauge. Check the voltage of the sensor's pin# 2 using a DVM.
Is the output signal (Pin #1-Pin #3) short-circuited?
I went to the shop today and talked to him about how he is testing it and he told me:
"Sensor was not outputting any signal, when he took it out and tested it outside the car it did display and output yet when he connected it directly to the instrument panel on seperate wiring (to see if it was the wiring) it did not output anything."
He is bringing another 90-93 LS400 to the shop from a friend of his to see what may be the issue.
regarding your questions Yamae I may be thinking question #2 you had could be the likely culprit since outside the car it did output a sgnal but not when connected to the cluster apparently.
I'm gonna pick the car up tomorrow, guy didn't touch it for a week last week and I told him if he couldn't fix it this week I was gonna take it away, he has not called me so I'm positive he couldn't figure it out. Already talked to another shop to bring it in tomorrow after taking it from this shop.
Got the car back, no cost since nothing was fixed.
I found the 1990 LS400 wiring diagrams for basically all things and I bought a dakota digital SGI-5E. I see in the diagrams that the speed sensor ground cable and output cable all go straight to the instrument panel and there the panel converts the signal to a 4 pulse instead of a 20 pulse. The issue I have apparently is the signal "dissapears" when reaching the instrument panel so it never reaches the ECU. With the Dakota Digital box I plan on bypassing the instrument panel and connecting ground, output and power to the SGI-5E because that box should convert the signal from 20 pulse to 4 pulse and I'm going to wire it straight to the ECU. 90% sure I will not have a working speedometer, odometer or trip meter but if my car runs good then I don't need that.
My car currently shifts crazy and misfires and drives like pure crap basically. I'm hoping the speed sensor issue is responsible for all that and that I can get it fixed. In theory it should work perfectly but we will see when it arrives and I manage to install it.
I have been dealing with other stuff lately BUT I did notice today that my speed sensor's connector had all 3 cables cut and others matched with them for X or Y reason. I also noted the white ground cable that goes on connector C-8 (to the instrument panel) was not actually there. I'm thinking it's all wiring related but it's very uncomfortable to work where it is and I don't know where to route new cables under the car.
The speed sensor signal and ground go to the back of the instrument cluster. On the connectors I showed on previous posts. When you changed your speed sensor, did you change the plastic gear and metal that holds it? I didn't and when I connected everything directly to my SGI-5E I noticed the signal came and went intermitently. I saw an old post from Yamae with a link to a japanese based forum saying that the plastic gear can be bad without showing much signs of wear and that makes it not turn inside the tranny or be wacky. I think he said something in previous posts about it also. I had to order that piece from a page that has original parts straight from Japan and it arrived 1 week ago. I'm waiting on my mechanic to have time since holidays he is free and has a list of cars first. I also bought solenoid 3 and 4 original parts for cheap on clearance (different story tho)
Edit: that japanese post about the plastic gear is in this exact thread. I love you Yamae. Mine looked mint but J decided to test it and bought a new one just in case because of the intermittent SGI-5e signal pickup
Mmmm, I know signal goes from sensor to instrument panel and panel to ECU. You will need to check if you are getting signal reaching the panel and if you get signal going out of the panel and then if it even reaches the ECU.
There is a webpage with diagrams for basically everything on LS models. I will PM you the link, it's part russian/ucranian? But most things are in english and you will understand (the documents are all in english)
08-15-18, 01:19 PM
