cumminsdriver635

I took off for school this morning and i looked down about 10 seconds from the house, and i had no Tachometer, or Speedometer. I said, well ok, ill go ahead and drive to school. I get out off my subdivision, and i click overdrive on, and it just goes to 3rd, and no overdive. I thought well, crap, and stopped, and got out, and jiggled a few wires, and stuff, but still the same. So i drove it all the way to school in 3rd gear(at least i have 3:55's), and back, which is not that far, but i need this thing fixed ASAP! Scheid is next week, and im going to that, and stuff. If i use my torque converter lockup switch, the TC will lockup, but if i dont use it, it wont lockup, even with overdrive off(since it will only go to 3rd gear)(shifts fine other than no 4th). Anyway. Im pretty sure its something electrical, but i dont have the slightest idea where it gets the tach/spedometer signal from so if u guys could help me out i would appreciate it. Also, it worked fine when i parked it last night, so i dont know. Thanks.

Eric

Crimedog

If you do the check engine light test does it give any codes? I'm no expert, but all of those things are controlled by the ecm aren't they? All other gauges are working? All of the warning lights light up when you start the truck up (ya know that test they do so you can verify all of them light up). That's all I can think of, but I am no expert.

cumminsdriver635

First of all, thanks foir the reply. I dont really know how you can pull up codes by that check engine light test thing, so maybe you could explain a little more. All of the lights do light up when i start the truck, and all my other gauges work fine. I did notice my volt meter was a little low yesterday though, like there was a short. And, yes, im pretty sure the ecm controls most of those things. Thanks for the help. Anyone else know anything. I got to leave for school now.


Eric

kandgo

Have a pen and paper handy to write the numbers down, turn ignition key to on,off,on,off and end on, the codes will start flashing, the light will flash the first number example 25 is two flashes pause then five flashes. Try that and find out what the code numbers are, Goodluck,,,Rick

Mopar1973man

To get trouble code for your Truck...

On/Off/On/Off/On and the check engine light should start to flash trouble codes (1st Generation) or the odometer will should P codes (2nd Generation).

To check guages...(2nd Generation)

HOLD the TRIP RESET down and turn ignition ON release the TRIP RESET... Watch the pretty light show on your dash and the needles.

Crimedog

Any updates? BTW, it sucks ya gotta start school so early I have to go back for my senior HS year in about 2 weeks

cumminsdriver635

Well, i guess i have the code or whatever. I did it a few times to get this first: 33755

Thenb i left the positive battery cables off for about 20 minutes, and when i tried it again i got this: 355

Do either one of these sound right to you guys? How do i find out what they mean, or if any of you know how, please tell me. It will be alright if i have to drive it like that again tomorow, but i would sure like to have it fixed by next week at least. Also, a little while back i started noticing that it would come out of lockup(while in overdrive), but then lock right back up just as soon as it unlocked. I have a light that comes on when the TC is locked, and i noticed it would go out, and come right back on when it did this. It never did this before. My TPS wouldnt be causing a problem would it??? I also checked where it gets the reading for the RPM's on the pulley on the crtankshaft, and the wires were plugged up right. Id love to get it fixed tonight if any of you could help quickly, but if not, thats fine.At least i dont have 4:10 gears.lol Thanks

Crime Dog: Yeah, this is our second FULL week of school, and we started on a wednesday, so tomorow will make our 13th day back . Im a junior in High School, and i cant wait till i can co-op next year, and leave school at half a day .

Eric

cumminsdriver635

O.k. I didnt realize there are only 2 numbered codes. The 2nd one is 12, and 55, but not sure what the first one was darn it.
I checked in my unlces hanes manual and it says that code #12 means power has been disconnected to the ECM within last 50 cycles of key(and it has), and 55 is an ending code by what it says. I might get up about 30 minutes early tomorrow morning and see if i can figure it out or something. To bad i unhooked the battery cables.

Seems like on the first code i said, that it flashed once with a brief pause like that first 3 was supposed to be a 12, but that cant be right( i was thinking i hadnt unhooked the battery); actually it can, cause i unplugged the ECM's connector, and that cuts power to the ECM.Ill check tomorrow morning and see what code 37 means. The first code i gave(33755)should be codes 12, 37, and 55.Thanks for the help. Ill eventually figure this out.lol

Eric

Eskimo

Speedo, O/D, and lockup... no cruise, either, right?

I would guess at speedo sender? Dunno why this would affect your tach though. There was one little sensor that affects a whole bunch of stuff like the tach, A/C, etc... I think it's on the front of the engine, down on the right side...

I noticed that my tach and speedo aren't very smooth, either, they kinda jump up in notches...

RATTLINRAM

Hey Eric,
Take a look at THIS PAGE from Dave Fritz's site. It might help ya out a little.

cumminsdriver635

Eskimo: I dont have cruise, so i cant check that. And i dont really think it is the VSS(vehicle speed sensor), because that shouldnt cause my tach any problems, but who knows.

Rattlinram: thanks for the site, it shows what my uncles shop manual shows which is this:

37 Open or short in the Torque converter clutch solenoid CKT circuit or Voltage high or low at transmission Temperature sensor

What could i check for to find out how to fix this? And, does this sound right? Thanks

Eric

AlpineRAM

Had the same problem with a 97. No tach or erratic tach, no OD, no lockup, no AC etc. It was a wiring problem in the loom that contains the fat cable from tha alternator to the PDC under the hood. Bending this wire loom around a bit either solved it or made it worse.

HTH

AlpineRAM

cumminsdriver635

What exactly is the PDC? Ill have to try that.

AlpineRAM

Power distribution center under the hood- the gizmo with all the fuses and relais in it

cumminsdriver635

OK i know what your talking about. Ill try it here in a second. Thanks


Eric