Troubleshooting

[Durandal]

I just got a 1993 J-Spec supra tt and although I've been reading forums for quite awhile on possible problems before I even got it, some things I am unclear on.

When I turn the ignition on all my dash lights come on except for the cluster on the right with oil level, oil temp, and check engine and nothing in the little screen above those although that one kind of looks like nothing would display there anyway.

The reason I'm asking is I have been getting a warning light come on randomly when I'm driving and sometimes it goes off but mostly stays on. At first I thought it was a problem with the active front spoiler's auto feature which I found people with aftermarket stereos have problems with. I do have an aftermarket japanese stereo that was in the car when I bought it.

Some times when I start up the car, mostly a cold start, I can hear kind of a rattling coming from the back end and it idles low around 500rpm.

So I'm starting to get paranoid and want to do some troubleshooting. When I jumper E1 and TE1 in the diagnostic port 1 or 2 nothing happens to tell me if there are any problem codes.

Does any of this sound familiar or does anyone have any trouble shooting tips I can start with?

Thanks and sorry for the long post.

[Durandal]

OK the electrical connection to that cluster of telltale lights is bad and after taking it apart and taking out the LED's and putting them back in on whats left of the copper coating, I got them working.

Bad news is I do have 2 error codes

14 and 42

14 is Ignition signal, I don't know about this one and doesn't seem like a problem to me so I think I will clear it and see if it comes back.

42 is Speed Sensor, I'm pretty sure the speed sensor is on its way out just due to how its been acting and from what I hear is a common thing to go bad.

I just got to figure out a way to keep the check engine cluster from losing electrical connection.

[pwpanas]

Originally Posted by Durandal

OK the electrical connection to that cluster of telltale lights is bad and after taking it apart and taking out the LED's and putting them back in on whats left of the copper coating, I got them working.

Originally Posted by Durandal

Bad news is I do have 2 error codes

14 and 42

14 is Ignition signal, I don't know about this one and doesn't seem like a problem to me so I think I will clear it and see if it comes back.

42 is Speed Sensor, I'm pretty sure the speed sensor is on its way out just due to how its been acting and from what I hear is a common thing to go bad.

I just got to figure out a way to keep the check engine cluster from losing electrical connection.

Regarding the speed sensor signal, it's possible the problem is with the oem odometer cluster. Note these instructions are for the USDM-spec Mkiv-TT:

• Remove the dash trim that houses the Odometer, on the odometer harness find the pink wire and cut it then splice the pink wire with the blue and red VSS input wire.
• First try resolder the cold solder points on the board.

More info here:
http://www.mkiv.com/techarticles/trac_off_mil_odo/index.html

[Durandal]

Pulled the Check Engine light cluster out again to inspect the connections once more and I did find that some of the solder joints had broke off. After re-soldering them the telltale lights work fine.

When I started the supra up today it made some rattling and choking noises than preceded to rev from 500 RPM to 1500 RPM. I definitely need to look into the speed sensor fault more.

*Edit: I reset the ECU and then took it for spin to see if anything came back up. After driving it for about 10 mins and putting it through all the gears except 6, the engine light came on along with the warning light. I brought it back to the house to check the ECU code. I noticed it randomly revving up and down a bit while I let it run for about 2 mins before shutting it off.

Only Code 42 came back up after checking the ECU.

*Edit2: After doing a lot of reading on many different supra forums I have come to the conclusion the speed signal is getting lost in the buffer that happens in the ODO. I'm going to touch-up solder all my connections on the ODO cluster tomorrow and see if it gets resolved. If not I will just bypass the buffer by cutting the pink wire as Phil has mentioned.

[Durandal]

Cleaned up all my solder connections in my ODO and took it for a long test drive. I did not have any warning lights come on or code 42.

I was running low on gas so I filled up at what used to be a shell station where I got V-Power gasoline. After I had completely filled the tank I realized it wasn't shell anymore and the pumps were Ultramar. I had got the 91 Octane Supreme fuel. Will this be all right for my Supra? The reason I'm asking is 5 minutes later right in front of my house the car stalled.

Also on the way back I tried the cruise control. Pushed in the button the light came on and I clicked it down to set the speed and took my foot of the gas and it did not maintain speed. Is my cruise not working or am I missing something in the operation.

[pwpanas]

Originally Posted by Durandal

...Also on the way back I tried the cruise control. Pushed in the button the light came on and I clicked it down to set the speed and took my foot of the gas and it did not maintain speed. Is my cruise not working or am I missing something in the operation.

Try holding it down for a few seconds (i.e. not just a click)...and be sure you're over 40mph.

Originally Posted by Durandal

...*Edit2: After doing a lot of reading on many different supra forums I have come to the conclusion the speed signal is getting lost in the buffer that happens in the ODO. I'm going to touch-up solder all my connections on the ODO cluster tomorrow and see if it gets resolved. If not I will just bypass the buffer by cutting the pink wire as Phil has mentioned.

Um....my post above mentioned more than just cutting the pink wire, right? Either way, I'm glad that the ODO turned out to be the problem - hopefully my post (and not just the "many other supra forums" you read) helped you to isolate it.